PH 4.3에서 재광화 용액의 포화도에 따른 인공 탈회된 법랑질의 동력학적 변화

이지숙,노병덕,신수정,이윤,공형규,이찬영 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.1

법랑질의 재광화에 영향을 주는 요인으로는 PH, 불소 농도, 포화도 등이 있다. 본 연구에서는 유산 완충 탈회용액을 이용하여 법랑질 시편을 인공 탈회시킨 후, pH 4.3에서 포화도를 0.22, 0.30, 0.35로 달리한 세가지 재광화 용액에 10일간 처리하여 나타나는 변화를 편광현미경으로 관찰하여 전체 탈회 깊이와 건전 표층 폭의 변화를 조사하였다. 또한 Image program (Scion Image analyzer)을 이용하여 병소 부위의 평균 mineral density를 측정하여 탈회와 재광화 후 무기질 변화량을 통해 인공 탈회된 법랑질의 동력학적 변화를 관찰하였다. 1 재광화 후 모든 군에서 건선 표층의 폭이 증가하였는데, 포화도가 증가할수록 건전 표층 폭이 증가하였다 (P< .05) 2 재광화 후 mineral density 변화를 관찰한 결과 포화도가 낮은 군에서는 이온의 침착이 병소 전반적으로 일어났으나, 포화도가 높은 군에서는 건전 표층 부위와 표층하 병소의 하층부에서 이온의 침착으로 mineral density 가 증가하였고 표층하 병소의 상층부에서는 탈회가 진행되어 mineral density가 감소하였다. 3 재광화 후 모든 군에서 무기질량이 증가하였고 전체 탈회 깊이도 증가하였으나 각 군간에 통계적 유의차는 없었다. 본 실험에서 인공 탈회된 시편을 pH 4.3인 재광화 용액에 처리시 포화도가 높을수록 건전 표층에서 더 많은 재광화 현상이 일어났고 표층하 병소에서는 재광화 현상이 적게 일어났으며 재광화 후 모든 군에서 전체 탈회 깊이는 증가하였다. The purpose of this study is to observe and compare the dynamic change of artificially demineralized enamel by remineralization solutions of different degrees of saturation at pH 4.3 In this study, 30 enamel specimens were demineralized artificially by lactic acid buffered solution. Each of 10 specimens was immersed in pH 4.3 remineralization solution of three different degrees of saturation (0.22, 0.30, 0.35) for 10 days. After demineralization and remineralization, images were taken by a polarizing microscope (× 100). The density of lesion were determined from images taken after demineralization and remineralization. During remineralization process, mineral deposition and mineral loss occurred at the same time. After remineralization total mineral amount and width of surfacc lesion increased in all groups. The higher degree of saturation was, the more mineral deposition occurred in surface lesion and the amount of mineral deposition was not much in subsurfacc lesion. Total demineralized depth increased in all groups.

폴리머형 습도센서의 선형성 개선에 관한 연구

허원녕,이지공,이성필 慶南大學校 附設 工業技術硏究所 2003 硏究論文集 Vol.21 No.1

poly-4 vinylpyridine과 1.4-dichlorobutane의 조성을 변화시켜 공중합(co-polymerizaton)시키고 methanol (+PVP)에 용해시켜 감습물질을 제조하였다. 알루미나 기판에 Au전극을 형성한 후 제조된 감습물질을 dipping함으로써 폴리머형 습도센서를 제작하였다. Poly-4 vinylpyridine, 1.4-dichlorobutane 및 methanol의 함량비에 따른 감습특성을 조사한 결과 poly-4 vinylpyridine : 1.4-dichlorobutane : methanol의 중량비가 1: 1: 0.5인 소자의 경우, 상대습도 30%-90%로 변화했을 때 임피던스 변화는 275 ㏀에서 2.5 ㏀으로 변화하였다. PCB 기판 보다 알루미나 기판에서 히스테리시스 특성이 우수함을 알 수가 있었고, poly-4 vinylpyridine : 1.4-dichlorobutane : methanol의 중량비가 1: 1: 0.5인 소자의 경우 히스테리시스가 1.5% 이하로 나타났다. Humidity sensing materials which were co-polymerized poly-4 vinylpyridine. 1.4-dichlorobutane and methanol(+PVP) were prepared. Polymer humidity sensors were fabricated as dipping method on alumina substrates formed Au electrode. When the content ratio of poly-4 vinylpyridine, 1,4-dichlorobutane and methanol was 1: 1: 0.5, the impedance of the sample changed 275 ㏀ to 2.5 ㏀ in the relative humidity range of 30% - 90%. We can observe that the hysteresis characteristics of sensors with alumina substrate were less than 1.5% and better than the sensor with PCB one.

