• 한국식품조리과학회지
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• 제7권3호
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• pp.53-59
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• 1991

This study was carried out in order to investigate the change of protein functionalities such as foaming and emulsifying properties by succinylation of protein isolates. Succinylated and unsuccinylated munghean protein isolates were tested for finding out the effects of pH, heat treatment and sodium chloride concentration on the solubility, emulsion capacity, emulsion stability, foaming capacity, and foam stability. The results are summarized as follows: 1. Succinylation enhanced the solubility of MPI except at pH 4.5. When heated, succinylation greatly increased the solubility of succinylated MPI above $60^{\circ}C$. With the addition of NaCl, succinylation increased the solubility of MPI at acidic condition. 2. Emulsion capacity of succinylated MPI showed the lowest value at pH 7 and higher values at acidic and alkaine condition. when succinylated MPI was heated, emulsion capacity showed the highest at $80^{\circ}C$. With NaCl was added, emulsion capacity of succinylated MPI lincreased at pH 7, 9 or 11 decreased at pH 3 except addition of 1.0M NaCl. 3. Emulsion stability of MPI and succinylated MPI showed the highest at pH 4.5. Succinylation enhanced the emulsion stability of MPI at acidic condition. 4. The foaming capacity of MPI was increased at pH 3, 7 or 9 by succinylation. 5. When heated, foam stability of MPI and succinylated MPI showed the highest at pH 4.5 and at pH 11, respectively. When heated, both proteins showed the highest stability at $100^{\circ}C$.

• Corrosion Science and Technology
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• 제13권3호
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• pp.112-119
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• 2014

In this work, it is aimed to develop the fabrication method of axial stress corrosion cracking (SCC) defects having various sizes, on the outer diameter surface of the steam generator (SG) tubings. To control the length of the artificial SCC defect, the specific area of the SG tubing samples was exposed to an acidic solution after a sensitization heat treatment. During the exposure to an acidic solution, a direct current potential drop (DCPD) method was adopted to monitor the crack depth. The size of the SCC defect was first evaluated by an eddy current test (ECT), and then confirmed by a destructive examination. From the comparison, it was found that the actual crack length was well controlled to be similar to the length of the surface exposed to an acidic solution (5, 10, 20 or 30 mm in this work) with small standard deviation. From in-situ monitoring of the crack depth using the DCPD method, it was possible to distinguish a non-through wall crack from a through wall crack, even though the depth of the non-through wall crack was not able to be precisely controlled. The fabrication method established in this work was useful to simulate the SCC defect having similar size and ECT signals as compared to the field cracks in the SG tubings of the operating Korean PWRs.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1999년도 한국생물과학협회 학술발표대회
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• pp.150.2-150
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• 1999

To investigate the weathering soil buffering capacities of the artificial acidic precipitation, the weathering soils and their leachate solutions were sampled from the host rocks(granite;GR, rhyolite;RH, gabbro;GA, basalt;BA, two serpentinite;SE1, SE2 and limestone;LI) and analyzed for pH and chemical properties. 1n the soil pH of the GR and RH ,the acidic rocks, were 5.02 and 5.95, respectively. And the GA and BA, basic rocks, were 6.52 and 7.57. The SE1 and SE2 were 8.90 and 8.89. While the LI was 7.84. These results means the typical soil pH properties by host rocks. After the artificial acidic precipitation input 5OOml, the average changes of soil leachate solutions treated by pH levels(pH 5.0, 4.0 and 3.0), were pH 5.73, 5.00 and 4.40. in GR soil, and pH 6.19, 5.99 and 5.57 in RH. GA were pH 6.31, 6.04 and 5.86, BA were pH 7.05, 6.85 and 6.56 and SE1 were pH 8.31, 8.26 and 7.71. SE2 were pH 8.29, 8.24 and 7.96. LI were pH 7.55, 7.46 and 6.79. The soil leachate pHs from volcanic rocks were higher than those from the plutonic rocks and GR soils showed greater response than other soils. With increasing 100ml input-solution, the soil leachate pHs were mainly decreased. Cation concentrations, CEC, EC and total nitrogen concentrations of RH and BA soils, the volcanic rocks, were higher than those of GR and GA soil, the plutonic rocks. On the contrary, Al concentrations of the GR and GA soils were higher than those of RH and BA soils, partly because of high quartz content in GR and Al content in the biotite and plagioclase in GA.

