• Journal of the Korean Society of Marine Environment & Safety
• /
• v.21 no.5
• /
• pp.577-582
• /
• 2015

This paper is the fundamental study for the application of cold storage system to the transportation equipment by sea and land. This numerical study presents the solid-liquid phase change phenomenon of calcium chloride solution of 30wt %. The governing equations are 1-dimensional unsteady state heat transfer equations of $1^{st}$ order partial differential equations. This type of latent heat storage material is often usable in fishery vessel for controlling the temperature of container with constant condition. The governing equation was discretized with finite difference method and the program was composed with Mathcad program. The main parameters of this solution were the initial temperature of heat storage material, ambient temperature of cold air and the velocity of cold air. The data of boundary layer thickness becomes thin with the increasing of cold air flowing velocity and also the heat storage completion time become shorten.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.1
• /
• pp.529-536
• /
• 2011

In this study, we confirmed that the SWRO(Sea Water Reverse Osmosis) production water has more hard corrosiveness than the tap water by fundamental experiment. According to the result, the target of this study was aimed at developing maintenance and anti-corrosion method. In the early stages of the research, batch tests using mild steel coupons and electrochemical experiments were applied to compare the corrosiveness between SWRO production water and the tap water. After then, two corrosion control methods for SWRO production water were applied. Liquid lime($Ca(OH)_2$) and Carbon Dioxide($CO_2$) were inserted and compared with the combination of liquid lime with phosphate corrosion inhibitor and carbon dioxide. The water qualities were evaluated through LSI(Langelier Saturation Index) and proper injection ratio was deduced by the result. Since then, simulated loop system test were performed to evaluate anti-corrosion effect depending on corrosion inhibitors. Subsequently, carbon steel pipes equipped at the loop system were detached for SEM, EDX and XRD analysis to acquire quantitative and qualitative data of the major corrosion products inside the pipes. In conclusion, the controled groups with anti-corrosion techniques applied were effective by appearing 97.4% and 90.9% of improvements in both case of liquid lime and the liquid lime with a phosphate corrosion Inhibitor. furthermore, major components of scale were iron oxides, on the other hand, protective effect of film formation by calcium carbonate($CaCO_3$) could be confirmed.

• The Korea Journal of Herbology
• /
• v.23 no.2
• /
• pp.41-49
• /
• 2008

Objectives : In order to distinguish morphological characteristics of trunk bark and root bark of Ulmus davidiana var. japonica (Rehder) Nakai and the trunk bark and root bark of Hemiptelea davidii Planchon were sampled and compared in terms of their external and internal features with flour states according to their medical use, through microscopic examination. Methods : The slice of the tested material made by paraffin section technique was colored with Safranine Malachite Green contrast methods, and the flour of it was mounted by the liquid made by the same ratio of each of glycerin, acetic acid, and water, and then observed and photographed by olympus-BHT. Results : 1. Internal Features 1) A large parenchymatous cell was observed in the phloem of the slice of both trunk bark and root bark of Ulmi Cortex. However, both of the trunk bark and root bark of Hemipteleae Cortex did not have parenchymatous cell in the phloem; instead, stone cells including much square crystal of calcium oxalate were distributed around fiber bundle, and the parenchymatous cell included much druse crystal of calcium oxalate. 2) In both the Ulmi Cortex and Hemipteleae Cortex, rhytidome was observed in trunk bark, but not in root bark, but in the parenchymatous cell of the root bark of the Ulmi Cortex contained starch grain. 2. Flour States 1) In the flour of root bark of the Ulmi Cortex, a large parenchymatous cell was observed. However, in the flour of trunk bark and root bark of Hemipteleae Cortex, no parenchymatous eel was found; instead, stone cell including square crystal of calcium oxalate and druse crystal of calcium oxalate were observed. 2) There was no remarkable difference between the trunk bark and root bark of Hemipteleae Cortex. However, starch grain was contained in the parenchymatous cell of the root bark of Ulmi Cortex but not in the trunk bark of it. Conclusions : There were some morphological differences in external, internal, and flour parts of Ulmi Cortex and Hemipteleae Cortex. In particular, there was a morphological difference in flour states between the trunk bark and root bark of Ulmi Cortex, it is possible to use microscope to distinguish their flour states.

