• 대한가정학회지
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• 제32권5호
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• pp.143-152
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• 1994

To investigate the changes of taste perception by aging, sixty one healthy elderly people and sixty five young adults were participated in the study. Most preferred levels of salt sour and sweet taste were chosen in bean sprout soup radish salad and yaksing respectively. Threshold levels of each taste were also chosen in NaCl solution for salt taste in citric acid solution for sour taste and in sucrose solution for salt taste, in citric acid solution for sour taste and in sucrose solution for sweet taste. The results are as follow: 1.Most preferred salt concentration in bean sprout soup was significantly higher in the elderly than in the young adults(p$\leq$0.001). There was no difference in sour taste preference of radish salad in both age groups. Most preferred sweetness in yacksig was significantly higher in both elderly men and women(p$\leq$0.001) 2. Threshold levels of salt and sweet taste were significantly higher in the elderly (p$\leq$0.001) However there was no difference in threshold level of sour taste in both age groups.

• 한국식품과학회지
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• 제24권4호
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• pp.335-340
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• 1992

무의 염절임 과정에서 일어나는 염의 확산과 관련하여 무의 조직 변화를 측정하고 시간의 함수와 관련된 기계적인 모델을 제시하였다. 침지 염용액의 농도와 침지 온도가 증가할수록 염의 확산은 더 잘 일어났으나 침지온도보다는 염용액의 농도에 의해서 더 많은 염의 확산에 영향을 미쳤다. 염장하지 않은 무는 높은 조직의 강도와 점탄성을 보였으나 온도와 소금농도를 증가시킴에 따라 초기 응력에 대한 조직의 강도 약화를 보여주었으며 응력완화의 정도도 빨라졌고 평형 상태에서 남아있는 탄성 고체의 양도 감소하였다. 또한 침지 용액의 농도와 온도가 증가할수록 무 조직의 점탄성 성분들도 낮아졌는데, 무의 조직변화도 염장 온도보다 염용액의 농도에 의해서 더 많은 영향을 받았다. $Ca^{2+}$과 $Mg^{2+}$이온을 첨가한 경우 점탄성 상수들은 더 큰 것으로 나타났으나 일정 변형에서의 응력의 완화는 더 빠르게 진행되었다. 일정 염농도, 일정 염장 농도와 비순수 소금을 사용했을 때 평형에 도달하기 전의 임의의 시간이 경과한 후에 무 조직의 최종 강도 변화를 점탄성 상수를 이용하여 예측하는 일반식을 제시하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제21권5호
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• pp.527-534
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• 1997

Freezing of an aqueous sodium cWoride solution (Nacl- H20) saturating a packed bed with ini¬tial salt concentrations of 5, 10, 15(k by weight is investigated experimentally in a rectangular cav¬ity. The system was cooled from the top, bottom and a vertical side wall. For the freezing experi¬ments from below, there was little effect of the initial salt concentration throughout the freezing process, and the global freezing rate was not affected by the initial salt concentration. For the freezing from above, the size of the mush region decreased and the mushlliquid interface became flatter as the initial liquid concentration is decreased. For the freezing from vertical side wall, reheating of the mixture was intensified with an increase in the initial salt concentration. For Ci= 5%, supercooling was observed only at the early times of freezing process, but for Ci= 15% small supercooling was observed throughout the freezing process.

• 한국식품영양과학회지
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• 제17권2호
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• pp.110-114
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• 1988

무우의 소금절이 과정중 소금의 농도별 시간경과에 따른 소금침투와 칼슘의 용출 및 수분의 유출정도를 조사하였다. 또 가정 및 백화점으로부터 수집한 김치중 관능적으로 양호한 김치를 선별하여 그 소금농도를 조사하였다. 가정과 백화점으로부터 수집한 20종의 김치중 짠맛에 대한 관능검사에서 양호한 것은 8종이었고 소금농도는 $1.2{\sim}2.2%$ 범위였다. 무우의 절임시 소금농도를 3, 5 및 10%로 증가시킴에 따라 수분유출과 칼슘의 용출은 더욱 증가되었고 고농도 단시간 절임보다 저농도 장시간 절임이 효과적이었다. 관능검사에 의하여 양호하다고 판정된 소금의 농도까지의 염적시간은 3% 경우는 2시간, 5%는 1시간, 10%는 30분이었다.

