• Journal of the Korea Concrete Institute
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• v.22 no.3
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• pp.287-295
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• 2010

In this study, ordinary Portland cement was used and the air void was minimized by using minute quartz as the filler. In addition, steel fibers were used to mitigate the brittle failure problem associated with high strength concrete. This study is in progress to make an Ultra-high strength powdered concrete (UHSPC) which has compressive strength over 300 MPa. To increase the strength of concrete, we have compared and analyzed the compressive strengths of the concretes with different mix proportions and curing conditions by selecting quartz sand, dolomite, bauxite, ferro silicon which have diameters less than 0.6 mm and can increase the bond strength of the transition zone. Ultra-high strength powdered concrete, which is different from conventional concrete, is highly influenced by the materials in the mix. In the study, the highest compressive strength of the powdered concrete was obtained when it is prepared with ferro silicon, followed in order by Bauxite, Dolomite, and Quartz sand. The amount of ferro silicon, when the highest strength was obtained, was 110%, of the weight of the cement. SEM analysis of the UHSPC showed that significant formation of C-S-H and Tobermorite due to high temperature and pressure curing. Production of Ultrahigh strength powdered concrete which has 28-day compressive strength upto 341MPa has been successfully achieved by the following factors; steel fiber reinforcement, fine particled aggregates, and the filling powder to minimize the void space, and the reactive materials.

• Journal of Periodontal and Implant Science
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• v.40 no.1
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• pp.3-10
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• 2010

Purpose: Periodontal regenerative therapies for defects created by severe periodontitis are mainly focused on bone regeneration. Although cementum regeneration needs to be better understood, it is believed to play an important role in periodontal regeneration. The first step toward a full understanding of cementum regeneration is to compare repaired cementum to pristine cementum. This study, which used histological techniques, was designed to focus on cementum regeneration and to compare pristine cementum to repaired cementum after surgical procedures with 8 and 24 week healing periods in a canine model. Methods: Buccal and lingual mucoperiosteal flaps of 10 beagle dogs were surgically reflected to create critical-sized defects. Intrabony one-wall defects, of which dimension is 4 mm width and 5 mm depth, were made at the distal aspect of mandibular second premolars and the mesial aspect of mandibular fourth premolars in the right and left jaw quadrants. Animals were sacrificed after 8 and 24 weeks post-surgery for histological specimen preparation and histometric analysis. Results: The repaired cementum was composed mostly of acellular cementum and cellular mixed fiber cementum and was thicker in the apical area than in the coronal area. The acellular cementum of the supracrestal area appeared to be amorphous. The newly formed cellular cementum was partially detached from the underlying circumpulpal dentin, which implied a weak attachment between new cementum and dentin, and this split was observed to a lesser extent in the 24 week group than in the 8 week group. The vertical height of the repaired cementum was greater in the 24 week group than in the 8 week group. Conclusions: Within the limitations of this study, we can conclude that repaired cementum after root planing was mainly acellular cementum and cementum tissue that matured to a shape similar to pristine cementum as the healing progressed from 8 to 24 weeks.

• Food Science and Preservation
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• v.12 no.6
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• pp.546-551
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• 2005

The new developed production process and the coating equipment were used to prepare the alginate coated rice having functional property. Then, the quality characteristics such as proximate analysis, moisture sorption properties, influence on the retrogradation, sensory evaluation were investigated. The moisture content of the alginate coated rice was $16.5-18\%$ which is $1.5\%$ higher than the normal rice. About $0.3\%$ alginate was coated on the rice by the measurement of carbohydrate content after coating with $2\%$ alginate. The rice coated with higher alginate concentration showed the higher moisture absorption. The rice coated with $2\%$ alginate solution stored $30^{\circ}C$ and $85\%$ RH conditions for 6 weeks and it increased $1.8\%$ of the moisture content The alginate coated rice has delayed the retrogradation more than 6 hrs as well as got the higher scores for the appearance, stickiness, and taste. The alginate coated rice is a good source of the fiber in the nutritional aspect and it improves the quality and functionality of the rice.

