치주치료 후 구강 내 Volatile Sulfur Compounds(VSC)의 변화

김성현,채경준,정의원,김창성,최성호,조규성,채중규,김종관,방은경,Kim, Sung-Hyun,Chae, Gyeong-Jun,Jung, Ui-Won,Kim, Chang-Sung,Choi, Seong-Ho,Cho, Kyoo-Sung,Chai, Jung-Kyu,Kim, Chong-Kwan,Bang, Eun-Gyeong 대한치주과학회 2006 Journal of Periodontal & Implant Science Vol.36 No.3

Oral malodor may cause a significant social or psychological handicap to those suffering from it. Oral malodor has been correlated with the concentration of volatile sulfur compounds (VSC) produced in the oral cavity. Specific bacteria identified in the production of VSC have been reported and many of these bacteria are commonly suspected periodontal pathogens. The aim of this study was to estimate the change of the VSC concentration after periodontal treatment, Twenty subjects with probing depth $(PD)\;{\geq}5mm$ (experimental group) and 20 subjects with PD<5mm (control group) participated. VSC concentration measurement was made with gas chromatography. VSC concentration was measured at pre-treatment, 2 weeks after scaling and 1 month after periodontal treatment(root planning and flap operation). Maximum probing depth and bleeding on probing(BOP) were also examed at pretreatment and 1 month after periodontal treatment, The conclusions were as follow: 1. In the experimental group VSC concentration and CH3SH/H2S ratio were higher than control group. (p<0.05) 2. Both VSC concentration and CH3SH/H2S ratio showed decrease after periodontal treatment, But only CH3SH/H2S ratio after 1 month periodontal treatment was statistically significantly different from pre-treatment. (p<0.05) 3. CH3SH/H2S ratio tended to be on increase according to maximum probing depth and bleeding on probing. Periodontal disease could be a factor that caused oral malodor and oral malodor could be decreased after periodontal treatment.

풀러렌-물 클러스터의 상호작용에 대한 양자 역학적 이론 연구

김성현,신창호,김지선,강소영,김승준,Kim, Sung-Hyun,Shin, Chang-Ho,Kim, Ji-Sun,Kang, So-Yung,Kim, Seung-Joon 대한화학회 2015 대한화학회지 Vol.59 No.1

풀러렌(fullerene)의 내부에 캡슐화될 수 있는 물 분자의 수와 물 분자들이 증가함에 따라 풀러렌의 안정적인 구조에 미치는 영향을 조사하기 위해 밀도 범함수 이론(density functional theory, DFT)을 이용하여 풀러렌-물 클러스터$(H_2O)_n@C_{60}$, (n=1-10)의 구조 변화에 따른 열역학적 안정성 및 결합에너지를 계산하였다. 각각의 구조들에 대해서 여러 이론 수준에서 최적화하였으며 진동주파수를 계산하여 가장 안정한 구조를 조사하고 IR 스펙트럼을 예측하였다. 또한 풀러렌 내의 물 분자 수가 증가함에 따른 수소결합의 세기 변화를 순수한 물 클러스터$(H_2O)_n$, (n=1-6)의 수소결합과 비교 분석하였다. The density functional theory (DFT) calculations on $(H_2O)_n@C_{60}$, (n=1-10) complexes have been performed to elucidate hydrogen interaction between fullerene and water clusters. The optimized geometries, harmonic vibrational frequencies, and binding energies are predicted at various levels of theory. The harmonic vibrational frequencies for the molecules considered in this study show all real numbers implying true minima. We also compare the H-bond interaction between $(H_2O)_n$ and $(H_2O)_n@C_{60}$, (n=1-10) clusters.

골절 방지 시스템의 개발을 위한 낙상 시뮬레이션과 충격 흡수 시스템에 관한 연구

김성현,김동욱,김남균,Kim, S.H.,Kim, D.W.,Kim, N.G. 대한의용생체공학회 2010 의공학회지 Vol.31 No.6

The social activities of the elderly have been increasing as our society progresses toward an aging society. As their activities are increased, the occurrence of falls that could lead to fractures are increased. Falls are serious health hazards to the elderly and we need more thorough understanding of falls including the progress of falls and the impact area in various fall directions. Many of the traditional methods of falls research dealt with voluntary falls by younger subject since older subject can easily get fracture from voluntary falls. So, it has been difficult to get exact data about falls of the elderly. Here, we tried to capture the characteristics of the movements of major joints using three dimensional motion capture system during falls experiments using a moving mattress that can safely induce unexpected falls. Healthy younger subjects participated in the actual falls experiment and the moving mattress was actuated by a pneumatic system. The kinematic parameters such as velocities of major segments were imported to a computer simulation environment and falls to hard surfaces were simulated in a computational environment using a realistic human model of aged persons. The simulation was able to give approximations to contact forces which can occur during actual falls. And we designed impact absorption system to reduce the impact during falls. We can adapt this system to fracture prevention system that we are going to study.