• Environmental Engineering Research
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• 제14권1호
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• pp.41-47
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• 2009

Column experiments were performed in this study to investigate humic acid adhesion to iron oxide-coated sand (ICS) under different experimental conditions including influent humic acid concentration, flow rate, solution pH, and ionic strength/composition. Breakthrough curves of humic acid were obtained by monitoring effluents, and then column capacity for humic acid adsorption ($C_cap$), total adsorption percent (R), and mass of humic acid adsorbed per unit mass of filter media ($q_a$) were quantified from these curves. Results showed that humic acid adhesion was about seven times higher in ICS than in quartz sand at given experimental conditions. This indicates that humic acid removal can be enhanced through the surface charge modification of quartz sand with iron oxide coating. The adhesion of humic acid in ICS was influenced by influent humic acid concentration. $C_cap$ and $q_a$ increased while R decreased with increasing influent humic acid concentration in ICS column. However, the influence of flow rate was not eminent in our experimental conditions. The humic acid adhesion was enhanced with increasing salt concentration of solution. $C_cap$, $q_a$ and R increased in ICS column with increasing salt concentration. On the adhesion of humic acid, the impact of CaCl2 was greater than that of NaCl. Also, the humic acid adhesion to ICS decreased with increasing solution pH. $C_cap$, $q_a$ and R decreased with increasing solution pH. This study demonstrates that humic acid concentration, salt concentration/composition, and solution pH should be controlled carefully in order to improve the ICS column performance for humic acid removal from water.

• 산업기술연구
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• 제21권B호
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• pp.27-30
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• 2001

For the development of a large-scale dialysis process for silk fibroin solution, a batch and continuous dialysis chamber was designed and built, which are to be used as a unit module for the process. A series of dialysis experiments were carried out to estimate the kinetic parameters for dialysis using the solutions of salt-solubilized silk fibroin. The solution was dialyzed by distilled water either batch-wise or continuously. Dialysis kinetics was monitored by measuring refractometery at high salt concentration and conductivity at lower salt concentration. The apparent dialysis coefficients were $5.4g/m^2-hr$ and $1.8g/m^2-hr$, for well mixed batch and continuous dialysis, respectively. The alteration of molecular weight distribution of dialyzed silk fibroin solution was monitored.

• 한국세라믹학회지
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• 제24권3호
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• pp.257-262
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• 1987

The characteristics of cobalt oxide powders prepared by hot petroleum drying method from the cobalt acetate were evaluated by DTA/TGA, XRD, BET, SEM and density measurement. The cobalt oxide powder could be prepared by hot petroleum drying of the emulsion of cobalt acetate salt solution and the subsequent thermal decomposition of the acetate at 300$^{\circ}C$. As the concentration of the salt solution and the calcination temperature of the dried powder increased, the surface area of the synthesized powder decreased due to the particle growth, so that after sintering the density and grain size decreased. For the same concentration of the salt solution, the surface area and sinterability of the powder by hot petroleum drying increased in comparision with those by conventional drying.

• 한국식품조리과학회지
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• 제19권2호
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• pp.210-215
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• 2003

