• Journal of Environmental Health Sciences
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• v.44 no.5
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• pp.491-501
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• 2018

Objectives: The aims of this study were to compare concentrations and the correspondence of human blood cadmium by using graphite furnace atomic absorption spectrometry (GF-AAS) and inductively coupled plasma-mass spectrometry (ICP-MS), which are representative methods of heavy metal analysis. Methods: We randomly selected 79 people who agreed to participate in the research project. After confirming the linearity of the calibration curves for GF-AAS and ICP-MS, the concentrations of cadmium in a quality control standard material and blood samples were measured, and the correlation and the degree of agreement were compared. Results: The detection limit of ICP-MS (IDL: $0.000{\mu}g/L$, MDL: $0.06{\mu}g/L$) was lower than that of GF-AAS (IDL: $0.085{\mu}g/L$, MDL: $0.327{\mu}g/L$). The coefficient of variation of the quality control standard material showed stable values for both ICP-MS (clinchek-1: 5.35%, clinchek-2: 6.22%) and GF-AAS (clinchek-1: 7.92%, clinchek-2: 5.22%). Recovery was relatively high for both ICP-MS (clinchek-1: 95.1%, clinchek-2: 92.8%) and GF-AAS (clinchek-1: 91.4%, clinchek-2: 98.8%), with more than 90%. The geometric mean, median, and percentile of blood samples were all similar. The agreement of the two instruments compared with the bias of the analytical values found that about 81% of the analytical values were within ${\pm}30%$ of the deviation from the ideal reference line (y=0). As a result of the agreement limit, the value included in the confidence interval was about 94%, which shows high agreement. Conclusion: In this study, we confirmed there was no significant difference in concentrations of a quality control standard material and blood samples. Since ICP-MS showed lower concentrations than GF-AAS at concentrations below the method detection limit of GF-AAS, it is expected that more precise results will be obtained by analyzing blood cadmium with ICP-MS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.334-339
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• 2020

In this study, the adhesion properties between aluminum and composite materials, composite materials, and composite materials were compared according to the physical surface treatment to improve mechanical bonding at the bonding surface when considering carbon fiber and glass fiber-reinforced composite materials. Bonded specimens were classified into the type of base material and the surface treatment method of the bonding surface. Sandpaper, sandblasting, and plasma were applied as physical surface treatment methods. The bonded specimen was prepared as a single lap joint test specimen. An experiment to measure the lap shear strength was conducted, and the results were compared. The experimental results confirmed that the mechanical abrasion and sandblasting treatment improved the lap shear strength approximately 4 to 5 fold compared to the general specimen without physical surface treatment. In plasma treatment, the experiment was conducted by defining the respective plasma output and treatment time as follows: 150 W and 5 minutes, 150 W and 10 minutes, and 300 W and 3 minutes. Moreover, the lap shear strength results were similar to the previous mechanical surface treatments. On the other hand, the effect on the adhesion properties was small, depending on the plasma treatment conditions.

• Journal of Conservation Science
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• v.8 no.1 s.11
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• pp.51-57
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• 1999

Although the mummies of Lee, Myeong-Jung and his wife whose family name is Moon, were buried in similar sites in 1560's, the degree of decay of the dead bodies and antiquities between two people were quite different. This study was focused on the cause of those differences in the view of engineering concept. Granular soil around the study site shows good drainage and such characteristic could be a factor of excellent conservation of dead body. From the physical characteristics of the material containing lime that is considered to be a barrier from water and air, it was observed that the material around dead body of the wife was more compact and denser than that of the husband. This may suggest that the former is better than the latter in keeping away from the water and air. To understand those differences of physical characteristics between two materials containing lime, minerals had to be identified from the two materials. It was revealed that material containing lime around dead body of the wife contains gypsum and more calcite, which could be the reason for better barrier Preventing from water and air than that around the husband.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.4
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• pp.106-113
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• 1997

