• 제목/요약/키워드: protective wall

검색결과 83건 처리시간 0.024초

Preparation and characterization of Melamine-Formaldehyde Resin Microcapsules Containing Fragrant Oil

  • Hwang, Jun-Seok;Kim, Jin-Nam;Wee, Young-Jung;Yun, Jong-Sun;Jang, Hong-Gi;Kim, Sun-Ho;Ryu, Hwa-Won
    • Biotechnology and Bioprocess Engineering:BBE
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    • 제11권4호
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    • pp.332-336
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    • 2006
  • In this study, melamine-formaldehyde microcapsules were prepared via in situ polymerization using peppermint oil as a core material, melamine-formaldehyde as the wall material, Tween 20 as the emulsifier, and poly (vinyl alcohol) as a protective colloid. The melamine-formaldehyde microcapsules prepared in this study were then evaluated with regard to their structures, thermal properties, particle size distributions, morphologies, and release behaviors.

전원설비에 의한 공간조건별 전위분포 사례 연구 (Case Studies for Potential Distribution due to Power Source by Environmental Condition)

  • 정진수;정종욱;김선구
    • 조명전기설비학회논문지
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    • 제25권1호
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    • pp.50-58
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    • 2011
  • In this paper, potential distribution analysis through the six kinds of case studies examined in the environmental conditions change within a limited space, by the power supply system installed. To interpret the potential distribution using electromagnetic field analysis program and the parameters were state of the ground, the outer wall of the configuration state and the presence of human potential distribution was simulated. Potential distribution analysis, the size of nominal voltage, depending on the impedance of human body to be determined on the impact of surprise decision, but if equipped with appropriate protective equipment can be protected from lightning have been confirmed.

제당 PIPING 결궤 원인분석 - 성암제 붕괴 중심으로 - (Cause Analysis of Dam Body piping Failure -Centering on the Example of Seungam Reservoir Failure-)

  • 이인형
    • 한국농공학회:학술대회논문집
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    • 한국농공학회 2001년도 학술발표회 발표논문집
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    • pp.344-350
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    • 2001
  • Piping is a phenomenon where seeping water progressively erodes or washes away soil particles, leaving large voids (Pipes led to the development of channels) in the soil. Piping failure caused by heave can be expected to occur on the downstream side of a hydraulic structure such as fill dams when the uplift forces of seepage exceed the downward forces due to the submerged weight of the soil. The way to prevent erosion and piping and to reduce damaging uplift pressures is to use a protective filter or to construct cutoff wall/imperious blanket. Therefore, all the hydraulic structures faced/with soil materials should be taken the safety against piping into consideration.

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다결정 3C-SiC 박막의 마그네트론 RIE 식각 특성

  • 온창민;정귀상
    • 한국반도체및디스플레이장비학회:학술대회논문집
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    • 한국반도체및디스플레이장비학회 2007년도 춘계학술대회
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    • pp.183-187
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    • 2007
  • The magnetron reactive ion etching (RIE) characteristics of polycrystalline (poly) 3C-SiC grown on $SiO_2$/Si substrate by APCVD were investigated. Poly 3C-SiC was etched by $CHF_3$ gas, which can form a polymer as a function of side wall protective layers, with additive $O_2$ and Ar gases. Especially, it was performed in magnetron RIE, which can etch SiC at lower ion energy than a commercial RIE system. Stable etching was achieved at 70 W and the poly 3C-SiC was undamaged. The etch rate could be controlled from $20\;{\AA}/min$ to $400\;{\AA}/min$ by the manipulation of gas flow rates, chamber pressure, RF power, and electrode gap. The best vertical structure was improved by the addition of 40 % $O_2$ and 16 % Ar with the $CHF_3$ reactive gas. Therefore, poly 3C-SiC etched by magnetron RIE can expect to be applied to M/NEMS applications.

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Cerebral Aneurysm and Aortic Coarctation in a 46, XY Female. Is it Causal or Coincidental?

  • Ju, Sun-Min;Yi, Hyeong-Joong;Ko, Yong;Kim, Kwang-Myung
    • Journal of Korean Neurosurgical Society
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    • 제37권2호
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    • pp.137-140
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    • 2005
  • Most vascular disorders tend to affect both the brain and heart, and among them, a clinical syndrome constituting cerebral aneurysm and aortic coarctation(AC) has been well recognized. Persistent hypertensive impact to the cerebral vasculature with developmental anomaly of the neural crest, precursor of ectomenchymal, would be closely associated with development of the cerebral aneurysm in AC. Gonadal steroid hormone, a guardian of the cardiovascular system, has been known for its protective effects on the vascular wall. Gonadal steroid hormone (androgen) insensitivity such as 46,XY female syndrome may increase the risk of hypertention and subsequent vascular anomalies. The authors report on a 46-year-old 46,XY female patient with AC who underwent surgical clipping of the ruptured cerebral aneurysm. Clinical implications and proposed pathogenetic mechanisms of aneurysm in this intersex syndrome are presented and discussed.

