• Title/Summary/Keyword: Liquid level control

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Synthesis of Zr-Ti Alloy Powder by Magnesium Reduction (마그네슘환원에 의한 지르코늄-티타늄 합금분말 합성)

  • Lee, Dong-Won;Park, Geun-Tae;Lim, Tae-Soo;Lee, Hye-Moon;Yu, Ji-Hun
    • Journal of Powder Materials
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    • v.18 no.4
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    • pp.359-364
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    • 2011
  • Zr-Ti alloy powders were successfully synthesized by magnesium thermal reduction of metal chlorides. The evaporated and mixed gasses of $ZrCl_4+TiCl_4$ were injected to liquid magnesium and the chloride components were reduced by magnesium leading to the formation of $MgCl_2$. The released Zr and Ti atoms were then condensed to particle forms inside the mixture of liquid magnesium and magnesium chloride, which could be dissolved fully in post process by 1~5% HCl solution at room temperature. By the fraction-control of individually injected $ZrCl_4$ and $TiCl_4$ gasses, the final compositions of produced alloy powders were changed in the ranges of Zr-0 wt.%~20 wt.%Ti and their purity and particle size were about 99.4% and the level of several micrometers, respectively.

Synthesis and kinetic of ultrafine titanium carbide particles by Mg-thermal reduction of liquid metal chlorides (마그네슘의 금속염 환원에 의한 초미립 탄화티탄 분말 합성거동)

  • 이동원;백진호;김병기
    • Journal of Powder Materials
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    • v.11 no.4
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    • pp.322-327
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    • 2004
  • Ultrafine titanium carbide particles were synthesized by the reaction of liquid-magnesium and vaporized TiCl$_{4}$+C$_{x}$Cl$_{4}$(x = 1 and 2) solution. Fine titanium carbide particles with about 50 nm were successfully produced by combining Ti and C atoms released by chloride reduction of magnesium, and vacuum was then used to remove the residual phases of MgCl$_{2}$ and excess Mg. Small amounts of impurities such as O, Fe, Mg and Cl were detected in the product, but such problem can be solved by more precise process control. The lattice parameter of the product was 0.43267 nm, near the standard value. With respect to the reaction kinetics, the activation energy for the reactions of TiCl$_{4}$+C$_{2}$Cl$_{4}$and Mg was found to 69 kJ/mole, which was about half value against the use of TiCl$_{4}$+CCl$_{4}$, and such higher reactivity of the former contributed to increase the stoichiometry until the level of TiC$_{0.96}$ and decrease the free carbon content below 0.3 wt.%.

Determination of Mertansine in Rat Plasma Using Liquid Chromatography-Tandem Mass Spectrometry and Pharmacokinetics of Mertansine in Rats

  • Choi, Won-Gu;Kim, Ju-Hyun;Jang, Hyun-Joon;Lee, Hye Suk
    • Mass Spectrometry Letters
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    • v.11 no.3
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    • pp.59-64
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    • 2020
  • Mertansine, a thiol-containing maytansinoid, is a tubulin inhibitor used as the cytotoxic component of antibody-drug conjugates for the treatment of cancer. Liquid chromatography-tandem mass spectrometry was described for the determination of mertansine in rat plasma. 50-μL rat plasma sample was pretreated with 25 μL of 20 mM tris-(2-carboxyethyl)-phosphine, a reducing reagent, and further vortex-mixing with 50 μL of 50 mM N-ethylmaleimide for 3 min resulted in the alkylation of thiol group in mertansine. Alkylation reaction was stopped by addition of 100 μL of sildenafil in acetonitrile (200 ng/mL), and following centrifugation, aliquot of the supernatant was analyzed by the selected reaction monitoring mode. The standard curve was linear over the range of 1-1000 ng/mL in rat plasma with the lower limit of quantification level at 1 ng/mL. The intra- and inter-day accuracies and coefficient variations for mertansine at four quality control concentrations were 96.7-113.1% and 2.6-15.0%, respectively. Using this method, the pharmacokinetics of mertansine were evaluated after intravenous administration of mertansine at doses of 0.2, 0.5, and 1 mg/kg to female Sprague Dawley rats.

Antimicrobial Effect of Buffered Sodium Citrate (BSC) on Foodborne Pathogens in Liquid Media and Ground Beef

  • Ryu, Si-Hyun;Fung, Daniel -Y. C.
    • Preventive Nutrition and Food Science
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    • v.15 no.3
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    • pp.239-243
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    • 2010
  • The antimicrobial effects of a commercially available, buffered sodium citrate (BSC) were evaluated for the reduction of total aerobic bacteria count, Salmonella Typhimurium, Escherichia coli O157:H7, Listeria monocytogenes and Staphylococcus aureus in a liquid medium and ground beef. BSC at 0, 1, 2 and 4.8% (wt/vol) or 0, 3, and 4.8% (wt/wt) was mixed into inoculated brain heart infusion (BHI) broth and ground beef (80% lean), respectively. BSC at concentrations of 1 and 2% did not inhibit growth of the pathogens tested in BHI broth. E. coli O157:H7 in BHI broth with 4.8% BSC was significantly reduced (p<0.05) by 3~4 log CFU/mL compared with the control for up to 4 days. At 4.8%, BSC treatment of ground beef most significantly reduced (p<0.05) total aerobic count and E. coli O157:H7 by 2.1 and 2.0 log CFU/g, respectively. This study indicates that the legally allowable level of 1.3% (wt/wt) BSC is not effective for reducing the pathogens tested in ground beef stored at $7^{\circ}C$.