Dynamic loading of structures often causes excursions of stresses well into the inelastic range, and the influence of the geometric changes on the dynamic response is also significant in many cases. Therefore, both material and geometric nonlinearity effects should be considered in case that a dynamic load acts on the structure. A structure in a nuclear power plant is a structure of importance which puts emphasis on safety. A nuclear container is a pressure vessel subject to internal pressure and this structure is constructed by a reinforced concrete or a pre-stressed concrete. In this study, the material nonlinearity effect on the dynamic response is formulated by the elasto-viscoplastic model highly corresponding to the real behavior of the material. Also, the geometrically nonlinear behavior is taken into account using a total Lagrangian coordinate system, and the equilibrium equation of motion is numerically solved by a central difference scheme. The constitutive relation of concrete is modeled according to a Drucker-Prager yield criterion in compression. The reinforcing bars are modeled by a smeared layer at the location of reinforcements, and the steel layer model under Von Mises yield criteria is adopted to represent an elastic-plastic behavior. To investigate the dynamic response of a nuclear reinforced concrete containment structure, the steel-ratios of 0, 3, 5 and 10 percent, are considered. The results obtained from the analysis of an example were summarized as follows 1. As the steel-ratio increases, the amplitude and the period of the vertical displacements in apex of dome decreased. The Dynamic Magnification Factor(DMF) was some larger than that of the structure without steel. However, the regular trend was not found in the values of DMF. 2. The dynamic response of the vertical displacement and the radial displacement in the dome-wall junction were shown that the period of displacement in initial step decreased with the steel-ratio increases. Especially, the effect of the steel on the dynamic response of radial displacement disapeared almost. The values of DMF were 1.94, 2.5, 2.62 and 2.66, and the values increased with the steel-ratio. 3. The characteristics of the dynamic response of radial displacement in the mid-wall were similar to that of dome-wall junction. The values of DMF were 1.91, 2.11, 2.13 and 2.18, and the values increased with the steel-ratio. 4. The amplitude and the period of the hoop-stresses in the dome, the dome-wall junction, and the mid-wall were shown the decreased trend with the steel-ratio. The values of DMF were some larger than those of the structure without steel. However, the regular trend was not found in the values of DMF.

• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.530-537
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• 2014

Moisture is a major factor causing the deteriorative physical change, microbial growth, and chemical reaction of the products. In this study, the moisture absorbing composite films have been prepared with moisture absorbing material of polyacrylic acid partial sodium salt (PAPSS) impregnated on LLDPE polymer for the functional packaging applications. The results showed that PAPSS impregnated film illustrated uniformly dispersed PAPSS particles in the LLDPE polymer matrix. The transparency of the PAPSS impregnated film decreased slightly at higher PAPSS concentrations. An increase in the PAPSS content for moisture-absorbing films showed a similar decrease in tensile strength, percent elongation at break, and tear strength. Their values of films impregnated with PAPSS of 0.5, 1, and 2% showed no significant difference. Meanwhile, 4% PAPSS films significantly decreased the values of mechanical properties compared to the films impregnated with different PAPSS levels. Values of the oxygen permeability and water vapor permeability for PAPSS impregnated films decreased significantly with greater PAPSS. The results indicate that 4% PAPSS impregnated in LLDPE films had high affinity of moisture absorbencies compared to the other films. The mathematical equation that best described the moisture sorption isotherm of each film sample was the GAB equation at $25^{\circ}C$. The crystallization and melting temperatures of PAPSS films were influenced by the addition of PAPSS material, but showed good thermal stability.

• Journal of the Mineralogical Society of Korea
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• v.32 no.4
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• pp.273-285
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• 2019

This study is aimed to interpret the raw material characteristics and manufacturing technology through physical, mineral and geochemical analysis of the brown-glazed stonewares and roof tiles excavated from the Hong Nang Sida temple in Laos, which was built in the 12th century. The glaze of brown-glazed stoneware is a typical lime serial with CaO content of more than 15 % and they were vitrified. The body is the combination of quartz, mullite and cristobalite, but had not vitrified texture, and therefore, which is assumed to have been fired more than 950 ℃. Meanwhile, The roof tiles are unglazed and its outer color is reddish brown, whitish grey and bluish grey. The bluish gray tiles has sandwich structure, which seem to experience imperfect reducing environment. The tile samples with a number of amorphous iron oxide nodule had a very similar chemical composition. In conclusion, it is assumed that the clay source was made from raw material produced from the same bedrock. The firing temperature of roof tiles were divided into less than 900 ℃, 900~950 ℃ and greater than 950 ℃ according to detection of micas, hercynite and mullite.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.2
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• pp.118-126
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• 2006

In oral and maxillofacial surgery, bone graft is very important procedure for functional and esthetic reconstruction. So, many researcher studied about bone graft material like autogenous bone, allograft bone and artificial bone materials. The purpose of this study is to evaluate the quantity of bone generation induced by $Grafton^{(R)}$ graft, human allogenic demineralized bone matrix. Total 24 sites of artificial bony defects prepared using trephin bur(diameter 8 mm) on parietal bone of six adult New Zealand White rabbits. Experimental group had six defect sites which grafted $Grafton^{(R)}$(0.1 cc). Active control group had nine defect sites, into which fresh autogenous bone harvested from own parietal bone was grafted and passive control group had nine defect sites without bone graft. After six weeks postoperatively, the rabbits were sacrificed. The defects and surrounding tissue were harvested and decalcified in 10% EDTA, 10% foamic-acid. Specimens were stained with H&E. New bone area percentage in whole defect area was measured by IMT(VT) image analysis program. Quantity of bone by $Grafton^{(R)}$ graft was smaller than that of autograft and larger than that of empty defects. In histologic view $Grafton^{(R)}$ graft site and autograft site showed similar healing progress but it was observed that newly formed bone in active control group was more mature. In empty defect, quantity and thickness of new bone formation was smaller than in $Grafton^{(R)}$-grafted defect. $Grafton^{(R)}$ is supposed to be a useful bone graft material instead of autogenous bone if proper maintenance for graft material stability and enough healing time were obtained.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.4
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• pp.313-323
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• 2010

