• 한국치위생학회지
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• 제17권5호
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• pp.817-826
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• 2017

Objectives: The aim of this study was to investigate the effects of bamboo salts on remineralization effects on subsurface of artificial carious enamel. Methods: Incipient carious enamel was formed in permanent bovine incisors and then specimens were divided into three groups randomly: 3% bamboo salt (BS), 2% (NaF) and the solution of mixed 3% BS and 2% NaF. For remineralization, specimens of each of the three groups were treated for 24 hrs at $37^{\circ}C$ incubator. After treatment, specimens were analyzed using SEM and VHN. Statistical analysis used was one-way ANOVA. Results: In SEM observation, the BS group showed narrower distances between enamel rods than the cases of incipient subsurface caries enamel. The NaF and BS+NaF groups showed that the enamel rods near the surface were destructed, and innumerable round small particles were deposited near the surface of enamel. The BS+NaF group showed more minerals attachment between enamel rods than the cases of other groups. The differences in subsurface microhardness (${\Delta}VHN$) increased all of three groups in total by $80{\mu}m$. The ${\Delta}VHN$ of the BS+NaF group increased significantly more than NaF and BS groups in depth of $50{\mu}m$, $80{\mu}m$. Conclusions: The 3% bamboo salt with 2% NaF solution was found to increase subsurface hardness of incipient caries enamel. Thus, bamboo salt will be used to contribute to prevention on dental caries.

• 동아시아식생활학회지
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• 제15권3호
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• pp.323-333
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• 2005

This study was performed to analyze the quality characteristics of Oiji solution and Oiji preserved with $7\%$ salt brine and the others preserved with Pulsatilla koreana additives of varied concentrations $(3,\;6\;and\;9\%)$ during fermentation (24 days) at room temperature $(20\pm2^{\circ}C)$. The resuls of this experiment was as follows: The pH of Oiji added with Pulsatilla koreana of 3, 6 and $9\%$ tended to decrease as a fermentation period got longer. The acidity of Oiji was increased as a fermentation period got longer and reached the highest value in the 21st day. The acidity of Oiji solution was $0.92\~1.06\%$ and that of Oiji itself was $0.77\~1.61\%$. The Brix value showed $0.77\%$ for Oiji at the frist day and $3.33\~3.70\%$ at the 24th day. The Brix value of the Oiji with no addition showed the lowest value. Salt content was $2.39\~2.53\%$ for Oiji solution and $3.20\~3.33\%$ for Oiji. The tumidity as $\%T$ of Oiji solution was $52.67\%$ at the first day, that of Oiji solution with no addition of Pulsatilla koreana showed $-10.53\%$ and one which added $9\%$ Pulsatilla koreana showed $-1.16\%$ of tumidity as $\%T$ at the 24th day. As the fermentation period got longer, Oiji solution became tumid The tumidity of Oiji . solution with addition of Pulsatilla koreana showed a low level. For the texture of Oiji, hardness decreased in all cases and fracturability also decreased drastically, but adhesiveness increased as fermentation proceeded Sensory evaluation of Oiji with $6\%$ Pulsatilla koreana additives showed the highest score of taste, crispness and overall acceptance expect smell.

• 한국식품과학회지
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• 제21권6호
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• pp.845-850
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• 1989

