• Title/Summary/Keyword: 소진조건

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The current status and future tasks of the prosthodontics curriculum in Korean dental schools and graduate dental schools (치과대학 및 치과전문 대학원의 보철학 교과과정 실태 조사 및 개선 방향에 대한 고찰)

  • Kim, Jee-Hwan;Lee, Sojin;Park, Young-Bum;Chung, Moon-Kyu
    • The Journal of Korean Academy of Prosthodontics
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    • v.51 no.2
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    • pp.90-98
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    • 2013
  • Purpose: Prosthodontics education of Korean dental schools is developing under liberal regulation according to the character of each school. Diversity in the current environment and condition for each school make it impossible to apply the same and uniform education curriculum. Therefore the purpose of this paper is to analyze and validate the status of the 2012 prosthodontics education curriculum in Korean dental schools, and to suggest future direction. Materials and methods: A survey was completed by all the 11 dental schools in South Korea. Results: The number of students, age, sex, credits for prosthodontics lecture and practice courses, evaluation method before senior students' clinical practice, modalities for minimum requirement for graduation, beginning and finishing timing of clinical practice and faculty personnel involved in the education varied among the dental schools. Conclusion: High-quality educators leading an expanded teaching personnel are required, education hours must be increased and efficient curriculum must be organized to improve the prosthodontics education.

The Removal of NOx by Mediated Electrochemical Oxidation Using Ag(II) As a Mediator (Ag(II)를 매개체로 사용하는 전기화학적 매개산화에 의한 NOx 제거)

  • Lee, Min-Woo;Park, So-Jin;Lee, Kune-Woo;Choi, Wang-Kyu
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.9 no.3
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    • pp.121-129
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    • 2011
  • The effects of the applied current density, the $AgNO_3$ concentration, the scrubbing liquid flow rate and the NO-air mixed gas flow rate on the NO removal efficiency were investigated by using $Ag^{2+}$ mediated electrochemical oxidation (MEO). Results showed that the NO removal efficiency increased with increasing the applied current density. The effect of the $AgNO_3$ concentration on the NO removal efficiency was negligibly small in the concentration of $AgNO_3$ above 0.1 M. When the scrubbing liquid flow rate increased, the NO removal efficiency was gradually increased. On the other hands, the NO removal efficiency decreased with increasing the NO-air mixed gas flow rate. As a result of the treatment of NO-air mixed gas by using the MEO process with the optimum operating condition and the chemical absorption process using 3 M $HNO_3$ solution as a scrubbing liquid, the removal efficiency of NO and $NO_x$ was achieved as 95% and 63%, respectively.

Production of fermented Omija (Schizandra chinensis) beverage fortified with high content of gamma-amino butyric acid using Lactobacillus plantarum (오미자(Schizandra chinensis) 열매 추출물의 Lactobacillus plantarum 젖산발효를 통한 고농도 GABA 함유 발효음료 제조)

  • Lee, Hyo-Seon;Kwon, Soon-Young;Lee, Syng-Ook;Lee, Sam-Pin
    • Food Science and Preservation
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    • v.23 no.3
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    • pp.326-334
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    • 2016
  • Omija (Schizandra chinensis) extract (OE) was fermented by using Lactobacillus plantarum EJ2014 to produce a beverage fortified with gamma-aminobutyric acid (GABA). After 2 days of fermentation in the presence of 2% monosodium glutamate (MSG) and 0.5% yeast extract (YE), the four-fold-diluted OE showed a higher viable cell count ($2.2{\times}10^9CFU/mL$) and lower acidity (1.2%) than that of the unfermented OE. In particular, addition of MSG as a precursor resulted in a small increase in the initial pH. MSG (2%) was completely converted to GABA (0.92%) during lactic acid bacteria fermentation for 3 days. Furthermore, the acidity of the fermented OE decreased from 1.74% to 0.56%. In addition, the original red color of the OE disappeared during LAB fermentation. However, when the fermented OE was mixed with 50% of the original OE, the original red color was recovered, with 19.56 and 13.92 for Hunter L and a values, respectively. The mixture of 50% original OE and 50% fermented OE showed the highest sensory score including the highest overall preference. In conclusion, the OE fortified with GABA and probiotics was produced by fermentation with a static culture, L. plantarum EJ2014.

