• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.3
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• pp.223-233
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• 2015

In order to evaluate the pollution of heavy metals in offshore surface sediments around shipyards in Korea, surface sediment samples were collected at eleven stations around four major shipyards located in the southeastern coast of Korea in summer 2010 and nine kinds of heavy metals such as copper(Cu), zinc(Zn), cadmium(Cd), lead(Pb), chrome(Cr), arsenic(As), mercury(Hg), iron(Fe) and aluminum(Al) in sediments were analyzed. The concentrations of Cu at all sampling stations were in the range of 47.10~414.96 mg/kg and exceeded TEL(Threshold Effects Level) 20.6 mg-Cu/kg of Korean marine environmental standards for offshore sediments and ERL(Effect Range-Low) 34.0 mg-Cu/kg. The concentrations of Cu at seven stations around four shipyards were 65.18~414.96 mg/kg and exceeded PEL(Probable Effects Level) 64.4 mg-Cu/kg of Korean marine environmental standards for offshore sediments. The concentration of Cu at one station around B-shipyard was 414.96 mg/kg and exceeded ERM(Effect Range-Median) 270.0 mg-Cu/kg. The concentrations of Zn at all stations were in the range of 135.09~388.79 mg/kg which exceeded ERL 150.0 mg-Zn/kg. The concentrations of Zn at seven stations around four shipyards were 157.57~388.79 mg/kg and exceeded PEL 157.0 mg-Zn/kg. The concentration of Zn at one station around B-shipyard was 388.79 mg/kg and was approaching ERM 410.0 mg-Zn/kg. The concentrations of Cd at all stations were in the range of 0.11~0.54 mg/kg and were below TEL 0.75 mg-Cd/kg and ERL 1.2 mg-Cd/kg. The concentrations of Pb at all stations were in the range of 18.04~105.62 mg/kg. The concentrations of Pb at two stations around B-shipyard were 73.87~105.62 mg/kg which exceeded TEL 44.0 mg-Pb/kg and ERL 46.7 mg-Pb/kg, and were below PEL 119.0 mg-Pb/kg and ERM 218.0 mg-Pb/kg. The concentrations of Cr at all stations were in the range of 51.26~85.39 mg/kg. The concentration of Cr at one station around B-shipyard was 85.39 mg/kg and exceeded ERL 81.0 mg-Cr/kg. The concentrations of As at all stations were in the range of 8.70~22.15 mg/kg which exceeded ERL 8.2 mg-As/kg and were below ERM 70.0 mg-As/kg. The concentrations of As at eight stations around A-shipyard, B-shipyard and D-shipyard were 14.93~22.15 mg/kg which exceeded TEL 14.5 mg-As/kg and were below PEL 75.5 mg-As/kg. The concentrations of Hg at all stations were in the range of 0.02~0.35 mg/kg. The concentrations of Hg at three stations around A-shipyard were 0.11~0.13 mg/kg which were almost equal to TEL 0.11 mg-Hg/kg. Those at two stations around B-shipyard were 0.27~0.35 mg/kg which exceeded TEL 0.11 mg-Hg/kg and ERL 0.15 mg-Hg/kg, and were below PEL 0.62 mg-Hg/kg and ERM 0.71 mg-Hg/kg. The concentrations of Fe and Al at all stations were in the range of 2.90 3.66 % and 3.12 6.80 %, respectively. These results imply that heavy metals such as copper, zinc, lead, arsenic and mercury were likely to be transferred to marine environment from shipyards, especially from B-shipyard.

• The Journal of Advanced Prosthodontics
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• v.6 no.5
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• pp.372-378
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• 2014

PURPOSE. The porcelain fused to gold has been widely used as a restoration both with the natural esthetics of the porcelain and durability and marginal fit of metal casting. However, recently, due to the continuous rise in the price of gold, an interest towards materials to replace gold alloy is getting higher. This study compared the bond strength of porcelain to millingable palladium-silver (Pd-Ag) alloy, with that of 3 conventionally used metal-ceramic alloys. MATERIALS AND METHODS. Four types of metal-ceramic alloys, castable nonprecious nickel-chrome alloy, castable precious metal alloys containing 83% and 32% of gold, and millingable Pd-Ag alloy were used to make metal specimens (n=40). And porcelain was applied on the center area of metal specimen. Three-point bending test was performed with universal testing machine. The bond strength data were analyzed with a one-way ANOVA and post hoc Scheffe's tests (${\alpha}=.05$). RESULTS. The 3-point bending test showed the strongest ($40.42{\pm}5.72$ MPa) metal-ceramic bond in the nonprecious Ni-Cr alloy, followed by millingable Pd-Ag alloy ($37.71{\pm}2.46$ MPa), precious metal alloy containing 83% of gold ($35.89{\pm}1.93$ MPa), and precious metal alloy containing 32% of gold ($34.59{\pm}2.63$ MPa). Nonprecious Ni-Cr alloy and precious metal alloy containing 32% of gold showed significant difference (P<.05). CONCLUSION. The type of metal-ceramic alloys affects the bond strength of porcelain. Every metal-ceramic alloy used in this study showed clinically applicable bond strength with porcelain (25 MPa).