Quantification of Fargesin in Mouse Plasma Using Liquid Chromatography-High Resolution Mass Spectrometry: Application to Pharmacokinetics of Fargesin in Mice

  • Lee, Min Seo;Lim, Chang Ho;Bang, Young Yoon;Lee, Hye Suk
    • Mass Spectrometry Letters
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    • v.13 no.1
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    • pp.20-25
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    • 2022
  • Fargesin, a tetrahydrofurofuranoid lignan isolated from Flos Magnoliae, shows anti-inflammatory, anti-oxidative, anti-allergic, and anti-hypertensive activities. To evaluate the pharmacokinetics of fargesin in mice, a sensitive, simple, and selective liquid chromatography-high resolution mass spectrometric method using electrospray ionization and parallel reaction monitoring mode was developed and validated for the quantification of fargesin in mouse plasma. Protein precipitation of 6 µL mouse plasma with methanol was used as sample clean-up procedure. The standard curve was linear over the range of 0.2-500 ng/mL in mouse plasma with the lower limit of quantification level at 0.2 ng/mL. The intra- and inter-day coefficient variations and accuracies for fargesin at four quality control concentrations including were 3.6-11.3% and 90.0-106.6%, respectively. Intravenously injected fargesin disappeared rapidly from the plasma with high clearance values (53.2-55.5 mL/min/kg) at 1, 2, and 4 mg/kg doses. Absolute bioavailability of fargesin was 4.1-9.6% after oral administration of fargesin at doses of 1, 2, and 4 mg/kg to mice.

Effect of Mixed Liquid Fertilization on Growth Responses of Red peppers and Soil Chemical Properties

  • Park, Ji-Suk;Lee, Min-Jin;Lee, Seo-Youn;Kim, Jong-Sung;Lee, Tae-Kyu;Ro, Hee-Myong
    • Korean Journal of Soil Science and Fertilizer
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    • v.48 no.3
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    • pp.225-232
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    • 2015
  • We evaluated the effect of mixed liquid fertilizer (MLF) on growth responses of plants and soil chemical properties. A pot experiment with red pepper (Capsicum annuum L.) using loam soil was conducted for 81 days in a temperature-controlled glasshouse, and four N fertilization treatments were laid out in a completely randomized design with three replicates: control (C), chemical fertilizer treatment (CF), and two rates (MLF-0.5 and MLF-1.0) of MLF treatment. Soils were periodically sampled and analyzed for pH, EC(Electrical Conductivity), total N, inorganic N and total C, and some growth characteristics of red peppers were measured. During the experimental periods, the pH of MLF soils was higher than that of CF soils. Soil EC increased right after application of CF or MLF, and the intial increase persisted in CF and MLF soils at the end of experiment. Soil total-N increased right after application of CF or MLF, and this initial increase persisted only in MLF-1.0 soils. Soil inorganic N content initially increased in CF or MLF-1.0 soils, but the initial increase disappeared in 56 days after transplanting. Soil total-C was maintained higher in MLF-1.0 soils and lower in CF soils than in control soils, and the intial increase in MLF-1.0 soils finally disappeared to the level of control soils. Plant height, dry weight of plant organs (shoots, roots and fruit), and the number, diameter and length of red pepper fruits were greatest in CF plants. On the other hand, the effect of MLF-application was different depending on the rate of application. However, no consistent effect of N treatments on some major elements of the organs of red peppers was observed. The amounts of N taken up by plants were 1.3 g for CF, 0.8 g for MLF-1.0, 0.5 g for MLF-0.5 and 0.4 g for control treatments. The results of this study showed that mixed liquid fertilizer (MLF) could appropriately serve as an alternative to chemical N fertilizer in red pepper cultivation.