• Journal of Electrochemical Science and Technology
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• 제13권2호
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• pp.213-226
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• 2022

In the present study, the corrosion behavior of aluminum Al-7075 tempered (T-6 condition) alloy was evaluated by immersion testing and electrochemical testing in 1.75% and 3.5% NaCl environment at acidic, neutral and basic pH. The data obtained by both immersion tests and electrochemical corrosion tests (potentiodynamic polarization and electrochemical impedance spectroscopy tests) present that the corrosion rate of the alloy specimens is minimum for the pH=7 condition of the solution due to the formation of dense and well adherent thin protective oxide layer. Whereas the solutions with acidic and alkaline pH cause shift in the corrosion behavior of aluminum alloy to more active domains aggravated by the constant flux of acidic and alkaline ions (Cl^- and OH^-) in the media which anodically dissolve the Al matrix in comparison to precipitated intermetallic phases (cathodic in nature) formed due to T6 treatment. Consequently, the pitting behavior of the alloy, as observed by cyclic polarization tests, shifts to more active regions when pH of the solutions changes from neutral to alkaline environment due to localized dissolution of the matrix in alkaline environment that ingress by diffusion through the pores in the oxide film. Microscopic analysis also strengthens the results obtained by immersion corrosion testing and electrochemical corrosion testing as the study examines the corrosion behavior of this alloy under a systematic evaluation in marine environment.

• 생명과학회지
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• 제29권12호
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• pp.1329-1336
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• 2019

뇌에서 뇌실하 영역은 자가 복제 및 신경세포와 교세포로 분화하는 신경줄기세포가 위치한 곳이다. 이러한 신경줄기세포는 태어난 직후 뿐만 아니라, 성인기까지 존재한다. 세포 증식과 분화에 대한 결정은 세포 안과 밖의 상황에 따라 조절될 필요가 있기에, 많은 세포 내부 또는 세포 외부의 인자들이 이러한 결정에 관여한다. 이러한 인자들 중에서 미토콘드리아는 신경줄기세포의 운명 결정에 관여함이 보고된 바 있다. 본 저자들의 이전 논문에서, 미토콘드리아 저해제인 rotenone을 장시간 처리했을 때, 신경세포로의 분화가 거의 일어나지 않았음을 보여주었다. 이번 연구에서, rotenone을 뇌실하 영역 신경줄기세포에 단기간 처리했을 때의 영향에 대해 조사하였다. 이를 통해 다음과 같은 결과를 관찰하였다. (1) 하루 동안 rotenone을 처리하자 신경세포로의 분화가 크게 감소하였고, 특히 분화 초기 단계가 더 민감하게 억제되었다. (2) 일시적 증식세포인 Mash1+ 세포의 수가 rotenone을 하루 처리한 후 감소하였다. (3) 분화가 된 Tuj1+ 신경세포와 Olig2+ 희소 돌기 아교 세포 (oligodendrocytes) 모두 rotenone을 단기간 처리하자 감소하였다. 반면, glial fibrillary acidic protein (GFAP)+성상 세포 (astrocytes)의 수는 변화하지 않았다. (4) sulfiredoxin 1 (Srxn1) 유전자 발현이 rotenone을 하루 처리한 후 증가하였는데, 이는 nuclear factor (erythroid-derived 2)-like 2 (Nrf2) 신호전달 경로가 활성화 되었음을 말해준다. 이러한 실험 결과는 기능을 갖춘 미토콘드리아가 신경세포 또는 희소 돌기 아교 세포로의 분화 뿐 아니라, 이미 분화가 끝난 신경세포의 유지에도 필요함을 확인해 주었다. 또한, 이러한 결과는 rotenone과 같은 미토콘드리아의 저해제에 짧은 시간 노출 되더라도 신경줄기세포의 신경세포로의 분화 가능성에 장기적인 영향을 미칠 수 있음을 시사한다.

• 한국염색가공학회지
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• 제7권1호
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• pp.32-42
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• 1995

In order to reduce the amount of waste water generated from textile dyeing process and processing water, cotton fabric was bleached with ozone in ozone/water contact system, and dyed. The results obtained from the measurement of whiteness, reflectance, tensile strength, color difference, and K/S value of treated samples were as follow : 1) In ozone bleaching, factors affect whiteness most are treatment time and ozone dosage. As treatment time is lengthened, whiteness increases. Futhermore, bleaching effect is high in acidic treatment, but low in alkaline treatment. 2) As bleaching goes on, maximum absorption wave length shifts to shoter wavelengths. 3) As treatment time is lengthened or pH of treatment is low, tensile strenth of treated fabric decrease. 4) In all cases, color difference of dyed cotton fabrics in above 2% o.w.f. dyestuff concentration don't go beyond 1∼2 AN unit, compared with standard.