Purpose: This study was conducted to evaluate the effect of beta-tricalcium phosphate (Cerasorb$^{(R)}$, Germany) and deproteinized bovine bone (Bio-Oss$^{(R)}$, Switzerland) grafted to the defect of rat calvaria artificially created and the effect of use of absorbable membrane (BioMesh$^{(R)}$, Korea) on new bone formation. Materials and Methods: Transosseous circular calvarial defects with diameters of 5 mm were prepared in the both parietal bone of 30 rats. In the control group I, no specific treatment was done on the defects. In the control group II, the defects were covered with absorbable membrane. In the experimental group I, deproteinized bovine bone was grafted without absorbable membrane; in the experimental group II, deproteinized bovine bone was grafted with absorbable membrane; in the experimental group III, beta-tricalcium phosphate was grafted without absorbable membrane; in the experimental group IV, beta-tricalcium phosphate was grafted with absorbable membrane. The animals were sacrificed after 3 weeks and 6 weeks respectively, and histologic and histomorphometric evaluations were performed. Results: Compare to the control groups, the experimental groups showed more newly formed bone. Between the experimental groups, beta-tricalcium phosphate showed more resorption than deproteinized bovine bone. Stabilization of grafted material and interception of the soft tissue invasion was observed in the specimen treated with membrane. There was no statistical difference between the experimental group I, III and experimental group II, IV classified by graft material, but statistically significant increase in the amount of newly formed bone was observed in the experimental group I, II and II, IV classified by the use of membrane (P<0.05). Conclusion: Both beta-tricalcium phosphate and deproteinized bovine bone showed similar osteoconductibility, but beta-tricalcium phosphate is thought to be closer to ideal synthetic graft material because it showed higher resorption rate in vivo. Increased new bone formation can be expected in bone graft with use of membrane.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.421-431
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• 2007

The main purpose of this study is to develop a sprayed FRP repair and strengthening method, which is a new technique for strengthening the existing concrete structures by mixing one of the carbon or glass chopped fibers and one of the epoxy or vinyl ester resins with high-speed compressed air in open air and randomly spraying the mixture onto the concrete surface. At present, the sprayed FRP repair and strengthening method using the epoxy resin has not been fully discussed. In order to investigate the material property of the sprayed FRP, this study carried out tensile tests of the material specimens, which were changed with the combinations of various variables including the length of chopped fiber and the mixture ratio of chopped fiber and resin. These variables were set to have the equal material strength, compared with that of one layer of the FRP sheet. As a result, the optimal length of glass and carbon chopped fibers was fumed out to be 38 mm, and the optimal mixture ratio between chopped fiber and resin was also turned out to be 1 : 2 from each variable. And also, the thickness of the sprayed FRP to have the equal strength to one layer of the FRP sheet was finally calculated. In is study, a series of experiments were carried out to evaluate the strengthening effects of flexural beams, shear beams and damaged beams strengthened with the sprayed FRP method, respectively. The results revealed that the strengthening effects of the flexural and shear specimens were reasonably similar to those of the FRP sheet, and the developed Sprayed FRP technique is able to be used as a strengthening scheme of existing RC building.

• The Journal of Internal Korean Medicine
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• v.37 no.3
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• pp.427-441
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• 2016

Objectives: This study investigated the aconitine contents analysis of Buja extracts (raw material of Buja, hot water extract of Buja, and hot water extract of Sambu-tang) and the single oral dose toxicity of Sambu-tang-R in six-week-old Sprague-Dawley rats in order to compare the toxicity of Buja extracts.Methods: Aconitine content analysis is that Buja extracts were hold purity test. To detect single oral dose toxicity, six-week-old Sprague-Dawley rats were divided into two groups, a normal control group and a sambutang-R (2,000 mg/kg) group. For 14 days of treatment, clinical signs, body weight, clinical chemistry, necropsy, and histopathology were examined.Results: The aconitine contents of the Buja extracts were Buja-RH (0.1738%), Buja-RD (0.1746%), and Sambu-tang-R (0.0961%). There were no cases of death in either the control group or the experimental group. Nor was there any disorder to the clinical signs or any significant change in body weight in either group. There was no significant change of clinical chemistry or disorder of necropsy findings in either the control or the experimental group. And there was no difference in histopathological findings in comparing the control group with the experimental group.Conclusions: These results suggest that the aconitine content of the hot water extract of Buja was similar to the raw material of Buja, but the hot water extract of Sambu-tang had greatly decreased aconitine content. These results also suggest that a single oral lethal dose of Sambu-tang-R for Sprague-Dawley rats exceeds 2,000 mg/kg for both female and male rats.