• Tuberculosis and Respiratory Diseases
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• v.48 no.2
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• pp.260-267
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• 2000

Giant cell interstitial pneumonia. a synonym for hard metal pneumoconiosis, is a unique form of pulmonary fibrosis resulting from an exposure to hard metal dust. A case of biopsy-proved giant cell interstitial pneumonia in the absence of appropriate history of exposure to hard metal dust is reported. The patient presented with clinical features of chronic interstitial lung disease or idiopathic pulmonary fibrosis. He worked in a chemical laboratory at a fertilizer plant, where he had been exposed to various chemicals such as benzene and toluene. He denied having any other hobby in his house or job at work, which may have exposed him hard metal dust. High-resolution CT scan revealed multi-lobar distribution of ground glass opacity with peripheral and basal lung predominance. The retrieved fluid of bronchoalveolar lavage contained asbestos fiber and showed neutrotphil predominance. Surgical lung biopsy was performed for a definite diagnosis. Lung specimen showed alveolar infiltration of numerous multinucleated giant cells with mild interstitial fibrosis. Upon detailed examination of the lung tissue, one asbestos body was found. An analysis for mineral contents in lung tissue was performed. Compared with the control specimen, the amount of cobalt and several hard metal components in the lung tissue of this patient was ten times higher. We speculated that the inconsistency between occupational history and the findings of pathologic and mineralogical analyses could be explained by the difference in individual immunologic reactivity to hard metal dust despite the relatively small amount of unrecognized environmental exposure(ED: It's hard to understand what this phrase is trying to say).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.4
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• pp.371-381
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• 2020

The failure mode of concrete reinforced with FRP is defined as the concrete crushing and the fiber rupture and the definition of limit state is a slightly different according to the design methods. It is relatively difficult to predict of FRP reinforced concrete because the mechanical properties of fibers are quite depending on its of fibers. The design code by ACI440 committee, which has been developed mainly on GFRP having low modulus of elasticity, is widely used, but the applicability on other FRPs of this code has not been sufficiently verified. In addition, the ultimate and serviceability limit state based on the ACI440 are comparatively difficult to predict the behavior of member with the 0.8~1.2 𝜌_b because crushing and rupturing failure can be occurred simultaneously is in this region of reinforcement ratio, and predicted deflection is too sensitive according to the loading condition. Therefore, in this study, reliability and convenience of the prediction of structural performance by design methods such as ACI440 and MC90 concept, respectively, were examined through the experimental results and literature review of the beam and slab with the reinforcement ratio of 0.8 ~ 1.4. As a result of the analysis, it can be applied to the FRP reinforced structure in the case of the simple moment-curvature formula (LIM-MC) of Model Code, and the limit state design method based on the EC2 is more reliable than the ultimate strength design method.

• Journal of Food Hygiene and Safety
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• v.35 no.3
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• pp.213-218
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• 2020

This study was conducted to develop a method of analysis for 4-hydroxy-L-isoleucine in the seed extract of fenugreek (Trigonella foenum graecum), a health functional food that contains dietary fiber. The analytical method for 4-hydroxy-L-isoleucine was derived with O-phthaldialdehyde reagent (OPA) and determined by HPLC-PDA. The method was performed on a Capcell Pak C₁₈ UG 120 column (4.6×250 mm, 5 ㎛) in isocratic elution mode using disodium phosphate and acetonitrile. The validation of the developed analytical method was conducted by evaluating several parameters; selectivity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy and repeatability. Excellent linearity (R²=0.999) was observed for 4-hydroxy-L-isoleucine in the concentration range (5-100 ㎍/mL). Observed recoveries of these compounds were found to be between 91.7 and 96.4%. Precision was between 0.2 and 2.4% relative standard deviation (%RSD).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.458-465
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• 2006

This study was carried out to evaluate the nutritional properties of quality protein maize (QPM) and to select the elite lines for corn breeding. Two laboratory procedures for simultaneous identification of QPM and lysine content analysis were performed. The $BC_{1}F_{2}$ lines of KS5/QPM and KS135/QPM were analyzed with opaque-2(o2) specific SSR marker in order to differentiate the opaque-2 carrying QPM lines from the non-opaque genotypes. Although no significant difference in protein content, significant differences in lipid, ash, and crude fiber contents were observed. The composition of unsaturated fatty acid of QPM lines was slightly lower than non-QPM lines, but there was no significant difference. Sulphur-containing amino acids such as methionine and cystine showed no difference between QPM and non-QPM lines. However, lysine content of QPM lines was 38% higher than that of non-QPM lines, and the essential amino acid content of QPM lines (28.1%) was higher compared to non-QPM lines (27.1%).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.3
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• pp.139-145
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• 2011

