• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.1
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• pp.15-21
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• 2023

To prepare zinc oxide powder, three types of sodium-based alkali precipitants such as NaOH, Na₂CO₃, NaOH/NaHCO₃ were compared to the differences in the manufacturing process of zinc oxide powder from zinc precipitate products like intermediates with the consideration of thermodynamic reaction. The prepared zinc precipitate products by the reaction with the sodium-based alkali precipitant were confirmed to respectively hydroxy zinc chloride (Zn₅(OH)₈Cl₂·H₂O) and zinc carbonate hydroxide (Zn₅(OH)₆(CO₃)₂·H₂O) from XRD analysis. Zinc oxide particles were compared in heat treatment at 800℃ according to sodium-based alkali precipitants. The mixed NaOH and NaHCO₃ of alkali precipitant reaction was contributed to synthesize the more uniform zinc oxide particles.

• Journal of Nutrition and Health
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• v.49 no.2
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• pp.88-98
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• 2016

Purpose: We recruited 118 women in their early 20's to examine the relationship between sodium intake and salty taste thresholds and preference. We also examined the association of salty taste preference with sodium-related dietary behaviors and major dishes contributing to sodium intake. Methods: Daily sodium intake was estimated using a 127-item dish-frequency questionnaire. Salty taste thresholds and preference were measured using rating scales using water solution of NaCl and a self-administered questionnaire based on a Likert scale, respectively. Results: Salty taste preference showed positive correlation with daily sodium intake and sodium intake-increasing behaviors, and inverse association with sodium intake-decreasing behaviors, including salt and soy sauce use at the table, the frequency of eating out and home delivery of foods, broth consumption of soup, stew or noodle soup, the use of ready-to-serve or processed foods, fresh vegetable intake, and the accommodating attitude toward bland food. Intake of sodium-contributing dishes, including ramen, spicy soft-tofu stew, radish kimchi, and dishes containing kimchi, also showed positive association with salty taste preference. Unexpectedly, detection and recognition thresholds of salty taste showed no association with salty taste preference, sodium intake, and sodium-related dietary behaviors. Conclusion: These findings suggest that salty taste preference could reflect sodium intake of individuals rather than thresholds of saltiness, and may be used as a simple and effective proxy for usual sodium intake.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.3
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• pp.301-305
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• 2013

This study aims to design a portable desalination device and discusses the feasibility of the device for overcoming a shortage of safe drinking water. A low-energy, self-supporting, and portable desalination device is designed based on forward osmosis (FO) using an ammonium bicarbonate solution. Experiments with various concentrations of ammonium bicarbonate solution and sodium chloride solution showed that the portable desalination device's performance such as volume and flow rate of desalting water and time required satisfied drinking water standards. The device performance is controlled by varying the concentration and temperature of the solution.

• Journal of the Korean Chemical Society
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• v.38 no.4
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• pp.265-270
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• 1994

The aquation and base hydrolysis of [Co(en)$_2$NH$_3$Cl]$^{2+}$ were studied by UV spectroscopic method in various SDS aqueous solution. The base hydrolysis of [Co(en)$_2$NH$_3$Cl]$^{2+}$ with the addition of 0, 0.05, 0.1 mol dm$^{-3}$ sodium chloride was studied. For the aquation of the complex, the rate constant in the micellar phase(kH$^M$) was a little larger than that in the aqueous phase(kH$^W$). With the increase of SDS concentration, the second order rate constant(kOH) for the base hydrolysis unchanged below the CMC and sharply decreased down to a limiting value after the CMC was reached. The effect of added NaCl on the rate behavior of the complexes in the micellar solution were investigated by using an ion-exchanged model.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.187-198
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• 2000

Chitosan oligosaccharide with an average degree of polymerization 2-3 was prepared by degradation reaction using sodium nitrite, and the resulting aldehyde group was reduced to hydroxy group. N-palmitoyl, O-palmitoyl chitosan oligosaccha was obtained from the reaction between palmitoyl chloride and oligosaccharide under DMAP catalyst. Alkaline hydrolysis was carried out to remove the O-palmitoyl group. After dispersion and ultrasonication in aqueous solution, N-palmitoyl chitosan oligosaccharide gives vesicle structure. Its structure and size was analyzed by TEM.