본 연구는 오이지를 발효시킬 때 열처리 효과를 조사하기 위하여 오이를 높은 온도의 소금물에 담금과 생오이를 microwave로 가열처리한 뒤 $25^{\circ}C$에서 10일간 10% 소금용액에 넣어 발효시켰을 때 pH, 총산도, 텍스쳐 및 관능적 성질에 미치는 영향을 측정하였다. 초기 절임온도를 $60-90^{\circ}C$로 하였을 때 pH의 감소경향은 60-70-표준시료 $-80-90^{\circ}C$순으로 감소속도가 점점 낮아져 $80-90^{\circ}C$에서의 담금이 오이지의 숙성을 현저히 지연시켰으며 산의 생성은 $70^{\circ}C$가 가장 많고 $90^{\circ}C$가 가장 적게 나타났고. 오이의 견고성은 발효 4일째부터 $80-90^{\circ}C$ 처리구가 높았다. 생오이에 microwave 열처리함은 오이지 담금액의 pH 변화가 발효 2일부터 표준시료보다 빠르게 밀어져 모든 microwave 처리구가 비교 적 낮은 pH값을 보였으며 산생성도 2일 후부터 급격히 증가하여 무처리구보다 많은 양의 산이 생성되어 발효가 촉진되었다. 한편 텍스쳐 변화는 4일 이후 2-3분 처리구가 높게 나타나 생오이의 microwave 열처리는 발효를 촉진시켰으나 텍스쳐에 유익한 것으로 나타났다. 관능적 성질의 평가는 7일 경과한 오이지를 비교하였을 때 열수에 담금과 micorwave에 의한 열처리는 맛이나 냄새에 큰 영향이 없이 사각사각한 성질이 높게 나타나 오이지 텍스쳐의 연화현상을 감소시키는데 유익함을 알 수 있었다.

• 한국식생활문화학회지
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• 제25권1호
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• pp.61-69
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• 2010

This study was carried out to investigate the effects of various kinds of commercial salts, including sun-dried (Korea), purified, and traditional salts on the chemical and sensory properties and growth of microorganisms involved in kimchi fermentation. Kimchi was prepared by salting in 10% NaCl solution for 2 hours followed by addition of other spices and fermentation at $20^{\circ}C$. The decreases in pH suggested that kimchi fermentation can be classified into 3 steps: initial, intermediate, and final stages. In texture analysis, the hardness and fracturability of traditional salt kimchi were higher than those of regular kimchi. From the sensory evaluation test for kimchi, sensory scores were high for traditional salt addition, especially taste, overall preference and texture. Among various microorganisms related to kimchi fermentation, the growth of Leuconostoc mesenteroides, Lactobacillus plantarum, Pichia membranaefaciens and Escherichia coli were examined. Based on the conditions of kimchi fermentation, a 2% and 5% concentration of each salt were studied. Also, the conditions of the cultures at $37^{\circ}C$ were examined. There was no considerable difference in the growth of Leuconostoc mesenteroides, Lactobacillus plantarum, Escherichia coli in the different kinds of salts. However, the growth of Pichia membranaefaciens was strongly inhibited by a 5% concentration of traditional salt during incubation at $37^{\circ}C$.

• 한국식품영양과학회지
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• 제30권1호
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• pp.25-31
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• 2001

가을무 품종별 깍두기 무의 절임 특성을 알아보기 위해, 절임염수의 소금 농도(10, 15 또는 20%)를 달리하여 절임염수를 제조한 후 $2{\times}2{\times}2\;cm$로 절단한 5품종('태백', '백자', '관동', '백광' 및 '백봉')의 가을무를 2배의 절임염수에 넣어 $15^{\circ}C$에서 절이면서 절임 중 깍두기 무의 염도, 중량, 수분함량, 가용성 고형물 함량, pH 및 조직감 특성(TPA)을 알아보았다. 5품종의 깍두기 무 모두 절임 염수의 염도가 높을수록, 절임 시간이 경과될수록 염도, 가용성 고형물 함량은 증가하였으며, 중량 및 수분함량은 강소하는 경향을 나타내었고, Texture Analyser에 의한 TPA값중 경도 및 파쇄성은 감소하는 경향을 나타내었다. 깍두기 무의 소금 농도가 3%에 달할 때까지의 절임 염수의 소금 농도에 따른 최적 절임 시간은 10% 절임 염수에서는 '태백'이 5시간, '백자'는 4시간, '관동' 및 '백봉'은 3시간, '백광'은 2시간이 적당하였으며, 15% 절임 염수에서는 '태백'이 2시간, '백자', '관동', '백봉' 및 '백광'은 1시간이 적당하였다. 절이는 동안 중량 감소율은 '백광' 및 '백봉'이 가장 컸고, '태백'이 가장 작았다. 절이는 동안 pH 감소 정도가 큰 품종은 '백광'이였고, pH 변화가 거의 없는 품종은 '백자'이었다. '태백'과 '백자'는 수분함량이 적고 가용성 고형물 함량이 많았으며 경도가 높았으며 '백광'은 수분함량이 많고 가용성 고형물 함량이 적였고 경도가 낮았으며, '관동'과 '백봉'은 '백자'과 '백광'의 중간 정도의 특성을 나타내었다.

