• Title/Summary/Keyword: improving reaction

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Effects of pH of Reaction Solution on the Structural and Optical Properties of CdS Thin Films for Solar Cell Applications (태양전지용 CdS 박막의 구조적 및 광학적 특성에 미치는 반응용액의 pH 영향)

  • Lee, Jae-Hyeong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.8
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    • pp.616-621
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    • 2011
  • In this paper, CdS thin films, which were widely used window layer of the CdTe and the Cu(In,Ga)$Se_2$ thin film solar cell, were grown by chemical bath deposition, and effects of pH of reaction solution on the structural and optical properties were investigated. For pH<10.5, as the pH of reaction solution was higher, the deposition rate of CdS films was increased by improving ion-by-ion reaction in the substrate surface and the crystallinity of the films was improved. However, when the pH was higher than 10.5, the deposition rate was decreased because of smaller $Cd^{2+}$ ion concentration in the reaction solution. Also, the crystallinity of the films were deteriorated. The CdS films deposited at lower pH showed poor optical transmittance due to adsorbed colloidal particles, while the transmittance was improved for higher pH.

Comparison of difference in muscle activity ratio, ground reaction force and knee valgus angle during single leg squat and landing according to dynamic taping

  • Ha, Tae-Won;Park, Sam-Ho;Lee, Myung-Mo
    • Physical Therapy Rehabilitation Science
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    • v.9 no.4
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    • pp.281-286
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    • 2020
  • Objective: This study examined the effects of dynamic tape applied to the patellofemoral joint on the knee valgus angle, muscle activity, and ground reaction force during a single leg squat (SLS) and single leg landing (SLL). Design: Cross-sectional study. Methods: Twenty-four subjects (11 male, 13 female) who met the inclusion criteria were screened by the knee palpation and patella compression tests. First, the knee valgus angle and muscle activity during SLS were measured. Second, the knee valgus angle and ground reaction force during SLL were measured. For the intervention, a patella joint loop using dynamic tape was used. The knee valgus angle, muscle activities in SLS and SLL after the intervention, and the ground reaction force were measured in the same way. A paired t-test was used to examine the difference between before and after the intervention. Results: The knee valgus angle showed a statistically significant improvement after dynamic taping application in SLS and SLL (p<0.05). The differences in muscle activity of the VL/VMO and ground reaction forces were not statistically significant after dynamic taping application in SLS and SLL. Conclusions: This study showed that dynamic taping applied around the patellofemoral joint was effective in improving the knee valgus angle in SLS and SLL and had a reduced risk of secondary injury during sports activity.

Surface Modification Reaction of Photocatalytic Titanium Dioxide with Triethoxysilane for Improving Dispersibility

  • Lee, Myung-Jin;Kim, Ji-Ho;Park, Young-Tae
    • Bulletin of the Korean Chemical Society
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    • v.31 no.5
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    • pp.1275-1279
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    • 2010
  • We have carried out the surface modification of photocatalytic $TiO_2$ with triethoxysilane through dehydrogenation reaction and characterized the modified photocatalyst by spectroscopic methods, such as FT-IR, solid-state $^{29}Si$ MAS NMR, XPS, and XRF, etc. We also examined photocatalytic activity of the immobilized photocatalytic titanium dioxide with triethoxysilane by decolorization reaction of dyes such as cong red and methylene blue under visible light. Dispersion test showed that the photocatalytic titanium dioxide immobilized with triethoxysilane group has kept higher dispersibility than titanium dioxide itself. No appreciable precipitation takes place even after standing for 24 h in the 4:6 mixture ratio of ethanol and water.

Retention Efficiency and Flocculation Mechanism of Microparticle Systems Based on Colloidal Silica (콜로이달 실리카에 의한 마이크로 파티클 시스템의 보류 효과 및 응집 기구)

  • 김향수;이학래
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.34 no.4
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    • pp.7-15
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    • 2002
  • It is of critical importance to understand the characteristics of papermaking additives and their reaction mechanisms to fully utilize the benefits they provide. Among the papermaking additives, retention aids play critical roles in improving productivity, product quality and process economy. Diverse research efforts to understand the reaction mechanisms between cationic polymers and anionic microparticles have been made since microparticle retention systems were introduced into the market. And it is most commonly accepted that flocs formed by the addition of cationic polymers are dispersed by shear force and the broken flocs are reflocculated instantly with the addition of microparticles. There are still many unanswered questions, however, on the reaction phenomena between cationic polymers and anionic microparticles. In this study, several cationic polymers including waxy maize starch, com starch and guar gum were used to investigate their retention efficiency when they were used along with anionic colloidal silica.

