• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.5
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• pp.911-921
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• 1997

Recently the interest in natural dyeing has been increased because of the color clarity, natural grace and reactionism in fashion. Indigo dyeing, safflower dyeing and Gal-ott in Cheju-Do become generally known, so the study about the natural dyeing is continued with national intrust and support. In this study, 1 used artemisia for various dyeing tests because we can get it easily. 1 tested the dyeability in wool as well as cotton and silk with wormwood in natural dyeing material. I also dyed nylon with the same material for the comparison of the molecular structure. The mercerization and the chitosan treatment were done in cotton to improve the low dyeability in the natural dyeing. The result of this study are as follows; We have to dye repeatedly to get deep color in natural dyeing, and mordant treatment brought good result in color difference and dyeing fastness. 1. Compared with silk, wool and nylon, the dyeability of cotton was the worse. The color difference of cotton was 18.81 without mordants , and 24.05 with mordant. The dyeability of cotton was much increased by mordants such as potassiumdichromate, copper sulfate, iron sulfate and salt water. The color of cotton was turned into yellow-green in potassium dichromate and yellow-green with deep green in copper sulfate. The mercerization and the chitosan treatment of cotton made the improvement in color, dyeability, laundering fastness, abrasion fastness. 2. The color difference of silk was 3 times as high as cotton. It showed the similar degree with the chitosan treated-cotton. That is to say, silk had good dyeability because it contains amino group and carboxyl group. The dyebility of silk was increased by a mordant such as iron sulfate, potassium dichromate and salt water, Drycleaning fastness showed 5 grade, abrasion-fastness was high over 4~5 grade and sunlight fastness showed 1 grade in all case. 3. The color difference of wool was the best among four fabrics because of 18 kinds of amino acids. It is considered that the sulfate of wool has the polarity and help metal- mordants get the better dyeability such as potassium dichromate, iron sulfate, copper sulfate, and aluminum chloride. The color was reddish-green in potassium dichromate, yellow.greenin iron sulfate and copper sulfate, and yellow in the rest mordants. Drycleaning fastness of wool showed over 4~5 grade, abrasion fastness 5 grade. Sunlight-fastness 1 grade. 4. The dyeability of nylon was almost same because of the similar molecular structure with silk. The clarity of color was poor. The color was yellow-green in copper sulfate and yellow in the rest mordants. Laundering fastness and abrasion-fastness of nylon was good. Sunlight- fastness represented 1 grade.

• Applied Biological Chemistry
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• v.44 no.3
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• pp.185-190
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• 2001

Alginate, a well-known biopolymer, is universally applied for immobilization of microbial cells. Biosorption characteristics of lead by waste biomass of immobilized A. niger beads, used in fermentation industries to produce citric acid, were studied. The immobilized A. niger beads, prepared via capillary extrusion method using calcium chloride, were applied in the removal of lead. Pb uptake was the highest in A. niger beads cells grown for 3 days with medium producing citric acid (12% sucrose, 0.5% $NH_4NO_3$, 0.1% $KH_2PO_4$, and 0.025% $MgSO_4$). Lead uptake by the immobilized A. niger beads and free A. niger mycellia beads increased sharply with time. However, while uptake by the immobilized A. niger beads continued to increase slowly, that by free A. niger mycellia beads stopped after 30 min. The optimum pH and temperature of lead uptake were found to be 6 and $35^{\circ}C$, respectively. The maximum uptake of lead was achieved with $50{\sim}100$ beads and 50 ml lead solution in a 250-ml Erlenmeyer flask, while, at over 100 beads, uptake of the lead decreased. The order of biosorption capacity for heavy metals was Pb>Cu>Cd. Pb uptake capacity of the immobilized A. niger beads treated with 0.1 M $CaCI_2$, 0.1 M NaOH, and 0.1 M KOH decreased compared to the untreated beads. On testing the desorption of Pb from the immobilized A. niger beads, re-uptake of Pb was found possible after desorption of the binding metal with 0.1 M HCI.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.10
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• pp.709-716
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• 2011

Effect of inorganic coagulants dosing on the performance of electro-chemical process was studied when treating hospital wastewater having low electrolyte concentration. It is thought that adding inorganic coagulants caused increase in concentration of electrolyte and this caused increase in free chloride concentration and consequently, caused increase in indirect oxidation effect. Thus, COD removal efficiencies more than doubled in percentage terms at the 2 hrs of reaction time and current density of $1.76A/dm^2$ compared with the results obtained from the parallel experiments without adding inorganic coagulants. T-N removal efficiencies approximately doubled in percentage terms at the 2 hrs of reaction time and 700 ppm of coagulants addition and applied current density of $1.76A/dm^2$ due to the increase of free residual chlorine such as HOCl caused by increase of electrolyte concentration through the addition of inorganic coagulants. Under the same experimental condition, more than 90% of T-P removal efficiencies was obtained. The reason can be explained that increase of chemical adsorption rate between phosphate and insoluble metal compounds caused by dissolved oxygen generated from anode by the increased electrolyte concentration through inorganic coagulants addition make a major role in improving T-P removal efficiencies. It can be concluded that inorganic coagulants addition as the supplemental agent of electrolyte is effective way in improving organic and nutrient salt removal efficiency when treating hospital wastewater having low electrolyte concentration.

