• Fire Science and Engineering
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• v.34 no.1
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• pp.18-25
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• 2020

In this study, the heat release rate of pipe insulation is analyzed by considering the installation status in accordance with the standards ISO 20632 and NFPA 274. The flame retardation rate was evaluated for six types of test samples: polyethylene foam covered with beaten silver (PE(S)), PE foam tapped (PE(N)), elastomeric closed cell thermal insulation (rubber), Japanese PE foam (PE(J)), Japanese polyurethane foam (PU(J)), and Japanese styro form (ST(J)) by EN 13501-1 and fire growth curve. The results show that PU(J), PE(J), and PE(N) were Class E and ultra-fast, NFPA 274 test standards for Class D and Fast, and PE(S) by ISO 20632 were Class C and Slow, and Rubber and ST(J) were Classes and Low. However, the changes in the time-averaged maximum heat release rate for each test standard (ISO 20632 and NFPA 274) to evaluate the flame retardation rate differed among identical materials. This means that the fundamental study is necessary to analyze the more accurate reasons.

• Proceedings of the KSPS conference
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• 2007.05a
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• pp.155-157
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• 2007

Objective : There are close relationship between intraoral abnormal structure and speech-functional problem. Patients with cleft palate & ankyloglossia are typical examples. Patients with abnormal structure can be repaired toward normal structure by operation. Ankyloglossia may cause functional limitation - for example, speech disorder - even if adequate surgical treatment were done. And, each individuals have each speech disorders. The objective of this study is to evaluate the speechs of childrens with ankyloglossia, and to determine whether ankyloglossia is associated with articulation problem. We wanted to present criteria for indication of frenectomy. Study design The experimental group is composed of 10 childrens who visited our department of oral and maxillofacial surgery, dental hospital, Chonbuk university, due to ankyloglossia and articulation problem,. The average age is 5 Y 7M, M : F ratio is 4 : 1 at the time of speech test. The VPI consonant discrimination degree, PPVT, PCAT, Nasometer II, Visi-Pitch test result were obtained from each group. Result : There was significant difference for 'language development' through PPVT. Except 3 members of experimental group, all remainder showed retardation for 'language development'. For 'errored consonant rate', data showed more higher scores in alveolar consonant. There 'consonant error' in experimental group, mostly showed 'alveolar consonant', also a major modality of 'consonant error' was mostly distortion. Conclusion : We can judge the severity of ankyloglossia patient by examinig language development degree & speech test of 'alveolar consonant' . And we can make a decision for frenulotomy using these results.

• Journal of Surface Science and Engineering
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• v.24 no.1
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• pp.34-34
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• 1991

Corrosion behavior of TiN coated steel was studied in terms of thickness of interlayer Ti and TiN coating TiN was are ion plated to a thickness of 1$\mu\textrm{m}$ and 2$\mu\textrm{m}$ respectively with interlayer coating of Ti of 1$\mu\textrm{m}$, 2$\mu\textrm{m}$ and 3$\mu\textrm{m}$. Corrosion resistance of TiN coated steel was evaluated by anodic palarization test in 1N H2SO4 as well as salt spray test. Porosity of each coating was also tested by using SO2 test method. Corrosion current density decreased with increasing TiN coating thickness and Ti interlayer coating markedly enhanced the corrosion resistance. Ti interlayer coating of 2$\mu\textrm{m}$ and 3$\mu\textrm{m}$ prior to 2$\mu\textrm{m}$ TiN coating decreased the corrosion current density of active range by an order of 4 and that of passive range by an order of 2. This improvement was associated with the retardation of corrosive agent penetration with increasing coating thickness and inherent corrosion resistance of Ti interlayer. Ti interlayer coating was also very effective in improvement of corrosion resistance under salt atmosphere.

• Transactions of Materials Processing
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• v.8 no.3
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• pp.309-309
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• 1999

Effects of rare earth metals addition and aging treatment on corrosion resistance and mechanical properties of super duplex stainless steels were investigated using optical/SEM/TEM metallographic examination, an X-ray diffraction test, a potentiodynamic anodic polarization test and a tensile test. The performance of the experimental alloy with 0.32% REM addition was compared with commercial super duplex stainless steel such as SAF 2507 when they were exposed to solution annealing heat treatment and aging treatment. The corrosion resistance in CF environments and mechanical properties of the experimental alloy were found superior to those of the commercial duplex stainless steel. The REM with larger atomic radii than those of Cr, Mo and W may fill vacancies inside the matrix and around the grain boundaries, retarding formation of harmful intermetallic σ and χ phases. In addition, fine REM oxides/oxy-sulfides (1-3㎛) seemed to enhance the retardation effects. With REM additions, strength and ductility increased due to the phase and grain refinement caused by fine REM oxides and oxy-sulfides.

• Journal of Surface Science and Engineering
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• v.25 no.1
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• pp.34-39
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• 1992

Corrosion behavior of TiN coated steel was studied in terms of thickness of interlayer Ti and TiN coating. TiN was arc ion plated to a thickness of 1$\mu\textrm{m}$ and 2$\mu\textrm{m}$ respectively with interlayer coating of Ti of 1$\mu\textrm{m}$, $2\mu\textrm{m}$ and $3\mu\textrm{m}$. Corrosion resistance of TiN coated steel was evaluated by anodic palarization test in 1N $H_2$SO$_4$ as well as salt spray test. Porosity of each coating was also tested by using $SO_2$ test method. Corrosion current density decreased with increasing TiN coating thickness and Ti interlayer coating markedly enhanced the corrosion resistance. Ti interlayer coating of $2\mu\textrm{m}$ and $3\mu\textrm{m}$ prior to $2\mu\textrm{m}$ TiN coating decreased the corrosion current density of active range by an order of 4 and that of passive range by an order of 2. This improvement was associated with the retardation of corrosive agent penetration with increasing coating thickness and inherent corrosion resistance of Ti interlayer. Ti interlayer coating was also very effective in improvement of corrosion resistance under salt atmosphere.