Factors Affecting the Characteristics of Melamine Resin Microcapsules Containing Fragrant Oils

  • Hwang, Jun-Seok;Kim, Jin-Nam;Wee, Young-Jung;Jang, Hong-Gi;Kim, Sun-Ho;Ryu, Hwa-Won
    • Biotechnology and Bioprocess Engineering:BBE
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    • 제11권5호
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    • pp.391-395
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    • 2006
  • Microcapsules containing fragrant oils as a core material were prepared by in situ polymerization, using melamine-formaldehyde prepolymer as the wall material. The several parameters, such as stirring times, stirring rates, emulsifier types, emulsifier concentrations, and the viscosity of the core materials, affect the characteristics of the microcapsules. These parameters were investigated by the analyses of microcapsule size, particle size distribution, and morphology. The average microcapsule size decreased with an increase in stirring time, stirring rate, emulsifier concentration, and viscosity of the core material. It was also found that poly(vinyl alcohol) as a protective colloid could enhance the stability of the melamine-formaldehyde microcapsules.

폴리이소부틸렌 및 밀폐제 처리가 메칠도파의 마이크로캅셀화에 미치는 영향 (Effect of Polyisobutylene and Sealant Treatments on Ethylcellulose-Walled Methyldopa Microcapsules)

  • 신상철;고익배
    • Journal of Pharmaceutical Investigation
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    • 제19권1호
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    • pp.29-37
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    • 1989
  • For the prevention of the aggregation during microencapsulation, the effects and role of polyisobutylene(PIB), as a protective colloid, were studied. The effects of sealant treatment on the microencapsulation were studied. Methyldopa was microencapsulated with ethylcellulose (EC) by polymer deposition from cyclohexane by temperature change using PIB. The EC-microencapsulated methyldopa was sealed with spermaceti. The dissolution of methyldopa was influenced by the drug to wall ratio. When PIB was used, low aggregation of microcapsules occurred and the surface was smooth with a few pores. Treatment of microcapsules with spermaceti retarded the release of methyldopa, the release being affected by the percentage of sealant used and the particle size of the product.

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Inhibitory effect of chitosan oligosaccharides on the growth of tumor cells

  • Kim, Se-Kwon;Nam, Mi-Young;Nam, Kyung-Soo
    • 한국어업기술학회:학술대회논문집
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    • 한국어업기술학회 2000년도 춘계수산관련학회 공동학술대회발표요지집
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    • pp.416-417
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    • 2000
  • Chitin, a poly $\beta$-(1longrightarrow14)-N-acetyl-D-glucosamine, is best known as a cell wall component of fungi and as a skeletal materials of invertebrates. Chitosan is derived from chitin by deacetylation in the presence of alkali. Chitosan has been developed as new physiological materials since it possesses antibacterial activity, hypocholesterolemic activity and antihypertensive action. However, the actions of chitosan in vivo still remain ambiguous as the physiological functional properties because most animal intestines, especially the human gastrointestinal tract, do not possess enzyme such as chitosanase which directly degrade the $\beta$-glucosidic linkage in chitosan, and consequently the unbroken polymers may be poorly absorbed into the human intestine. Therefore, recent studies as chitosan have attracted interest for chitosan oligosaccharides, because the oligosaccharides process not only water-soluble property but also versatile functional properties such as antitumor activity, immune-enhancing effects, enhancement of protective effects against infection with some pathogens in mice and antimicrobial activity (Kingsnorth et al., 1983, Mori et al., 1997). (omitted)

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경호기법에 의한 위급상황의 발견과 대처 방안에 관한 고찰 (The consideration about prevention ways of discovery of emergency situation which is based on guard techniques)

  • 공배완
    • 한국재난정보학회 논문집
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    • 제6권2호
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    • pp.11-20
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    • 2010
  • All of the people or objects which are contacted during the activity of guard are added to range of objects. guard has to notice decision, question proposal, observation, accomplish to be happened them at the same time recognizing the steps as soon as possible. Before a lot of information of client are shown, guard expert has to search observation of materialization, extension of reservation, notification of business and causes of danger through personal interviews. Rapid communication system has to be assumed and effective caution, protection and shelter and following prevention are cooperated as well as has to care about safe of guard object by a protective wall. And also has to get out of the ground, keep the large shape when moves, prevent the trials of attack from the assassinators after takeing control over weapons.

Analysis of luminous efficacy of a PDP cell using a hybrid simulation with an electron-fluid and ion-particle model

  • Lee, Hae-June;Shim, Seung-Bo;Song, In-Cheol;Lee, Ho-Jun;Park, Chung-Hoo
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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    • pp.24-27
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    • 2009
  • A hybrid model has been developed which adopts a fluid model for electrons and a particle-in-cell (PIC) model for ions. Using the hybrid simulation, the discharge characteristics are investigated with the diagnostics for the electric field and the wall charge profile, density distributions of charged and excited particles, distributions of ultraviolet lights on phosphor, and the visible lights emitted from the PDP cell. Also, energy and angle distributions of the ions at the MgO protective layer are obtained for the analysis of material effect. The comparison of hybrid simulation results with experimental results as well as that with the conventional fluid simulation shows that the new model is more adequate for the simulation of PDP cells.

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