Effects of Organic Liquid Fertilizer on Growth and Fruit Quality of Hot Pepper (유기액비 시용량이 고추의 생육 및 품질에 미치는 영향)

  • Joo, Seon-Jong;Jeon, Jong-Ok;Lee, Guang-Jae
    • Korean Journal of Organic Agriculture
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    • v.18 no.2
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    • pp.209-219
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    • 2010
  • This study was carried out to evaluate the effects of applying levels of organic liquid fertilizer (OLF) on growth and fruit quality of hot pepper. The OLF was made with compositions of chicken dung : rice bran : soybean meal (2:1:1). Hot pepper was applied with 5 treatments; control (chemical fertilize), OLF-1.0X (standard applying levels), OLF-0.7X (70% of standard applying level), and OLF-1.3X (130% of standard applying level). The plant height was reduced at 23cm in the OLF-1.0X treatment compared to control of 293cm. The number of hot pepper fruits was significantly increased. The content of capsaicin in the ripened pepper decreased by 23.6% in the OLF-1.0X treatment with $253mg{\cdot}kg^{-1}$ compared with control of $331mg{\cdot}kg^{-1}$, but the content of free sugar increased by 19.5%. The content of capsaicin and soluble solid content in OLF-1.3X treatment were significant different with other treatments. The yield of red pepper in OLF-1.0X treatments increased by 15% with $4,190kg{\cdot}10a^{-1}$ compared to control of $3,643kg{\cdot}10a^{-1}$, and OLF-1.3X and OLF-0.7X treatments showed increase by 10% and 6%, respectively.

Impact of Working Capital Management on Firm Performance in Different Business Cycles: Evidence from Vietnam

  • NGUYEN, Co Trong
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.12
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    • pp.863-867
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    • 2020
  • This study was conducted on financial data of 38 economic groups listed on Vietnam's stock market for the period 2009 - 2019 and it aims to provide an empirical evidence on the impact of working capital management policy on performance in all phases of the economic cycle of Vietnamese economic groups. The study uses FGLS estimation method with 2 dependent variables ROA, GOP, independent variables including INV, AR, AP, CCC, dummy variable representing different phases of the economic cycle, variables Control includes CAT, CR, LEV, SZ, GR. Research shows that the greater the level of investment by companies in liquid assets corresponding to a certain level of activity (shown by average days of inventory (INV), average days of collection. (AR), cash flow cycle (CCC)) the lower the rate of return on assets. The study also provides additional evidence of the negative effects of economic crisis on the performance of economic groups. The study also shows that the number of short-term asset cycles has a positive impact on operational efficiency, and the level of debt use has a negative impact on operational efficiency. This result implies that the managers of economic groups can increase the efficiency of businesses through a reasonable working capital policy.

Physical and Mechanical Properties of Particleboard made with Powdered Tannin Adhesives (분말상 탄닌수지로 제조한 PB의 물리.기계적 특성)

  • 강석구;이화형
    • Journal of the Korea Furniture Society
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    • v.14 no.2
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    • pp.1-12
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    • 2003
  • This study was carried out to determine the mechanical and physical properties of particle boards glued with condensed tannin (Wattle Tannin) powder that was single-molecule phenolic compounds like powdered phenolic resin. Our findings are; 1) It is necessary to spray water on the chip surfaces for effective application of powdered -form tannin resin. It shows that the best and optimum mat moisture increase is 14% of water spray on the surface of chips for developing PB properties. 2) In general, for both liquid and powdered tannin adhesives, their physical and mechanical properties has been proportional to the increase of resin level. But, the most efficient addition ratio is 16% of resin on dry basis. Specially, it is found that the resin level influences on the amount of free formaldehyde emission. The higher the resin level is, the lower the emission is. These phenomena seem to result from the increase of hexamine or formaline in the adhesives used as a hardener, that reduce the free-formaldehyde amount by reaction of tannin of poly-molecule and water. 3) The optimum condition for manufacturing PBs is the condition of hexamine of 5% and formaline of 6% in mechanical and physical properties. Hexamine is superior to formaline in mechanical and physical properties along with the control of the free formaldehyde emission amount. The result of NaOH's addition is insignificant in all experiments of both mechanical and physical properties.

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Chlorogenic Acid was Specifically Induced among Phenolic Compounds in Centipedegrass by Gamma Irradiation

  • An, Byung Chull;Barampuram, Shyamkumar;Lee, Seung Sik;Lee, Eun Mi;Chung, Byung Yeoup
    • Journal of Radiation Industry
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    • v.4 no.1
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    • pp.47-51
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    • 2010
  • Centipedegrass is a warm season turfgrass in the world. Chlorogenic acid (CA) is one of the important compounds present in the leaf of centipedegrass and already known as an antioxidant, CA has become a key resistance against insect pests and bacteria pathogens of agricultural and horticultural plants during seedling stage. Furthermore, CA is accumulated by abiotic stress such as an UV irradiation. In present study, we investigated enhancement of the level of CA upon gamma irradiation in centipedegrass. The high performance liquid chromatography (HPLC) data analysis showed an approximately increasing of the CA levels from among the irradiated samples. However, plants irradiated at 50 Gy showed a constant increase in the CA level (0.0066 to $0.114mg\;ml^{-1}$ and 0.0258 to $0.2211mg\;ml^{-1}$, respectively) from $3^{rd}$ to $15^{th}$ day among one and three month irradiated plants compared to control. The present study, indicates an increase in the CA level upon gamma irradiation, suggests strategy for conferment of strong resistance in seedling stage plants by gamma irradiation as simplicity and cheaply method.