N과 AlN 시트에 다양한 기체(CO_x, NO_x, SO_x)의 흡착에 관한 이론 연구

김성현,김백진,신창호,김승준,Kim, Sung-Hyun,Kim, Baek-Jin,Shin, Chang-Ho,Kim, Seung-Joon 대한화학회 2017 대한화학회지 Vol.61 No.1

본 연구는 그래핀과 유사한 2차원 붕소-질소(BN)와 알루미늄-질소(AlN) 시트에 여러 대기 유해 가스($CO_x$, $NO_x$, $SO_x$)가 흡착될 때의 구조적 특징과 결합에너지를 밀도 범함수 이론(DFT)과 MP2 방법을 사용하여 연구하였다. 분자 구조는 $B3LYP/6-31G^{**}$와 $CAM-B3LYP/6-31G^{**}$이론 수준에서 최적화하고, 진동 주파수를 계산하여 열역학적으로 가장 안정한 분자 구조를 확인하였다. 결합에너지는 $MP2/6-31G^{**}$ 이론 수준에서 한 점(single point) 에너지를 계산하고, 영점 진동에너지(ZPVE)와 바탕집합 중첩에러(BSSE)를 모두 보정하였다. BN 시트에 가스의 흡착은 모두 물리흡착으로 예측되었으며, AlN 시트에 대한 가스 흡착은 $CO_x$나 $NO_x$에 대해서는 물리흡착이 그리고 $SO_x$에 대해서는 화학 흡착이 일어날 것으로 예측되었다. The adsorption of various atmospheric harmful gases ($CO_x$, $NO_x$, $SO_x$) on graphene-like boron nitride(BN) and aluminum nitride(AlN) sheets was theoretically investigated using density functional theory (DFT) and MP2 methods. The structures were fully optimized at the $B3LYP/6-31G^{**}$ and $CAM-B3LYP/6-31G^{**}$ levels of theory and confirmed to be a local minimum by the calculation of the harmonic vibrational frequencies. The MP2 single-point binding energies were computed at the $CAM-B3LYP/6-31G^{**}$ optimized geometries. Also the zero-point vibrational energy (ZPVE) and 50%-basis set superposition error (BSSE) corrections were included. The adsorptions of gases on the BN sheet were predicted to be a physisorption process and the adsorptions of gases on the AlN sheet were predicted to be a physisorption process for $CO_x$ and $NO_x$ but to be a chemisorption process for $SO_x$.

기천(氣喘)에 대(對)한 문헌적(文獻的) 고찰(考察)

김성현,Kim, Sung-Hyun 대한한방내과학회 1992 大韓韓方內科學會誌 Vol.13 No.2

This study has been carried out to investigate the cause, symptom and treatment of Gi-Chun (氣喘) by referring to 32 literatures. The results were obtained as follows; 1. The factor causing Gi-Chun (氣喘) is almost damage of feeling (七情損傷). 2. The symptom of Gi-Chun (氣喘) is as follows. agony, breathing urgent, cold hand and feet, body tired, low appetite 3. The treatment of Gi-Chun (氣喘) is as follows. Sunpaeganggi(宣肺降氣), Jihaepyungchun(止咳平喘), gudam(去痰) 4. The drugs(herb) of Gi-Chun (氣喘) is as follows. Samatang(四磨湯), Sachiltang(四七湯), Sojaganggitang(蘇子降氣湯), Gilgyungjigaktang(桔梗枳殼湯), Gamisachiltang(加味四七湯), Gamisoyosan(加味逍遙散).

FR4 PCB면적과 Via-hole이 LED패키지에 미치는 열적 특성 분석

김성현,이세일,양종경,박대희,Kim, Sung-Hyun,Lee, Se-Il,Yang, Jong-Kyung,Park, Dae-Hee 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.3

In this study, the heat transfer capability have been improved by using via-holes in FR4 PCB, when the LED lighting is designed to solve the thermal problem. The thermal resistance and junction temperature were measured by changing the dimension of FR4 PCB and size of via hole. As a result, when the dimension was increased initially, the thermal resistance and junction temperature was decreased rapidly, the ones was stabilized after the dimension of 200 $[mm^2]$. Also, the light output was improved up to maximum 17% by formation of via-hole and expansion of dimension in FR4 PCB. Therefore, the thermal resistance and junction temperature could be improved by expansion of PCB dimension and configuration of via-hole ability.

