• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
• /
• 2003.10a
• /
• pp.165.1-165
• /
• 2003

복숭아는 절단 후 표면의 갈변현상이나 당도 저하 등이 발생하여 신선편이 식품화시 품질열화의 원인이 된다. 이에 본 실험에서는 일차적으로 유명 품종에 한해 fresh-cut peach의 anti-browning chemicals를 탐색하고, 그 결과를 통해 이차적으로 효과가 우수한 chemicals를 선정하여 백향 품종에 농도별 실험을 행하였다. 유명 품종을 반으로 절단한 후 제핵하고 8등분하여 1% ascorbic acid, 1% sodium chloride, 1% sodium ascorbate monohydrate, 0.005% 4-hexylresorcinol 용액에 3분간 침지시켜 draining한 후, PP tray에 담고 PP film으로 밀봉하여 4$^{\circ}C$에서 저장하였다. 가용성고형분은 to sodium chloride 용액으로 처리한 구에서 가장 높게 유지되었고 pH 또한 비교적 일정하였으며, 1% sodium chloride과 1% sodium ascorbate monohydrate 용액으로 처리한 구의 L값이 높게 유지되었다. 따라서 fresh-cut peach에 효과가 있는 것으로 판단되는 이 두 chemicals의 농도별 용액을 조제하여 같은 방법으로 백향 품종의 갈변저해제로서 처리하였다. 그 결과 2% sodium chloride의 가용성고형분이 가장 높게 유지되었으며 2% sodium ascorbate monohydrate 다음으로 2% sodium chloride 용액 처리구의 L값의 변화 양상이 가장 양호한 것으로 나타났다. 따라서 종합적으로 살펴볼 때, 2% sodium chloride 용액의 처리가 fresh-cut peach의 품질 변화 억제에 적합하다고 판단되었다.

• Membrane and Water Treatment
• /
• v.1 no.1
• /
• pp.39-47
• /
• 2010

Using a conventional two-compartment cell with stirrers the separation of an aqueous solution of HCl-$NiCl_2$ by an anion-exchange membrane Neosepta-AFN was investigated. The dialysis process was characterized by the permeability coefficient of the membrane towards to $Cl^-$ ions. This quantity was determined by the numerical integration of equations, which describe the time dependence of the total concentration of $Cl^-$ ions in compartment initially filled with stripping agent (water), combined with an optimizing procedure. The analysis of the experimental results showed that this permeability coefficient is a satisfactory characteristic for the process studied. It can be graphically correlated with the initial acid and initial salt concentrations in the compartment initially filled with acid+salt mixture.

• Applied Chemistry for Engineering
• /
• v.5 no.1
• /
• pp.114-120
• /
• 1994

Esterolysis reactions of PNPDPP (p-nitrophenyldiphenylphosphate) by DCI ( dichloroisocyanuric acid sodium salt) in borate buffer pH8.0 micellar phase were studied. The rate of hydrolysis reaction was rapidly increased by adding cationic surfactants, CTAC (cetyltrimethylammonium chloride) or CTAB (cetyltrimethylammonium bromide), to the DCI solution. Especially in CTAB micellar system, the N-Cl bond of DCI was transformed to the N-Br bond during the reaction.

• Journal of the Korean Chemical Society
• /
• v.39 no.9
• /
• pp.749-754
• /
• 1995

The synthetic procedures to synthesize polymethacryloylsulfadiazine were searched by DCC method and Acid Chloride mothod. Polymeric drug was synthesized by Acid Chloride method in high yield (72%) but DCC method in low yield (23%). The antimicrobial activities of polymeric drug were investigated in terms of minimum inhibitory concentrations by the common two-fold dilution technique. Polymeric drug revealed an excellent antimicrobial Bacillus subtillis ATCC 6633, Mycrobacterium phlei IFO 3158, Micrococus luteus ATCC 9341, Salmonella typhimurium KCTC 1925, Klebsiella pneumoniae KCTC 1560 and similar activity against Staphylococcus aureus IFO 12732, Escherichia coli BE 1186, Escherichia coli AB 0111, Pseudomonas aeruginosa IFO 13130. Polymeric drug have no antimicrobial activity against Candida albicans IFO 1594.

