• Restorative Dentistry and Endodontics
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• v.31 no.1
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• pp.11-19
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• 2006

The purpose of this study was to compare and evaluate the shaping abilities of various hybrid instrumentation method using constant tapered file systems with $ProTaper\^{(R)}$ S1 and the difference between experts and inexperienced clinicians in use of NiTi file. Three hybrid methods used in this study were composed of $ProTaper\^{(R)}\;S1\;and\;K-Flexofile\^{(R)}\;(group S),\;ProTaper\^{(R)}\;S1\;and\;HeroShaper\^{(R)}\;(group\;H),\;and\;ProTaper\^{(R)}\;S1\;and\;ProFile\^{(R)}\;(group\;P)$respectively. The $ProTaper\^{(R)}$-alone method (group C) was introduced as a control group. After canal preparation, the lapse of time was recorded. The images of pre- and post-operative canal were scanned and superimposed. Amounts of instrumented canal widths and centering ratio were measured at apical 1, 2 and 3 mm levels and statistical analysis was performed In this study. both of the group C and S took more time to prepare canals than other groups, Inexperienced operators required more time for the entire preparation with the groups C and H than the experienced (p<0.05). And the centering ratio of group P were preferable to $ProTaper\^{(R)}$-alone method or the hybrid technique using stainless steel files. As such, within experienced operators, group H also showed better results in addition to the group P. Under these condition, the hybrid methods of each the $ProFile^{(R)}$ system and $HeroShaper^{(R)}$ with ProTaper are recommendable comparative to $ProTaper\^{(R)}$-alone method. According to the results, the hybrid instrumentation method is a more appropriate method of canal preparation than single file system for narrow or curved canals.

• Journal of Oral Medicine and Pain
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• v.10 no.1
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• pp.73-89
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• 1985

This study comprised 157 extracted teeth, 73 of the teeth originated from mates and 84 from females, the age range was 12-79 years. The correlation coefficient of each Gustafson's criteria in relation to age was carried out. Age estimation were performed on 157 teeth according to the method by Gustafson and by use of multiple regression, as used by Johanson, after evaluating the six criteria of Gustafson by multiple regression computer analysis. Two prediction formulas and standard deviations were compared with each other. The results were as follows : 1. The author found that six Gustafson's criteria had strong correlation with age except root resorption, and correlation coefficients were r = 0.79 (Transparent dentin), r=0.72 (Secondary dentin), r 0.69 (Periodontal change), r=0.63(Attrition), r = 0.39 (Root resorption), respecti vely. 2. The age estimation formula by Gustafson's method was calculated as follows: Y 8.88 + 3.52X r =0.87, r2 = 0.76, SD = 8.18, F = 483.56, P < 0.01 The age estimation formula by multiple regression was calculated as follows: Y 8.57 + 6.37T + 6.37T + 4.63P + 2.70S + 2.40C + 3.08A + 1.34R r= 0.89, r2 = 0.78, SD = 7.82, F = 91.62, P < 0.01, Durbin-Watson Coefficient = 1.09 3. In comparison of two estimation formulas, the formula by multiple regression, the method of Johanson, was found to be slightly more reliable than Gustafson's method. Gustafson's method SD = 8.18, Multiple regression (Johanson's method) SD = 7.82 4. It was reaffirmed that Gustafson's six criteria could be a independent variable in multiple regression analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.4
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• pp.242-251
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• 2001

Flow boiling heat transfer coefficients (HTCs) of R22, R134a, R407C, and R410A were measured for a horizontal plain tube. The test section was made of a copper tube of 8.8mm inner diameter and 1000mm length respectively. The refrigerant was heated by passing hot water through an annulus surrounding the test section. All tests were performed at a fixed refrigerant saturation temperature of $5^{\circ}C$ with mass fluxes of 100~300 kg/$m^2$,/TEX>s. HTCs were measured by two methods: the direct wall temperature measurement method and the indirect Wilson plot method. Experimental results showed that the Wilson plot method was affected greatly by the external test conditions and yielded inconsistent results. For the mass flux of 100kg/$m^2$,/TEX>s, HTCs were almost constant regardless of the quality for a given refrigerant HTCs of R134a and R407C were similar to those of R22 while those of R410A were 60% higher than those of R22. For the mass fluxes of 200 and 300kg/$m^2$,/TEX>s, HTCs of R407C were almost the same as those of R22, while HTCs of R134a and R410A were 12-13% and 20~23% higher than those of R22 respectively. For pure refrigerant, Shah\`s correlation yielded a good agreement with the measured data both qualitatively and quantitatively.

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1429-1435
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• 2002

The absolute stereochemistry of tetrin B (1), an antifungal antibiotic isolated from a soil actinomycete was determined by applying Rychnovsky analysis, the modified Mosher method, and CD exciton chirality to be 4R, 5R, 7S, 9R, 11S, 12R, 13S, 15R, 24S, and 25R.

