치아미백제가 치아의 색상에 미치는 영향

정석민 대구보건대학 2000 대구보건대학 論文集 Vol.20 No.-

This study was purposed to evaluate the effect of commercial home tooth bleaching agent application on the color of tooth. Fifty sound extracted teeth were randomly divided and the color differences between before and after treatment with 5 types of tooth bleaching agents (Nite White Excel, Insta-Brite, Opalescence, Plus White and StarBrite Contrast _(P.M).) were evaluated. Teeth were treated with 5 types of bleaching agents and the color changes were evaluated. The results were as follows; 1. By 4 weeks bleaching agents treatment, the difference of value (L^(*)) of the tooth were increased as high as 3.61 ~ 7.75 and the color difference (E^(*)) showed as high as 9 ~14. 2. L^(*) and E^(*) between 2 week treated- and 4 week treated-groups did not show significant changes (p>0.05), except L^(*) and E^(*) in the cases of Plus White and E in the cases of StarBrite Contrast treated group (p<0.05). 3. Nite White Excel among tested bleaching agents induced greatest L^(*) increase for teeth showing significant changes of L^(*) by 2 weeks bleaching agent treatments and by 4 weeks bleaching agent treatments except in the case of Opalescence (p<0.05). Nite White Excel induced significantly greater E^(*) for teeth by 2 and 4 weeks bleaching agent treatments when comparing to the E^(*) induced by all other tested bleaching agents groups (p<0.05). These results demonstrate that all the commercial tooth bleaching agents have appreciable bleaching effect on teeth.

Binding of Ag Adatoms to Dangling Bond Defects on a H-terminated Si(001) Surface

정석민,김규형 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.4

Using a first-principles calculation method, we investigate the binding of Ag adatoms with dangling bond (DB) defects on a H-terminated Si(001) surface and the diffusion of a single Ag adatom near the DB defects. We find that the Ag adatoms saturate DBs with binding energies ~2.0 eV/Ag,much larger that on a perfect H/Si(001) surface. This means that Ag atoms preferentially bind to the DB sites on the surface. The addition energy, which reflects the energy gain when a Ag atom is added from the perfect region (0.35 ~ 1.72 eV), decreases very much when the number of Ag atoms exceeds the number of DBs. This suggests that the Ag atoms cover the DB areas to form Ag nanostructures. The simulated scanning-tunneling microscopy (STM) images of the Ag/H/Si(001)surfaces with the DB defects reproduce the experimental ones well. It is also found that a Ag adatom diffuses anisotropically (along the dimer rows) and that the Schwoebel barriers are small near the DB defects.

치아에 대한 치아미백제의 효과에 관한 연구

정석민 광주보건대학 2002 論文集 Vol.27 No.-

This study was purposed to evaluate the effect of commercial home tooth bleaching agent application on the color of tooth. Fifty sound extracted teeth were randomly divided into 5 groups and were evaluated by the color differences between before and after treatment with 5 types of tooth bleaching agents (Nite White Excel, Insta-Brite, Opalescence, Plus White and StarBrite Contrast _(P.M.)). Teeth were treated with 5 types of bleaching agents and the color changes were evaluated. The results were as follows; 1. By 4 weeks bleaching agents treatment, the difference of value (L^(*)) of the tooth were increased as high as 3.61 ∼ 7.75 and the color difference (E^(*)) showed as high as 9 ∼ 14. 2. L^(*) and E^(*) between 2 week treated- and 4 week treated-groups did not show significant changes (p>0.05), except L^(*) and E^(*) in the cases of Plus White and E^(*) in the cases of StarBrite Contrast treated group(p<0.05). 3. Nite White Excel among tested bleaching agents induced greatest L^(*) increase for teeth showing significant changes of L^(*) by 2 weeks bleaching agent treatments and by 4 weeks bleaching agent treatments except in the case of Opalescence (p<0.05). Nite White Excel induced significantly greater E^(*) for teeth by 2 and 4 weeks bleaching agent treatments when comparing to the E^(*) induced by all other tested bleaching agents groups (p<0.05), These results demonstrate that all the commercial tooth bleaching agents have appreciable bleaching effect on teeth.

