• The Journal of Korea Assosiation for Disability and Oral Health
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• v.1 no.1
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• pp.25-32
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• 2005

The purpose of this study was to furnish data on the disabled's oral health status of the disabled in Busan, Korea. Material and Methods: Two dentists who were well experienced in caries examination surveyed the oral health status on 793 of disabled men in Busan from March to June in 2000 under natural solar light with plane mirror by the criteria which are suggested by World Health Organization (WHO). Results: The number of present permanent teeth of the disabled are lower than the undisabled. DMF rate and DMFT indices of the disabled were higher than the undisabled. DT rate of the disabled was higher than the undisabled. Conclusions: The development of community oral health care programs for the prevention and treatments of dental caries for the disabled is needed and active administrative policies should be established for the promotion of the disabled's oral health.

• The Journal of the Korean dental association
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• v.19 no.6 s.145
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• pp.535-540
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• 1981

In order to collect the basic data for planning school dental health programmes, the author had examined dental health conditions of 120 males and 120 females of Changgyung Primary School children in the first grade. The percentages of persons with conditions requiring immediate attention, toothbrushing times and daily frequency, df rate, df index, dt index, ft index, it index, DMF rate, DT index, MT index, FT index, IT index, DMFT index, percentages of persons with periodontal status in every of the four categories with soft deposits, calculus, intense gingivitis, and advanced periodontal involvement were calculated and evaluated. The obtained results were as follows: 1. Persons with requiring immediate attention was 7.1% of all the examined children. 2. The df rate was 88.3%, and df index was 3.4 teeth per person. And then the DMF rate was 17.1%, while DMFT index was 0.3 teeth per person. 3. As the periodontal status, the persons with soft deposits was 90.0% of children, calculus 26.3%, intense gingivitis 0.4%, and no advanced periodontal involvement. 4. Average toothbrushing frquency was 1.2 times in a day per person. But 71.5% of toothbrushing was performed before meals, while the others after meals.

• Journal of Korean society of Dental Hygiene
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• v.5 no.1
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• pp.29-38
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• 2005

In 2001, as a subject of this study, the first grade 165 kids in Yomju elementary school had been guided in pit and fissure sealant, fluoride rinse, group tooth brushing, and Dental health education as a part of oral disease preventive program. From the data, this author has estimated incremental dental health care program in school dental clinic in order to make it more effective and enlarge it. For that purpose, the program has been continued at six month intervals for two years. The retention condition of pit and fissure sealant in first molar and DMF rate had been investigated. The conclusions are as follows: 1. Full and partial retention of pit and fissure sealant was measured as 80.69% in maxillary right first molar, 83.20% in maxillary left first molar, and 86.72% in mandibular right first molar, and 86.28% in mandibular left first molar. 2. Retention of pit and fissure sealant in first molar was measured as 76.55% in maxillary right first molar, 81.03% in maxillary left first molar, 80.65% in mandibular left first molar, and 82.03% in mandibular right first molar. 3. Among Yomju elementary school students, DMF rate was measured as 8.7%, and DMFT index as 1.03. However, in Yangdong elementary school students the former was measured as 13.8% and the latter as 1.76. When the DMF rate difference between Yomju and Yangdong elementary school kids was considered, the oral health condition of the former was much better than that of the latter because the former had received incremental dental health care program for two years and on the other hand, the latter had not. So it is necessary that we should enlarge school dental clinic, improve and keep students' oral health.

• Journal of dental hygiene science
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• v.6 no.2
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• pp.113-117
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• 2006

The purpose of this study was to evaluate caries preventive effects of a school-based weekly mouthrinsing program with a 0.2% sodium fluoride solution for five years at elementary school in Yangsan city, which were conducted for 330 children of elementary school from 2000 to 2005. The surveyed data was analyzed with SPSS statistical package. The obtained results were as follows; 1. DMF rate was 58.4% before the mouthrinsing program in 2000 and 48.3% after the program in 2005. DMF rate in 2005 decreased by 10.1% compared to DMF rate in 2000. 2. DT index was 2.46 before the mouthrinsing program and 1.70 after the program. DT index in 2004 decreased by 0.76 compared to DT index in 2000. 3. FT index was 0.55 before the mouthrinsing program and 0.37 after the program. Filled teeth due to decay after the program decreased by 0.18 compared to filled teeth before the program. 4. DMFT score was 2.61 before the mouthrinsing program and 1.64 after the program. DMFT score in 2004 decreased by 0.97 compared to DMFT score in 2000. 5. PHP index was 12.12 before the mouthrinsing program and 5.95 after the program. PHP index in 2005 decreased by 6.17 compared to PHP index in 2000.

• Journal of the Korean Ceramic Society
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• v.36 no.9
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• pp.893-900
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• 1999

Silica films were prepared on Si single crystal substrates by sol-gel process using TEOS as starting materials. Films were fabricated by a spin coating technique. Sol solutions were prepared by varying the compositions of CH3OH, H2O and DMF with fixed molar ratio of TEOS=1, HCl=0.05(mol). Wetting behavior viscosity of solutions gelation time thickness of films and cracking behavior were investigated with the various solution compositions. Wetting behaviors of solutions depended on the solution compositions mixing method and mixing rate. The optimum composition of sol was TEOS : DMF ; CH3OH: H2O :HCl=1:2:4:4:0.05(mol) and the mixing rate of solution was optimized at 1 ml/min. Viscosity of solutions were controlled by choosing a reaction time(elapsed time after mixing) at a room temperature so that we could get up to 800nm thick film The surface roughness was getting poor when thickness of films was thicker than 500nm. Thickness of coated films were increased with decreasing amount of CH3OH. The best surface roughness was obtained at the content of CH3OH 4 mol. The shortest gelation time was obtained with the content of CH3OH 8 mol. Crack-free filkms were fabricated when sintered at 500$^{\circ}C$ for 1 hr with heating rate of 0.6$^{\circ}C$/min.

