• Title/Summary/Keyword: O/W

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Metal-Dinitrosyl Complexes(III) : Synthesis and Structural Study of Homo-, Hetero-dinuclear Molybdenum and Tungsten Complexes, $[Cl(phen)(NO)_2M({\mu}-pyz)M'(NO)_2(phen)Cl][ClO_4]_2 $(phen = 1,10-phenanthroline, pyz = pyrazine) (금속-디니트로실 착물 (제 3 보) : 몰리브덴과 텅스텐의 호모 및 헤테로 이핵 착물, $[Cl(phen)(NO)_2M({\mu}-pyz)M'(NO)_2(phen)Cl][ClO_4]_2 (phen=1,10-phenanthroline,\;pyz=pyrazine)$의 합성 및 구조에 대한 연구)

  • Sang-Oh Oh;Seong-Jong Mo
    • Journal of the Korean Chemical Society
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    • v.37 no.7
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    • pp.655-661
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    • 1993
  • The neutral monomeric compounds $[Mo(NO)_2Cl_2(phen)]$ and $[W(NO)_2Cl_2(phen)]$ (phen= 1,10-phenanthroline) have been prepared by reactions of polymeric compounds $[{Mo(NO)_2Cl_2}n],\;[{W(NO)_2Cl_2}n]$ with chelate ligands. Additions of one equivalent of silver(I) perchlorate to these cis-dinitrosyl compounds in acetone solution produce $[Mo(NO)_2(phen)(S)Cl][ClO_4]\;and\;[W(NO)_2(phen)(S)Cl][ClO_4]$ (S = acetone). The homo- and hetero-dinuclear complexes, $[Cl(phen)(NO)_2M(pyz)M'(NO)_2(phen)Cl][ClO_4]_2$ (M = Mo, W) and $[Cl(phen)(NO)_2M(pyz)M'(NO)_2(phen)Cl][C1O_4]_2$ (M = Mo, M' = W) have been prepared by these monocationic complexes with pyrazine ligand respectively. These complexes characterized by elemental analysis, $1^H-\;and\;^{13}C-NMR$, infrared, and UV-visible spectroscopy are reported. The spectral data indicate that homo- and hetero-dinuclear complexes were symmetrical structures of $C_{2v}$.

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Optimization of O/W Emulsion with Natural Surfactant Extracted from Medicago sativa L. using CCD-RSM (CCD-RSM을 이용한 알팔파 추출물인 천연계면활성제가 포함된 O/W 유화액의 최적화)

  • Seheum Hong;Jiachen Hou;Seung Bum Lee
    • Applied Chemistry for Engineering
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    • v.34 no.2
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    • pp.137-143
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    • 2023
  • In this study, natural surfactants were extracted from Medicago sativa L. The O/W emulsification processes with the extracted natural surfactants were optimized using central composite design model-response surface methodology (CCD-RSM) and a 95% confidence interval was used to confirm the reasonableness of the optimization. Herein, independent parameters were the ratio of saponins to total surfactant (P), amount of surfactant (W), and emulsification speed (R), whereas the reaction parameters were the emulsion stability index (ESI), mean droplet size (MDS), and viscosity (V). Using the multiple reaction, the optimal conditions for the ratio of saponins to total surfactant, amount of surfactant, and emulsification speed for O/W emulsification were 49.5%, 9.1 wt%, and 6559.5 rpm, respectively. Under these optimal conditions, the expected values of ESI, MDS, and V as the reaction parameters were 89.9%, 1058.4 nm, and 1522.5 cP, respectively. The values of ESI, MDS, and V from these expected values were 88.7%, 1026.4 nm, and 1486.5 cP, respectively, and the average experimental error for validating the accuracy was about 2.3 (± 0.4)%. Therefore, it was possible to design an optimization process for evaluating the O/W emulsion process with Medicago sativa L. using CCD-RSM.

