• Title/Summary/Keyword: $Ca^{2+}$ flux

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A Study on Effect of Flex Additions for Selecting the Process Parameters in GMA Welding processes (GMA 용접공정에서 공정변수 선정을 위한 플럭스 첨가에 관한 연구)

  • Kim, In-Ju;Kim, Jun-Ki
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.1
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    • pp.17-22
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    • 2011
  • As the quality of a weld joint is strongly influenced by process parameters the welding process, an intelligent algorithms that can predict the bead geometry and shape to accomplish the desired mechanical properties of the weldment should be developed. In this study, prepared by ${\Phi}1.6mm$ GMA welding of metal wire nose Advice jowelui 350A 600A grade level inverter welder and DAIHEN SCR's were carried out using welding. Welding conditions were 5.5m/min wire feed rate the welding current is rapidly transmit approximately 260A, welding voltage was about 30V. CTWD a 22mm, shielding gas was Ar 20L/min and the welding speed was a 240mm/min. Using data collected during welding equipment welding current and welding voltage waveform was analyzed by measuring the volume of the transition mode. Addition of $CaCO_3$ as a loss of the spread of the weld bead dilution rate decreased, suggesting that, GMA in the overlay welding bead shape control, dilution control and may be used as a welding flux is considered. Stabilizing effect of the arc by the Ca-containing $CaF_2$, $CaCO_3$, $CaMg(CO_3)_2$, respectively, welding flux 0.1wt.% added GMA welding and weld overlay were evaluated with dilution, $CaF_2$, and $CaMg(CO_3)_2$ added to the dilution of Seemed to increase.

Effect of $Ca^{2+}$ on Phvsiological Activites of the Acrosome Reaction on Spermatozoa ($Ca^{2+}$이 정자 첨체반응의 생리적 활성에 미치는 영향)

  • 장재호;오영근
    • The Korean Journal of Zoology
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    • v.39 no.2
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    • pp.182-189
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    • 1996
  • It has been known that spermatozoa should obtain their fertilizing ability through capacitation and acrosome reaction, and that in these processes of fertilization, Ca2+ platys an important role for their conjugation. Therefore the present study has been designed in order to clarify the effect of fluctuation of the media Ca2+ level and the intracellular concentration of the spermatozoa on the acrosomes. During the incubation of spermatozoa, a considerable fluctuation in the media Ca2+ level has been observed after the BSA administration and the media concentration of Ca2+. It is deduced that these fluctuation rates may have an effect on the acrosome reaction. The fluctuation of K+ flux has been observed in accordance with the incubation period over time, and it's concentration seems to be closely related with the acrosomal reaction. The respiratory exchange rate (RERI of the spermatozoa is kept more regular in the BSA and Cacl2 administration groups than the non-administration group. Based on the experimental findings, it is possible to deduce a hypothesis from these findings that physiological activities of the acrosome reaction are not functionally related to the media Ca2+ level and the intracellular influx of Ca2+ concentration, although Ca2+ platys an important role as a stimulating factor in the acrosome reaction.

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Electromagnetic Properties of BiPbSrCaCuO Superconductor (BiPbSrCaCuO 초전도체의 전자기특성)

  • Lee, Sang-Heon;Nam, Sugn-Pill;Lee, Sung-Gap;Lee, Young-Hie
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1549-1551
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    • 2004
  • The Electromagnetic properties in BiPbSrCaCuO superconductor was studied. In the measurement of current-voltage characteristics, a voltage across the superconducting sample was observed on applying an external magnetic field. The voltage continues to appear the removal of the magnetic field. The appearance of the voltage is ascribed to the trapping of magnetic flux. Depanding on the direction of applied magnetic flux less than 2.5${\times}$10-5 T, the voltage in the magnetized sample increases or decreases. It is considered that mechanism of voltage occurrence can be explained by applying filament model.

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AC Loss Measurement and Analysis of Ag-sheathed Bi-2223 Conductors in Terms of Eddy Currents and Flux Creep

  • Jang, Mi-Hye
    • KIEE International Transactions on Electrophysics and Applications
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    • v.3C no.6
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    • pp.211-215
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    • 2003
  • Alternating current (AC) losses of two Bi-2223 ([Bi, Pb] : Sr : Ca : Cu :O = 2:2:2:3) tapes [one untwisted (Tape I, twist-pitch of $\infty$ mm) and the other with a twist-pitch of 8mm (Tape II) ] were measured and compared. These samples, produced by the powder-in-tube (PIT) method, are multi-filamentary and have a Ag/Au and Ag matrix, respectively. Susceptibility measurements were conducted while cooling in a magnetic field. Flux loss measurements were conducted as a function of ramping rate, frequency and field direction. The AC flux loss increases as the twist-pitch of the tapes decreased, in agreement with the Norris Equation.

