• Title/Summary/Keyword: liquid additive

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Effect of acid or base additive in the mobile phase on enantiomer separation of amino alcohols using polysaccharide derived chiral columns (다당유도체를 기초로 한 키랄 컬럼에서 이동상에서의 산 또는 염기 첨가제가 아미노 알코올의 광학분리에 미치는 영향)

  • Huang, Hu;Jin, Jing Yu;Lee, Wonjae
    • Analytical Science and Technology
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    • v.22 no.4
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    • pp.313-318
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    • 2009
  • Liquid chromatographic enantiomer separation of amino alcohols was performed on several chiral columns based on polysaccharide derivatives under the mobile phase conditions containing acid or base additive. The chromatographic parameters were greatly influenced by the nature of the mobile phase containing acid or base additive as well as the used chiral columns. Compared to chromatographic results obtained in the mobile phase containing base additive (0.1% triethylamine), especially, Chiralcel OD showed dramatically enhanced separation factors and resolution factors with reduced capacity factors under the mobile phase condition containing acidic additive (0.1% trifluoroacetic acid). When the mobile phase containing 0.05% trifluoroacetic acid and 0.05% triethylamine was used on Chiralcel OD, the greatest separation factors and resolution factors among all other mobile phase conditions in this study were observed.

Fabrication and Strength Properties of LPS-SiC based materials

  • Lee, Sang-Pill;Kohyama, Akira
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2006.11a
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    • pp.25-28
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    • 2006
  • This paper dealt with the LPS process for the development of high performance SiC materials, based on the detailed analysis of their microstructure and mechanical properties. The submicron SiC powder was used for the fabrication of LPS-SiC materials. A mixture of $Al_2O_3$ and $Y_2O_3$ particles was also used as a sintering additive in the LPS process. LPS-SiC materials were fabricated at different temperatures, using various additive composition ratio ($Al_2O_3/Y_2O_3$). The total amount of additive materials ($Al_2O_3+Y_2O_3$) was fixed as 10 wt%. The characterization Of LPS-SiC materials was investigated by means of SEM, XRD and three point bending test. The LPS-SiC material represented a relative density of about 98 % and a flexural strength of about 800MPa, when it was fabricated at the temperature of $1820^{\circ}C$ and the additive compositional ratio of 1.5.

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Effect of Dampening Component on Printed Quality of Textbook in lithography printing (평판인쇄의 축임물 조성이 교과서 인쇄품질에 미치는 영향)

  • Koo, Chul-Whoi;Sim, Woo-Seok;Ha, Young Baeck
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.48 no.1
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    • pp.134-141
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    • 2016
  • Dampening in printing is not only used with plain water but also used with various substances like dampening additive, in order to improve the wetting property by lowering the surface tension and to control material for modifing the ink transfer characteristic with proper emulsification. We have studied the printing quality according to these, looking into interrelationship among the dampening solution's pH, electrical conductivity and IPA content, prescribing the proper usage and minimum usage of fountain solution and dampening additive. In this study, it shows good result when mixing at the 7 wt% dampening with additive solution, which is result from the color density of printed sheets in accordance with the change of dampening solution condition. And the printed density value calculated 1 hour after printing, it shows relatively safe value at the etch liquid 4 wt% and IPA addition 2 wt%. The dry down at this test showed similar results regardless of various dampening conditions on coated paper, but in case of uncoated paper, the dry down showed a quite gap of different due to the fast penetration to the paper.

Effect of Mobile Phase Additive on Enantiomer Resolution for Chiral Amines on Polysaccharide-derived Chiral Stationary Phases by High Performance Liquid Chromatography (고성능 액체크로마토그래피의 다당유도체를 기초로 한 키랄 고정상에서 이동상 첨가제가 키랄 아민의 광학분리에 미치는 영향)

  • Paik, Man-Jeong;Yoon, Hye-Ran;Lee, Wonjae
    • KSBB Journal
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    • v.29 no.3
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    • pp.205-209
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    • 2014
  • Chromatographic enantiomer resolution of chiral amines was performed on several covalently immobilized and coated chiral stationary phases (CSPs) based on polysaccharide derivatives under the mobile phase conditions containing base or acid or acid/base additive. The chromatographic parameters including separation factors and capacity factors were greatly influenced by the nature of the mobile phase containing base or acid or salt additive as well as the used CSPs. When 0.05% triethylamine/0.05% trifluoroacetic acid as an additive in the mobile phase was used on all CSPs in this study, the greatest enantiomer resolution was observed except for Chiralpak AD. Also, it was shown that the change of base additive into acid or salt in the mobile phase may directly affect chiral recognition mechanisms between the chiral selectors and analytes occurring during enantiomer separation, resulting in the change of elution orders.