Objectives: This investigation is purposed to evaluate the airborne asbestos concentrations in the public buildings having asbestos containing materials(ACMs) in Seoul. Methods: The Seoul Metropolitan Government carried out an asbestos survey to the city-owned public buildings to identify the level of risk exposure, classified into low, moderate and high risk. To evaluate the airborne concentration of asbestos, 11 sampling sites in ten buildings based on the survey were selected. The air samples from the eleven sites were analyzed by Phase Contrast Microscopy(PCM) and Transmission Electron Microscopy (TEM), and compared the analytical results from the both. Results: 1. The airborne fiber concentrations by PCM were less than the detection limit($7f/mm^2$) in 9(82%) out of 11 sampling sites. The highest concentration was 0.0043 f/cc, but it was below the guideline value for indoor air quality(0.01 f/cc), proposed by the Ministry of Environment, Korea. 2. In two sampling sites, having moderate risk level, the chrysotile was identified and showed it's concentrations of 0.0102 s/cc and 0.0058 s/cc, less than $5{\mu}m$ lengths. 3. The ACMs identified in the two sampling sites were a packing material(65% of chrysotile) in mechanical area and a thermal system insulation(5% of chrysotile) in a boiler room. Having more possibility of asbestos emission in the mechanical area, it would be required to set up and carry out the asbestos management plan. Conclusions: Based on the result of this study, the airborne asbestos concentrations in the public buildings with ACMs were generally lower than the guideline value for indoor air quality. There are widespread concerns about the possible health risk resulting from the presence of airborne asbestos fibers in the public buildings. Most of the previous studies about airborne asbestos analysis in Korea were performed based on PCM method that asbestos and non-asbestos fibers are counted together. In the public and commercial buildings, having ACMs, it is suggested that the asbestos be analyzed by TEM method to identify asbestos due to concerns about asbestos exposure to workers and unspecified people.

• Korean Journal of Veterinary Research
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• v.43 no.3
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• pp.423-428
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• 2003

The purpose of this study is to compare the morphology, general composition, elemental composition and mineral contents of Phellinus linteus, Phellinus baumii and Phellinus gilvus. In the scanning electron microscopy, P. gilvus and P. linteus had a similar shape. In the elemental composition, all of the three Phellinus spp. showed similar percent for the analyzed components. In the general composition, the water content of P. linteus. P. baumii and P. gilvus were 13%, 15% and 10%, respectively. The dietary fiber of three Phellius spp. showed more than 30%. The range of vitamin C and protein content was 1.5-2.1 g% and 3.63-3.73 g%. respectively. In mineral analysis, P. baumii of the three Phellinus spp. has the highest calcium concentration (1,135 ppm). From the above results, P. linteus. P. baumii and P. gilvus did not show any differences in the general composition and elemental composition.

• Conservation Science in Museum
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• v.13
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• pp.51-58
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• 2012

The Conservation Science Team of the National Museum of Korea has carried out the conservation on the mandolin-type bronze sword that was excavated from Weolnae-dong, Yeosu as had been requested by the Research Center of Dolmens in Northeast Asia. The mandolin-type bronze sword from Weolnae-dong, Yeosu is accounted to be the longest one among all the bronze swords of the same type that have ever been excavated until now and it was in a treated condition with the primary conservation treatment already achieved. Due to the corrosion in progress, it was in a very brittle condition being in two separate parts of the upper and lower parts. With the upper part exposed and the lower part with earth, they were urgently collected. The Conservation Science Team carried out the conservation treatment on them by connecting the lower part of the mandolin-type bronze sword to the upper part after making the lower part exposed, and then by using an estimated restoration method for lost portions. When carrying out the conservation treatment, the glass fibers of 10 wt% Paraloid B-72 (in Xylene) was used as a method for strengthening the brittle artifact, and a non-destructive analysis was carried out to identify the ingredients using the X-ray fluorescence spectrometer.