제26차 학술대회 : 67. 우발적인 표재성 위암

정석민,이중달 대한외과학회 1974 대한외과학회 학술대회자료집 Vol.- No.-

Carbamide peroxide의 함량에 따른 치아미백제의 치아에 대한 효과

정석민,남상용,곽동주,Chung, Suk-Min,Nam, Sang-Yong,Kwak, Dong-Ju 대한치과기공학회 2001 대한치과기공학회지 Vol.23 No.1

The purpose of this study was to evaluate the effects of commercial home-tooth bleaching agents on the color of tooth. Twenty five sound extracted teeth were randomly divided into five groups. The color differences between before and after treatment with five types of tooth bleaching agents (7.5% hydrogen peroxide Nite White $Excel^{(R)}$, 10% carbamide peroxide Nite White $Excel^{(R)}$, 16% carbamide peroxide Nite White $Excel^{(R)}$, 10% carbamide peroxide Insta-BriteTM, 20% carbamide peroxide Insta-$Brite^{TM}$) were evaluated. The results were as follows: 1. By 2 week home tooth bleaching agent applications, the values ($L^*$) of bovine teeth increased as high as 4.38 $\sim$ 8.80 when comparing to those of the samples before treatment, and the color difference (${\Delta}E^*$) showed as high as 10.16 $\sim$ 15.04. 2. 16% carbamide peroxide Nite White Excel induced significantly greater ${\Delta}L^*$ than other test edgroups except for 7.5% hydrogen peroxide Day White Excel, and significantly greater ${\Delta}E^*$ than other tested groups by 2 week bleaching agent treatments (p<0.01). 3. 16% carbamide peroxide Nite White Excel(${\Delta}L^*$=8.80, ${\Delta}E^*$=15.04) induced significantly greater ${\Delta}L^*$ and ${\Delta}E^*$ than 10% carbamide peroxide Nite White Excel(${\Delta}L^*$=5.01, ${\Delta}E^*$=10.16)(p<0.01), but significant difference between 10% carbamide peroxide Insta-Brite(${\Delta}L^*$=4.38, ${\Delta}E^*$=10.51) and 20% carbamide peroxide Insta-Brite(${\Delta}L^*$=5.63, ${\Delta}E^*$=11.23) was not shown in ${\Delta}L^*$ and ${\Delta}E^*$(p>0.01). 4. 16% carbamide peroxide Nite White Excel(${\Delta}L^*$=8.80, ${\Delta}E^*$=15.04) which were applied in night time induced significantly greater ${\Delta}L^*$ and ${\Delta}E^*$ than 7.5% hydrogen peroxide Day White Excel(${\Delta}L^*$=8.47, ${\Delta}E^*$=12.75) which were applied in day time. Conclusions: These results demonstrate that all the commercial home-tooth bleaching agents have appreciable bleaching effect on teeth, and the effects of home-tooth bleaching agents which are used during night time are affected by content of carbamide peroxide. Especially the whitening effect of home tooth bleaching agents that are used through night time is greater than that of short time-applying tooth bleaching agent.

Origin of the Modied Electronic Properties of Au Formed on Pentacene

정석민,허혜은,임규욱,Joung-Real Ahn,송우석,홍준용,박종윤,강태희 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.2

A Au lm formed on a pentacene layer, as a model system of a metal contact on a pentacenebased field-effect transistor, has been investigated. Unexpected pentacene derivatives and coarse morphology depending on the Au thickness are suggested as origins of the abnormal electronic structure of the Au film and the poor reproducibility of organic-based devices. The morphology of the Au film shows a strong dependency on the Au coverage. At 600 A of Au, a lift of the pentacene layer is shown as a result of deformation of the cracked Au film induced by a relaxation of the intergranular stresses accumulated during the growth process.

Dissociation of NO on Si(001) and Incorporation of N into the Subsurface

정석민 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.III

We present our first-principles calculation on NO (nitric oxide) dissociation on the Si(001) surface and subsequent nitrogen incorporation into the subsurface. NO adsorbs on the surface as a molecular form parallel or perpendicular to a Si dimer, but its dissociated structures are much more stable than the molecular forms. In the dissociated configurations, nitrogen or oxygen tends to incorporate into the subsurface to saturate its dangling bonds. Investigation of the elementary processes using a nudged elastic band method reveals that the energy barrier for NO dissociation is nearly absent ($\sim$0.02 eV) for the parallel configuration and is 0.07 eV for the vertical configuration, suggesting that NO can dissociate at very low substrate temperatures. The subsequent stabilization processes lead to the structures with O bridging a Si dimer and subsurface atoms or with N incorporation into the subsurface. The resulting energy barriers are 0.16 eV for both cases. The dissociation across two dimers is also possible. The present findings are consistent with experimental studies reporting low-temperature NO dissociation and N$\equiv$Si$_{3}$ formation.

