• 동력기계공학회지
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• 제18권6호
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• pp.29-33
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• 2014

The electrochemical characteristics of Al-Si casting alloys (Al-10%Si, Al-9%Si, Al-7%Si) in 3.5% NaCl solution at room temperature was studied using potentiodynamic techniques. The electrochemical values of corrosion potential($E_c$), corrosion current density($I_c$) and corrosion rate(mpy) were examined. The Al-Si alloys had several compounds such as $Mg_2Si$, ${\pi}$-$Al_8Si_6Mg_2Fe$ and $Al_2CuMg$ which could affect corrosion resistance significantly. The potentiodynamic polarization curve exhibited typical active behavior in anodic polarization curve. The major corrosion mechansim for the Al-Si alloys were pitting and grain boundary corrosion. As increasing Si and Cu contents, their corrosion resistance was decreased.

• Applied Biological Chemistry
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• 제28권2호
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• pp.56-61
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• 1985

전기전도도법과 화학적 분석방법을 병행하여 두부의 제조공정중 Ca염의 수지를 분석하였다. 전기전도도법에 의한 Ca염의 수지분석(收支分析)이 $CaSO_4$를 응고제로 사용한 경우에는 불가능하였으나, $CaCl_2$를 응고제로 사용한 경우에는 화학적 방법에 의해 구한 것과 잘 일치하였다. 두유 및 두부의 제조공정중 대두에서 두유로 이동되는 고형분량과 Ca량은 각각 66%, 63%였고, 대두에서 두부로 이행되는 고형분은 47.8%였다. $CaCl_2$를 응고제로 사용한 경우 두부중 Ca 농도$(Y_{Tofu},\;mg{\cdot}Ca/g{\cdot}Tofu,\;wet\;basis)$ 및 순물중 Ca농도$(Y_{drained\;soln},\;mg{\cdot}Ca/ml{\cdot}drained\;soln)$는 두유중 첨가되는 $CaCl_2$의 량$(C,\;mg{\cdot}CaCl_2/ml{\cdot}soy\;milk)$에 비례해서 증가하였고, $81{\pm}0.5%$의 수분을 포함한 두부에 대하여 r=0.9898에서의 관계를 $Y_{Tofu}=0.3369C+1.2689$ 얻었고, 순물에 대해서는 r=0.9991에서 $Y_{drained\;soln}= 0.2899C+0.0399$의 관계를 보였다. $CaCl_2$를 응고제로 사용할 경우 원료대두를 제외한 모든 공정에서 전기전도도법에 의해 Ca 농도를 측정할 수 있음이 밝혀졌다.

• 한국재료학회지
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• 제28권12호
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• pp.738-747
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• 2018

For the aerospace structural application of high-strength 2xxx series aluminum alloys, stress corrosion cracking(SCC) behavior in aggressive environments needs to be well understood. In this study, the SCC sensitivities of 2024-T62, 2124-T851 and 2050-T84 alloys in a 3.5 % NaCl solution are measured using a constant load testing method without polarization and a slow strain rate test(SSRT) method at a strain rate of 10-6 /sec under a cathodic applied potential. When the specimens are exposed to a 3.5 % NaCl solution under a constant load for 10 days, the decrease in tensile ductility is negligible for 2124-T851 and 2050-T84 specimens, proving that T8 heat treatment is beneficial in improving the SCC resistance of 2xxx series aluminum alloys. The specimens are also susceptible to SCC in a hydrogen-generating environment at a slow strain rate of $10^{-6}/sec$ in a 3.5 % NaCl solution under a cathodic applied potential. Regardless of the test method, low impurity 2124-T851 and high Cu/Mg ratio 2050-T84 alloys are found to have relatively lower SCC sensitivity than 2024-T62. The SCC behavior of 2xxx series aluminum alloys in the 3.5 % NaCl solution is discussed based on fractographic and micrographic observations.

• 원예과학기술지
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• 제31권5호
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• pp.573-579
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• 2013

본 연구는 국내육성 절화 장미의 수확 적기와 수확단계에 따른 전처리의 효과를 알아 보고자 수행하였다. 장미 절화는 3단계의 각기 다른 시기에 수확되었다. 국내육성 장미의 수확 적기는 품종에 따라 달랐다. 스탠다드 장미 'Pink Song'은 I 단계, 스프레이 장미 'Peace One'은 III 단계에서 수확 시절화 수명이 가장 길었다. 수확단계에 상관없이 대부분의 절화 수명은 2% S + $200mg{\cdot}L^{-1}$ AS + $200mg{\cdot}L^{-1}$ $Mg(NO_3)_2$ + $50mg{\cdot}L^{-1}$ $CaCl_2$ 전처리 시 무처리에 비해 연장되었고, 품질이 향상되었다. 하지만 전처리의 효과는 수확 단계에 따라 다르게 나타났다.

• 한국식품조리과학회지
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• 제10권3호
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• pp.284-290
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• 1994

To prepare soybean curds, the concentration of $CaCl_2,\;MgCl_2,\;CaSO_4$ and glucono-%{\delta}$-lactone fresh solution as coagulants were determined by transmittance of whey using spectrophotometer. The concentrations of four coagulants at which the transmittance had the highest value were chosen. Moisture content, yield and protein recovery of soybean curds prepared with four coagulants were investigated. The textural properties were examined by Instron Universal Testing Machine, and sensory evaluation was carried out. The microstructure of soybean curds was examined by SEM. Soybean curds obtained with $CaCl_2\;and\;MgCl_2$ were hard and coarse, and had roasted nutty taste, whereas those with $CaSO_4$ and GDL revealed very smooth, soft and uniform. Soybean curd prepared with GDL had the lowest acceptability because of sour taste. The texture and acceptability of soybean curds were influenced by the type of coagulant.