• 청정기술
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• 제11권3호
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• pp.153-164
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• 2005

This study found a reliable evaluation for four kinds of pb-Free plating solutions and it's layers, through pure Sn, SnAg, SnBi and SnCu. These four kind of solutions are widely used to pb-Free plating. Hull-cell, Harring-blum, coverage, throwing power, current efficiency, stability, life-time, composition, hardness, roughness, abrasion, scratch, solderability, corrosion, contact angle, morphology, SIR(Surface insulation resistance) and Whisker test were experimented. Also, Using ICP, XRF, FE-SEM, EDS, temperature/humidity chamber, solderability tester, hardness tester, roughness tester, abrasion tester, salt spray tester, contact angle tester, SIR tester, and microscope. In this paper could be shown the systematic and various analysis for reliability about four kinds of pb-Free plating solutions, processes and it's deposit surface.

• 한국염색가공학회지
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• 제31권3호
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• pp.177-186
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• 2019

In this study, we investigated for synthetic hydrotalcite in chloroprene rubber foam. Experiments were carried out to find the optimum content ratio by controlling the contents of MgO and Hydrotalcite. Swelling test in toluene immersion was made to measure the crosslinking density of CR foams, and the cure properties were investigated with flat die rheometer and Mooney viscosity. The difference of hardness, tensile strength and elongation at break were observed after immersing in 7% NaCl or 21% NaCl solutions for a day and four days. In addition, the volume change and water content remaining in CR foam were measured after immersing NaCl solution. As content of MgO increased, the value of the cure torque tended to increase, but it was almost constant above 2phr of MgO. However, the Mooney viscosity decreased with increasing MgO content. The crosslinking density, determined by the swelling ratio, showed that the CR compound without MgO showed a higher degree of swelling. When the content of hydrotalcite/MgO was 3:2, it was the lowest volume change of CR form. Also, As the content of hydrotalcite decreased, the difference of mechanical properties before and after immersion NaCl solution increased.

• Corrosion Science and Technology
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• 제6권5호
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• pp.257-260
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• 2007

In order to further improve the corrosion resistance and wear resistance of the Ni-P coatings of electroless plating, electroless Ni-P/n-$Al_2O_3$ composite deposits were prepared by adding some nano $Al_2O_3$ Particles in Ni-P plating bath. The bath composition and proproties were studied in this paper. The orthogonal test was applied in order to get the new composite solution, taking the initial stable potential as evaluation standard and considering the elements correlation at the same time. The processing parameters have been optimized by single factor experiment in which the depositing speed was chosen as the evaluation standard. The results showed that the process is stable and the composite Ni-P/n-$Al_2O_3$ deposits werebright and smooth, whose hardness and corrosion resistance are much better than simple Ni-P coatings. Furthermore the surface appearance and structure of the composite Ni-P/n-$Al_2O_3$ coating were investigated by SEM and XRD method. It was proved that the coating surface is typical cystiform cells and its structure is amorphous. All test results ofcomposite coating showed that all various physical coating properties had been improved by adding nano-particles. The hardness of optimal coating is more than 600HV and increases to 1000HV after heat-treating, and its hardness is 20~50% higher than Ni-P coating. The rust points appeared in 200 hour by immersing the coating into the 10%HCl solution and the corrosive speed is $3{\times}10^{-3}mg/(cm^2{\cdot}h)$which was obtained after 300 hour. In the same condition Ni-P coating is $5.6{\times}10^{-3}mg/(cm^2{\cdot}h)$. The salt spray resistance of the layers can exceed 600h with the thickness $20{\mu}m$.

