• Title/Summary/Keyword: ${\alpha}-F_2O_3$

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Triterpenoidal Saponins from the Bark of Kalopanax pictum var. typicum

  • Cho, Soon-Hyun;Hahn, Dug-Ryong
    • Archives of Pharmacal Research
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    • v.14 no.1
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    • pp.19-24
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    • 1991
  • One new triterpenoidal saponin, saponin F(2) has been isolated from the bark of Kalopanax pictum Nakai var. typicum (Araliaceae), together with one known saponin, kizuta saponin $K_{12}$ (1). On the basis of chemico-spectral evidences, the structure of 2 has been elucidated to be 3-O-${\beta}$-D-xylopyranosyl$(1{\rightarrow}3)$-${\alpha}$-L-rhamnopyranosyl$(1{\rightarrow}2)$-${\alpha}$-L-arabinopyranosyl-23-hydroxyolean-12-en-28-O-${\alpha}$-L-rhamnopyranosyl$(1{\rightarrow}4)$-${\beta}$-D-glucopyranosyl$(1{\rightarrow}6)$-${\beta}$-D-glucopyranosyl ester.

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Site spectroscopy probing of Eu3+ incorporated into novel LiYxSryZrO3+α host matrix

  • Ahemen, I.;Dejene, F.B.
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1359-1367
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    • 2018
  • In this work, we investigated the spectroscopic properties of $LiY_xSr_yZrO_{3+{\alpha}:Eu^{3+}$, a red emitting nanophosphor based on $SrZrO_3$ perovskite. The synthesis process was an auto-combustion process. X-ray diffractograms show the orthorhombic structure of $SrZrO_3$. Photoluminescence (PL) excitation spectra display a split charge transfer band revealing the presence of two possible sites for the $Eu^{3+}$ ions. The emission spectra at 231 nm excitation illustrate the dominance of the $^5D_0-^7F_1$ transition, which is an indication that the smaller sized $Eu^{3+}$ ions are mostly situated at the more ordered (symmetric) $Sr^{2+}$ sites. The emission spectra at 292 nm & 397 nm excitations show the dominance of $^5D_0-^7F_2$ transition which suggests some of the $Eu^{3+}$ ions are also situated at the distorted $Zr^{4+}$ sites. Both the intensity parameters, asymmetry ratio and the decay lifetimes of the nanophosphors show dependence on $Y^{3+}$ concentration, signifying a modification in the host structure. Maximum quantum efficiency value of ${\approx}46%$ was obtained for the nanophosphors which indicate the need for improvement for practical applications. CIE coordinates show the suitability of this phosphor for both red emission in LED and as a complementary colour for white LED applications.

Characteristics of the Tactile Brainwave on the Surface of Interior Finishing Materials - Focusing on the measurement of 'α-wave against β wave' - (실내마감재 표면에 감각하는 촉각적 뇌파특성 - '베타파에 대한 알파파' 측정 중심으로 -)

  • Yeo, Mi;Lee, Chang No
    • Korean Institute of Interior Design Journal
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    • v.25 no.2
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    • pp.59-69
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    • 2016
  • This study aimed to understand the importance of applying finishing materials into interior space, and to add meaning to the creation of functional space, associated interior finishing materials with brain science. To achieve this purpose, brainwave(EEG) experiment was conducted. The brainwave appearing when sensing the surface of interior finishing materials with hands was measured. The locations of the electrode were FP1, FP2, F3, F4, C3, C4, P3, P4, O1, O2, F7, F8, T3, T4, T5, T6, CZ, FZ, and PZ and in addition to these, AFZ was added. Eight(8) kinds of finishing materials: metallic material, film paper, lumbar, stone, glass, silk wallpaper, fabric, and paint were used to measure '${\alpha}$-wave against ${\beta}$ wave.' As a result, it was found that the most activated finishing material in term of relaxation was film paper, followed by metallic, glass, paint, fabric, stone, lumbar, and silk wallpaper. To explain in light of this, (1) '${\alpha}$-wave against ${\beta}$ wave' was the most activated at ch1-FP1 and ch2-FP2, and at ch17-AFZ and ch19-FZ, which indicated that metopic-prefrontal lobe showed the highest activation in relaxation. Film paper, among the finishing materials, showed the highest increase in relaxation. (2) In general, '${\alpha}$-wave against ${\beta}$ wave' relaxation was inhibited at ch13-T3 and ch14-T4, and at ch15-T5 and ch16-T6 and the arousal in the temporal lobe was prominent. Silk wallpaper, among the finishing materials, showed the highest arounsal effect. As a result of measuring the superficial touch on the silk wallpaper, which was regarded as the most rough material among the eight finishing materials, the arousal effect of ${\alpha}$-wave against ${\beta}$-wave, among the brainwave characteristics, was found to be the highest. (3) to judge from the scope of this experiment regarding the tactile sensation over the finishing materials, it is considered that the brainwave reaction sometimes appeared contrastive depending on whether the surface was smooth or rough and there also appeared a difference in relaxation and arousal reaction of the brainwave depending on whether the surface was hot or cold, but the sensation on the surface texture was often evaluated differently depending on who you were. For this reason, this study has some limitations.

