• 대한소아치과학회지
• /
• 제1권1호
• /
• pp.41-47
• /
• 1974

The dental caries survey of "K" primary school children was performed twice for one year interval and evaluated the transitional trend of dental caries prevalences. The number of children surveyed at the first year, 1973, was 819 boys and 653 girls; and the second year, 1974, was 815 boys and 661 girls aged 6 to 12. Under this survey, the following results were detected: 1. The average df person rate in deciduous teeth was increased by 7.52% in boy, 5.59% in girl and 6.65% of both. 2. The average df Index in deciduous teeth was increased by 0.13 in boy, 0.04 in girl and 0.1 of both. The average dt Index was decreased by 0.59 in boy, 0.64 in girl and 0.61 of both. The average ft Index was increased by 0.73 in boy, 0.68 in girl and 0.71 of both. 3. There showed no significant differences in DMF person rate between 1973 and 1974. 4. The DMFT Index of the permanent teeth was decreased by 0.19 in boy, and increased by 0.22 in girl. There showed no significant differences in both sexes between 1973 and 1974. The average DT Index was decreased by 0.43 in boy, 0.03 in girl and 0.31 of both. The average FT Index was increased by 0.23 in boy; 0.35 in girl and 0.29 of both. The average MT Index showed no significant differences in both sexes between 1973 and 1974.

• 대한화학회지
• /
• 제32권3호
• /
• pp.179-185
• /
• 1988

과염소산이 존재하는 디메틸포름아미드 수용액에서 벤질알코올과 VO_2\;^+$를 반응시키면 $VO^{2+}$와 벤즈알데히드를 생성한다. 이때 생성물인 $VO^{2+}$와 벤즈알데히드는 적외선 분광광도법과 기체크로마토그래피법으로 확인하였다. 벤질알코올에 의한 VO_2\;^+$의 환원반응에 대한 속도론적 연구는 분광광도법으로 행하였다. 이 반응에 대한 실험속도식은 다음과 같이 나타낼 수 있으며 속도결정단계는 $VO^{2+}$와 $C_6H_5CHOH$의 생성과정이다. $-d[VO_2\;^+]/dt=2\{\\{k_O+k_H[HClO_4]\}\[VO_2\;^+][C_6H_5CH_2OH]$이 반응의 활성화파라미터는 ${\Delta}H^{\neq}=13.32{\pm}1.73\;kcalmol^{-1}$ 이고 ${\Delta}S^{\neq}$ 는 $-31.02{\pm}0.09\;calmol^{-1}K^{-1}$이다.

• 치위생과학회지
• /
• 제14권3호
• /
• pp.342-348
• /
• 2014

본 연구는 김제시 B면 K면에 소재하고 있는 초등학교 중에서 학교구강보건실이 설치된 1개교(실험군), 학교구강보건실이 미설치된 3개교(대조군)를 표본학교로 선정하여 김제시 K보건지소의 학교계속구강건강관리사업이 중지되기 전 사업의 혜택을 받은 3~6학년, 사업이 중지된 후 혜택을 받지 못한 1~2학년을 비교대상으로 구강상태를 평가하여 다음과 같은 결과를 얻었다. 영구치우식경험자율은 전체 실험군 50.6%, 대조군 66.8%로 유의한 차이를 나타냈으며 (p<0.01), 사업혜택을 받은 3~6학년에서 실험군 58.9%, 대조군 76.1%로 나타나 유의한 차이를 나타냈다(p<0.05). 우식경험영구치율은 전체 실험군 34.8%, 대조군 56.5%로 나타나 유의한 차이를 보였고(p<0.001), 사업혜택을 받은 3~6학년 실험군 41.1%, 대조군 64.2%로 나타나 유의한 차이를 보였다(p<0.01). 우식경험영구치지수는 전체 실험군 1.35개, 대조군 2.97개로 유의한 차이를 보였고(p<0.001), 사업혜택을 받은 3~6학년 실험군 1.73개 대조군 3.66개로 나타나 역시 유의한 차이를 나타냈다(p<0.001). 우식영구치지수는 전체 실험군 0.72개, 대조군 1.96개로 나타나 유의한 차이를 보였고(p<0.001), 충전영구치 지수는 실험군 0.63개, 대조군 0.99개로 나타나 유의한 차이를 보였다(p<0.05). 사업중지 1~2학년 실험군에서 우식영구치지수 0.42개, 대조군 1.12개로 나타나 유의한 차이를 보였고(p<0.05), 사업혜택을 받은 3~6학년 실험군에서 우식영구치지수 0.89개 대조군 2.34개로 나타나 역시 유의한 차이를 보였다(p<0.01) 우식영구치율은 전체 실험군 57.23%, 대조군 64.16%, 충전영구치율은 실험군 42.77%, 대조군 34.81%로 나타났고 사업중지 1~2학년 우식영구치율은 실험군 63.89%, 대조군 76.17%로 나타났으며, 사업혜택을 받은 3~6학년의 우식영구치율은 실험군 54.81%, 대조군 60.98%로 나타났다. 이상의 결과를 토대로 초등학교 구강보건실에서 실시하는 학생계속구강건강관리사업의 효과를 확인하였으며, 학생들의 구강건강증진을 위해 계속적인 유지와 활성화를 위한 노력이 필요할 것으로 생각된다.

