• Title/Summary/Keyword: C.V.A.

Search Result 10,497, Processing Time 0.046 seconds

Water Vapor Adsorption and Hydrogen Peroxide Decomposition on Date Pit Carbonization Products

  • Youssef, A.M.;El-Nabarawy, Th.;Ahmed, S.A. Sayed;Rashwan, W.E.
    • Carbon letters
    • /
    • v.6 no.4
    • /
    • pp.227-233
    • /
    • 2005
  • Carbonization products C1, C2, C3, C4 and C5 were prepared by the carbonization of date pit in limited air, at 500, 600, 700, 800 and $1000^{\circ}C$, respectively. C1-V-600, C3-V-600, C1-V-1000 and C3-V-1000 were prepared by thermal treatment of C1 and C3 under vacuum at 600 and $1000^{\circ}C$. The textural properties were determined from nitrogen adsorption at 77 K and from carbon dioxide adsorption at 298 K. The surface pH, the FTIR spectra and the acid and base neutralization capacities of some carbons were investigated. The amounts of surface oxygen were determined by out-gassing the carbon-oxygen groups on the surface as $CO_2$ and CO. The adsorption of water vapor at 308 K on C1, C2, C3 and C4 was measured and the decomposition of $H_2O_2$ at 308 K was also investigated on C1, C2, C3, C4 and C5. The surface area and the total pore volume decreased with the rise of the carbonization temperature from 500 to $1000^{\circ}C$. The adsorption of water vapor is independent on the textural properties, while it is related to the amount of acidic carbon-oxygen groups on the surface. The catalytic activity of $H_2O_2$ decomposition does not depend on the textural properties, but directly related to the amount of basic carbon-oxygen complexes out-gassed as CO, at high temperatures.

  • PDF

Differences in Neurotransmitters Level as Biomarker on Sleep Effects in Dementia Patients with Insomnia after Essential Oils Treatment

  • Kyung-Bok Lee;Sana Latif;Young-Sook Kang
    • Biomolecules & Therapeutics
    • /
    • v.31 no.3
    • /
    • pp.298-305
    • /
    • 2023
  • This study aimed to examine the effects of several essential oils on insomnia in dementia patients following transdermal treatment (aromatherapy). The mean change rates (%) of sleep biomarkers were compared between the single essential and jojoba (vehicle) oil massage groups in this study. The lavender (L) essential oil massage group demonstrated a significant decrease in the mean change rate (%) of 24-h urinary free cortisol, whereas the valerian (V) essential oil massage group demonstrated a significant increase in the mean change rate (%) of serum 5-hydroxytryptamine. In addition, a significant increase in the mean change rate (%) of 24-h urinary norepinephrine was observed in the chamomile (C) essential oil massage group only. Based on these results, valerian, lavender, and chamomile oils were mixed in different ratios to produce blending oils A (L:C:V=2:2:1), B (L:C:V=3:1:1) and C (L:C:V=1:3:1). The highest level of serum 5-hydroxytryptamine was observed after administering blending oil A. These results suggest that blending oil A might possess therapeutic effects against insomnia. Overall, it is hypothesized that the optimally blended essential oil will produce synergic effects when combined with hypnotic drugs.

Single-Electron Pass-Transistor Logic with Multiple Tunnel Junctions and Its Hybrid Circuit with MOSFETs

  • Cho, Young-Kyun;Jeong, Yoon-Ha
    • ETRI Journal
    • /
    • v.26 no.6
    • /
    • pp.669-672
    • /
    • 2004
  • To improve the operation error caused by the thermal fluctuation of electrons, we propose a novel single-electron pass-transistor logic circuit employing a multiple-tunnel junction (MTJ) scheme and modulate a parameters of an MTJ single-electron tunneling device (SETD) such as the number of tunnel junctions, tunnel resistance, and voltage gain. The operation of a 3-MTJ inverter circuit is simulated at 15 K with parameters $C_g=C_T=C_{clk}=1\;aF,\;R_T=5\;M{\Omega},\;V_{clk}=40\;mV$, and $V_{in}=20\;mV$. Using the SETD/MOSFET hybrid circuit, the charge state output of the proposed MTJ-SETD logic is successfully translated to the voltage state logic.