A Study on The Effect of Current Density on Copper Plating for PCB through Electrochemical Experiments and Calculations (전기화학적 해석을 통한 PCB용 구리도금에 대한 전류밀도의 영향성 연구)

  • Kim, Seong-Jin;Shin, Han-Kyun;Park, Hyun;Lee, Hyo-Jong
    • Journal of the Microelectronics and Packaging Society
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    • v.29 no.1
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    • pp.49-54
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    • 2022
  • The copper plating process used to fabricate the submicron damascene pattern of Cu wiring for Si wafer was applied to the plating of a PCB pattern of several tens of microns in size using the same organic additives and current density conditions. In this case, the non-uniformity of the plating thickness inside the pattern was observed. In order to quantitatively analyze the cause, a numerical calculation considering the solution flow and electric field was carried out. The calculation confirmed that the depletion of Cu2+ ions in the solution occurred relatively earlier at the bottom corner than the upper part of the pattern due to the plating of the sidewall and the bottom at the corner of the pattern bottom. The diffusion coefficient of Cu2+ ions is 2.65 10-10 m2/s, which means that Cu2+ ions move at 16.3 ㎛ per second on average. In the cases of small damascene patterns, the velocity of Cu2+ ions is high enough to supply sufficient ions to the inside of the patterns, while sufficient time is required to replenish the exhausted copper ions in the case of a PCB pattern having a size of several tens of microns. Therefore, it is found that the thickness uniformity can be improved by reducing the current density to supply sufficient copper ions to the target area.

Effect of Cosurfactant on Microemulsion Formation and Cleaning Efficiency in Systems Containing Alkyl Ethoxylates Nonionic Surfactant, D-Limonene and Water (보조계면활성제 첨가가 Alkyl Ethoxylates계 비이온 계면활성제, D-limonene, 물로 이루어진 시스템에서의 마이크로에멀젼 형성 및 세정력에 미치는 효과)

  • Lee, Jong Gi;Bae, Sang Soo;Cho, In Sik;Park, So Jin;Park, Byeong Deog;Park, Sang Kwon;Lim, Jong Choo
    • Applied Chemistry for Engineering
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    • v.16 no.5
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    • pp.664-671
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    • 2005
  • In this study, the effect of sosurfactant on microemulsion phase behavior was investigated in ternary systems containing alkyl ethoxylates nonionic surfactant, water and d-limonene. The addition of a cosurfactant produced a microemulsion phase over a wide range of temperature and promoted formation of a microemulsion phase at lower temperatures. In particular, small amounts of n-propanol, as a cosurfactant, were found to be the most effective in extending a microemulsion phase region over a wide range of temperature. Temperature sensitivity of a nonionic surfactant system was effectively relieved by addition of the anionic surfactant sodium dodecyl sulfate. And the formation of one phase microemulsion was not affected by pH, hardness concentration and addition of an antioxidation agent. The cleaner candidates were determined from microemulsion phase behavior study, and their cleaning efficiency was tested using a dipping method. All the cleaner candidates selected during this study showed excellent removal efficiency for abietic acid over a temperature range from 30 to $40^{\circ}C$ presumably due to a decrease in interfacial tension.

