• Title/Summary/Keyword: Aqueous system

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A Study On The Development Of An Automatic Fire Extinguishing System For The Engine Compartment Use Of Automobiles (자동차 엔진 화재용 자동 소화 시스템 개발에 관한 연구)

  • Lim, Sung-Muk;Jung, Ki-Chang;Kim, Hong;Kang, Young-Goo;Lee, Chang-Sub
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 1996.11a
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    • pp.57-61
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    • 1996
  • Our goal was to make a cost-effective automatic fire extinguishing system for the engine compartment use of automobiles. We designed this system for the engine compartment. This system consists of 1)foam extinguisher, 2)four nozzles, 3)a pipe arrangement, and 4)an extinguishing device which is equipped with a glass bulb as detector. First and foremost, the extinguishing device was carefully designed to keep the system cost to a minimum. Second, a AFFF foam extinguisher was used because no other fire-fighting agents proved effective against fire in the engine compartment. The AFFF(Aqueous Film Forming Foam) agent which was used in the extinguisher is the 3M company's Light Water. We sought, however, to make other foams by using Halon 1301 and Halon alternatives such as HCFC Blend A, HFC-227ea. We selected these alternatives instead of air in order to raise the expansion ratio of the AFFF agent. By these means we discovered that it is possible to increase the expansion ration of the AFFF agent up to 44:1. We then demonstrated that our automatic fire extinguishing system is the most effective and lowest cost-system yet devised for passenger cars.

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Analgesic Effects of Gyejibokryeong-hwan Aqueous Extracts on the Rat Model of Primary Dysmenorrhea (원발성 월경통에 대한 계지복령환(桂枝茯苓丸) 열수 추출물의 진통 효과)

  • Cho, Su-Yun;Kim, Dong-Chul
    • The Journal of Korean Obstetrics and Gynecology
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    • v.33 no.3
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    • pp.95-118
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    • 2020
  • Objectives: The objective of this in vivo study is to observe the analgesic effects or improvements of Gyejibokryeong-hwan aqueous extracts (GJBRHe) on the Primary dysmenorrhea (PD) in rats as compared to those of Indomethacin (IND). Methods: The rats were administered with estradiol benzoate for 10 days and oxytocin 1 hour after the last 10th administration of estradiol benzoate to make the primary dysmenorrhea rat model. Gyejibokryeong-hwan aqueous extracts 500, 250 and 125 mg/kg were orally administrated, for 10 days once a day. Then the changes on the body weights and gains during experimental periods, uterine weights and gross inspections, abdominal writhing response for analgesic activities, uterus lipid peroxidation (malondialdehyde (MDA) levels), antioxidant defense system - glutathione (GSH) contents, activities of superoxide dismutase (SOD) and catalase (CAT), Nuclear factor-κB (NF-κB) and Cyclooxygenase (COX)-2 mRNA expressions, were monitored with uterus histopathology and immunohistochemistry for tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS). The results of Gyejibokryeong-hwan aqueous extracts were compared to those of Indomethacin adminstered rats. Results: As results of estradiol benzoate and oxytocin treatment, noticeable decreases of body weights and gains, uterus GSH contents, SOD and CAT activities, increases of abdominal writhing responses, uterus lipid peroxidation (MDA level), uterus weights, NF-κB and COX-2 mRNA expressions were observed with increases of TNF-α and iNOS immunolabeled cells, inflammatory cell infiltrations, congestion and enlargement of the uterus at gross and histopathological inspections. These means classic inflammatory and oxidative stress mediated primary dysmenorrhea are relatively well induced. However, these signs were favorably and dose-dependently inhibited by administration of three different dosages of Gyejibokryeong-hwan aqueous extracts, but lesser than those of Indomethacin. Conclusions: The results obtained in this study suggest that Gyejibokryeong-hwan aqueous extracts has favorable analgesic and refinement activities dose-dependently on the estradiol benzoate and oxytocin treatment-induced primary dysmenorrhea signs.

Preparation of perovskite-based catalysts and fuel injection system for high durability of diesel reforming (디젤 개질을 위한 페로브스카이트 구조 촉매와 연료주입 시스템의 개발)

  • Rhee, Junki;Park, Sangsun;Shul, Yong-Gun
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.115.2-115.2
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    • 2010
  • Autothermal reforming(ATR) processes of hydrocarbon liquids such as diesel fuels are spotlighted as methods to produce hydrogen for Fuel cell. However, the use of heavy hydrocarbons as feedstocks for hydrogen production causes some problems which increase the catalyst deactivation by the carbon deposition. Coking can be inhibited by increasing the water dissociation on the catalyst surface. This results in catastrophic failure of whole system. Performance degradation of diesel autothermal reforming leads to increase of undesirable hydrocarbons at reformed gases and subsequently decrease the performance. In this study, perovskite-based catalysts were investigated as alternatives to substitute the noble metal catalyst for the ATR of diesel. The investigated perovskite structure was based on LaCrO3. and metals were added at the A-site to enhance oxygen ion mobility, transition metals were doped on the B-site to enhance the reformation. Substituted Lanthanum chromium perovskite were made by aqueous combustion synthesis, which can produce high surface area. And for the homogeneous fuel supply, we made ultrasonic injection system for reforming. We compared durability of evaporation system and ultrasonic system for fuel injection.