• Journal of Surface Science and Engineering
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• v.25 no.2
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• pp.82-89
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• 1992

The effect of interlayer coating of Ni and Ti on corrosion behavior was studied in TiN ion plated steel plate. Interlayer coating was carried out in a single and bi-layer to a various thickness combination prior to final TiN coating of $2\mu\textrm{m}$. Corrosion behavior was evaluated by anodic polarization test in 1N H2SO4 as well as salt spray test. Porosity of each coating was also tested by using SO2 test. Corrosion resistance was improved with increasing the thickness of Ni interlayer coating and Ni-Ti interlayer coating markedly enhanced the corrosion resistance. Ni/Ti interlayer coating of $2\mu\textrm{m}$/2$\mu\textrm{m}$ prior to $2\mu\textrm{m}$ TiN coating decreased the corrosion current density of active range by an order of 4 and that of passive range by an order of 1. This improvement was associated with the retardation of corrosive agent penetration with increasing coating thickness and inherent corrosion resistance of Ni and Ti interlayers, Ni/Ti interlayers coating were also very effective in improvement of corrosion resistance under salt atmosphere.

• Applied Chemistry for Engineering
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• v.21 no.6
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• pp.627-631
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• 2010

This study was performed to test the combustion-retardation properties of Pinus rigida-based materials by the treatment of ammonium salts. Pinus rigida plate was soaked by the treatment with three 20 wt% ammonium salt solutions consisting ammonium sulfate (AMSF), monoammonium phosphate (MAPP), and diammonium phosphate (DAPP), respectively, at the room temperature. After the drying specimen treated with chemicals, combustion properties were examined by the cone calorimeter (ISO 5660-1). When the ammonium salts were used as the retardant for Pinus rigida, the flame retardancy improved due to the treated ammonium salts in the virgin Pinus rigida. However the specimen shows increasing CO over virgin Pinus rigida and It is supposed that toxicities depend on extents. Also, the specimen with ammonium sulfate showed both the lower total smoke release (TSR) and lower total smoke production (TSP) than those of virgin plate. Among the specimens, the sample treated with diammonium phosphate showed a strong inhibitory effect of combustion.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.117-121
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• 1969

Germination and field test were made with the spring barley sprouted with gibberellin solution of 5 levels from 5 to 100 ppm. Temperatures of room for germination were classified as ordinary and low. Results obtained will be summarized as follows: 1. Sprouting with Gibberellin promoted the germination by two days in ordinary and three days in low temperature without reducing the germination rate. 2. The higher concentration of gibberellin showed the more promotion of growth in early stage. 3. No retardation of root-growth was found by gibberellin sprouting. 4. No promoting effects to germination by gibberellin sprouting was found in field tests. In high concentration, percentage of germination, number of spike and grain yields reduced remarkably. 5. More remarkable tendency of weak growth and longer duration of recovery were found in the higher concentration of gibberellin, but all plots recovered from weak growth at middle stage of plant growth. 6. In gibberellin concentration of 5 to 10 ppm, retardation of germination, weakness of early growth and reducing of spike number were not remarkable while length of spike and 1000 grain weight were increased. Therefore grain yields showed increasing tendency. 7. Promoting the germination may be expected but hastening of heading and maturing may not be available by gibberellin treatment in sprouting.

• Polymer(Korea)
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• v.24 no.4
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• pp.545-555
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• 2000

Surface defects in injection molded parts due to the unsteady flow are related to the dimension of gate, operational conditions and rheological properties of polymer. In this study we have examined surface defects in injection molding for PC, PBT and PC/ABS alloy with several injection speeds. We have used various cavity shapes that are tensile, flexural and impact test specimens with various gate and cavity thicknesses. Through this study we have observed that the formation of surface defect associated with jetting during filling stage in injection molding is strongly related to not on]v die swell but retardation of die swell. Large die swell eliminates jetting however the large retardation of die swell stimulates jetting. Reducing the thickness ratio of cavity to gate can reduce or eliminate jetting and surface defects. It also enlarges process window that can produce steady flow of polymer melt in injection molding.

• Clinical and Experimental Pediatrics
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• v.61 no.7
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• pp.221-225
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• 2018

Purpose: Congenital hypothyroidism (CH) is the most common endocrine disorder in children. Thyroid hormone deprivation results not only in mental retardation but also growth retardation. This study investigates the final height (FH) in Korean patients with CH detected by newborn screening and examines factors that may affect the FH. Methods: The medical records of Korean CH patients (n=45) were reviewed. The FH was examined and target height (TH) was calculated based on mid-parental height. The FH z score (FHZ) and TH z score (THZ) were computed using the 2007 Korean National Growth Chart. The FHZ and THZ were compared with a Student t test. The impact of the etiology of CH (athyreosis, dyshormonogenesis, ectopic thyoid, hypoplastic thyroid), initial serum thyroid stimulating hormone (TSH) level, initial free thyroxine (T4) level, and time of therapy initiation based on FH was assessed. Results: The mean FHZ was $0.10{\pm}1.01$ for male patients and $-0.11{\pm}1.09$ for female patients. There were no significant differences between FHZ and THZ for both female (P=0.356) and male patients (P=0.237). No significant relationship was found between FH and the etiology of CH, initial TSH level, initial free T4 level, and the time of therapy initiation. Conclusion: Early intervention and satisfactory management do not appear to impede growth in Korean patients with CH. Thus, early detection and proper management of patients with CH detected by newborn screening program are necessary.