• 치위생과학회지
• /
• 제5권1호
• /
• pp.19-24
• /
• 2005

본 연구는 성남시에 거주하는 65세 이상의 노인구강건강상태를 현존영구치아수, 치아우식발생실태, 영구치치료필요자율, 지역사회치주요양필요자율 및 치아보철상태 등을 파악하고 노인구강보건사업에 필요한 구강보건정보 및 기초 자료로 활용하는데 그 목적을 두고 조사한 결과 다음과 같은 결론을 얻었다. 1. 성남시 65세 이상 노인의 치아우식경험율은 남자 98.3%, 여자 99.0%로 나타났고, 우식경험영구치지수는 20.8개 이었다. 2. 65세 이상 노인의 제 3대구치를 제외한 현존영구치아수는 13개로 나타났다. 3. 치주요양필요자율을 조사한 결과 치면세균막관리필요자율 74.9%, 치면세마필요자율 56.2%, 치주조직병치료필요자율은 8.0%로 나타났다. 4. 65세 이상 노인의 전체적인 평균 총의치장착율은 상악 26.1%, 하악 17.8%로 조사되었으며, 총의치장착필요자율은 상악 7.4%, 하악 4.3%로 조사되었다. 5. 성남시는 노인구강건강증진을 위한 목표를 설정하고 노인 구강건강증진 사업을 개발할 필요가 있는 것으로 검토되었다.

• 한국치위생학회지
• /
• 제8권4호
• /
• pp.115-125
• /
• 2008

The purpose of this study was to examine the relationship between the Dentocult SM and LB scores of students and their DMF rate. The subjects in this study were 134 special school students in south Gyeong-sang province. After they were tested to find out their, they received tooth brushing education and preventive treatment. The test, education and treatment were all conducted from March 17 to April 9, 2008. Their oral state was checked and recorded by using a mirror and explorer, and then the data on oral state were analyzed to their DMFT, DT, FT and MT rates. All the collected data were analyzed with SPSS 15.0 for Windows program, and independent-samples t-test, one-way ANOVA and crosstabs analysis were implemented to see what differences their disability type, gender, Dentocult-SM scores and Dentocult-LB scores made. The findings of the study were as follows: 1. As for connections between disability type and DMFT rate, the students with mental retardation were similar to the other students in that regard. The mentally retarded students had higher DT and FT rates than the other students, and the MT rate of the latter was higher than that of the former. 2. Concerning the relationship of gender to DMFT and DT rates, the girls had larger DMFT and DT rates than the boys, and the FT and MT rates of the boys were higher than those of the girls. 3. As to links between Dentocult SM scores on the tongue and DMFT, the students whose bacteria was mildly activated had the highest DMFT rate, and the students who had a severely activated bacteria had the highest DT and FT rates. Those who had a moderately activated bacteria had the highest MT rate. 4.Regarding the connection of Dentocult SM scores on maxillyright molar to DMFT and DT rates, the students whose bacteria was severely activated had the highest DMFT and DT rates. Those who had no activated bacteria had the largest FT rate, and the students who had a mildly activated bacteria had the highest MT rate. 5.Regarding the connection of Dentocult SM scores on maxillyleft molar to DMFT and DT rates, the students whose bacteria was severely activated had the highest DMFT and DT rates. Those who had no activated bacteria had the largest FT rate, and the students who had a mildly activated bacteria had the largest MT rate. 6. Regarding the connection of Dentocult SM scores on mandibularright molar to DMFT and DT, FT rates, the students whose bacteria was severely activated had the highest DMFT and DT, FT rates. Those who had a moderately activated bacteria had the highest MT rate. 7. Regarding the connection of Dentocult SM scores on mandibularleft molar to DMFT and DT rates, the students whose bacteria was mildly activated had the highest DMFT and DT rates. Those who had no activated bacteria had the largest FT rate, and the students who had a moderately activated bacteria had the highest MT rate. 8. Regarding the connection of Dentocult LB scores to DMFT and DT rates, the students whose bacteria was severely activated had the highest DMFT and DT rates. Those who had no activated bacteria had a moderately FT rate, the students who had a mildly activated bacteria had a mildly MT rate.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2010년도 하계학술대회 논문집
• /
• pp.388-388
• /
• 2010