Effect of Solvents on Phase Behavior and Flux Removal Efficiency in Alkyl Ethoxylates Nonionic Surfactant Based Cleaners (Alkyl Ethoxylates계 비이온 계면활성제를 주체로 한 세정제에서 용제에 따른 상거동과 플럭스 제거 효능)

  • Lee, Jong-Gi;Bae, Sang-Soo;Cho, In-Sik;Park, So-Jin;Park, Byeong-Deog;Park, Sang-Kwon;Lim, Jong-Choo
    • Applied Chemistry for Engineering
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    • v.16 no.5
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    • pp.677-683
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    • 2005
  • In this work, the effect of additives such as solvent, sodium dodecyl sulfate and NaCl on microemulsion phase behavior and flux removal efficiency in systems containing commercial alkyl ethoxylates nonionic surfactant was investigated. The addition of a n-hydrocarbon as a solvent produced on O/W (Oil/Water) microemulsion phase over a wider range of temperature and cosurfactant to surfactant ratios. Especially, the addition of n-hexadecane to the surfactant system, which was the most hydrophobic solvent among the solvents used in this study, produced a microemulsion phase over a wide range of temperatures and promoted formation of a microemulsion phase at lower temperatures. The candidate for cleaner samples, prepared from phase behavior experiments, showed excellent removal efficiency for abietic acid at $40^{\circ}C$. These data suggested the potential applicability of hydrocarbons to actual cleaner formulations.

A Study on the CO2 Removal Efficiency with Aqueous MEA and Blended Solutions in a Vortex Tube Type Absorber (Vortex Tube 형 흡수장치에서 MEA와 혼합흡수용액을 이용한 CO2 제거 효율 고찰)

  • Ryu, Woo-Jung;Han, Keun-Hee;Choi, Won-Kil;Lee, Jong-Sub;Park, So-Jin
    • Korean Chemical Engineering Research
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    • v.47 no.6
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    • pp.795-800
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    • 2009
  • In this study, the $CO_2$ removal characteristics of the Vortex tube type absorbtion apparatus were investigated to enhance the compactness of $CO_2$ absorption process and to reduce the amount of absorbing solution of the $CO_2$ separation process. The Vortex tube with the diameter of 17 mm and the length of 250mm was introduced in the experimental apparatus to treat $20Nm^3/hr$ of $CO_2$ containing flue gas. The flue gases for experiments containing 11~13 vol% of $CO_2$ were supplied from the coal-firing CFBC power plant with 12 ton/hr of steam producing capacity. The mixed solutions of 20 wt% of MEA as base solution with the adding solutions like HMDA, AMP and KOH were used as absorbents. The experiments were executed under the various conditions like the absorbing solution concentrations in the range of 20 to 50 wt%, the flow rate of $CO_2$ containing flue gases in the range of 6 to $15Nm^3/hr$ and the flow rate of absorbing solution in the range of 1.0 to 3.0 l/min. As a results, the $CO_2$ removal efficiency of mixed absorbent of 20 wt% of MEA with HMDA was remarkable. From this study, we concluded that the efficient separation of $CO_2$ from flue gases using the features of the Vortex tube type absorbing unit for gas/liquid contact and the separation of gas/liquid be possible. But more works are needed to increase the $CO_2$ removal efficiency of Vortex tube process.

Experimental Design of AODV Routing Protocol with Maximum Life Time (최대 수명을 갖는 AODV 라우팅 프로토콜 실험 설계)

  • Kim, Yong-Gil;Moon, Kyung-Il
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.17 no.3
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    • pp.29-45
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    • 2017
  • Ad hoc sensor network is characterized by decentralized structure and ad hoc deployment. Sensor networks have all basic features of ad hoc network except different degrees such as lower mobility and more stringent energy requirements. Existing protocols provide different tradeoffs among some desirable characteristics such as fault tolerance, distributed computation, robustness, scalability and reliability. wireless protocols suggested so far are very limited, generally focusing on communication to a single base station or on aggregating sensor data. The main reason having such restrictions is due to maximum lifetime to maintain network activities. The network lifetime is an important design metric in ad hoc networks. Since every node does a router role, it is not possible for other nodes to communicate with each other if some nodes do not work due to energy lack. In this paper, we suggest an experimental ad-hoc on-demand distance vector routing protocol to optimize the communication of energy of the network nodes.The load distribution avoids the choice of exhausted nodes at the route selection phase, thus balances the use of energy among nodes and maximizing the network lifetime. In transmission control phase, there is a balance between the choice of a high transmission power that lead to increase in the range of signal transmission thus reducing the number of hops and lower power levels that reduces the interference on the expense of network connectivity.