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Poly(vinyl pyrrolidone) Conjugated Lipid System for the Hydrophobic Drug Delivery

  • Lee, Hye-Yun;Yu, Seol-A;Jeong, Kwan-Ho;Kim, Young-Jin
    • Macromolecular Research
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    • v.15 no.6
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    • pp.547-552
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    • 2007
  • Water soluble polymer, poly(vinyl pyrrolidone) was chosen to conjugate with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(succinyl) (N-succinyl DPPE) to make a new drug delivery system. PVP with an amine group (amino-PVP) was polymerized by free radical polymerization. The amine group of amino-PVP was conjugated with the carboxylic group of N-succinyl DPPE. The resultant conjugate could form nanoparticles in the aqueous solution; these nanoparticles were termed a lipid-polymer system. The critical aggregation concentration was measured with pyrene to give a value of $1{\times}10^{-3}g/L$. The particle size of the lipid-polymer system, as measured by DLS, AFM and TEM, was about 70 nm. Lipophilic component in the inner part of the lipid-polymer system could derive the physical interaction with hydrophobic drugs. Griseofulvin was used as a model drug in this study. The loading efficiency and release profile of the drug were measured by HPLC. The loading efficiency was about 54%. The release behavior was sustained for a prolonged time of 12 days. The proposed lipid-polymer system with biodegradable and biocompatible properties has promising potential as a passive-targeting drug delivery carrier because of its small particle size.

Artificial photosynthesis the first chapter: Light driven hydrogen generation from water

  • Kang, Sang Ook
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.69-69
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    • 2013
  • In the area of artificial photosynthesis, particularly for the generation of hydrogen form water, much attention has been paid on organic-inorganic hybrid system. Most of all, a dye/TiO2-combined system has been suggested and its potential utility was well manifested. However, due to its complicated nature of charge interactions in between dye and TiO2 -interface there remains a great challenge to establish the charge-activity relationship, per se light driven charge generation and recombination kinetics with respect to the amount of hydrogen produced. Further complexity of that hybrid system has been witnessed when sacrificial donor and aqueous media are considered. To unveil the operating mechanism on such a dye/TiO2-combined system, we have prepared organic dyes suitable to account for the effect of sacrificial donor as well as water interactions, and prepared the typical dye-grafted TiO2 films to investigate charge-activity relationship. Femtosecond flash photolysis clearly defined the dye effects anchored on to the TiO2 platform. In addition, photodynamic data contemplated well to the dye orientation proposed by the DFT calculations. Recent findings provide fundamental understanding on the dye-grafted TiO2 system and establish a firm background how future dye-sensitized organic-inorganic hybrid system can be designed for the light driven hydrogen generation from water.

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Enhancement of the round-trip efficiency of liquid air energy storage (LAES) system using cascade cold storage units

  • Kim, Jhongkwon;Byeon, Byeongchang;Kim, Kyoung Joong;Jeong, Sangkwon
    • Progress in Superconductivity and Cryogenics
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    • v.22 no.4
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    • pp.45-50
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    • 2020
  • In this research, the variation of round-trip efficiency in a liquid air energy storage system (LAES) is calculated and an optimal configuration is found. The multiple stages of cold energy storage are simulated with several materials that process latent heat at different temperature ranges. The effectiveness in the charging and discharging processes of LAES is newly defined, and its relationship with the round-trip efficiency is examined. According to defined correlation, the effectiveness of the discharging process significantly affects the overall system performance. The round-trip efficiency is calculated for the combined cold energy storage materials of aqueous dimethyl sulfoxide (DMSO) solution, ethanol, and pentane theoretically. The performance of LAES varies depending on the freezing point of the cold storage materials. In particular, when the LAES uses several cold storage materials, those materials whose freezing points are close to room temperature and liquid air temperature should be included in the cold storage materials. In this paper, it is assumed that only latent heat is used for cold energy storage, but for more realistic analyzes, the additional consideration of the transient thermal situation to utilize sensible heat is required. In the case of such a dynamic system, since there is certainly more increased heat capacity of the entire storage system, the volume of the cold energy storage system will be greatly reduced.