In this study, Ferroelectric vinylidene fluoride-trifluoroethylene (VF2-TrFE) copolymer films were directly deposited on degenerated Si (n+, $0.002\;{\Omega}{\cdot}cm$) using by spin coating method. A 1~5 wt% diluted solution of purified vinylidene fluoride-trifluoroethylene (VF2:TrFE = 70:30) in a dimethylformamide (DMF) solvent were prepared and deposited on silicon wafers at a spin rate of 2000 ~ 4000 rpm for 2 ~ 30 seconds. After annealing in a vacuum ambient at 100 ~ $200^{\circ}C$ for 60 min, upper aluminum electrodes were deposited by vacuum evaporation for electrical measurement. X-ray diffraction results showed that the VF2-TrFE films on Si substrates had $\beta$-phase of copolymer structures. The capacitance on highly doped Si wafer showed hysteresis behavior like a butterfly shape and this result indicates clearly that the copolymer films have ferroelectric properties. The typical measured remnant polarization ($P_r$) and coercive filed ($E_c$) values were about $5.7\;{\mu}C/cm^2$ and 710 kV/em, respectively, in an applied electric field of ${\pm}$ 1.5 MV/em. The gate leakage current densities measured at room temperature was less than $7{\times}10^{-7}\; A/cm^2$ under a field of 1 MV/cm.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
• /
• pp.169-170
• /
• 2006

In this study, ultra thin films of ferroelectric vinylidene fluoride-trifluoroethylene (VF2-TrFE) copolymer were fabricated on degenerated Si (n+, $0.002\;{\Omega}{\cdot}cm$) using by spin coating method. A 1~5 wt% diluted solution of purified vinylidene fluoride-trifluoroethylene (VF2:TrFE=70:30) in a dimethylformamide (DMF) solvent were prepared and deposited on silicon wafers at a spin rate of 2000~5000rpm for 30 seconds. After annealing in a vacuum ambient at $200^{\circ}C$ for 60 min, upper gold electrodes were deposited by vacuum evaporation for electrical measurement. X-ray diffraction results showed that the VF2-TrFE films on Si substrates had $\beta$-phase of copolymer structures. The capacitance on $n^+$-Si(100) wafer showed hysteresis behavior like a butterfly shape and this result indicates clearly that the dielectric films have ferroelectric properties. The typical measured remnant polarization (2Pr) and coercive filed (EC) values measured using a computer controlled a RT-66A standardized ferroelectric test system (Radiant Technologies) were about $0.54\;C/cm^2$ and 172 kV/cm, respectively, in an applied electric field of ${\pm}0.75\;MV/cm$.