포스코 ICT의 도로/철도사업서비스

정석민 한국철도학회 2015 철도저널 Vol.18 No.3

신호교차로의 정지선 검지기를 위한 수동형 적외선 검지기 알고리즘 개발(점유시간을 중심으로)

정석민,이승환,김남선 한국ITS학회 2003 한국ITS학회논문지 Vol.2 No.1

본 논문은 신호교차로의 정지선 검지기를 위한 수동형적외선 검지기의 검지알고리즘의 개발이다 신뢰성 있는 교통상황정보의 획득을 위하여 수동형 적외선 검지기의 기존검지영역(1.8*4.0m)에 세부검지영역을 설정하여 신호교차로에서 교통상황정보(교통량, 점유시간, 비점유시간)를 수집하였다. 기존검지영역(1.8*4.0m)의 수동형 적외선 검지기와 본 연구에서 개발한 알고리즘을 적용한 수동형 적외선 검지기를 각각 기존PIR과 제안PIR로 명명하였다. 이와 같이 개발된 알고리즘은 교통량, 점유시간, 비점유시간, 속도 및 차로변경 유무 정보를 수집할 수 있으나 본 연구에서 알고리즘의 평가는 교통량, 점유시간 및 비점유시간으로 한정하였다. 개발된 알고리즘의 수행과정과 단계별 연구내용은 다음과 같다. (1) 제안 PIR의 검지영역은 1.8*4.0m의 영역에 1.8*0.6m 영역 2개(검지영역 1, 검지영역 3)와 1.8*1.78m 영역 1개(검지영역 2)이 다. (2) 비디오 카메라 촬영자료는 모니터 상에 수동형 적외선 검지기의 검지영역과 동일하게 영역을 설정하여 비디오 프레임 분석을 실시하였다. (3) 검지영역 1과 검지영역 3으로 점유시간, 비점유시간, 속도자료를 수집하고, 검지영역 1, 검지영역 2, 검지 영역 3의 조합으로 차로변경 유무에 대한 정보를 수집할 수 있다. 알고리즘의 현장 적용성 검토 및 알고리즘 평가를 위하여 교통량, 점유시간, 비점유시간에 대한 평균절대편차(MAD), 평균절대비율오차(MAPE)를 정확도의 비교척도로 사용하였다. 그 결과 개발된 알고리즘을 적용한 제안검지기의 효과는 기존검지기보다 우수한 것으로 나타났고, 교통량, 점유시간 및 비점유시간은 각각 53%, 40%, 61%의 개선효과를 보였다. The purpose of this thesis is development of detection algorithm for stop-line detector. Detail detection area is set in basing detection area(1.8*4.0m) and traffic information(volume, occupancy, nonoccupancy) is collected by passive infrared detector at designing detection area. The basis detection area(1.8*4.0m) is named existing PIR and detection area applied on development algorithm is named proposal PIR. The proposal PIR is collected data such volume, occupancy, nonoccupancy, speed and lane change, but this thesis is limited to evaluate for volume, occupancy and nonoccupancy The procedure and each step of being developed algorithm is described in the next (1) The detection area of proposal PIR is made up of 2 of 1.8*0.6m size(the detection area is named 1 and 3) and 1 of 1.8*1.78m size(the detection area is named 2) (2) The image detection area is set on monitor to analyze outdoor photographing data then video frame analysis has been done by analyzer. (3) The occupancy, nonoccupancy and speed data of vehicle have been collected with the detection area 1 and 3 and lane change has been collected with combination of detection area 1, 2 and 3 The MAD and MAPE have been utilized to being compared with volume, occupancy and nonoccupancy for the field application and evaluation of a algorithm As the result, the proposal PIR data have been identified superior to the existing PIR data and the effect has been improved its information(volume, occupancy and nonoccupancy)

Interaction of an Adenine Molecule with a Ag-terminated Si(111) Surface

정석민 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.2

The adsorption of an adenine molecule, one of four DNA bases, on a Ag/Si(111)p3×p3 surface is investigated using a first-principles total-energy calculation. Extensive search of the adsorption structures reveals that two structures are energetically competing. One is a structure with a hexagonal ring of adenine on a large Ag triangle (LT) of the substrate. The molecular plane is inclined at a tilt angle of 10.2∘with respect to the surface plane due to weak bonds between N and substrate Ag atoms. The other is a structure with N just above a Ag atom (T) with the molecular plane vertical to the surface. The N· · · Ag bond energy in the LT structure is of similar magnitude to the N· · ·H hydrogen bonds of an adenine dimer. The local-density approximation (LDA) and the generalized-gradient approximation (GGA) produce different energy orders between the LT and the T structures. An incorrect treatment of the van der Waals interaction in the density-functional theory could be the origin of the difference.