  • PDF

Assembly of Six-Membered Vanadium Borophosphate Cluster Anions: Synthesis and Structures of (NH4)2(C2H10N2)6[BaH2O)5]2[V2P2BO12]6.8H2O and (NH4)8(C3H12N2)4[Ba(H2O)7][V2P2BO12]6.17H2O

  • Yun, Ho-Seop;Do, Jung-Hwan
    • Bulletin of the Korean Chemical Society
    • /
    • v.26 no.1
    • /
    • pp.146-150
    • /
    • 2005
  • Two new barium vanadium borophosphate compounds, $(NH_4)_2(C_2H_{10}N_2)_6[Ba(H_2O)_5]_2[V_2P_2BO_{12}]_6{\cdot}8H_2O$, Ba- VBPO1 and $(NH_4)_8(C_3H_{12}N_2)_4[Ba(H_2O)_7][V_2P_2BO_{12}]_6{\cdot}17H_2O$, Ba-VBPO2 have been synthesized by interdiffusion methods in the presence of diprotonated ethylenediamine and 1,3-diaminopropane. Compound Ba-VBPO1 has an infinite chain anion (${[BaH_2O)_5]_2[V_2P_2BO_{12}]_6}$$^{14-}$, whereas Ba-VBPO2 has a discrete cluster anion {[$Ba(H_2O)_7][V_2P_2BO_{12}]_6$}$^{16-}$. Crystal Data: $(NH_4)_2(C_2H_{10}N_2)_6[Ba(H_2O)_5]_2[V_2P_2BO_{12}]_6{\cdot}8H_2O$, triclinic, space group P$\overline{1}$ (no. 2), a = 13.7252(7) $\AA$, b = 15.7548(8) $\AA$, c = 15.8609(8) $\AA$, α = 63.278(1)$^{\circ}$, $\beta$ = 75.707(1)$^{\circ}$, $\gamma$ = 65.881(1)$^{\circ}$, Z = 1; $(NH_4)_8(C_3H_{12}N_2)_4[Ba(H_2O)_7][V_2P_2BO_{12}]_6{\cdot}17H_2O$, monoclinic, space group C2/c (no. 15), a = 31.347(2) $\AA$, b = 17.1221(9) $\AA$, c = 22.3058(1) $\AA$, $\beta$ = 99.303(1)$^{\circ}$, Z = 4.

Enzyme treatment for clarification of spoiled oriental melon juice (참외 저급과 주스의 청징화를 위한 효소처리 조건)

  • Jang, Se-Jin;Jo, Yong-Jun;Seo, Ji-Hyung;Kim, Ok-Mi;Jeong, Yong-Jin
    • Food Science and Preservation
    • /
    • v.21 no.4
    • /
    • pp.506-511
    • /
    • 2014
  • In Gyeongsangbuk-do seongju area, hundreds of tons of spoiled oriental melon are harvested annually. Therefore, ways to prevent such spoilage are needed. This study was conducted to investigate the quality characteristics of spoiled oriental melon juice after enzyme treatment for the production of oriental melon concentrate. The treatment of the oriental melon juice with three kinds of enzymes with variable concentrations showed the following results. PECE(1), which was compounded pectinase and cellulase at 0.01% (v/v), gave the melon a 0.16 brown color and 0.01 turbidity, and the highest L value of 97.00. The detected free sugar contents were fructose, glucose and sucrose, with the amount of sucrose the highest at roughly 4,000 mg%. The mixture of different enzyme treatments resulted in a 0.15 brown color and 0.01 turbidity at 60 minutes, and the L value was high at 97.25. The enzyme treatment temperatures of $50^{\circ}C$ and $60^{\circ}C$ yielded a low-level brown color and low turbidity, but the L values were high at $60^{\circ}C$ and $70^{\circ}C$. These results showed that 0.01% (v/v) mixing enzyme, i.e., pectinase and cellulose compounded at $60^{\circ}C$ for 60 min, must be used for the production of oriental melon concentrate.

Characterization of Oil Degrading Bacterium Pseudomonas sp. BCK-1 Isolated from the Coastal Water of Yosu, Korea (여수주변해역에서 분리한 유류분해세균 Pseudomonas sp. BCK-1의 특성)

  • KOO Hoen-Seo
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.34 no.2
    • /
    • pp.145-150
    • /
    • 2001
  • A marine bacterium having a high oil-degrading activity was isolated from the coastal water of Yosu, Korea, identified as Pseudomonas sp. and named Pseudomonas sp. BCK-1. The optimal temperature, pH and NaCl concentration for cell growth was $30^{\circ}C$, 7.0 and $3\%$ (w/v), respectively. After cultivation at $30^{\circ}C$, 180 rpm in 250 mL erlenmeyer flask for 72 and 168 hours, $2\%$ (w/v) arabian light crude oil (ACO) and bunker C oil (BCO) which are considered to be hardly biodegradable compounds were degraded $92\%$ (w/w) and $72\%$ (w/w), respectively.