Studies on the Sedative Alkaloids from Zizyphus spinosus Semen

  • Han, Byung-Hoon;Park, Myung-Hwan;Park, Jeong-Hill
    • Korean Journal of Pharmacognosy
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    • v.16 no.4
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    • pp.233-238
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    • 1985
  • A number of sedative alkaloids were isolated from Sanjoin(酸棗仁), the seeds of Zizyphus vulgaris Lamark var. spinosus Bunge (Rhamnaceae) which is an important Chinese medicinal material used to treat insomnia and sometimes to treat sleepiness. Those compounds were designated as Sanjoinine-A, B, C, D, etc. depending on the order of increasing polarity. Sanjoinine-A, $C_{31}H_{42}N_4O_4$, $mp\;249^{\circ}$, $[{\alpha}]^{27}_D-316$, Sanjoinine-B, $C_{30}H_{40}N_4O_4$, $mp\;212{\sim}4^{\circ}$, Sanjoinene, $C_{29}H_{35}N_3O_4$, $mp\;281{\sim}2^{\circ}$, $[{\alpha}]^{22}_D-272$, Sanjoinine-D, $C_{32}H_{46}N_4O_5$, $mp\;256{\sim}8^{\circ}$, $[{\alpha}]^{22}_D-53.6$, Sanjoinine-F, $C_{31}H_{42}N_4O_5$, $mp\;228{\sim}9^{\circ}$, $[{\alpha}]^{22}_D-215$, and $Sanjoinine-G_1,\;C_{31}H_{44}N_4O_5,\;mp\;236{\sim}8^{\circ},\;[{\alpha}]^{22}_D-68.6$, were found as 14-membered cyclic peptide alkaloids, $Sanjoinine-G_2,\;C_{30}H_{42}N_4O_4,\;mp\;182^{\circ},\;[{\alpha}]^{22}_D-79.2$, as being open chain peptide alkaloid, and Sanjoinine-E, $C_{19}H_{21}NO_2$, $mp\;166^{\circ}$, $[{\alpha}]^{20}_D-146.2$, N-Methylasimilobine, $C_{18}H_{19}NO_2$, $mp\;193{\sim}5^{\circ}$, $[{\alpha}]^{20}_D-204$, Sanjoinine-Ia, $C_{18}H_{19}NO_2$, $mp\;155{\sim}7^{\circ}$, $[{\alpha}]^{20}_D-140$, Sanjoinine-Ib, $C_{19}H_{21}NO_4$, $mp\;184^{\circ}$, Sanjoinine-K, $C_{16}H_{19}NO_3$, $mp\;159{\sim}61^{\circ}$, $[{\alpha}]^{20}_D+35$, Caaverine, $C_{17}H_{17}NO_2$, $mp\;204^{\circ}$, $[{\alpha}]^{20}_D-80$, and Zizyphusine, $C_{20}H_{24}NO_4$, $mp\;214{\sim}6^{\circ}$, $[{\alpha}]^{20}_D+317$ as being aporphine alkaloids. The heat treatment of the cyclic peptide alkaloids produced their isomeric products which showed enhanced sedative activity. The chemical structure of the isomeric products will be discussed.