• Membrane Journal
• /
• v.21 no.1
• /
• pp.39-45
• /
• 2011

An amphiphilic graft copolymer consisting of a poly(vinyl chloride) (PVC) backbone and poly(styrene sulfonic acid) (PSSA) side chains (PVC-g-PSSA) was synthesized via atom transfer radical polymerization (ATRP). This polymer electrolyte membrane was ion-exchanged to Ag ions by immersing in 10 wt% $AgNO_3$ aqueous solution and templated the growth of Ag nanoparticles by a reducing agent. The formation of Ag nanoparticles was confirmed using UV-visible spectroscopy and X-ray diffraction (XRD). Transmission electron microscopy (TEM) revealed that utilization of $NaBH_4$ was the most effective in the formation of Ag nanoparticles with 10~15 nm in size. The formation of Ag nanoparticles was also strongly affected by the concentration of reducing agent and reduction time.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2003.11a
• /
• pp.43-48
• /
• 2003

This paper investigate that the effect of the concrete containing mineral admixtures(pozzolanic materials such as fly-ash, ground granulated blast-furnace slag, silica fume and meta kaolin) on the resistance properties to chloride ion invasion. The purposed testing procedure was applied to the concrete added mineral admixtures for 3~4 replacement ratios under W/B ratios ranged from 0.40 to 0.55. For the electrical migration test, Tang and Nilsson's method was used to estimate the migration coefficient of chloride ion. As a results, the W/B ratios, kinds of admixture and replacement ratios, water curing periods had a great effect on the migration coefficient of chloride ion, and the optimal replacement ratios of admixture had a limitation for each admixtures. Also, the addition of mineral admixtures by mass(replacement of OPC) enhanced the resistance of the mixture to chloride penetration compared with the plain concrete. The amount of acid soluble chloride ions and water soluble chloride ions were varied with the kinds of mineral admixtures. The compressive strength was shown related to the migration coefficient of chloride ion, the compressive strength increased with the decreasing migration coefficient of chloride ion. Below the 50MPa, the variation of migration coefficient of concrete added mineral admixtures was bigger than plain concrete.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2003.05a
• /
• pp.43-48
• /
• 2003

This paper investigate that the effect of the concrete containing mineral admixtures(pozzaolanic materials such as fly-ash, ground granulated blast-furnace slag, silica fume and meta kaolin) on the resistance properties to chloride ion invasion. The purposed testing procedure was applied to the concrete added mineral admixtures for 3∼4 replacement ratios under W/B ratios ranged from 0.40 to 0.55. For the electrical migration test, Tang and Nilsson's method was used to estimate the migration coefficient of chloride ion. As a results, the W/B ratios, kinds of admixture and replacement ratios, water curing periods had a great effect on the migration coefficient of chloride ion, and the optimal replacement ratios of admixture had a limitation for each admixtures. Also, the addition of mineral admixtures by mass(replacement of OPC) enhanced the resistance of the mixture to chloride penetration compared with the plain concrete. The amount of acid soluble chloride ions and water soluble chloride ions were varied with the kinds of mineral admixtures. The compressive strength was shown related to the migration coefficient of chloride ion, the compressive strength increased with the decreasing migration coefficient of chloride ion. Below the 50MPa, the variation of migration coefficient of concrete added mineral admixtures was bigger than plain concrete.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.1
• /
• pp.27-28
• /
• 2009

• Journal of the Korean Chemical Society
• /
• v.35 no.6
• /
• pp.750-752
• /
• 1991

• Food Science and Preservation
• /
• v.21 no.2
• /
• pp.157-162
• /
• 2014

To enhance the commercialization of fresh cut kimchi cabbage, the short-term storage effect of cut kimchi cabbage treated with $Ca^{2+}$ was studied. Cut kimchi cabbages ($3{\times}3$ cm) were treated with 2% calcium chloride (Ca), ascorbic acid (As), citric acid (Ct), and calcium chloride and citric acid (Ca/Ct), were put inside LDPE bags, and stored at $5^{\circ}C$ for 6 weeks. The weights reduced about 0.13~0.72%, and the ratio was the lowest in the Ca/Ct treatment. The reduction ratios of soluble soilds were 18.85~35.00%, and were the lowest in the Ca/Ct treatment. The titratable acidity decreased in all the treatments. The L values decreased, but a and b values of Hunter colorimeter increased in all the treatments. The preference for Ca/Ct treatment was the highest among all the treatments in the sensory evaluation. The marketing shelf-life of cut kimchi cabbage can be prolonged by the combination treatment of $Ca^{2+}$ and citric acid.