Characteristics of the Ceramic Filter Using $0.05Pb(Al_{2/3}W_{1/3})O_3-0.95Pb(Zr_{0.52}Ti_{0.48}O_3$Ceramic System ($0.05Pb(Al_{2/3}W_{1/3})O_3-0.95Pb(Zr_{0.52}Ti_{0.48})O_3$계를 이용한 세라믹 필터 특성)

  • 김남진;윤석진;유광수;김현재;정형진
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.2 no.2
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    • pp.71-76
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    • 1992
  • Piezoceramic filters were fabricated by adding $MnO_2 and FeZ0_3$ to the $0.05Pb(Al_{2/3}W_{1/3})O_3-0.95Pb(Zr_{0.52}Ti0.48)O_3$ system using photolithography method. As the amounts of $MnO_2$ increased, the electro-mechanical coupling factor(Kp) decresed. On the other hand, for $Fe_2O_3$ added samples, Kp was 57%, but mechanical quality factor(Qm) showed relatively low value. The passband widths were 155kHz for 0.3wt % $MnO_2$ addition and 260kHz for 0.1 wt % $Fe_2O_3$ addition, and were inversely propotional to Qm values. Group delay time characteristics showed Gausian for $MnO_2$ additions and Butterworth for$Fe_2O_3$ additions.

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The effect of osmotic pressure in W/O/W multiple emulsion (다상 에멀전 형성에 있어 삼투 현상이 미치는 영향)

  • 신중진;이근수;강기춘;표형배
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.26 no.1
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    • pp.139-148
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    • 2000
  • The osmotic pressure is a one of the most important factor affecting stabilization of multiple emulsion in a law hours after experiment. To understand and decrease osmotic pressure between Wl phase and W2 phase, a kinds of humectants were introduced in outer water phase. As a result, Betaine and Glucose had an excellent effect reducing osmotic pressure and NaCl made W/O/W emulsion more stable than MgSO4 did when introduced in inner water phase.

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Hydrodesulfurization of Thiophene over $Ni-W/TiO_2-ZrO_2$ catalysts ($Ni-W/TiO_2-ZrO_2$ 촉매상에서 Thiophene의 수첨탈황반응)

  • 전광승;김문찬;김경림
    • Journal of Korean Society for Atmospheric Environment
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    • v.8 no.1
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    • pp.84-91
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    • 1992
  • Hydrodesulfurization of thiophene was studied over $Ni-W/TiO_2-ZrO_2$ catalysts in a fixed bed flow reactor. The ranges of experimental conditions were at the temperatures between 200$^\circ$C and 360$^\circ$C, the pressures between 20 X $10^5$ Pa. The catalysts were reduced with the flow of 10 L/hr of $H_2$ at the temperature of 350$^\circ$C. It was found that $TiO_2-ZrO_2$ supported catalysts had similar activity to $\gamma-Al_2O_3$ supported. The largest surface areas and the highest acidity occured as the binary oxides were mixed with equal molar ratios. The HDS increased with increasing temperatures, pressures and contact times.

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Toughening of SiC Whisker Reinforced Al2O3 Composite (SiC 휘스커 강화 Al2O3 복합재료의 고인화)

  • Kim Yon Jig;Song Jun Hee
    • Korean Journal of Materials Research
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    • v.14 no.9
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    • pp.649-654
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    • 2004
  • In this paper, the fracture toughness and mechanisms of failure in a random SiC-whisker/$Al_{2}O_3$ ceramic composite were investigated using in situ observations during mode I(opening) loading. $SiC_{w}/Al_{2}O_3$ composite was obtained by hot press sintering of $Al_{2}O_3$ powder and SiC whisker as the matrix and reinforcement, respectively. The whisker and powder were mixed using a turbo mill. The composite was produced at SiC whisker volume fraction of $0.3\%$. Compared with monolithic $Al_{2}O_3$, fracture toughness enhancement was observed in $SiC_{w}/Al_{2}O_3$ composite. This improved fracture toughness was attributed to SiC whisker bridging and crack deflection. $SiC_{w}/Al_{2}O_3$ composite exhibited typically brittle fracture behavior, but a fracture process zone was observed in this composite. This means that the load versus load-line displacement curve of $SiC_{w}/Al_{2}O_3$ composite from a fracture test may involve a small non-linear region near the peak load.