  • PDF

Hydrogen Gas Sensing Characteristics of Pd-SiC Schottky Diode (Pd-SiC 쇼트키 다이오드의 수소 가스 감응 특성)

  • Kim, Chang-Kyo;Lee, Joo-Hun;Lee, Young-Hwan;Choi, Suk-Min;Cho, Nam-Ihn
    • Journal of Sensor Science and Technology
    • /
    • v.8 no.6
    • /
    • pp.448-453
    • /
    • 1999
  • A Pd-SiC Schottky diode for detection of hydrogen gas operating at high temperature was explored. Hydrogen-sensing behaviors of Pd-SiC Schottky diode were analyzed as a function of hydrogen concentration and temperature by I-V and ${\Delta}I$-t methods under steady-state and transient conditions. The effect of hydrogen adsorption on the barrier height was investigated. Analysis of the steady-state kinetics using I-V method confirmed that the atomistic hydrogen adsorption process is responsible for the barrier height change in the diode.

  • PDF

Hydrolysis Mechanism of N-(benzoyl)-C-(N-methylanilino)imidoylchloride Derivatives (N-(benzoyl)-C-(N-methylanilino)imidoylchloride 유도체의 가수분해 반응메카니즘)

  • Kwon Ki-Sung;Lee Yong-Gu;Sung Nack-Do;Kim Chon-Suk
    • Journal of the Korean Chemical Society
    • /
    • v.37 no.6
    • /
    • pp.618-625
    • /
    • 1993
  • Rate constants of hydrolysis of N-(benzoyl)-C-(N-methylanilino)imidoylchlorides were determined by UV spectrophotometry in 50% (v/v) aqueous methanol at 25$^{\circ}C$. On the basis of rate equation, substituent effect, solvent effect, salt effect, thermodynamic parameters and hydrolysis product analysis, it may be concluded that the hydrolysis of N-(benzoyl)-C-(N-methylanilino)imidoylchlorides proceed through $S_N$1 mechanism via azocarbonium ion intermediate in the range of from pH 3.0 to pH 10.0, while above pH 10.0 and below pH 3.0 the hydrolysis proceeds through nucleophilic addition-elimination (A$d_{N-E}$) mechanism.

  • PDF

Self-Assembly of Vanadium Borophosphate Cluster Anions: Synthesis and Structures of (NH4)(C2H10N2)5.5[Cu(C2H8N2)2]3[V2P2BO12]6·17H2O and (NH4)(C2H10N2)3.5[Cu(C2H8N2)2]5[V2P2BO12]6·18H2O

  • Jung, Kyung-Na;Cho, Yoon-Suk;Yun, Ho-Seop;Do, Jung-Hwan
    • Bulletin of the Korean Chemical Society
    • /
    • v.26 no.8
    • /
    • pp.1185-1189
    • /
    • 2005
  • Two new copper vanadium borophosphate compounds, $(NH_4)(C_2H_{10}N_2)_{5.5}[Cu(C_2H_8N_2)_2]_3[V_2P_2BO_{12}]_6{\cdot}17H_2O,\;Cu-VBPO1\;and\;(NH_4)(C_2H_{10}N_2)_{3.5}[Cu(C_2H_8N_2)_2]_5[V_2P_2BO_{12}]_6{\cdot}18H_2O$, Cu-VBPO2 have been hydrothermally synthesized and characterized by single crystal X-ray diffraction, thermogravimetric analysis, IR spectroscopy, and elemental analysis. The structure of Cu-VBPO1 contains a layer anion, {$[Cu(C_2H_8N_2)_2]_3[V_2P_2BO_{12}]_6$}$^{12-}$, whereas Cu-VBPO2 has an open framework anion, {$[Cu(C_2H_8N_2)_2]_5[V_2P_2BO_{12}]_6$}$^{8-}$. Crystal Data: $(NH_4)(C_2H_{10}N_2)_{5.5}[Cu(C_2H_8N_2)_2]_3[V_2P_2BO_{12}]_6{\cdot}17H_2O$, monoclinic, space group I2/m (no. 12), $\alpha$ = 15.809(1) $\AA$, b = 31.107(2) $\AA$, c = 12.9343(8) $\AA$, $\beta$ = 104.325(1)$^{\circ}$, Z = 2; $(NH_4)(C_2H_{10}N_2)_{3.5}[Cu(C_2H_8N_2)_2]_5[V_2P_2BO_{12}]_6{\cdot}18H_2O$, tetragonal, space group $P4_2$/mnm (no.136), $\alpha$ = 26.832(1) $\AA$, c = 18.021(1) $\AA$, Z = 4.