An Application Case Study of Improving Performance of Small Hydro-power (소수력 성능향상 사례연구)

  • Kim, Sang-Gyun;Park, Ji-Kun;Lee, Yeon-Ju
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.165.1-165.1
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    • 2011
  • In this paper, it is intended to study about deferences of design and operation properties between large and small hydro-power house's turbine which type is reaction. In generally, turbine of large hydro-power has a more safe and effective energy output mechanisms than small hydro-power's because the turbine of small hydro-power is more sensitive to hydraulic losses. But, it is more effective for the all energy market to improve the capability and efficiency of small hydro-power in the present status of increasing construction of small hydro-power than large hydro-power. Therefore, we intend to investigate and introduce the way to enhance the efficiencies of reaction turbine adopted to small hydro-power.

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Effect of Garlic, Chili and Ginseng on the Thermal Gelation of Alaska Pollack Surimi

  • Takeuchi, Atsuyoshi;Lee, Nam-Hyouck;Cho, Young-Je;Konno, Kunihiko
    • Food Science and Biotechnology
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    • v.14 no.1
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    • pp.16-20
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    • 2005
  • Additions of ground garlic, chili and ginseng powder did not affect the breaking force and strain of directly heated gel of Alaska pollack surimi. In comparison, these additives reduced the setting effect achieved by incubation of the salted surimi at $25^{\circ}C$, and resulted in a decreased breaking force and strain for the two step heated gel. Garlic almost completely inhibited the myosin cross-linking reaction, an important reaction for improving the gel properties occurring in the setting process. However, chili and ginseng powder minimally inhibited the cross-linking reaction. Thus, this study proposes that the mechanism for the suppression of the setting effect by chili and ginseng is different from that of garlic.

Study for Improving Properties of Squid Viscera Oil Using Transesterification and Adsorption (에스테르 교환반응과 흡착제를 이용한 오징어 내장유의 품질 개선)

  • Roh, Myong-Kyun;Uddin, Salim;Chun, Byung-Soo
    • Journal of Marine Bioscience and Biotechnology
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    • v.2 no.4
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    • pp.257-262
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    • 2007
  • Squid viscera oil was investigated by pretreatment method for enhancing the commercial value. Transeterification was performed to reduce rancidity of the oil, off-flavor was removed by using activated carbon adsorption. Analysis using ATD (Automatic Thermal Desorber) and GC/MG shows the efficacy of off-flavor removement. The rates of Transesterification employing inorganic catalyst and biocatalyst were tested, respectively. With stepwise addition of ethanol, the most efficiency of the reaction was achieved by inorganic catalyst. The efficiency of the reaction was estimated by acid value corresponding to rancidity of reaction product.

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An Experimental Study on Alkali-Silica Reaction due to Neutron Shielding Concrete Containing Borosilicate Glass Powder (붕규산 유리 분말을 혼입한 차폐용 콘크리트의 알칼리 실리카 반응에 의한 팽창 실험)

  • Jang, Bo-Kil;Kim, Ji-Hyun;Chung, Chul-Woo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.05a
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    • pp.160-161
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    • 2015
  • Borosilicate glass can be used for improving neutron shielding of concrete. The well known expansion of borosilicate glass caused by expansion of mortar bar was can cause serious damage to the concrete. In this research, borosilicate glass was powdered to reduce the particle size similar to that of cement, and 20% cement replacement set was reduced expansion rate about 30%. But aggregate replacement set was damaged because of Alkali-Silica Reaction expansion.

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Development of Silica Based Microgels and Evaluation of Their Performance in Microparticle Retention System

  • Kim, Tae-Young;Lee, Hak-Lae
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.32 no.1
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    • pp.33-40
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    • 2000
  • The effectiveness of silica-based microgels prepared through the reaction of sulfuric acid and sodium silicate as a component of Compozil system has been evaluated . Silica based microgels with better performance in retention and drainage than a commercial colloidal silica sol have been successfully prepared. Silica gels with the highest charge density were obtained when product pH was controlled to 9. And highly charged silica-based microgels showed greater retention and freeness performance than a commerical product. In particular the difference in retention, turbidity , and freeness between these microgels and a commercial product was eminent at low addition rate. The effects of reaction conditions including reaction temperature, process water quality and feeing rate on product efficiency in improving retention and drainage were also investigated and discussed.

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Effect of Waste Glass Fine Aggregate on Mechanical Properites and Alkali-Silica Reaction(ASR), After ASR Residual Mechanical Properties of High Strength Mortar (폐유리 잔골재가 고강도 모르타르의 역학적 특성 및 알칼리-실리카 반응(ASR), ASR 후, 잔류 역학적 특성에 미치는 영향)

  • Eu, Ha-Min;Kim, Gyu-Yong;Son, Min-Jae;Sasui, Sasui;Lee, Yae-Chan;Nam, Jeong-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.11a
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    • pp.31-32
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    • 2020
  • This study measured the mechanical performance and residual strength of high strength/normal strength mortar mixed with waste glass fine aggregate after alkali-silica reaction and alkali-silica reaction. As a result, the effect of improving the slip phenomenon of the waste glass fine aggregate in the high-strength mortar was not significant, but rather the amount of ASR was increased.

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