• The Journal of Advanced Prosthodontics
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• v.10 no.5
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• pp.340-346
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• 2018

PURPOSE. In this study, the shear bond strengths (SBS) of luting cements to fixed superstructure metal surfaces under various seating forces were investigated. MATERIALS AND METHODS. Seven different cements [Polycarboxylate (PCC), Glass-Ionomer (GIC), Zinc phospahate (ZPC), Self-adhesive resin (RXU), Resin (C&B), and Temporary cements ((RXT) and (TCS))] were bonded to a total number of 224 square blocks ($5{\times}5{\times}3mm$) made of one pure metal [Titanium (CP Ti) and two metal alloys [Gold-Platinum (Au-Pt) and Cobalt-Chrome (Co-Cr)] under 10 N and 50 N seating forces. SBS values were determined and data were analyzed with 3-way ANOVA. Pairwise comparisons and interactions among groups were analyzed with Tukey's simultaneous confidence intervals. RESULTS. Overall mean scores indicated that Co-Cr showed the highest SBS values ($1.96{\pm}0.4$) (P<.00), while Au-Pt showed the lowest among all metals tested ($1.57{\pm}0.4$) (P<.00). Except for PCC/CP Ti, RXU/CP Ti, and GIC/Au-Pt factor level combinations (P<.00), the cements tested under 10 N seating force showed no significantly higher SBS values when compared to the values of those tested under 50 N seating force (P>.05). The PCC cement showed the highest mean SBS score ($3.59{\pm}0.07$) among all cements tested (P<.00), while the resin-based temporary luting cement RXT showed the lowest ($0.39{\pm}0.07$) (P<.00). CONCLUSION. Polycarboxylate cement provides reliable bonding performance to metal surfaces. Resin-based temporary luting cements can be used when retrievability is needed. GIC is not suitable for permanent cementation of fixed dental prostheses consisting of CP Ti or Au-Pt substructures.

• Journal of Food Hygiene and Safety
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• v.17 no.4
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• pp.178-182
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• 2002

This study was conducted to estimate the status of heavy metal contamination in agricultural products (n = 280), soils (n = 280), and irrigation waters (n = 48) in abandoned mines & normal farm lands (n = 8). The samples were digested with acids, then analyzed fur the contents of lead (Pb), cadmium (Cd), copper (Cu), mercury (Hg), arsenic (As) and chrome (Cr) by an inductively coupled plasma spectrometer (ICP) and graphite- atomic absorption spectrophotometer (AAS). The contents of Hg were determined using a mercury analyzer. Abandoned mines had soils with higher contents of heavy metals except Cr and irrigation waters with higher heavy metals except Hg, compared to those of normal farmlands. The contents of heavy metals in agriculture products varied depending types of products. Agricultural products in abandoned mines generally showed with higher contents of heavy metals except Cu, compared to those of normal farmlands. There was no significant relationship in heavy metal contents between agricultural products and soils (p > 0.05). It is suggested that heavy metals of agricultural products and soils in abandoned mines should be continuously monitored.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.4
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• pp.465-474
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• 2005

This study was conducted to estimate the contents of heavy metals 'mercury(Hg), cadmium(Cd), lead(Pb), arsenic(As), zinc(Zn), copper(Cu), chrome(Cr) and manganese(Mn)' in root vegetables which were produced in Korea. The levels of heavy metals were determined using a mercury analyzer, an ICP(inductively coupled plasma spectrometer) and an AAS(atomic absorption spectrophotometer) after wet digestion. The values of heavy metals 'mean(minimum-maximum)' mg/kg(ppm) in root vegetables (radish, turnip, carrot, ginger, edible burdock, taro, Chinese yam, east indian lotus) were as follows ; Hg : 0.0019(0.0002${\~}$0.0062), Cd : 0.0088(ND${\~}$0.0402), Pb : 0.021(ND${\~}$0.1070), As : 0.0401(ND${\~}$0.1732), Zn : 1.865(0.4186${\~}$6.9319), Cu : 0.648 (0.1826${\~}$4.0172), Cr : 0.121(0.0132${\~}$1.2030), and Mn : 2.730(0.0477${\~}$10.0468) mg/kg. These results showed that Hg were generally similar to and Cd was lower but Ph, As, Zn, Co, Mn were little higher than the levels of those reported contents in root vegetables on retail markets in Korea. Although the tolerable limit of Cd and Hg is not set in a regulation of WHO/FAO, the tested mean levels(Pb, As, Zn, Cu) were lower than the regulated ones of WHO/FAO, Pb '0.1-2.0', As '1.0', Zn '5.0', and Cu 0.1${\~}$50 mg/kg from vegetables. Therefore, root vegetables sold in the retail markets were evaluated as safe in terns of the heavy metal contents.