• Polymer(Korea)
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• v.24 no.2
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• pp.159-167
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• 2000

The polymethylene-bridged dinuclear half-titanocenes [(CH$_2$)$_{n}$(C$_{5}$ H$_4$)$_2$][TiCl$_3$]$_2$ (n=5(10), 7(11), 9(12)) have been synthesized by treating the distannylated derivatives of the ligands with two equivalents of TiCl$_4$ in toluene. All complexes are characterized by IR, $^1$H NMR, $^{13}$ C NMR and mass spectrometry. In order to examine the catalytic properties of the dinuclear complexes styrene polymerization has been conducted in the presence of MMAO. From the polymerization experiments it was found that ( i ) all the prepared complexes 10-12 produced syndiotactic polystyrenes, ( ii ) the complex 12 holding the longest bridging ligand exhibited the highest activity but produced a polymer having the smallest molecular weight among the polymethylene-bridged dinuclear half-titanocenes. This behavior was attributed to the influence of electron-donating caused by the polymethylene bridge between two active centers as well as the effect of steric congestion around metal center caused by the proximal distance between two active sites.s.

• Korean Journal of Veterinary Research
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• v.51 no.1
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• pp.47-53
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• 2011

In Korea, groundwater is main water source in livestock farms. Most dairy and cattle farms have constructed their own wells for human drinking and livestock farming. However, these private residential wells have not been controlled by government and also there was scant study about livestock drinking water quality. Therefore this study was to monitor of the livestock farms' groundwater quality in Korea. Water samples were collected at 123 dairy and cattle farms and were analysed forty six substances with quality standard for drinking water approved by the Minister of Environment. Seventy eight (63.4%) of 123 samples failed to drinking water stand a test. The most frequent contaminants were nitrate-nitrogen and microbial. 22.8% (n=28) of samples showed nitrate-N concentration of higher than 10 mg/L meant that can't be used drinking water for human and the Nitrate-N concentration analysed in the range of 0.2 to 61.2 mg/L. All of 78 failed to drinking samples had microbial problems, especially 5.7% (n=7) of samples indicated water could be contaminated by feces. Other contaminants detected were zinc and evaporation residue. Especially detected zinc concentration (32 mg/L) was about ten times higher than standard of zinc (3 mg/L). Regression analysis indicated that groundwater pH did not influence to nitrate-N concentration but the hardness and chloride could affect to nitrate-N concentration in the groundwater. Most livestock farms were adjacent to crop farmland in Korea. This could cause contamination of groundwater with nitrate-N and pesticide that could accumulate livestock product. Moreover Heavy metal such as zinc and copper could be released from a corrosive plated water pipe in livestock farm. Put together, Korea livestock system is indoor, not pasture-based, hence livestock could be exposed to potential contaminated water consistently. Therefore on the basis of these data, appropriate livestock drinking water quality standards should be prepared to keep livestock healthy and their product safe. Further, livestock drinking water quality should be monitored continuously in suitable livestock drinking water standards.

• The Journal of Advanced Prosthodontics
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• v.7 no.1
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• pp.56-61
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• 2015

PURPOSE. The purpose of this study was to evaluate the effects of the surface treatment and shape of the dental alloy on the composition of the prosthetic work and its metallic ion release in a corrosive medium after casting. MATERIALS AND METHODS. Orion Argos (Pd-Ag) and Orion Vesta (Pd-Cu) were used to cast two crowns and two disks. One of each was polished while the other was not. Two as-received alloys were also studied making a total of 5 specimens per alloy type. The specimens were submersed for 7 days in a lactic acid/sodium chloride solution (ISO standard 10271) and evaluated for surface structure characterization using SEM/EDAX. The solutions were quantitatively analysed for the presence of metal ions using ICP-MS and the results were statistically analysed with one-way ANOVA and a Tukey post-hoc test. RESULTS. Palladium is released from all specimens studied (range $0.06-7.08{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$), with the Pd-Cu alloy releasing the highest amounts. For both types of alloys, ion release of both disk and crown pairs were statistically different from the as-received alloy except for the Pd-Ag polished crown (P>.05). For both alloy type, disk-shaped pairs and unpolished specimens released the highest amounts of Pd ions (range $0.34-7.08{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$). Interestingly, in solutions submerged with cast alloys trace amounts of unexpected elements were measured. CONCLUSION. Shape and surface treatment influence ion release from dental alloys; polishing is a determinant factor. The release rate of cast and polished Pd alloys is between $0.06-0.69{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$, which is close to or exceeding the EU Nickel Directive 94/27/EC compensated for the molecular mass of Pd ($0.4{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$). The composition of the alloy does not represent the element release, therefore we recommend manufacturers to report element release after ISO standard corrosion tests beside the original composition.