• 한국식품영양과학회지
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• 제24권6호
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• pp.932-936
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• 1995

김치의 보존성 향상을 위하여 0.5% 키토산용액을 0(대조군), 5, 10, 20 혹은 30%(키토산 첨가군) 첨가한 10% 소금용액에 배추를 절인 후 김치를 담구어 $10^{\circ}C$에서 숙성하는 동안 관능검사(신맛, 아삭아삭한 정도, 종합적인 맛)와 기계적인 조직감의 변화를 측정하였다. 관능검사에서 대조군은 숙성 10일 이후 신맛이 강하고 아삭아삭한 정도와 종합적인 맛은 크게 감소하였다. 반면 키토산 첨가군, 특히 20%와 30% 첨가한 군은 숙성 20일째 비로소 신맛을 나타내었으며, 아삭아삭한 정도와 종합적인 맛도 숙성 20일까지 조직감이 있고 맛이 있는 김치로 유지되었다. 한편 김치의 조직감을 기계적으로 측정한 hardness와 gumminess는 키토산 가군 사이에서는 첨가량이 증가함에 따라 hardness와 gumminess도 증가하는 경향이었다. 이상의 결과는 소금절임시 키토산 첨가가 김치의 보존성을 연장시킬 수 있음을 시사하였으며, 특히 키토산을 20% 혹은 30% 첨가한군은 대조군에 비해 보존기간을 10일 이상 연장시킬 수 있음을 나타내었다. 나타내었다.

• 한국식품과학회지
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• 제27권5호
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• pp.697-702
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• 1995

떫은감 품종의 하나인 비단시를 숙성정도를 달리하여 수확하고 이들의 감장아찌 제조조건을 염농도, 침지 온도, 침지 시간, 된장첨가량을 달리하여 조사하였다. 침지액의 초기염도는 $7.5{\sim}15%$였고 침지 20일까지 급격하게 낮아져서 $6.0{\sim}12.0%$가 되었으며 초기염도나 침지 옥도가 높을수록 크게 감소하였고 된장 첨가시에는 염도의 변화가 상대적으로 적었으며 특히 침지 40일 이후에는 거의 변화가 없었다. 수용성 탄닌 함량은 염농도에 관계없이 침지 10일째까지 급격하게 감소하다가 그 이후에는 거의 변화가 없었으며 이러한 변화 경향은 된장 첨가량과 원료감의 숙성정도에 영향을 받지 않았다. 감장아찌 침지액의 pH는 영농도가 높을수록 침지 초기의 pH 감소폭이 컸으나 침지 후기에는 염농도에 관계없이 거의 비슷한 경향을 보였으며 된장을 첨가하면 전체적인 pH 감소 폭이 작아짐을 알 수 있었다. 침지 온도에 따른 pH 변화는 $5^{\circ}C$에서 아주 느리게 낮아졌으며 원료감의 숙성정도와는 무관하였다. 감장아찌중의 염분 함량은 침지중에 계속 증가하였고 침지액의 염도가 12.5% 이상일때 침지 30일째부터 급격하게 증가하였으나 된장 첨가량과 원료감의 숙성정도를 달리하여도 증가하는 경향은 거의 비슷하였는데, 특히 된장 첨가량이 많을수록 감장아찌중의 염분 함량은 낮은 것으로 나타났다. 색도는 침지시간이 경과됨에 따라 명도는 감소하고 색도는 적색이 강해지는 것으로 나타났으며 경도는 침지 15일째까지 증가하다가 침지 40일 이후에는 다시 감소하였는데 숙성된 감은 경도가 계속 낮아졌다. 이와같이 감장아찌 제조 과정에서의 이화학적 변화와 관능검사 결과를 종합해 볼때 감장아찌는 숙성이 약간 덜된 연한색 원료감을 염도 10.0%, 침지온도 $15^{\circ}C$에서 40일간 침지했을때 가장 좋은 제품을 얻을 수 있었고 된장을 20% 첨가했을때 감장아찌의 총기호도가 가장 높았다.