Evaluation of calcium carbonate scale formation on system design of seawater reverse osmosis plants (해수담수화 시설의 시스템 구성에 따른 $CaCO_3$ 스케일 형성능 진단)

  • Kang, Nam-Wook;Choi, Yang-Hun;Lee, Hye-Ju;Lee, Seock-Heon;Kweon, Ji-Hyang
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.2
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    • pp.143-155
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    • 2010
  • Fouling by inorganic scales needs to be prevented to effectively operate sea water reverse osmosis(SWRO) membrane systems. The extents of inorganic scaling with different array designs including one-pass, two-pass and several hybrid designs were evaluated using seawater from southern sea near the city of Chang-Won. The used methods for evaluation were Stiff and Davis Index(S&DSI) calculation and several laboratory experiments. The formation potential of inorganic scale fouling was quite great under the examined conditions, which was confirmed by the laboratory experimental results. The inorganic scale was not avoidable fouling if any anti-scaling measures were not applied. The RO showed decreased flux under the scale formation conditions. The increases in S&DSI from 1.43 to 5 made small decreases in flux, which indicated that formation of inorganic scales had more substantial effects on RO flux than amount of inorganic scales.

Synthesis and pressure effects on the La doped CaFe2As2

  • Shin, Soohyeon;Shang, T.;Yuan, H.Q.;Park, Tuson
    • Progress in Superconductivity and Cryogenics
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    • v.16 no.3
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    • pp.1-3
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    • 2014
  • We have synthesized La doped $CaFe_2As_2$ single crystals with Sn flux in an evacuated quartz ampule. Doping and pressure effects on the magnetic and superconducting properties of the under-doped $Ca_{1-x}La_xFe_2As_2$ (x=0.08, 0.1) were studied by measuring electrical resistivity under quasi-hydrostatic pressure up to 21 kbar. Magnetic transition temperatures for all studied concentrations were sharply suppressed with slight amplitude of pressure, less than 3 kbar, while superconducting transition temperatures were robust against pressure. In this communication, we report temperature-pressure phase diagram for the La-doped $CaFe_2As_2$ single crystals.

Study on the Hollow Fiber Nano-composite Membrane Preparation onto the Porous PVDF Membrane Surfaces using the Interfacial Polymerization (다공성 PVDF 막의 polyamide 계면중합법처리를 통한 나노 중공사 복합막 제조 연구)

  • Kang, Su Yeon;Cho, Eun Hye;Kim, Ihl hyung;Kim, Cheong Sik;Rhim, Ji Won
    • Membrane Journal
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    • v.24 no.2
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    • pp.107-112
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    • 2014
  • The composite membranes were prepared on the surface of hydrophobic porous poly (vinylidene fluoride) (PVDF) hollow fiber membranes through the interfacial polymerization. The preparation variables were the concentrations of piperazine (PIP), trimesoyl chloride (TMC) and the contents of polyethylene glyco l (PEG). The separation characterization of the resulting membranes were carried out for aqueous 100 ppm solution of NaCl, $CaSO_4$, and $MgCl_2$ and also mixed 300 ppm solution of NaCl and $CaSO_4$ in terms of the flux and rejection. Both the flux and rejection were the highest when the interfacial polymerization was conducted using TMC. When TMC concentration was 0.1 wt%, the flux and rejection were shown 48.3 LMH ($L/m^2{\cdot}hr$) and 59%, respectively. To improve the flux, the annealing post-treatment and the addition of PEG into piperazine were done. As expected, the overall flux was enhanced while the rejection was reduced.

Synthesis and Luminescent Properties of Aluminate-based Phosphors Doped with Mn4+ Ions (Mn4+ 이온이 도핑된 알루미네이트계 형광체 합성과 발광특성)

  • Park, Jungkyu;Kim, Young Jin
    • Journal of the Korean Ceramic Society
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    • v.51 no.1
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    • pp.37-42
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    • 2014
  • $Mn^{4+}$-doped $CaAl_4O_7$ ($CA_2$) and $CaAl_{12}O_{19}$ ($CA_6$) powders were prepared under different conditions, with changes in the amounts of flux, Mn concentration, and mole ratio of $Al_2O_3$ to $CaCO_3$ in the starting mixtures, which affected the structure and the luminescence. $CA_2:Mn^{4+}$ and $CA_6:Mn^{4+}$ had the same excitation and emission spectra but with different intensities. The excitation spectra exhibited broad bands (320 - 470 nm) centered at 395 nm, while red emission bands were observed at 656 nm. The emission intensity of $CA_6:Mn^{4+}$ was nearly twice as high as that of $CA_2:Mn^{4+}$, as the $Mn^{4+}$ ions were located in an octahedral crystal field in the $CA_6$, but not in the $CA_2$.

A study on the luminescence characterization of red long persistent phosphors by the $B_2O_3$ addition ($B_2O_3$ 첨가에 의한 적색 축광성 형광체의 발광특성에 관한 연구)

  • Hwang, Ku-Hyeon;Choi, Jong-Koen
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.18 no.1
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    • pp.22-26
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    • 2008
  • Red long persistent phosphors of $CaZrO_3$ : Pr was synthesized by a solid reaction method. $CaCO_3\;and\;ZrO_2$ were used as hosting materials and Pr was doped as luminescence center element, and $B_2O_3$ was used as flux. The XRD pattern confirmed crystalline phase of the phosphor, and photoluminescence investigation showed emission spectrum at $480{\sim}570nm\;and\;590{\sim}700nm$. Phosphor samples were synthesized with $B_2O_3$ flux concentration of 1, 5, 10%, and luminescent peak of maximum intensity at 494 nm was obtained for 1% $B_2O_3$. Luminescent peak of red color at 620 nm was of highest intensity for 10% $B_2O_3$.