• Journal of Ginseng Research
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• 제38권2호
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• pp.146-153
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• 2014

A systematic comparison of the physicochemical properties of white ginseng (WG), extruded white ginseng (EWG), red ginseng (RG), and extruded red ginseng (ERG) was performed. The aim of the present study was to identify the effects of the physicochemical properties of ginseng by extrusion cooking. The highest value of the water absorption index (WAI) was 3.64 g/g obtained from EWG, and the highest value of the water solubility index (WSI) was 45.27% obtained from ERG. The ERG had a better dispersibility compared with other samples. Extrusion cooking led to a significant increase in acidic polysaccharide and total sugar content but resulted in a decrease in crude fat and reducing sugar contents. Enzyme treatment led to a sharp increase in acidic polysaccharide content, especially the cellulose enzyme. Extrusion cooking led to a significant increase in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power, and the increases in WG and RG were 13.56% (0.038) and 3.56% (0.026), respectively. The data of this study provide valuable information about the effects of extrusion on quality changes of EWG and ERG.

• 한국세라믹학회지
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• 제46권6호
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• pp.592-595
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• 2009

Nanosize NiO powder was prepared by mixing acidic nickel nitrate with basic nickel carbonate. The particle size and morphology of NiO were mainly governed by the mole ratio of the nitrate to the carbonate. The effects were studied by DSC, XRD, FTIR, and SEM. Heat treatment conditions influence the particle size distribution of produced NiO powder extensively for the case of 3N7C (3 moles of the nitrate and 7 moles of the carbonate) and 4N6C, but only slightly for 1N9C and 2N8C. Uniform pseudospherical NiO particles were obtained in $50{\sim}70$ nm for 1N9C and $30{\sim}60$ nm for 2N8C by calcination at $750{^{\circ}C}$ for 2 h.

• Preventive Nutrition and Food Science
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• 제13권4호
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• pp.354-361
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• 2008

A novel bacterium isolated from Cheonggukjang was identified as a glutamate-dependent Bacillus subtilis HA with 98.3% similarity to Bacillus subtilis Z99104. Optimization of poly-$\gamma$-glutamic acid ($\gamma$-PGA) production by modulating fermentation factors including carbon sources, nitrogen sources, inorganic salts and fermentation time was investigated. Optimum culture broth for $\gamma$-PGA production consisted of 3% glutamate, 3% glucose and various salts, resulting in the PGA production of 22.5 g/L by shaking culture for 72 hr at $37^{\circ}C$. Average molecular weight of $\gamma$-PGA was determined to be 1,220 kDa through MALLS analysis. The $\gamma$-PGA solution showed a typical pseudoplastic flow behavior, and a great decrease in consistency below pH 6.0 regardless of the same molecular weight of $\gamma$-PGA. The molecular weights of isolated $\gamma$-PGA were drastically decreased by heat treatment in various acidic conditions, resulting in different hydrolysis of $\gamma$-PGA. The consistency of $\gamma$-PGA solution was greatly decreased with increase heating time in acidic conditions.

• 복식문화연구
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• 제13권2호
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• pp.248-254
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• 2005

In this study, wool fabric specimens were pre-mordanted using Sn, Al, Cu, Cr, and Fe, and subsequently dyed using cochineal, maintaining the pH of the dye bath constant using pH buffer solutions of 4, 5, 6, 7, and 8. In the case of wool fabric specimen, regardless of the type of mordanting agents, peak dye-uptake amount was obtained at the acidic region, pH 4, and above pH 6, the dye-uptake amount decreased remarkably. Differing from the cotton fabric case, the dyed wool fabric specimen exhibited red shade even in the case of non-mordanting, at the region of pH values of 4 and 5. It is presumed that in the acidic dye bath the effect of cationic amine group present in the structure of wool fiber molecules took place. The amount of color difference, among the mordanting agents, due to the increase of pH value, was highest for the Fe mordanting case. It seems, therefore, that the Fe mordanting is affected most by the pH value.