• 제목/요약/키워드: microparticle

검색결과 128건 처리시간 0.03초

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

  • 정세훈;손창현
    • Journal of Advanced Marine Engineering and Technology
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    • 제24권3호
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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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양이온성 구아검과 콜로이달 실리카를 이용한 마이크로파티클 보류시스템의 탈수 및 전단안정성 (Drainage and Shear Stability of Microparticle Retention Systems Based on Cationic Guar Gums and Colloidal Silicas)

  • 함충현;이학래
    • 펄프종이기술
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    • 제40권2호
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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.

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

  • 황현두;이도현;박제균
    • 센서학회지
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    • 제18권2호
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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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    • 제27권1호
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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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    • 제10권4호
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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.

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

  • 정철헌;이진호;길정하;박종문
    • 펄프종이기술
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    • 제44권4호
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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.

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

  • 김재화;송은영;이희구;최용경;최명자;김용호;최인성;정태화
    • 대한의생명과학회지
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    • 제2권1호
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    • pp.41-48
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    • 1996
  • 환자의 복수와 늑막액으로부터 p-diazonium phenylphosphorylcholine(DPPC) coupled Separose-4B affinity chromatography와 hydroxylapatite chromatography를 실시하여 C-reactive protein (CRP)를 분리, 정제하였다. 정제된 CRP를 토끼에게 면역화하여 항혈청을 얻고 affinity chromatography를 하여 면역항체(IgG)를 분리하였다. 분리된 면역항체를 미립자에 감작시킨 후 미립자 응집반응에 의하여 3분내에 CRP를 측정할 수 있는 간이 면역 측정법을 개발하였다. 본 연구에서 개발된 CRP측정법의 검출범위는 0.5~20mg/㎗이며, 임상 시험 결과 0.7~2.9mg/㎗에서는 강한 응집 반응을, 5.O~l3.2mg/㎗에서는 약한 응집반응을 보였고 28mg/dl이상에서는 항원 과잉으로 인한(zone of Ag excess phenomenon) 위음성을 나타냈다. 74명의 환자 혈청을 대상으로 CRP의 농도를 조사한 결과 평균치는 3.8mg/dl이었으며 대부분의 환자에서는 10mg/dl 이하의 농도로 존재하였다. 그러므로 1차 판정시 음성을 나타낸 시료라도 혈청을 5~10배정도 희석하여 재분석한다면 오차없이 CRP 를 검출할 수 있었다. 환자 혈청을 검체로 하여 본 연구에서 개발한 면역측정법과 현재 수입 시판 중인 프랑스의 B사 제품과 일본의 I사 제품을 비교한 결과 좋은 상관관계를 보였다. 이와 같은 평가 분석을 통하여 볼 때 본 연구에서 개발한 간이 면역 측정법은 사용이 비교적 간편하며 신빙성이 있어 CRP를 스크리닝하는데 효과적임을 알 수 있었다.

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