• Journal of Soil and Groundwater Environment
• /
• v.28 no.1
• /
• pp.1-14
• /
• 2023

In this study, column tests using relatively uniform Jumunjin sand media were conducted to evaluate the feasibility of calcium polysulfide (CaS_x, CPS) in removing high concentration of Zn²⁺ in groundwater. The injected CPS solution reacted rapidly with Zn²⁺ in artificial groundwater and effectively reduced Zn²⁺ by more than 99% through metal sulfide precipitation. Since the density (d = 1.27 g/cm³ ) of CPS solution was greater than that of water, CPS solution settled down rapidly while capturing Zn²⁺ and formed stable CPS layer similar to dense nonaqueous phase liquid. Mass balance analysis on Zn²⁺ in CPS solution suggested that CPS solution effectively reacted with Zn²⁺ to form metal sulfide precipitates except for high groundwater seepage velocity of 400 cm/d. With greater groundwater seepage velocity, injected CPS did not completely dissolve at the CPS-water interface, but a partially-misible CPS layer continuously moved and reacted with Zn²⁺+ in the direction of groundwater flow. Since hydraulic conductivity (K_h) decreased slightly due to the generated metal precipitates in the inter-pores of media, injection of CPS solution should be optimized to prevent clogging. As evidenced by both XRF and SEM/EDS results, ZnS precipitates were clearly observed through the reaction between the CPS solution and Zn²⁺. Further study is warranted to evaluate the feasibility of CPS to remove high-concentration heavy metalcontaminated groundwater in complex and heterogeneous media.

• Journal of Food Hygiene and Safety
• /
• v.26 no.4
• /
• pp.322-329
• /
• 2011

This study was done to analyze the contents of minerals and vitamins to compare the measured values of minerals, vitamins with labeled values of them in food labeling and to investigate the ratio of measured values to labeled values in 437 specimen with minerals and vitamins - fortified commercial beverages and liquid teas. Content of calcium and sodium in samples after microwave digestion was analyzed with an ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer) and vitamins were determined using by HPLC (High Performance Liquid Chromatography). The measured values of calcium were ranged 80.3~142.6% of the labeled values in 21 samples composed calcium - fortified commercial beverages and liquid teas. In case of sodium, measured values were investigated 33.9~48.5% of the labeled values in 21 sports beverages. The measured values of vitamin C, vitamin $B_2$ and niacin were ranged 99.7~2003.6, 81.1~336.7, 90.7~393.2% of the labeled values in vitamins - fortified commercial beverages and liquid teas, 57, 12, 11 samples. To support achievement of the accurate nutrition label, there must be program and initiatives for better understanding and guidances on food labelling and nutrition for food manufacture.

• BMB Reports
• /
• v.28 no.4
• /
• pp.323-330
• /
• 1995

Recent studies have shown that dopamine applied to cultured swimming motor neurons of Polyorchis penicillatus produces an inhibitory action by opening potassium channels through $D_2$-like receptors. In this study, it was demonstrated that dopamine found in the hydromedusa was not from exogenous sources and the content of dopamine depended on the $Ca^{2+}$ content of the dissecting media. In addition, a combination of thin layer chromatography and high performance liquid chromatography showed the presence of DOPA and DO PAC-like compounds in the jellyfish. The glyoxylic acid method for catecholamines suggested that a population of small cells, neither swimming motor neurons nor B-like neurons, had dopaminergic systems. From all these results, it is suggested here that DA synthesized from DOPA in some cells is released. being dependent on calcium concentrations, into a synaptic cleft and degraded into DOPAC after acting as an inhibitory transmitter to swimming motor neurons.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1994.04a
• /
• pp.294-294
• /
• 1994