Ceramic Stereolithography: Additive Manufacturing for 3D Complex Ceramic Structures

  • Bae, Chang-Jun;Ramachandran, Arathi;Chung, Kyeongwoon;Park, Sujin
    • Journal of the Korean Ceramic Society
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    • v.54 no.6
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    • pp.470-477
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    • 2017
  • Ceramic processing to fabricate 3D complex ceramic structures is crucial for structural, energy, environmental, and biomedical applications. A unique process is ceramic stereolithography, which builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This approach directly writes layers in liquid ceramic suspension and allows one to fabricate ceramic parts and products having more accurate, complex geometries and smooth surfaces. In this paper, both UV curable materials and processes are presented. We focus on the basic material principles associated with free radical polymerization and rheological behavior, cure depth and broadening of cured lines, scattering at ceramic interface and their corresponding simulation. The immediate potentials for ceramic AM to change industry fabrication are also highlighted.

Effect of Co additive on the Abnormal Grain Growth of WC (Co첨가에 의한 WC의 비정상입성장)

  • 이동범;채기웅
    • Journal of the Korean Ceramic Society
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    • v.41 no.2
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    • pp.131-135
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    • 2004
  • The effect of Co additive on the microstructural evolusion of WC was investigated. A small amount of Co powder was placed on the top-center of the pure WC powder compact and then sintered at 1950$^{\circ}C$. During sintering some abnormally large WC grains of different size and shape observed depending on the distance from the liquid source. However, in the region far away from Co liquid source, it showed low densification and the grains of WC were very small and uniform in size. A small amount of Co liquid phase has a remarkable influence on the AGG of WC and it has been explained in terms of 2-D nucleation and growth mechanism.

A Study on the Supercooling Improvement of TMA -Clathrate Compound by Ethanol (에탄올에 의한 TMA- 포접화합물의 과냉각 개선에 대한 연구)

  • Kim, Jin-Heung;Chung, Nak-Kyu;Kim, Chang-Oh
    • Proceedings of the SAREK Conference
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    • 2005.11a
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    • pp.392-397
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    • 2005
  • This study is investigated the supercooling improvement and the phase change temperature of the TMA clathrate compound including TMA(Tri-Methyl-Amine, ($(CH_3)_3N$) of 25 wt% with additive as a low temperature storage material at $6^{\circ}C$ and $-7^{\circ}C$ of heat source. The additive is ethanol of 0.1, 0.3 wt% and 0.5 wt%. The results showed that as the concentration of ethanol is increased, the phase change temperature, the degree of supercooling and the retention time of liquid phase are decreased. Especially, TMA 25 wt% clathrate compound with ethanol of 0.5wt% has the average of phase change temperature of $3.8^{\circ}C$, degree of supercooling of $0.9^{\circ}C$, $0.8^{\circ}C$ and retention time of liquid phase for 6, 5 minutes at $-6^{\circ}C$, $-7^{\circ}C$ of heat source. From the results of this study, TMA 25wt% clathrate compound with ethanol 0.5wt% showed supercooling repression effect.

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Sintering of Alumina in the Presence of Oxynitride Additives (Oxynitride의 첨가에 의한 알루미나의 소결)

  • Bae, Won-Tae;Kim, Hae-Du
    • 연구논문집
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    • s.30
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    • pp.111-119
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    • 2000
  • Sintering of alumina powder was studied in the presence of Y-Si oxide and oxynitride additives. The main crystalline phase of the sintering aids pre-reacted at $1400^{\circ}C$ was $\alpha$ - $Y_2$$SiO_2$>$O_7$. Y-N apatite was co-existed in the Si-40N sintering aid because of its high content of N. During the sintering process, liquid phases were formed by the reaction between additives and alumina, and these liquid phases promote the densification of alumina. SEM micrographs showed that uniform grain growth occurred in the system with oxide additive(Si-0N). In the case of oxynitride additive system(Si-20N and Si-40N), bimodal microstructure was observed due to the exaggerated grain growth, As the nitrogen content in the additive system increased the exaggerated grain growth occurred extensively. Bloating, which seemed to be originated by the liberation of $N_2$ gas, occurred un the Si-40N oxynitride additive system.

Evaporation Characteristics of a Water Droplet Containing Sodium Acetate Trihydrate as an Additive (첨가제로 아세트산 나트륨-3수화물을 함유한 물 액적의 증발 특성)

  • Park, Jae-Man;Shin, Chang-Sub
    • Journal of the Korean Society of Safety
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    • v.19 no.2
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    • pp.61-68
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    • 2004
  • The evaporation phenomena of waterr droplet which has sodium acetate trihydrate($CH_3COONa{\cdot}3H_2O$) as a fire suppression additive were studied. Solutions of sodium salt up to 50% and heated stainless-steel surface were used in the experiment. The evaporation process was recorded using a charge-coupled-device camera at 120 frames per second. The average evaporation rate of the sodium acetate trihydrate soluation was lower than that of pure water at a given surface temperature and decreased with the concentration increase due to the precipitation of salt in the liquid film and change of surface tension. The variation of liquied film diameter was measured by time and it was increased by the hot surface temperature increase.