• ALGAE
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• 제19권2호
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• pp.123-127
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• 2004

A more rapid and efficient method to extract RNA from Ecklonia cava Kjellman (Laminariales, Phaeophyceae) was introduced in this study. Each step of the procedure was evaluated and the optimal concentration of each chemical in the lysis solution was determined. Tissue pulverization with PVPP and β-mercaptoethanol in the lysis solution were not essential for RNA extraction of this species. The highest yield and purity of E. cava RNA were obtained by the lysis solution containing 1% CTAB, 1 M NaCl, 0.7% PVP, 10mM EDTA and 100mM Tris-Cl (pH 9.0). Approximately 8μg of RNA was obtained from 200 mg of ground tissue. The ratios of the absorbance at 260 nm and 280 nm were from 1.6 to 1.8 and those of at 230 nm and 260 nm were from 1.8 to 2.0. The extracted RNAs obtained in this study turned out to have a sufficient quality for cDNA synthesis.

• Journal of Advanced Marine Engineering and Technology
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• 제19권4호
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• pp.42-50
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• 1995

To study the effect of welding methods on the Stress Corrosion Cracking (SCC) behavior of welded AISI type 316L and 304 austenitic stainless steel, the Slow Strain Rate Technique(SSRT) has been adopted in the boiling 45 wt% $MgCl_2$ solution. The results are as follows. 1) Welded sections are more susceptible than base metal in SCC, and the rank of SCC, and the rasistance in welding method is TIG, MIG, $CO_2$ and ARC. 2) The Ultimate tensile strength(UTS) and the strain of both base metal and welded joint are reduced as decreasing extension rate. 3) The SCC resistance of 316L base metal and welded sections are superior than that of 304. 4) The tendency of pitting and the SCC suseptibility are agreed well, and the SCC site is welded deposit section in 316L whereas HAZ in 304.

• Applied Microscopy
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• 제31권2호
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• pp.175-184
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• 2001

본 연구의 목적은 염화수은이 간 미세구조에 미치는 독성에 대한 키토산의 억제효과를 연구하는데 있다. 염화수은 단독 투여군(A군)에는 $HgCl_2$ (5.0 mg/kg)만을 구강투여하였다. 그리고 키토산과 염화수은 동시투여군(B군)에는 키토산 (3% solution, 2times/day)과 $HgCl_2$, (5.0mg/kg)을 구강투여하였다. 그러고 각 군은 24, 48, 72, 96 시간대에 관찰하여 다음과 같은 결과를 얻었다. 1. A군 핵막은 다소 불규칙한 상태를 유지하였고, 사립체는 내외막이 파괴된 채로 관찰되었다. 과립형질내세망은 층판구조가 파괴되었고, 무과립형질내세망은 세포질 전체에 퍼져있는 것이 관찰되었다. 2. B군 핵막은 비교적 원형을 유지하였고, 사립체는 내외 막의 구분이 일부에서 불분명하게 관찰되었지만, 전자밀도가 높게 관찰되었다. 과립형질내세망의 내강 팽대가 앞시간대에서 관찰되었지만 전형적인 층판구조를 형성하였다. 그리고 무과립형질내세망이 세포질주변에서 관찰되었다. 이상의 결과는 키토산이 마우스 간중독을 야기한 염화수은의 독성을 감소시키는 것으로 사료된다.

• Journal of Advanced Marine Engineering and Technology
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• 제9권2호
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• pp.153-158
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• 1985

The dependence of the corrosion potential on the stress corrosion cracking of 304 austenitic stainless steel was inspected by using the specimen of constant displacement type under the environment of 42% $MgCl_2$ boiled solution. The relationship of the corrosion potential to the intermittent propagation behaviour in stress corrosion cracking was cleared. As the results, a possible model of stress corrosion cracking of 304 austenitic stainless steel in $MgCl_2$ boiled solution was presented on the basis of the Film Rupture Model. This model is specified by the following process. Rupturing of passive film at notch tip .rarw. Dissolution of metal ion and formation of tunnel .rarw. Initiation of microcrack .rarw. Propagation of main crack .rarw. Recreation of passive film at new crack surface.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.151.1-151.1
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• 2017

This work studied the corrosion behavior of AZ31 Mg alloy galvanically coupled with Cu during immersion in 0.1 and 0.5 M NaCl solutions by in-situ observation and galvanic corrosion current measurement using a zero resistance ammeter. The corrosion behavior of AZ31 Mg alloy was also studied by salt spray test. The average galvanic corrosion density during 2 h immersion in 0.1 NaCl solution was found to decrease as an exponential function with increasing the surface area ratios between AZ31:Cu or with increasing the distance between AZ31 and Cu. The corrosion of electrodeposited Cu on AZ31 Mg alloy was concentrated at the area next to Cu (about 5 mm for immersion test and 2 mm for salt spray test) and pitting corrosion was accelerated at the area beyond the severely corroded area by the galvanic coupling effect.