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Synthesis of Aluminum Nitride Whisker by Carbothermal Reaction I. Effect of Fluoride Addition (탄소환원질화법을 이용한 AIN Whisker의 합성 I. 불화물 첨가의 영향)

  • 양성구;강종봉
    • Journal of the Korean Ceramic Society
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    • v.41 no.2
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    • pp.118-124
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    • 2004
  • The properties of AlN made by carbothermal reaction depend on the starting materials, quantity of liquid, the liquid-vapor phase reaction, the N$_2$ flow rate, and the reaction temperature. AlN whisker was synthesized by the VLS and VS methods. Solid ${\alpha}$-A1$_2$O$_3$(AES-11) was carbothermally reduced with carbon black in a high-purity N$_2$ atmosphere with AlF$_3$ to cause whisker grown and additional aluminum liquid to increase whisker yield. Aluminum nitride was perfectly formed at reaction temperatures of 1600$^{\circ}C$. At reaction temperature higher than 1600$^{\circ}C$ the aluminum nitride was completely formed, while the composition remains unaffected. Needle-shaped whiskers formed best at 1600$^{\circ}C$ while higher temperatures disrupted whisker formation. Adding 0 to 15 wt% aluminum to the synthesis favorably affects the microstructure for formation of needle-shaped AlN whisker. Additions over 15 wt% degraded formation of AlN whisker.

Physiological Differentiation of Emotional States Induced by Pictorial Stimuli of Positive And Negative Valence in Passive Viewing Mode (시각 자극에 의하여 유발된 긍/부정 정서의 뇌파 및 자율신경계 반응의 차이)

  • Imgap Yi;Lee, Kyung-Hwa;Estate Sokhadze;Park, Sangsup;Sohn, Jin-Hun
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
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    • 1998.11a
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    • pp.143-147
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    • 1998
  • Autonomic and EEG responses of 38 college students were studied during 60-sec long presentation of International Affective Picture System (IAPS )slides evoking, according to subjective reports, negative (disgust, sadness, surprise) and positive (happiness, exciting) emotional. states. Observed were significant heart rate (HR) deceleration, large skin conductance responses (SCR), moderate respiration frequency slowing, reduction of frontal (F 3, F 4 ) and occipital (O 1, O 2 ) fast alpha, and increases of theta, delta and beta relative spectral power values during the first 30 sec of exposure of IAPS pictures. Analysis carried out to differentiate emotion categories according to autonomic responses indicated that observed HR deceleration was larger in magnitude in surprise and sadness than in disgust, SCR amplitude higher in sadness than in disgust. EEC showed significant differences in theta (F 3, F 4 ) and delta (O 1) power increase in disgust vs. happiness, fast alpha (F 3, F 4 ) power was lower in surprise than in happiness, and slow beta power higher. in happiness than in disgust (0 1). Despite some differences. observed within discrete emotion conditions, overall responses pattern of monitored parameters exhibited similar profiles with few variations, most. obvious. in disgust state, which suggests that affective visual stimulation elicits stereotypical responses in a given passive viewing paradigm. However, the magnitude of physiological responses may vary to certain extent across discrete emotional states making it possible to differentiate among particular experimentally-induced emotional states, e.g., disgust vs. sadness by ANS responses or disgust vs. happiness by EEG measures.

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Spin-Flop of α-Fe2O3 Nano Particles (α-Fe2O3 나노 입자에서 Spin-Flop에 관한 연구)

  • Sur, Jung-Chul;Park, Chul-Jin;Choi, Jung-Wan;Gee, S.H.;Hong, Y.K.
    • Journal of the Korean Magnetics Society
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    • v.14 no.5
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    • pp.169-173
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    • 2004
  • We have synthesized monodispersed $\alpha$-F $e_2$ $O_3$ nano particles to investigate the spin change during the Morin transition temperature( $T_{M}$). The particle size was founded to have a very uniform distribution of 80 nm by x-ray diffraction and size dispersion analyzer. The Mossbauer spectra between the 4.2 K and the room temperature show that $T_{M}$ was shifted and the spin states of Fe ion were changed with the particle size. The Morin transition temperature of bulk usually quoted in literature is 265 K but, it decreases with the size and no transition was found at the critical size down to 4.2K. The spin direction of 80 nm sized particles are normal to the hexagonal c-axis above the $T_{M}$ and are tilted about 28~29$^{\circ}$ below $T_{M}$, which is the [110] direction of rombohedral structure.