Alcohol Detecting Characteristics of Catalytic Sensor (접촉연소식 센서의 알코올 검지 특성)

  • Kim, Jong-Won;Son, Young-Mok;Sim, Kyu-Sung;Park, Kee-Bae;Lee, Sang-Ho
    • Journal of Sensor Science and Technology
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    • v.3 no.1
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    • pp.32-39
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    • 1994
  • Catalytic combustion type sensor was fabricated for alcohol detection, and its characteristics were tested. When the resistance of Pt coil for pellistor is 2.0 ohm, suggestible input power to bridge circuit was about 300 mW for methanol detection, and in the range from 350 mW to 400 mW for ethanol. Pellistors were prepared by means of impregnating Pt or Pd on the ${\gamma}$-alumina bead for sensing element, and transition metals such as $Co_{3}O_{4}$, $Fe_{2}O_{3}$ for compensating element.

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An Estimation on the Stability of W/O Type Emulsified Fuel Using by Capacitance Sensor (정전용량센서를 이용한 W/O형 유화연료의 안정성 평가)

  • Cho, Seong-Cheol;Oh, Yang-Hwan;Im, Seok-Yeon
    • Journal of the Korean Applied Science and Technology
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    • v.28 no.1
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    • pp.95-101
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    • 2011
  • We estimated on the stability of W/O type emulsified fuel using by capacitance sensor, so it concluded the following conclusions. For the first 24 hours, prepared emulsified fuel reveals phase separation ratio of 5%, maintains stable status which verifies the stability of emulsified fuel. Adding more water increases the phase separation ratio rapidly, and adding more surfactant displays stable emulsification. Adding water causes larger size of water droplet diameter, and adding surfactant mixture causes smaller size of water droplet diameter. In conclusion, the size of W/O type emulsified fuel water droplet diameter is directly related to the volume of surfactant, and density of water droplet diameter changes thedistribution according to water contents.

Microstructure and Sintering Behavior of W-15 wt%Cu Nanocomposite Powder Prepared from W-CuO Mixture (W-CuO 혼합물을 이용하여 제조된 W-Cu나노복합분말의 미세구조와 소결거동에 관한 연구)

  • 김길수;김대건;김영도
    • Journal of Powder Materials
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    • v.10 no.4
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    • pp.270-274
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    • 2003
  • Recently, the fabrication process of W-Cu nanocomposite powders has been researched to improve the sinterability by mechanochemical process (MCP), which consists of ball milling and hydrogen-reduction with W- and Cu-oxide mixture. However, there are many control variables in this process because the W oxides are hydrogen-reduced via several reduction stages at high temperature over 80$0^{\circ}C$ with susceptive reduction conditions. In this experiment, the W-15 wt%Cu nanocomposite powder was fabricated with the ball-milling and hydrogen-reduction process using W and CuO powder. The microstructure of the fabricated W-Cu nanocomposite powder was homogeneously composed of the fine W particles embedded in the Cu matrix. In the sintering process, the solid state sintering was certainly observed around 85$0^{\circ}C$ at the heating rate of 1$0^{\circ}C$/min. It is considered that the solid state sintering at low temperature range should occur as a result of the sintering of Cu phase between aggregates. The specimen was fully densified over 98% for theoretical density at 120$0^{\circ}C$ for 1 h with the heating rate of 1$0^{\circ}C$/min.

A Study on the Preparation of Hollow Microspheres Using Waste Polystyrene (폐 Polystyrene을 이용한 중공 미세구 제조에 관한 연구)

  • Kwon, Soon Young;Woo, Je-Wan
    • Clean Technology
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    • v.12 no.4
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    • pp.205-210
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    • 2006
  • In this study, polystyrene hollow microspheres were prepared via optimized purifying steps for the reuse of waste polystyrene. PS/PVA double layered hollow microspheres were prepared using the multiple emulsion ($W_1/O/W_2$) method with recycled polystyrene. The sonication treatment at the first stage of $W_1/O$ emulsion formation was very important factor of control of particle size and its distribution. When sonication was treated for 20 seconds, the average particle size and distribution were $1.35{\mu}m$ and $0.8{\mu}m{\sim}2.8{\mu}m$, respectively. The double layered hollow microspheres that have smaller and uniformed particle size distribution were manufactured when gelatin or Tween 80 was used as surfactants in the $W_2$ phase.

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