To investigate analgesic mechanism of capsaicin and its analogues (capsaicinoids), release of adenosine was measured by high performance liquid chromatography from dorsal spinal cord synaptosomes, Exposure of synaptosomes to K$\^$+/ and morphine produced a dose dependent release of adenosine in the presence of Ca$\^$++/. Capsaicin (0.1, 1, 10 M), and its analogues 6-paradol (1, 10 M), NE-19550 (1, 10, 100 M), DMNE (1, 10, 100 M) and KR 25018 (0.1, 1, 10 M) produced a dose dependent release of adenosine in the presence of Ca$\^$++/. Nifedipine, L-type voltage sensitive calcium channel blocker, inhibited K$\^$+/ (6, 12 mM)- and morphine (10 M)-evoked release of adenosine completely, but inhibited capsaicin, and capsaicinoids-evoked release of adenosine partially. Capsazepine, a novel capsaicin select ive antagonist, blocked only capsaicin and capsaicinoids induced release of adenosine. Therefore, the adenosine release by capsaicin and capsaicinoids having antinociceptive effects involve activation of capsaicin specific receptor and capsaicin sensitive Ca$\^$++/ channel.

• Journal of Powder Materials
• /
• v.9 no.5
• /
• pp.346-351
• /
• 2002

Pure and fine, two-component titanate powders (barium titanate, calcium titanate etc.) were synthesized by an ethylene glycol method. Titanium isopropoxide and other metal ionic salts were dissolved in liquid-type ethylene glycol without any precipitation. In non-aqueous system, the amount of ethylene glycol affected the solubility and homogeneity of metal cation sources in the solution. At the optimum amount of the polymer, the metal ions were dispersed effectively in solution and a homogeneous polymeric network was formed. Most of the synthesized powders had sub-micron or nano-size primary particles after calcination and the agglomerated calcined powders were easily ground by ball milling process. All synthesized titanate powders had stable crystallization behavior at low temperature and high specific surface area after ball milling. The crystallization behavior and the microstructures of the calcined powders were affected on the ethylene glycol content.

• YAKHAK HOEJI
• /
• v.1 no.1
• /
• pp.4-6
• /
• 1948

The fruits of Rhus javanica L. distributed widely in Korea were extracted with cold water, the filtered clear liquid was evaporated and from the residue large colorless columns, M.P.about 180.deg., were obtained by recrystallisation from hot water. On being incinerated it left a considerable amount of solid residue consisting of calcium. Its aqueous solution which had a strong acid reaction was acidified with sulfuric acid, the precipitate, CaSO$_{4}$, was filtered off, the filtrate was evaporated and from the residue colorless needles, M.P.98-100.deg., were obtained by treating with alcohol. It was identified to be malic acid by determining the mixed melting points of itself and its p-bromphenacylester with authentic specimens. Thus the original substance was proved to be a kind of Ca-salt of malic acid.

• Journal of the Korean Ceramic Society
• /
• v.34 no.11
• /
• pp.1182-1186
• /
• 1997

La0.8Ca0.2Cr0.98O3 powder was prepared using the modified Pechini process. Various crystalline phases formed during thermal decomposition were investigated. (La,Ca)CrO4 phase, first formed from the precursor, was transformed to (La,Ca)CrO3 and CaCrO4 above 80$0^{\circ}C$, which remained up to 110$0^{\circ}C$. However, only (La,Ca)CrO3 phase consisting of orthorhombic and intermediate rhombohedral polymorphs was observed after sintering at 125$0^{\circ}C$. The specimens sintered at 140$0^{\circ}C$ exhibited 98% of relative density and rather wide grain size distribution with average grain size of 3-4 ${\mu}{\textrm}{m}$. Densification and grain growth of the specimens observed above 125$0^{\circ}C$ were presumably attributed to liquid phase sintering resulted from melting of Ca3(CrO4)2 phase.