봄철 익산지역 환경대기 중 수용성 이온성분의 일별 침적량

김남송,강공언,김정숙,김현아,신지혜,김병수,최석진 원광대학교 대학원 2008 論文集 Vol.40 No.-

Deposition samples were collected in wet gauge and dry gauge containers at downtown of Iksan city, located southwest of the Korean peninsula, from April 20 to May 1, 2004. The volume of 30-50㎖ deionized water was added for wet gauge before sampling, but dry gauge was installed in the dry state with no deionized water adding. These samples were collected twice a day during daytime and nighttime and were analyzed for anions(Cl^(-), NO^(3-), SO₄^(2-)) and cations (NH₄^(+), Na^(+), K^(+), Mg^(2+), Ca^(2+)) using ion chromatography. Data quality was checked by the data obtained from re-injection of standard solution, Dionex cross check standard solutions, and random several deposition samples, and measured data was estimated to be reliable. Considering the deposition sample volume, the sampling time, the surface area of sampling container, and the ion concentration measured, the deposition amounts were calculated in mg/㎡/day. The sum of ion dry deposition amounts for dry gauge and wet gauge was 9.1±6.7 mg/㎡/day and 26.5±9.1 mg/㎡/day, respectively. A significant increase in deposition amount during rainfall days and Asian yellow dust period was observed for both wet gauge and dry gauge, especially during rainfall days having no difference of deposition amount between in wet gauge and in dry gauge. The mean deposition of all ions measured in this study were higher in wet gauge than in dry gauge because of the surface difference of the sampling container. The mean deposition amount of NH₄^(+), SO₄^(2-), and NO^(3-) in wet gauge were found to be about 27.6 times, 5.5 times, and 3.4 times higher. than that in dry gauge, while the rest of the chemical species were equal or a little higher in wet gauge than in dry gauge. Dominant species in dry gauge were SO₄^(2-) and Ca^(2+), accounting for 14.7% and 47.3% of the total ion dry deposition, whereas those in wet gauge were SO₄^(2-) and NH₄^(+), accounting for 27.7% and 27.1% of the total ion dry deposition, respectively.

Nano-structured carbon nitride film for humidity sensor applications

Ji gong Lee,이성필 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.3

Nano-structured carbon-nitride lms (ca. 20 40-nm grain size) have been deposited for application in humidity sensors. The surface morphology, surface roughness and bonding structures of the lms were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. In the interdigitated-electrodes (IDE) type, the resistance of the lm changed from 8283.30 k to 827.63 k . In the sandwich type, the resistance decreased from 577.41 k to 24.95 k , however, the capacitance increased from 504.31 nF to 1.30 nF in the relative humidity range of 10 to 90 %.