Safening Activity of Optically Active ${\alpha}$-Methylbenzylphenylurea toward Bensulfuron-methyl and Pyribenzoxim Injury to Rice (광학활성 ${\alpha}$-Methylbenzylphenylurea 유도체의 bensulfuron-methyl과 pyribenzoxim의 벼에 대한 약해경감효과)

  • Ryoo, Jae-Hwan
    • The Korean Journal of Pesticide Science
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    • v.9 no.2
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    • pp.153-158
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    • 2005
  • Safening activities of optically active ${\alpha}$-methylbenzylphenylureas on crop injury of rice (Oryza sativa L., cv. Tsukinohikari, japonica) caused by bensulfuron-methyl (methyl 2-[[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]methyl]benzoate) and pyribenzoxim (benzophenone o-[2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy]benzoyl]oxime) were investigated. Some derivatives of the optically active compounds exhibited strong safening activity against growth inhibition of rice by bensulfuron-methyl. Out of the derivatives tested, (S)-2,3-diCl and (S)-2-F-4-Me derivatives showed greater relieving activity than that of dymuron. In addition, the stress relieving activity was also obtained when they were applied at 4 days after bensulfuron-methyl treatment. On the other hand, crop injury caused by pyribenzoxim was relieved by about 95% with (S)-2-F-4-Me derivative in shoots and roots of rice seedlings.

Crystal Structure of the Three-dimensional Metal Complex Host in Clusion Compound [$Cd(pn)Ni(CN)_4{\cdot}0.5(CH_3COCH_3{\cdot}H_2O$) (3차원 금속 착제를 Host로 하는 포접 화합물 [$Cd(pn)Ni(CN)_4{\cdot}0.5(CH_3COCH_3{\cdot}H_2O$)의 결정구조)

  • Park, Gi Min;Lee, Uk;Am, Bon Jin Mu
    • Journal of the Korean Chemical Society
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    • v.38 no.6
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    • pp.435-441
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    • 1994
  • The inclusion compound constituted with three-dimensional metal-complex $Cd(pn)Ni(CN)_4$ has been prepared and determined the crystal structure from single crystal X-ray diffraction data. Crystal data are as follows: $[Cd(pn)Ni(CN)_4]{\cdot}0.5(CH_3COCH_3{\cdot}H_2O)$, Fw = 387.35, Orthorhombic, $Pn2_1a$, a = 13.950(3) $\AA$, b = 26.713(7) $\AA$, c = 7.628(1) $\AA$, V = 2843(1) $\AA^3$, Z = 4, $D_x=1.81 gcm^{-3}$, $\mu(MoK{\alpha})$ = $28.153 cm^{-1}$, T = 297K, final R = 0.0418 for 3521($F_0>3{\sigma}(F_0)$). The metal-complex host provides tunnel cavity, similar to thiourea inclusion compounds, accommodated guest molecules $(=CH_3COCH_3\;and\;$H_2O).$ The stoichiometric host: guest ratio is 0.5. The title inclusion compound reveals another evidence for the host-selectivity, that is, the branched aliphatic guest molecule leads T-type host structure.

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Synthesis and Optical Properties of M-Si(Al)-O-N (M: Sr, Ca) Phosphors for white Light Emitting Diodes (백색 발광다이오드용 M-Si(Al)-O-N (M: Sr, Ca) 형광체의 합성 및 발광 특성)

  • Lee, Seung-Jae;Lee, Jun-Seong;Kim, Young-Jin
    • Journal of the Microelectronics and Packaging Society
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    • v.19 no.2
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    • pp.41-45
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    • 2012
  • Oxynitride green phosphors for white light emitting diodes (LEDs) were synthesized and their optical properties were evaluated. The N/O ratio ($\delta$) of $SrSi_2O_{2-{\delta}}N_{2+2/3{\delta}}:Eu^{2+}$ closely depended on the synthesizing conditions. The most excellent green emission (545 nm), which was assigned to the $5d{\rightarrow}4f$ transition of $Eu^{2+}$ ions, was achieved at the conditions of $1700^{\circ}C$, 5 mol% $Eu^{2+}$, and $H_2$ atmosphere. The well-developed $Ca-{\alpha}-SiAlON:Yb^{2+}$ particles with homogeneous size were obtained at m = 3 (n = 0.15) for the compound of $Ca_{0.5m-0.005}Yb_{0.005}Si_{12-(m+n)}Al_{m+n}O_nN_{16-n}$, resulting in the strong green emission at around 550 nm.