• Korean Journal of Veterinary Service
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• v.34 no.3
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• pp.279-284
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• 2011

This study was carried out to estimate the heavy metal contents (Pb, Cd, Cr, Cu, Mn) in avian eggs sold in Seoul area, Korea from August to December, 2010. The contents of lead, cadmium, chrome, copper, manganese were estimated by inductively coupled plasma mass spectrometry. The concentrations of heavy metals (mean${\pm}$standard deviation, mg/kg) in the avian eggs were as follows: Pb $0.010{\pm}0.018$, Cd $0.000{\pm}0.001$, Cr $0.018{\pm}0.022$, Cu $0.637{\pm}0.163$, Mn $0.397{\pm}0.132$. The contents of lead and cadmium in the eggs were lower than that in meat and other foods of previously reported results. Whereas the contents of copper, manganese were similar to the previously previous results. The average daily intakes of lead and cadmium in the avian eggs were 0.1 and 0.8% respectively, as compared with PTWI (Provisional Tolerable Weekly Intakes) established by FAO/WHO Expert Committee for Food Safety Evaluation.

• Textile Coloration and Finishing
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• v.8 no.6
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• pp.40-46
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• 1996

In order to investigate a practical application of fibrous absorbents to transition metals such as copper, nickel, cobalt, chrome, and iron, amidoximated fiber as a particular class of solid chelate agents were prepared from acrylic fibers treatment with hydroxylamine. The adsorption mechanisms of metal ions onto amidoximated acrylic fibers and their complexes were studied. Amidoximation of acrylic fiber with hydroxylamine is found to be first-order reaction, followed by the disappearance of infrared adsorption peaks due to nitrile groups of acrylic fibers. The uptake of metal ions onto amidoximated acrylic fiber is increased with temperature raising and the adsorption is also depended on pH of the soiutions. About 70% of metal ions can be recovered from aqueous solutions of Ni(II), Co(II), Cr(III), and Fe(II) on the concentration below 5x 10$^$^{-4}$ in the range of pH 2.1~10.0. Transition metals are adsorbed to form complex with amidoxime group by the ligand sites such as C=N, NH, NO, NHOH.OH.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.4
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• pp.100-106
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• 2007

In this paper, first we went through the deliming and degreasing as pre-treatment of limed pelt scrap which is derived from liming process during leather manufacturing processing. After that, we produced fine collagen using non-chrome tanning and heat treatment and using acryl monomer graft polymerization such as GMA and MMA. From the comparisonof final products made by various methods, they showed good features in pyrolysis temperature, heat-resisting, variation of moisture content and particle distribution.

• Journal of the Korean institute of surface engineering
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• v.44 no.5
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• pp.220-225
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• 2011

304 stainless steel plate was colored by hot dip and electrochemical treatment in a solution containing sulphuric and chromic acids. In the process, treatment variables such as operating time and methode were changed. The surface characteristics that changed by the treatment of the samples such as surface composition, oxide film thickness, color, surface roughness and reflectivity were studied. Surface composition was varied as follows. Fe was decreased, but Cr and O were increased. Ni was increased until 20 min, but reveals decreasing tendency as time passed after that. These means the surface film becomes chrome rich oxide phase as the treatment times increase. The thickness of film was about 220 nm at 30 min by dip treatment and it reduced as the treatment times increased. On the other hand, the thickness was about 150 nm at 10 min by electrochemical method and it doesn't increased with time. Surface color changed from metallic white of the base plate to gray, black, red, and green-blue, gradually, as the treating time increased. The reflectivity of colored surface measured by UVVIS-NIR spectrophotometer was reduced from max 38% of basis metal to min 3.5%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1739-1744
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• 2008

Non-toxic orgarnic inorgarnic complex green pigment using Fluidized Bed Vapor Deposition(FB-VD) process was developed to alternate green pigment used heavy metals chrome and lead in present domestic. Kaolin materials and $CaCO_3$ were used as supporter of pigment and surface and compositions of supporters were characterized by SEM and EDXS, respectively. Various kind of surface active agents(surfactants) were also used to optimize the dry condition or color revelation. Results showed that anion type surfactant is most suitable for dry and color revelation of pigment.