Induction of antioxygenic enzymes as defense systems in plant cells against low temperature stress : (I) Accumulation of pyruvate in cells during cold treatment and activation of antioxygenic enzymes during post-chilling period (식물의 냉해에 대한 생체방어기구로서 항산소성 효소의 유도 : (1) 저온처리중 pyruvate의 세포내 축적과 상온환원후 항산소성 효소의 활성화)

  • Kim, Jong-Pyung;Hahn, Chang-Kyun;Jung, Jin
    • Applied Biological Chemistry
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    • v.34 no.2
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    • pp.162-167
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    • 1991
  • In an attempt to explore the mechanistic aspects of chilling injury in plants and their defensive measures against the low temperature stress, the time sequential measurements of pyruvate, superoxide radicals$(O_{\overline{2}})$ and antioxygenic enzymes during whole period of injury-inducing treatment were performed using mostly rice seedlings. Pyruvate was substantialy accumulated in leaf tissues during the exposure period to $5^{\circ}C$ of the seedlings ; the relative extent of the accumulation was increased with increasing time of the cold treatment. When the cold-treated plants were translocated to ambient temperature$({\sim}25^{\circ}C)$, the accumulation started to dissipate, concomitantly accompaning a remarkable increase in the $O_{\overline{2}}$ level of tissues. Superoxide dismutase(SOD) and catalase were also activated during post-chilling period, although they showed a considerable lag time for activation. In contrast, glutathione peroxidase, another antioxygenic enzyme in cells, was not activated at all by preceding cold treatment of plants. The uptake of exogenous $O_{\overline{2}}$ by the roots of rice seedlings resulted in increase in the activities of SOD and catalase in root tissues. The supply of $H_2O_2$ to plan st brought about the activation of catalase in situ, while failing to exert any effect on the activation state of glutathione peroxidase. The results obtained in this work suggest that pyruvate accumulation in cells is the direct cause of the overproduction of $O_{\overline{2}}$ and thereby other toxic activated oxygen species, and that SOD and catalase may play a crucial role in the protection of plant cells against active oxygen-mediated chilling injury.

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Study of CO2 Absorption Characteristic and Synthesis of 1-(2-methoxyethyl)-3-methylimidazoLium Methanesulfonate Ionic Liquid (1-(2-methoxyethyl)-3-methylimidazolium Methanesulfonate 이온성 액체 합성 및 CO2 흡수 특성 연구)

  • Jin, Yu Ran;Jung, Yoon Ho;Park, So Jin;Baek, Il Hyun
    • Korean Chemical Engineering Research
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    • v.50 no.1
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    • pp.35-40
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    • 2012
  • In this study, 1-(2-methoxyethyl)-3-methylimidazolium methanesulfonate ionic liquid has been synthesized, characterized and tested with respect to carbon dioxide absorption with the aim to use it as advanced absorbent materials in fossil fuel processing. The ionic liquid was synthesized by a one step method, low cost. The thermal and chemical stability of selected ionic liquid has been investigated by DSC, TGA and the structure was verified by $^1H$-NMR spectroscopy. The solubility of carbon dioxide in the methanesulfonate-based ionic liquids were measured using a high-pressure equilibrium apparatus equipped with a variable-volume view cell at 30, 50 and $70^{\circ}C$ and pressure up to 195 bar. The results show that carbon dioxide solubilities of 1-(2-methoxyethyl)-3-methylimidazolium methanesulfonate increased with pressure increasing and temperature decreasing, and the carbon dioxide absorption capacity showed 27.6 $CO_2/IL$(g/kg) at $30^{\circ}C$, 13 bar.