Contribution of Water Chemistry in Initiation of Some Accelerated Corrosion Processes in CANDU-PHWR Primary System

  • Pirvan, Ioana;Radulescu, Maria;Fulger, Manuela
    • Corrosion Science and Technology
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    • v.7 no.2
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    • pp.85-91
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    • 2008
  • By operation in aqueous environment at high temperature and pressure, the structural materials from Primary Heat Transport System (PHTS) cover with protective oxide films, which maintain the corrosion rate in admissible limits. A lot of potential factors exist, which conduct to degradation of the protective films and consequently to intensification of the corrosion processes. The existing experience of different nuclear reactors shows that the water chemistry has an important role in integrity maintaining of the protective oxide films. To investigate the influence of water chemistry (pH, O2 dissolved, $Cl^-$, $F^-$) on corrosion of some structural materials (carbon and martensitic steel, Zr and Ni alloys) and to establish the maximum permissible values, corrosion experiments by static autoclaving and electrochemical methods were performed. The experimental results allowed us to establish the contribution of the water chemistry in initiation and evolution of some accelerated corrosion processes.

Constructing Overhauser Dynamic Nuclear Polarization-Nuclear Magnetic Resonance System Using Benchtop Electron Paramagnetic Resonance Spectrometer

  • Saun, Seung-Bo;Kim, JiWon;Han, Oc Hee
    • Journal of the Korean Magnetic Resonance Society
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    • v.22 no.2
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    • pp.34-39
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    • 2018
  • The Nuclear Magnetic Resonance (NMR) technique using Dynamic Nuclear Polarization (DNP) procedures is one of the promising techniques that enable overcoming low sensitivity problems in NMR spectroscopy. We constructed an ODNP-NMR system using a commercial benchtop EPR spectrometer. The $^1H$ NMR peak area of water in aqueous solutions of 4-hydroxy-TEMPO was enhanced more than 95 times in the ODNP-NMR experiments. Our signal enhancement results were about 55% of the previously reported result. This could be due to non-uniform microwave power over a sample and unwanted sample heating by microwave. However, this portable ODNP-NMR spectrometer will be eventually useful for site-specific detection with nano-scale spatial resolutions and molecular dynamics studies with significantly improved signal sensitivity.

Microscopy of Microbial Gas Vesicles

  • Park, Junhyung;Kim, Ki Woo
    • Applied Microscopy
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    • v.47 no.3
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    • pp.165-170
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    • 2017
  • Gas vesicles are intracellular gas-filled protein-shelled nanocompartments. The structures are spindle or cylinder-shaped, and typically $0.1{\sim}2{\mu}m$ in length and 45~250 nm in width. A variety of prokaryotes including photosynthetic bacteria and halophilic archaea form gas vesicles in their cytoplasm. Gas vesicles provide cell buoyancy as flotation devices in aqueous habitats. They are used as nanoscale molecular reporters for ultrasound imaging for biomedical purposes. The structures in halophilic archaea are poorly resolved due to the low signal-to-noise ratio from the high salt concentration in the medium. Such a limitation can be overcome using focused ion beam-thinning or inelastically scattered electrons. As the concentric bodies (~200 nm in diameter) in fungi possess gas-filled cores, it is possible that the concept of gas vesicles could be applied to eukaryotic microbes beyond prokaryotes.

Biosynthesis of Unnatural Phospholipids by Phospholipase D: II. Effect of Organic Solvents on Transphosphatidylation (PhosBholipase D에 의한 비천연 인지방질의 합성: IIl 포스타티딜기 전이반응에 미치는 유기용매의 효과)

  • 정의호;이해익이상영
    • KSBB Journal
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    • v.6 no.3
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    • pp.281-288
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    • 1991
  • This research was carried to investigate the effects of several organic solvents on the enzymatic transphosphatidylation in emulsion and two-phase solvent systems. The solvents having a similar dielectric constant with diethylether were effective for the enzyme activity. Diethylether and butylacetate were the most effective solvents, when added 12-15%(v/v) and 10-40%(v/v), respectively, for the synthesis of phosphatidylglycerol, phosphatidylethyleneglycol and phosphatidylpropyleneglycol. In the emulsion system, the size of ovolecithin liposome was increased and the clearness of the phospholipid bilayer was reduced as increasing the diethylether concentration. In the twophase solvent system, the rapidest reaction was obtained when water-organic solvent ratio was close to 1. The ratio of aqueous phase. however, should be lowered to 37% to gain the sole product of transphosphatidy1ation, without phosphatidohydrolysis.

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