The Reaction of Heterocyclic Nucleophiles and the DABCO Salts of the Baylis-Hillman Acetates

Gong, Ji-Hyeon,Kim, Hyoung-Rae,Ryu, Eung K.,Kim, Jae-Nyoung Korean Chemical Society 2002 Bulletin of the Korean Chemical Society Vol.23 No.6

Design and Implementation of a 40-kV, 20-kJ/s Capacitor Charger for Pulsed-Power Application

Ji-Woong Gong,Hong-Je Ryoo,Suk-Ho Ahn,Sung-Roc Jang IEEE 2014 IEEE transactions on plasma science Vol.42 No.11

<P>This paper presents the design and implementation of a 40-kV, 20-kJ/s high-voltage capacitor charger based on a series/parallel resonant converter. The inclusion of the parallel resonant capacitor component in this circuit results in the production of a trapezoidal resonant current, which reduces conduction loss. This capacitor is practically realized as a part of the balancing network of the high-voltage rectifiers in the secondary side of the circuit. Particular attention in this paper is paid to the high-voltage transformer, which must be carefully designed to provide the required functionality without negative impact on the resonant circuit. A PSpice simulation has been used to prove that the proposed control method for the circuit is valid. This is supported with the experimental results, which verify that the operation of the circuit is as expected and that the converter is able to meet all the design criteria with an efficiency of up to 96%.</P>

Low-dose-rate radiation exposure leads to testicular damage with decreases in DNMT1 and HDAC1 in the murine testis

Gong, Eun Ji,Shin, In Sik,Son, Tae Gen,Yang, Kwangmo,Heo, Kyu,KIM, Joong Sun JAPAN RADIATION RESEACH SOCIETY 2014 JOURNAL OF RADIATION RESEARCH Vol.55 No.1

<P>This study examined the effects of continuous low-dose-rate radiation exposure (3.49 mGy/h) of gamma rays on mice testicles. C57BL/6 mice were divided into sham and radiation groups (<I>n</I> = 8 each), and were exposed to either sham irradiation or 2 Gy for 21 days, 0.2 Gy for 2 days, or 0.02 Gy for 6 h of low-dose-rate irradiation. Testicular weight, seminiferous tubular diameter, and seminiferous epithelial depth were significantly decreased in the mice irradiated with 2 Gy at 1 and 9 days after exposure. Moreover, the low-dose-rate radiation exposure induced an increase in malondialdehyde levels, and a decrease in superoxide dismutase activity in the testis of mice irradiated with 2 Gy at 1 and 9 days after exposure. The sperm count and motility in the epididymis also decreased in mice irradiated with 2 Gy at 1 and 9 days after exposure, whereas there was no significant effect on the proportion of abnormal sperm. The expressions of DNA methlytransferases-1 and histone deacetylases 1 in testes irradiated with 2 Gy were significantly decreased compared with the sham group. In conclusion, the damage exerted on the testes and epididymis largely depended on the total dose of low-dose-rate radiation.</P>

Laxative role of uridine and uridine receptor in loperamide-induced constipation SD rats and intestinal cells

Ji Eun Kim,Su Ji Bae,Yun Ju Choi,Su Jin Lee,Jeong Eun Gong,Dae Youn Hwang 한국실험동물학회 2020 한국실험동물학회 학술발표대회 논문집 Vol.2020 No.7

Indium Mediated Barbier Reaction of Ninhydrin and Isatin

Gong, Ji-Hyeon,Lee, Ka-Young,Son, Ji-Suk,Kim, Jae-Nyoung Korean Chemical Society 2003 Bulletin of the Korean Chemical Society Vol.24 No.4

IoT기반 맨홀 상시 진단시스템 개발

공지선(Ji-Seon Gong),서인진(In-Jin Seo),이한별(Han-byeol Lee) 대한전기학회 2021 대한전기학회 학술대회 논문집 Vol.2021 No.10

We are developing an wide area on-line monitoring and diagnosis system based on IoT platform for distribution manhole. This system will diagnose electrical equipment conditions by monitoring PD and temperature of the 2.9kV XLPE Cables in manhole to prevent unexpected failure of the electrical insulation. This paper focuses on the manhole monitoring system, which is the core of the overall system configuration, and the efficient diagnostic techniques applied to it.