• Title/Summary/Keyword: wet chemistry

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Studies on wet polishing characteristic of rice (습식연미 도정특성에 관한 연구)

  • Lee, B.Y.;Son, J.R.;Yoon, I.H.;Kim, Y.B.
    • Applied Biological Chemistry
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    • v.35 no.6
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    • pp.475-478
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    • 1992
  • Series of study were conducted to investigated the condition of wet polishing and quality of wet polished rice. The optimal condition for wet polishing was determined to be 0.5% added water after removal bran layer of 95% by normal milling. Its polishing yield was 0.75% lower than normal polishing, and the moisture content of wet and normal polished rice was the same, but the whiteness of wet polished rice was higher by 3.5% than that of normal polished rice and the lightness was very good. The total solid as washing wet polished rice in water and the total solid in residual liquid of cooked wet polished rice was about 0.30 and 2% lower than those of normal polished rice, respectively. The storability of wet polished rice was better than that of normal polished rice.

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The Effects of Size Reduction and pH on Dispersion Characteristics of ATO (Antimony-Doped Tin Oxide) (입자 저감 및 pH가 ATO (안티몬도핑 산화주석)의 분산 특성에 미치는 영향)

  • Kim, Jin-Hoon;Jeong, Eui-Gyung;Lee, Sang-Hun;Han, Won-Hee;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.21 no.3
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    • pp.311-316
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    • 2010
  • This study aimed to prepare antimony-doped tin oxide (ATO) dispersion with high stability. The methods to achieve this goal were sought by investigating the changes of ATO particle size, size distribution, dispersion property as wet ball milling treatment time increased. And the changes of wet ball milled ATO dispersion property were also investigated, as pH increased. The changes of ATO particle size and size distribution, according to wet ball milling treatment time were evaluated with laser diffraction particle size analyzer and scanning electron microscope (SEM). The changes of ATO dispersion property, as wet ball milling treatment time and pH increased, were evaluated with zeta potential analysis and Turbiscan. By 60 min wet ball milling treatment time, ATO particle size decreased and size distribution became narrower, as the treatment time increased. After 60 min milling, the ATO particle size decreased to less than 30% of the initial size and the size distribution was narrowed to $0.1{\sim}5{\mu}m$ from $1{\sim}35{\mu}m$. However, more than 60 min milling, ATO particles aggregated and the particle size increased. ATO dispersion stability also increased as the treatment time and pH increased because the reduced particle size increased particle surface energy and repulsion between particles and the increased pH enhanced particle surface ionization. Hence, after proper length of wet ball milling treatment, highly stable ATO dispersion can be prepared, as increasing pH of the dispersion.

Accumulation Levels and Distribution Characteristics of Polychlorinated Biphenyls in Crucians and Leopard Frogs from the Nakdong River Basin (낙동강 유역에 서식하는 붕어와 황소개구리 체내의 Polychlorinated biphenyls의 축적도와 분포특성)

  • Moon, Ji Yong;Lee, Sung In;Song, Heeyoung;Lee, Kyoung Jin;Choi, Kyunghee;Jeong, Gi Ho
    • Analytical Science and Technology
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    • v.17 no.4
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    • pp.347-354
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    • 2004
  • We collected crucians (Carassius auratus) and leopard frogs(Rana pipiens) along the Nakdong River and the basin area at five locations from Koomi to Nakdong-estuary. The muscular tissue were separated and a GC-MSD system was used for quantification of PCBs. The 62 PCB congeners which represent total PCB levels were selected as analytes. We determined concentrations of PCBs and studied distribution characteristics by individual congeners and homologs. In the crucian, 24 congeners were detected and total PCB levels ranged from 0.74 to 5.41 ng/g wet weight. In the leopard frog, however, only 2 congeners were detected from Nakdong estuary only. The PCB level was 0.24 ng/g wet weight, around 22 times lower than the crucians. The PCB 153 showed the highest concentrations in the congeners and penta- and hexa-CBs showed the strong predominance which accounted for 78% of the total PCBs.

Total sizing system (총 사이징 시스템)

  • Proverb, Robert J.;Pawlowska, Lucyna;Komarowska, Kasia;Garro, Gina;Dilts, Kimberly
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • 2004.07a
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    • pp.19-42
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    • 2004
  • Sizing properties in paper are generally developed through the application of both internal and surface sizes. Rosin, wax, and synthetic sizes including ASA, AKD, and stearic anhydride are and have been used to provide wet-end sizing to paper. In many cases, the use of some of these sizes leads to runnability problems that are inherent in the wet-end operation. Variability in furnish, fines, broke, filler, water chemistry, conductivity, and pH control impacts the wet-end operation. Size press chemicals including starch and polymers such as styrene-acrylic, styrene-maleic, and styrene acrylate emulsions are used in conjunction with internal sizes to improve the paper surface for printing and strength properties, porosity, and opacity improvement. This paper will discuss results from a new, proprietary formulation and process that allows application of sizing chemistry more totally at the size press with reduced emphasis on wet end sizing. Runnability issues are thus minimized at the wet-end, chemical usage is more efficient, and significant cost savings can be realized. Case histories will be presented illustrating the advantages of this new application in commercial trials.