• Journal of the Korean Electrochemical Society
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• v.15 no.4
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• pp.216-221
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• 2012

Electrochemical reduction of carbon dioxide has been widely studied by many scientists and researchers. Recently, the production of formic acid, which is expensive but highly useful liquid material, is receiving a great attention. However, difficulties in the electrochemical reduction process and analyzing methods impede the researches. Therefore, it is important to design an adequate system, develop the reduction process and establish the analyzing methods for carbon dioxide reduction to formic acid. In this study, the production of formic acid through electrochemical reduction of carbon dioxide was performed and concentration of the product has been analyzed. Large scale batch cell with proton exchange membrane was used in the experiment. The electrochemical experiment has been performed using a series of metal catalysts. Linear sweep voltammetry (LSV) and chronoamperometry were performed for carbon dioxide reduction and electrochemical analysis using silver chloride and platinum electrode as a reference electrode and counter electrode, respectively. The concentration of formic acid generated from the reduction was monitored using high performance liquid chromatography (HPLC). The results validate the appropriateness and effectiveness of the designed system and analyzing tool.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.4
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• pp.157-161
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• 2006

InGaN layers on GaN templated sapphire (0001) substrates were grown by mixed-source hydride vapor phase epitaxy (HVPE) method. In order to get InGaN layers, Ga-mixed In metal and $NH_3$ gas were used as group III and group V source materials, respectively. The InGaN material was compounded from chemical reaction between $NH_3$ and indium-gallium chloride farmed by HCl flowed over metallic In mixed with Ga. The grown layers were confirmed to be InGaN ternary crystal alloys by X-ray photoelectron spectroscopy (XPS). In concentration of the InGaN layers grown by selective area growth (SAG) method was investigated by the photoluminescence (PL) and cathodoluminescence (CL) measurements. Indium concentration was estimated to be in the range 3 %. Moreover, as a new attempt in obtaining InAlGaN layers, the growth of the thick InAlGaN layers was performed by putting small amount of Ga and Al into the In source. We found the new results that the metallic In mixed with Ga (and Al) as a group III source material could be used in the growth process of the In(Al)GaN layers by the mixed-source HVPE method.

• Journal of the Korean Ceramic Society
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• v.42 no.7 s.278
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• pp.475-482
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• 2005

Zn$_{l-x}$Co$_{x}$O (x = 0.05 - 0.20) films were grown on Coming 7059 glass by sol-gel process. A homogeneous and stable Zn$_{l-x}$Co$_{x}$O sol was prepared by dissolving zinc acetate dihydrate (Zn(CH$_{3}$COO)$_{2}$$\cdot$2H$_{2}$O), cobalt acetate tetrahydrate ((CH$_{3}$)$_{2}$$\cdot$CHOH) and aluminium chloride hexahydrate (AlCl$_{3}$ $\cdot$ 6H$_{2}$O) as solute in solution of isopropanol ((CH$_{3}$)$_{2}$$\cdot$CHOH) and monoethanolamine (MEA:H$_{2}$NCH$_{2}$CH$_{2}$OH). The films grown by spin coating method were postheated in air at 650°C for 1 h and annealed in the condition of vacuum (5 $\times$ 10$^{-6}$ Torr) at 300$^{\circ}C$ for 30 min and investigated the nature of c-axis preferred orientation and physical properties with different Co concentrations. Znl_xCOxO thin films with different Co concentrations were well oriented along the c-axis, but especially a highly c-axis oriented Zn$_{l-x}$Co$_{x}$O thin film was grown at 10 at$\%$ Co concentration. The transmittance spectra showed that Zn$_{l-x}$Co$_{x}$O thin films occur typical d-d transitions and sp-d exchange interaction became activated with increasing Co concentration. The electrical resistivity of the films at 10 at$\%$ Co had the lowest value due to the highest c-axis orientation. X-ray photoelectron spectroscopy and alternating gradient magnetometer analyses indicated that no Co metal cluster was formed, and the ferromagnetic properties appeared, respectively. The characteristics of the electrical resistivity and room temperature ferromagnetism of Zn$_{l-x}$Co$_{x}$O thin films suggested the possibility for the application to dilute magnetic semiconductors.

• Journal of Food Hygiene and Safety
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• v.13 no.4
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• pp.360-364
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• 1998

The sun-dried, refined, and processed salt (roasted and bamboo salt) manufactured in Chonbuk province were analyzed their chemical compositions and minerals including heavy metals for safety evaluation. Average content of each eomponent as the lowest and the highest were as follows-pH; 6.80 (refined) to 10.35 (bamboo), water content; 0.13% (bamboo) to 10.7% (sun-dried), sodium chloride; 96.6% (roasted) to 84.3% (sun-dried), 804; 0.59% (bamboo) to 3.0% (sun-dried), water insoluble matters; 0.001% (refined) to 1.98% (bamboo), acid inoluble matters; <0.001% (refined) to 0.21% (bamboo), calcium; 0.038% (refined) to 0.213% (sun-dried), magnesium; 0.111% (refmed) to 1.078% (sun-dried), lead; 0.45 ppm (refmed) to 1.15 ppm (bamboo). Cadminium, arsenic and mercury were not detected in all salt. As the analytical results, all salts were differtent in their chemical compositions and safe in view of heavy metals.