수자원 전망 불확실성 분해 R Package 'UncDecomp'

김성현,온일상,김용대,Kim, Seong-Hyeon,On, Il-Sang,Kim, Yong-Dae 한국수자원학회 2019 물과 미래(한국수자원학회지) Vol.52 No.11

Removal of sulfur compounds in FCC raw C4 using activated carbon impregnated with CuCl and PdCl2

김성현,Kyu-Sung Kim,Sun Hee Park,Ki Tae Park,전병희 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.2

Fluid catalytic cracking (FCC) is one of the most important refinery processes for economical efficiency that produces commercial fuels with acceptable concentrations of sulfur. Several activated carbon (AC) based adsorbents were studied to develop a more efficient adsorbent for removal of mercaptanes and sulfides during the FCC C4 refinery process. The adsorbents were prepared by impregnating AC with CuCl and PdCl2. To evaluate the degree of metal halide impregnation into the AC support, each adsorbent was characterized by N2 adsorption, elemental analysis (EA) and XRF. Three types of ACs were used to investigate the effect of the structural properties such as surface area,total pore volume and pore size distribution. From this analysis, an AC micro pore size of 0.7 nm was found to be the most effective support material for FCC C4 removal of sulfur compounds. The experimental adsorption isotherms were compared with Langmuir and Freundlich models and were found to fit the Freundlich model much better than the Langmuir model. The sulfur removal performance of the prepared adsorbents was tested using the breakthrough experiments. The sulfur adsorption capacities of adsorbents decreased in the following order: AC impregnated PdCl2, AC impregnated CuCl and non-impregnated AC (NIAC). The saturated adsorbents were regenerated by toluene treatment and reactivated at 130 oC under a vacuum.

HMX/LLM-116 공결정의 고에너지 특성에 관한 이론 연구

김성현,고유미,신창호,김승준,Kim, Sung-Hyun,Ko, Yoo-Mi,Shin, Chang-Ho,Kim, Seung-Joon 대한화학회 2016 대한화학회지 Vol.60 No.1

폭발성능이 높은 HMX와 폭발성능은 떨어지지만 안정성이 높은 LLM-116의 분자복합체인 HMX/LLM-116 공결정(cocrystal)의 폭발 속도, 폭발 압력 그리고 열역학적 안정성에 대하여 이론적으로 연구하였다. 각 분자 구조는 B3LYP/cc-pVTZ 수준까지 최적화 하였으며 가장 약한 방아쇠 결합(trigger bond)과 클러스터에 대한 결합에너지를 계산 하여 열역학적 안정성을 확인하였다. 보다 정확한 에너지를 계산하기 위해 MP2 이론 수준에서 한 점(single point) 에너지를 계산하였으며, monte carlo integration 계산을 통해 밀도를 계산 하였다. 엔탈피는 CBS-Q 이론 수준에서 계산하였으며, 폭발 속도와 폭발 압력은 Kamlet-Jacobs 방정식을 이용하여 계산하였다. The theoretical investigation has been performed to predict detonation velocity, detonation pressure, and thermodynamic stability of HMX/LLM-116 cocrystal. All possible geometries of HMX, LLM-116, and cocrystal have been optimized at the B3LYP/cc-pVTZ level of theory. The binding energy for the trigger bond and cluster has been calculated to predict the thermodynamic stability. The MP2 binding energies were obtained using single point energy calculation at the B3LYP optimized geometries, and the density has been calculated from monte carlo integration. The detonation velocity and detonation pressure have been calculated using Kamlet-Jacobs equation, while enthalpy has been predicted at the CBS-Q level of theory.

수학적 재능에 대한 Krutetskii의 연구 분석

김성현,한인기,Kim, Sung-Hyun,Han, In-Ki 영남수학회 2011 East Asian mathematical journal Vol.27 No.4

In this study we study Krutetskii and Krutetskii's monograph 'The Psychology of Mathematical Abilities in Schoolchidren' which is published in Russia(in Russian) and USA(in English). We describe Krutetskii's biography briefly, which was not published in Korea. We analyze the methods, procedures, and results which are presented in the Krutetskii' work, and systemize these. Our study will give a overview of Krutetskii' viewpoint about mathematical abilities.