• Journal of the Korean Society of Tobacco Science
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• v.33 no.1
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• pp.16-20
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• 2011

This study was carried out in order to improve the Mohr method for protein-nitrogen concentration determining. Existing Mohr's method takes seven hours to analyze for one sample. In order to make up for these things tried to utilize filter bag(F75, ANKOM) for sample treatment. As a result of this implementation, have saved sample loss amount and analyzing time for a quarter comparing with Mohr's method. In addition, it have gotten high efficiency through five samples hydrolyze per one trial by using ANKOM hydrolysis system with 0.5% acetic acid. Besides, had a good reproducibility for analysis results in relation to nitrogen concentration determining with Dumas methodology. Thus, new Mohr's method takes one day to analyze for 40 sample. It is more efficiency about 6 times compare with existing Mohr's method. And, this modified Mohr's method was verified that is substitutable for the existing Mohr's method in statistical analysis.

• Journal of Microbiology
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• v.33 no.2
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• pp.136-141
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• 1995

From a cluster of structural rRNA genes which has previsouly been cloned (Hwang and Kim, in submission; J. Microbiol. Biotechnol.), a 1.0-kb Eco RI fragment of DNA which shows significant homology to the 25S and rRNA s of Tricholoma matsutake was used for sequence analysis. Nucleotide sequence was bidirectionally determined using delection series of the DNA fragment. Comparing the resultant 1016-base sequence with sequences in the database, both the 3'end of 25S-rRNA gene and 5S rRNA gene were searched. The 5S rRNA gene is 118-bp in length and is located 158-bp downstream of 3'end of the 25S rRNA gene. IGSI and IGS2 (partial) sequences are also contained in the fragment. Multiple alignment of the 5S rRNA sequences was carried out with 5S rRNA sequences from some members of the subdivision Basidiomycotina obtained from the database. Polygenetic analysis with distance matrix established by Kimura's 2-parameter method and phylogenetic tree by UPGMA method proposed that T. matsutake is closely related to efibulobasidium allbescens. Secondary structure of 5S rRNA was also hypothesized to show similar topology with its generally accepted eukaryotic counterpart.

• Electrical & Electronic Materials
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• v.10 no.2
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• pp.141-149
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• 1997

L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ powders were prepared by both GNP(Glycine-Nitrate Process) and solid state reaction method in various of calcination temperature(800-1000.deg. C) and time in air. Also, L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ cathode contacts on YSZ(Yttria-Stabilized Zirconia) substrate were prepared by screen printing and sintering method as a function of sintering temperature(1100-1450.deg. C) in air. Sintering behaviors have been investigated by SEM(Scanning Electron Microscope) and porosity measurement. Compositional and structural characterization were carried out by X-ray diffractometer and ICP AES(Inductively Coupled Plasma-Atomic Emission Spectrometry) analysis. Electrical characterization was carried out by the electrical conductivity with linear 4 point probe method. As the calcination period increased in solid state reaction method, L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ phase increased. Although L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ single phase was obtained only for 48hrs at 1000.deg. C, in GNP method it was easy to get single and ultra-fine L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ powders with submicron particle size at 650.deg. C for 30min. The particle size and thickness of L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ cathode contact by solid state reaction method did not change during the heat treatment, while those by GNP method showed good sintering characteristics because initial powder size fabricated from GNP method is smaller than that fabricated from solid state reaction method. Based on enthalpy change from thermodynamic data and ICP-AES analysis, it was suggested to make cathode contact in composition of (L $a_{0.7}$S $r_{0.3}$)$_{0.91}$ Mn $O_{3}$ which have little second phase (L $a_{2}$Z $r_{2}$ $O_{7}$) for high efficient solid oxide fuel cells applications. As (L $a_{0.7}$S $r_{0.3}$)$_{0.91}$Mn $O_{3}$ cathode contact on YSZ substrate was sintering at 1250.deg. C the temperature that liquid phase sintering did not occur. It was possible to obtain proper cathode contacts with electrical conductivity of 150(S/cm) and porosity content of 30-40%.m) and porosity content of 30-40%.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1049-1052
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• 2004

In general, contrary to the CRTs with impulsive emission, liquid crystal displays have motion artifacts such as blurring. ghost image, decrease of dynamic CR(contrast ratio), and stroboscopic motion due to hold type driving method. In this paper, to improve motion picture quality of LCDs. impulsive driving method of black data insertion was applied to the OCB mode which is well known for its fast LC response time and wide viewing angle properties. Subject evaluation was carried out with CRT, TN, SIPS(Super IPS). and impulsive driving OCB. Moving picture image quality near CRT was obtained in impulsive OCB driving mode

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.470-474
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• 2003

DNA sequence information on small-subunit rRNA gene (16S rDNA) obtained from food-poisoning bacterial culture was used to investigate the presence of bacterial pathogens in food. By reverse dot blot detection method, presence of food-poisoning bacteria could be confirmed on hybridization of digoxigenin-labeled 16S rDNA Polymerase Chain Reaction (PCR) primer product and biotin-labeled specific oligonucleotide probe. Escherichia coli, Bacillus cereus. and Salmonella sp. were used as the representative food-poisoning bacterial microorganisms. An oligonucleotide probe, based on the variable region of 16S rRNA gene, was used as the specific probe. These tools may be more useful than classic biochemical method for rapid identification of contaminated food.

• Journal for History of Mathematics
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• v.22 no.3
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• pp.255-272
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• 2009

R. L. Moore's discovery methods are known to have been very effective with certain classes of students. However when the method was attempted by others at the undergraduate level, the results sometimes were disappointing. In this article we study the history of developing modified Moore methods with small group discovery method for the purpose of undergraduate education, and then we discuss some educational point of view in our universities.