• Journal of the Korean Chemical Society
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• v.32 no.4
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• pp.291-296
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• 1988

Rates of the reaction for p-nitrobenzyl chloride, benzyl chloride and p-methylbenzyl chloride with pyridine in DMF solvent have been measured by an electric conductivity method at $40^{\circ}\;and\;50^{\circ}C$ under various pressures. From those rate constants, the activation parameters ${\Delta}V^{\neq},\;{\Delta}{\beta}^{\neq},\;{\Delta}H^{\neq},\;{\Delta}S^{\neq},\;{\Delta}G^{\neq}$) were evaluated. ${\Delta}V^{\neq}\;and\;{\Delta}{\beta}^{\neq}$ are both negative valued, but ${\Delta}H^{\neq}$ is positive and ${\Delta}S^{\neq}$ is large negative value. From the evaluation of the initial state and transition state which was resulted from substituents and pressure, it was found that this reaction proceeds through bimolecular reaction.

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.597-600
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• 2017

$(C_{10}H_8N_2H)_2Cr_2O_7$ was synthesized by reacting 4,4'-bipyridine and chromium (VI) trioxide. The structure of the product was characterized with FT-IR (infrared spectroscopy) and elemental analysis. The oxidation of benzyl alcohol using $(C_{10}H_8N_2H)_2Cr_2O_7$ in various solvents showed that the reactivity increased with the increase of the solvent dielectric constant, in the order of DMF (N,N'-dimethylformamide) > acetone > chloroform > cyclohexane. In the presence of DMF, an acidic catalyst such as $H_2SO_4$ $(C_{10}H_8N_2H)_2Cr_2O_7$ oxidized benzyl alcohol (H) and its derivatives ($p-OCH_3$, $m-CH_3$, $m-OCH_3$, m-Cl, $m-NO_2$). Electron donating substituents accelerated the reaction rate, whereas electron acceptor groups retarded the reaction rate. Hammett reaction constant (${\rho}$) was -0.70 (308 K). The observed experimental data were used to rationalize the hydride ion transfer in the rate determining step.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.2
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• pp.300-309
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• 2001

The purpose of this study was to investigate the caries prevalence and caries pattern of preschool children in a small city. Six hundred twenty four kindergarten children in Milyang city were examined for their caries experience of individual teeth and surfaces by dmf index. The obtained results were as follows. 1. The rate of children with caries experience(dmft rate) in primary teeth was 74.0% in 3-year-olds, 83.8% in 4-year-olds, and 90.6% in 5-year-olds. The mean number of decayed, missed, and filled primary teeth(dmft index) was 3.47 in 3-year-olds, 5.41 in 4-year-olds, and 6.01 in 5-year-olds. 2. The caries prevalence of children in this study was higher than those of other researches in past and in other cities. 3. The caries-experienced teeth in order in 5-year-olds were as follows : mandibular 2nd primary molar, mandibular 1st primary molar, maxillary 2nd primary molar, maxillary primary central incisor and maxillary 1st primary molar. 4. The pattern of dental caries development was different between the incisors and molars. The prevalent surface of caries was proximal surface in primary incisors, but occlusal surface in primary molars.

• Journal of the Korean Chemical Society
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• v.35 no.1
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• pp.24-37
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• 1991

We synthesized the binuclear Tetradentate Schiff base nickel(II) and copper(II) complexes ; [Ni(II)$_2$(SMPO)$_2$(L)$_2$], [Ni(II)$_2$(SPPD)$_2$(L)$_2$] and [Cu(II)$_2$(SMPD)$_2$] and [Cu(II)$_2$(SPPD)$_2$] (where, L : Py, DMSO and DMF). We identified the structure of these complexes by elemental analysis, IR-spectrum, T.G.A, D.S.C and ESR measurements. According to the results of cyclic voltammetry and DPP measurements in aprotic solvent included 0.1M TEAP as supporting electrolyte, we knew that diffusional controlled redox process of one step with one electron was irreversible process in 0.1M TEAP-Py solution. Also it was reversible or quasi reversible process in 0.1M TEAP-DMSO solution and reversible or E.C reaction mechanism in 0.1M TEAP-DMF solution at mononuclear complexes ; [Cu(II)(SOPD)] and [Ni(II)(SOPD)(L)$_2$]. But, we knew that diffusional controlled redox process of two step for one electron of binuclear complexes was as follows. The values of redox potential for dimeric complexes in 0.1M TEAP-L solution (where, L ; Py, DMSO and DMF) with scan rate 100mV/sec.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.6039-6046
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• 2013

Cr(VI)-heterocyclic complex[Cr(VI)-2-methylpyrazine] was synthesized by the reaction between of heterocyclic compound(2-methylpyrazine) and chromium trioxide, and characterized by IR and ICP analysis. The oxidation of benzyl alcohol using Cr(VI)-2-methylpyrazine in various solvents showed that the reactivity increased with the increase of the dielectric constant(${\varepsilon}$), in the order : cyclohexene${\rho}$) was Cr(VI)-2-methylpyrazine= -0.65(308K). The observed experimental data have been ratiolized. The hydride ion transfer causes the prior formation of a chromate ester in the rate-determining step.