• Journal of the Korean Society of Radiology
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• v.2 no.2
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• pp.31-38
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• 2008

Line scan diffusion weighted imaging (LSDI) pulse sequence for 0.32 T magnetic resonance imaging (MRI) system was developed. In the LSDI pulse sequence, the imaging volume is formed by the intersection of the two perpendicular planes selected by the two slice-selective $\pi$/2-pulse and $\pi$-pulse and two diffusion sensitizing gradients placed on the both side of the refocusing $\pi$-pulse and the standard frequency encoding readout was followed. Since the maximum gradient amplitude for the MR system was 15 mT/m the maximum b value was $301.50s/mm^2$. Using the developed LSDI pulse sequence, the diffusion weighted images for the aqueous NaCl solution phantom and triacylglycerol solution phantom calculated from the line scan diffusion weighted images gives the same results within the standard error range (mean diffusivities = $963.90{\pm}79.83({\times}10^{-6}mm^2/s)$ at 0.32 T, $956.77{\pm}4.12({\times}10^{-6}mm^2/s)$ at 1.5 T) and the LSDI images were insensitive to the magnetic susceptibility difference and chemical shift.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.2
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• pp.101-107
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• 2013

Cerium compounds such as Cerium hydroxide ($Ce(OH)_3$), Cerium chloride ($CeCl_3{\cdot}nH_2O$), Cerium carbonate hydrate ($Ce_2(CO_3)_3{\cdot}8H_2O$), Cerium oxide ($CeO_2$) were synthesized using recycled Ce precursor. Cerium(IV) oxide of nanoparticles were obtained by Ultra-sonication. Cerium-sodium- sulfate compound was synthesized through acid-leaching and addition of sodium sulfate from 99 wt% purity of Ce precursor as a starting material that was recycled from the waste polishing slurry. Moreover Cerium hydroxide was obtained from Cerium-sodium-sulfate compound by adding to sodium hydroxide solution. Then Cerium chloride was synthesized by adding of hydrochloric acid to Cerium hydroxide. Needle-shaped Cerium carbonate hydrate was synthesized in the continuous process and Cerium(IV) oxide with 30~40 nm size was subsequently obtained by the calcinations and dispersion.

• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.284-288
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• 2012

This work deals with the chemical characterization of glycine aqueous solution in $CO_2$ absorption. Three alkali elements were impregnated into the glycine in order to facilitate the formation of amino functionalities. The analysis by IR revealed the transformation of ammonium ions to the amino group. In addition, the NMR analysis showed that the substitution of metal cations to the chemical shift of hydrogen and carbon atoms in glycine; in order of lithium glycinate, sodium glycinate and potassium glycinate depending on the electro negativity. Meanwhile, the $CO_2$ absorption at room temperature was the highest in primary amine solution, but at the increasing temperature sodium glycinate could capture more $CO_2$ than that of the pure amine solution.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2140-2142
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• 2004

본 논문은 전기화학 합성으로 형성한 폴리피롤(polypyrrole : PPy) 전극에 신경 전달물질(neurotransmitter)인 에피네프린(epinephrine : Ep)을 치환도핑하여 전압인가에 따른 방출과 자외선 분광법에 의한 검출 결과를 보인다. 폴리피롤 막은 정전압법으로 금 전극에 합성하였고, potassium phosphate buffer(pH 7.0) 내에서 에피네프린을 폴리피롤 막에 치환도핑하였다. 폴리피롤 막에 10mM Ep 농도로 치환도핑한 후 염화나트륨 수용액에서 -0.9V의 환원전압을 인가하여 에피네프린을 방출하였다. 자외선 분광법을 이용하여 파장 250$^{\sim}$400nm 영역에서 방출된 에피네프린 용액의 최대흡광도가 약 0.021 임을 확인하였고 이는 에피네프린 표준용액의 정량선으로부터 16${\mu}$g 이 방출되었음을 의미한다.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1317-1323
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• 2001

The circumstance is giving the blow against fishermen with the incoming-decreasing and the difficulty of crew's supply & demand and management. In addition, the depression of the external situation like the departure of WTO system and the plan of EEZ proclaim is forcing fishery into improving their fishing condition. By this international and domestic circumstance, development of the sea water cooling apparatus for fish hold storage is demanded sincerely. First of all, we Investigated load characteristics which based on development of sea water cooling system and optimum fish hold storage. The experimental results is as follows. In creasing the speed of compressor and mass blew rate of refrigerant, the temperature of NaCl solution is low. And the load characteristics experiment on fish hold storage outlet is as fellows. As time goes by, increasing the mass flow rate of NaCl solution, temperature difference between inlet and outlet is small in a model of fish hold storage. These results provide many useful informations applicable to an actual design of sea water cooling system and optimum fish hold storage.