• Advances in nano research
• /
• 제10권1호
• /
• pp.59-69
• /
• 2021

Electrospinning is a cost-effective and versatile method for producing submicron fibers. Although this method is relatively simple, at the theoretical level the interactions between process parameters and their influence on the fiber morphology are not yet fully understood. In this paper, the aim was finding optimal electrospinning parameters in order to obtain the smallest fiber diameter by using Taguchi's methodology. The nanofibers produced by electrospinning a solution of Thermoplastic Polyurethane (TPU) in Dimethylformamide (DMF). Polymer concentration and process parameters were considered as the effective factors. Taguchi's L9 orthogonal design (4 parameters, 3 levels) was applied to the experiential design. Optimal electrospinning conditions were determined using the signal-to-noise (S/N) ratio with Minitab 17 software. The morphology of the nanofibers was studied by a Scanning Electron Microscope (SEM). Thereafter, a tensile tester machine was used to assess mechanical properties of nanofibrous scaffolds. The analysis of DoE experiments showed that TPU concentration was the most significant parameter. An optimum combination to reach smallest diameters was yielded at 12 wt% polymer concentration, 16 kV of the supply voltage, 0.1 ml/h feed rate and 15 cm tip-to-distance. An empirical model was extracted and verified using confirmation test. The average diameter of nanofibers at the optimum conditions was in the range of 242.10 to 257.92 nm at a confidence level 95% which was in close agreement with the predicted value by the Taguchi technique. Also, the mechanical properties increased with decreasing fibers diameter. This study demonstrated Taguchi method was successfully applied to the optimization of electrospinning conditions for TPU nanofibers and the presented scaffold can mimic the structure of Extracellular Matrix (ECM).

• Current Photovoltaic Research
• /
• 제10권4호
• /
• pp.101-106
• /
• 2022

We prepared a CsPbI₂Br solution using Cesium iodide (CsI), Lead (II) bromide (PbBr₂) and Lead (II) iodide (PbI₂) materials into a polar solvent mixture of N,N-dimethylformamide (DMF) and Dimethyl sulfoxide (DMSO). A simple spin coating technique was used for the fabrication of CsPbI₂Br absorber layer in the solution process. In order to prepare uniform coating of absorber film we adopted a hot-air process in assocation with the spin coating. It was confirmed that the thin film manufactured by the hot-air process had a higher absorption rate than that without it, and the optical band gap was measured 1.93 eV. The thin film of absorber was uniformly prepared and revealed the Black α-Cubic crystal phase as proved through X-ray diffraction analysis. Finally, a perovskite solar cell having an n-i-p structure was manufactured with a CsPbI₂Br perovskite absorption layer. From the solar cell, we obtained a power conversion efficiency (PCE) of 5.97% in a forward measurement.

• 치위생과학회지
• /
• 제12권5호
• /
• pp.459-468
• /
• 2012

본 연구는 2011년 6월 10일~11일까지 유아기의 비만과 구강건강과의 관계에 대하여 조사 분석하였다. 연구대상은 강원도에 위치한 K어린이집의 유아 90명을 대상으로 설문조사와 구강검사를 실시하였다. 수집된 자료는 SPSS WIN 15.0프로그램을 이용하여 분석한 결과 다음과 같은 결론을 얻었다. 1. 유치우식경험자율은 56.7%이었으며, 유치우식유병자율은 42.2%로 나타났다. 2. 일반적 특성에 따른 유치우식경험율을 조사한 결과 연령이 증가할수록 유치우식경험율이 높게 나타났다. 3. 성장과 비만 정도에 따른 유치우식경험율을 조사한 결과, 신장이 100~110 cm, 체중이 25 kg 이상인 유아가 다른 유아보다 유치우식경험율이 높게 나타났으며, 110~115cm인 유아가 다른 유아보다 유치우식유병율이 높게 나타났다. 4. 일반적 특성에 따른 우식경험유치(면)수를 조사한 결과, 연령이 많은 유아일수록 우식경험유치수와 우식경험유치면수가 높게 나타났다. 5. 성장과 비만 정도에 따른 우식경험유치(면)수를 조사한 결과, 체중이 높은 유아일수록 우식경험유치수와 우식경험유치면수가 높게 나타났으며, 과체중인 유아일수록 우식유치수, 충전유치수, 우식경험유치수와 우식유치면수, 우식경험유치면수가 높게 나타났다. 비만과 치아우식증이 관련성이 있는 것으로 나타났으므로, 보육기관에서는 유아들이 올바른 식습관을 익히도록 유아, 부모(보호자), 보육교사를 대상으로 지속적인 구강보건교육을 통하여 효율적인 구강건강관리에 도움을 주어야 할 것이다. 또한 간식 선택에 있어서도 신중을 기해야 할 것으로 사료된다. 학령전기인 유아를 대상으로 체계적으로 구강보건사업을 실시하여 유치뿐만 아니라 영구치도 효율적으로 관리할 수 있도록 구강보건사업의 연계성을 높여야 할 것이다.