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Extraction and Mixing Effects of Grape (Campbell) Seed Oil

  • Kang, Han-Chul;Min, Young-Kyoo;Hwang, Jong-Taek;Kim, Si-Dong;Kim, Tae-Su
    • Journal of Applied Biological Chemistry
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    • v.42 no.4
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    • pp.175-179
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    • 1999
  • Grape seed oil was extracted using different preparatory treatments as follows: (1) grinding, (2) grinding and roasting, (3) grinding and wet- roasting, (4) grinding, roasting, and wet-roasting, and (5) grinding, wet-roasting, and wet-roasting. The highest antioxidant activity was obtained from the sample with the method (2). Initial states of oxidation were similar except method (1) that showed more oxidized state, being P.O.V.8. Acid values were observed in the range from 1.42 to 1.89. The lowest acid value was found as 1.42 in method (1) and those of others were somewhat higher, indicating that heating process of roasting produced some free fatty acids. From the results of sensory evaluation, the best odor and taste were obtained from the methods (2) and (3). Repetitive procedure of wet-roasting, like method 5, caused some loss of flavor components and decrease in the sensory evaluation score. Addition of grape seed oil (method 2) to soybean and perilla oil at the level of 20% retained considerable antioxidant activities as much as 4.3 and 5 times, respectively, than 100% soybean or perilla oil stored for 12 weeks. When soybean or perilla oil was mixed with 20% grape seed oils, P.O.V. decreased to half of that of unmixed oils.

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Effect On Glass Texturing For Enhancement of Light Trapping in Perovskite Solar Cells

  • Kim, Dong In;Nam, Sang-Hun;Hwang, Ki-Hwan;Lee, Yong-Min;Boo, Jin-Hyo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.387.2-387.2
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    • 2016
  • Glass texturing is a sufficient method for changing the surface morphology to enhance the light trapping. In this study, glass texturing was applied to the perovskite solar cell for improving the current density. Glass substrates (back-side glass of FTO coated glass substrate) were textured by randomly structure assisted wet etching process using diluted HF solution at a constant concentration of etchants (HF:H2O=1:1). Then, the light trapping properties of suitable films were controlled over a wide range by varying the etching time (1, 2, 3, 4 and 5 min.). The surface texturing changed the reflected light in an angle that it can be reflected by substrate glass surface. As a result, Current density and cell efficiency were affected by light trapping layer using glass texturing method in perovskite solar cells.

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Experimental Study for the Identification of the Nascent Product of OH Heterogeneous Reaction with NaCl using Chemical Ionization Mass Spectrometry

  • Park, Jong-Ho;Ivanov, Andrey V.;Molina, Mario J.
    • Mass Spectrometry Letters
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    • v.3 no.4
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    • pp.108-111
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    • 2012
  • An experimental study on the nascent product of the OH heterogeneous reaction with NaCl was performed under dry and wet conditions using a bead-filled flow tube system coupled to a high-pressure chemical ionization mass spectrometer. The ozone concentration in the flow tube for the atomic hydrogen removal was varied in order to control the conversion reaction of molecular chlorine into HCl for the identification of the nascent product. The mass spectrometric observation was that the $O_3$ introduction reduced the concentration HCl, while it increased the concentration of $Cl_2$ and ClO. Based on the experimental results, we suggest that the nascent product of the titled reaction is gaseous $Cl_2$, which is followed by fast conversion into HCl in presence of H. No significant difference in the concentration profile between under dry and wet (RH = 2%) conditions was observed.

Preparation of Low Density Water Glass Based Silica Gels by Conventional Drying

  • Einarsrud, Mari-Ann;Elin Nilsen
    • The Korean Journal of Ceramics
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    • v.6 no.1
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    • pp.37-42
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    • 2000
  • To reduce shrinkage and the possibility of fracture during ambient pressure drying, it is of great importance to increase the strength and stiffness of the wet gels. In this paper is presented the strengthening and stiffening of wet silica gels prepared from sodium silicate (water glass) as well as properties of the corresponding xerogels. By washing gels containing different initial silica contents in water solutions at elevated pH, a maximum in shear modulus of ~4 MPa was obtained. The maximum stiffness enabled xerogels with bulk density of 0.28g/$\textrm{cm}^3$ to be made regardless of silica content and washing conditions. However, by aging the wet gels in a solution providing fresh monomers to the gel network, a shear modulus of 20 MPa was obtained after 27h. By this method monolithic xerogels with a density down to ~0.2g/$\textrm{cm}^3$ was prepared. The results are compared to alkoxide based gels.

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