• Title/Summary/Keyword: Microparticle

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Numerical Study about Heat Transfer Enhancement of Water-Microparticles Suspension (물-미립자 현탁액의 난류 열전달 향상에 관한 수치해석적 연구)

  • 정세훈;손창현
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.3
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    • pp.29-35
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    • 2000
  • The present numerical study investigates heat transfer enhancement mechanism for suspensions of polystyrene particles in water. Numerical simulations were done for turbulent hydrodynamic fully developed flows in a circular duct with constant wall heat flux. The experimental result of microparticle suspensions show 25∼45% heat transfer enhancement over those of water. The present numerical results show the main parameter for the heat transfer enhancement of microparticle suspension in a circular duct is the change of velocity profile by the non-Newtonian fluid behavior.

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Drainage and Shear Stability of Microparticle Retention Systems Based on Cationic Guar Gums and Colloidal Silicas (양이온성 구아검과 콜로이달 실리카를 이용한 마이크로파티클 보류시스템의 탈수 및 전단안정성)

  • Ham, Choong-Hyun;Lee, Hak-Lae
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.40 no.2
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    • pp.1-7
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    • 2008
  • The trend of using more hardwood and recycled fibers, and closing more tightly of the paper mill white water system has resulted in build-up of fines as well as organic and inorganic contaminants in the white water. This changes in papermaking wet end requires developing chemical additive system that provides good fiber retention and drainage in closed white water system. In this study the effect of charge densities and chemical characteristics of microparticle systems consisted of cationic guar gums and anionic colloidal silica sols on drainage and retention have been examined. Results showed that higher charge density of cationic guar gum and anionic colloidal silica sol gave better retention and drainage. Particularly highly structured silica gave greater retention efficiency.

Fabrication of channel-integrated optoelectrofluidic device using stamp-to-stick bonding and microtransfer methods (Stamp-to-Stick Bonding 및 Microtransfer Molding 방법을 이용한 미세유체 채널이 집적된 광전기유체소자의 제작)

  • Hwang, Hyun-Goo;Lee, Do-Hyun;Park, Je-Kyun
    • Journal of Sensor Science and Technology
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    • v.18 no.2
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    • pp.154-159
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    • 2009
  • This paper describes two methods - stamp-to-stick bonding and microtransfer molding - to integrate microfluidic channel into an optoelectrofluidic device for in-channel microparticle manipulation. We have demonstrated the optoelectronic microparticle manipulation in the channel-integrated optoelectrofluidic device using a liquid crystal display. As injecting a liquid sample containing $15{\mu}m$-diameter polystyrene particles into the fabricated channel, trapping and transport of individual microparticles have been successfully demonstrated. This channel-integrated optoelectrofluidic device may be useful for several in-channel applications based on the optoelectrofluidics such as optoelectronic flow control, droplet-based protein assay and bead-based immunoassay.

Control of Encapsulation Efficiency and Initial Burst in Polymeric Microparticle Systems

  • Yeo, Yeon;Park, Ki-Nam
    • Archives of Pharmacal Research
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    • v.27 no.1
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    • pp.1-12
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    • 2004
  • Initial burst is one of the major challenges in protein-encapsulated microparticle systems. Since protein release during the initial stage depends mostly on the diffusional escape of the protein, major approaches to prevent the initial burst have focused on efficient encapsulation of the protein within the microparticles. For this reason, control of encapsulation efficiency and the extent of initial burst are based on common formulation parameters. The present article provides a literature review of the formulation parameters that are known to influence the two properties in the emulsion-solvent evaporation/extraction method. Physical and chemical properties of encapsulating polymers, solvent systems, polymer-drug interactions, and properties of the continuous phase are some of the influential variables. Most parameters affect encapsulation efficiency and initial burst by modifying solidification rate of the dispersed phase. In order to prevent many unfavorable events such as pore formation, drug loss, and drug migration that occur while the dispersed phase is in the semi-solid state, it is important to understand and optimize these variables.

Use of 1,064-nm Q-switched Neodymium:Yttrium-aluminum-garnet Laser Therapy Assisted with Diamond Particle Suspension and Gold Microparticle Application for Acne Vulgaris and Enlarged Facial Pores

  • Park, Hee Ung;Cho, Hangrae;Lee, Sang Ju;Cho, Han Kyoung
    • Medical Lasers
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    • v.10 no.4
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    • pp.242-245
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    • 2021
  • Acne vulgaris is a common inflammatory skin disease of the pilose-baceous unit. It appears as lesions consisting of comedones, papules, pustules, and nodules of varying shapes and severity. In general, the first-line treatment for acne vulgaris includes topical and oral medication. Recently, various physical modalities have also been investigated. The use of laser therapy is steadily increasing because of its fewer side effects, short procedure time, and rapid results. In particular, laser therapy assisted with carbon suspension application is effective for acne vulgaris but may sometimes result in discomfort due to odor and dust formation during the procedure. Herein, we report that acne vulgaris and enlarged facial pores can be safely and effectively treated with laser therapy assisted with diamond particle suspension and gold microparticle application, which can address the discomfort caused by the carbon suspension application.

Application of PEO/Cofactor System on Papermaking Process for Recycled Fibers (재생 지료 공정에서의 PEO/cofactor 보류 시스템의 적용)

  • Jung, Chul-Hun;Lee, Jin-Ho;Kil, Jung-Ha;Park, Jong-Moon
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.44 no.4
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    • pp.25-31
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    • 2012
  • Ionic trash in furnish decreases retention and drainage performance of the microparticle retention system using recycled fibers in closed papermaking system. Two retention systems, such as the microparticle system and the PEO/cofactor system, were compared and analyzed to improve retention. The PEO/cofactor system achieved similar retention performance at low addition level as the microparticle system. Optimum ratio of PEO/cofactor dual polymer system was 1:10. Ash retention was increased when using the fixing agent. As the TMP ratio increased, the PEO/cofactor system was more efficient in retention and drainage than the other system. The high molecular weight and non-ionic polymer retention system had less effect on flocculation hindrance than the traditional electrostatic retention system.

Microparticle-based Immunonassay for the Detection of C-reactive Protein in Serum (미립자 응집반응을 이용한 C-reactive Protein의 면역 측정 법에 관한 연구)

  • 김재화;송은영;이희구;최용경;최명자;김용호;최인성;정태화
    • Biomedical Science Letters
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    • v.2 no.1
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    • pp.41-48
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    • 1996
  • The C-reactive protein(CRP) from ascitic and pleural fluid was purified using calcium dependent affinity chromatography of CNBr activated Sepharose-4B covalently coupled to p-diazonium phenylphosphorylcholine(DPPC) and hydroxylapitite chromatography. Polyclonal antibody was prepared from rabbit by immunizing the purified CRP. Specific immunoglobulin G was isolated using affinity chromatography and coupled to microparticles. A sensitive microparticle-based immunoassay was developed to measure CRP within 3 mins. The detection range was between 0.5mg/dl) and 20mg/dl in serum, showing strong response in the range of 0.7~2.9 mg/dl, weak response in 5.0~13.2 mg/dl and zone phenomenon over 28mg/dl. The average value of CRP in 74 samples was 3.8mg/dl and most of the values were lower than 10mg/dl .The CRP values of serum samples were determined by our microparticle-based immunoassay, and were compared with those obtained using the other commercial products(B Co., France and I Co., Japan). Good correlations were shown between the values obtained by our developed microparticle-based immunoassay system and those by other commercial products. All performance characteristics evaluated make our developed microparticles-based immunoassay suitable for a simple, rapid, and reliable screening of CRP in serum.

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