오늘날 우리의 김치제조는 가정 내 소규모 제조보다는 산업화, 공장화 제품으로 변화되어 가는 추세이다. 현장에서 도움이 되면서도 질적으로 우수한 김치 제조를 위한 가장 기초라 할 수 있는 절임 공정은 무시 될 수 없는 부문이기에 본 실험에서도 배추 절임 시 가장 중요한 염 용액의 농도와 절임 시 온도변화 절임 시간을 달리해 절임 배추의 조직감에 대한 기초자료 확립에 목적을 두었다. 최적염도 2.8 도달점과 조직감을 살펴볼 때 10% 염용액 $25^{\circ}C$ 10시간째, 15%염용액 $25^{\circ}C$ 6-8시간대에서 가장 빨리 도달한다. 조직감은 10-15% 염용액에서 6-10 시간대에서 우수한 질감으로 나타났다. 결과적으로 온도가 올라갈수록 적정 염농도인 2.80에 도달하는 시간이 각 시료마다 다르고 조직감에서는 질긴 조직감보다는 신선하고 청량감을 줄 수 있는 조직감을 보이는 시료가 10% 염용액, $25^{\circ}C$, 10시간째, 15%, $25^{\circ}C$, 6-8 시간째로 염농도 도달점, 조직감이 일치하므로 절임시간과 온도, 염용액의 염도를 보정함이 맛과 영양적으로 우수 할 뿐만 아니라 시간적, 경제적인 부문에서도 많은 경감효과를 가지고 올 수 있다고 본다.

• 한국표면공학회지
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• 제51권2호
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• pp.95-103
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• 2018

Recently, many types of constructional steels have been often exposed to under severe corrosive environments due to acid rain with increasing environmental contamination. In order to inhibit their corrosion in severe corrosive environments, a painting method has been widely applied to numerous constructional steels of land as well as marine. Therefore, development of paint having a good quality of corrosion resistance is considered to be very important. In this study, four types of anti-corrosive paints (AP: Phenol epoxy, AC: Ceramic epoxy, AT: Coal tar epoxy, AH: High solid epoxy) were coated to the specimens, and then, were immerged in various salt solutions (0.1, 0.3, 3, 6, 9 and 15% NaCl solutions) for 11 days. And, the corrosion resistance of these samples by effect of osmotic pressure with salt concentration was investigated with electrochemical methods such as measurement of corrosion potential, impedance and corrosion current density. The corrosion current densities of all samples (AC, AT and AH) submerged in 3% NaCl solution exhibited the smallest values compared to other salt solutions. However, in the case of lower values of salt solutions than 3% NaCl solution, the corrosion current density increased again because it makes easier for water, dissolved oxygen and chloride ion etc. to invade toward inner side of coating film due to increasing of the osmotic pressure than 3% NaCl solution, but in the case of higher values of salt solutions than 3% NaCl solution, the coating film is easily deteriorated due to high concentration of chloride ion rather than the osmotic pressure, which resulted in increasing the corrosion current density. In particular, the AC sample indicated the best corrosion resistance in 6% NaCl solution compared to other samples. Consequently, it is considered that the corrosion mechanism of the coated steel plate is completely different from bare steel plate, and the corrosion resistance of coating film by osmotic pressure and chloride ion depend on various types of epoxy of paint in NaCl solution.

• 한국식품조리과학회지
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• 제16권1호
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• pp.75-83
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• 2000

The effects of salting methods on sensory and microbiological properties of Kakdugi were evaluated during fermentation at 10$\^{C}$ for up to 52 days. Kakdugi samples were prepared by 4 different salting methods at the final salt concentration about 1.5%, which was appropriate for organoleptic quality. The salting methods for radish cubes(2cm size) of Kakdugi included; 1) Treatment S-1: spraying dry salt uniformly onto the radish cubes, at the concentration of about 1.5%(w/w) and cured for 1 hr, 2) Treatment S-5: spraying dry salt uniformly onto the radish cubes, at the concentration of about 1.2%(w/w) and cured for 5 hr, 3) Treatment B-1: brining radish cubes in a 8.5%(w/v) salt solution and cured for 1 hr, 4) Treatment B-5: brining radish cubes in a 4.0%(w/v) salt solution and cured for 5 hr. During the early stage of fermentation, sensory test showed higher scores in the overall acceptability of Kakdugi prepared with salting methods S-1 and S-5 than those with B-1 and B-5. However, the trend of acceptability has been reversed by the treatments B-1 and, more notably, by B-5 at the later stage of fermentation. The counts of lactic acid bacteria increased remarkably and then decreased gradually after the optimum ripening period. The major lactic acid bacteria isolated and identified from Kakdugi were Pediococcus, Streptococcus, Leuconostoc, and Lactobacillus.