수종 상아질 접착제의 결합강도와 중합률에 관한 연구

김병현,권혁춘 大韓齒科保存學會 1998 Restorative Dentistry & Endodontics Vol.23 No.1

The physical properties of polymer are greatly influenced by the extent to which resin cures. The presence of unreacted monomer can have a plasticizing effect on the polymer, thereby altering the physical and mechanical properties of dentin bonding agent(DBA). If the DBA does not polymerize sufficiently, it will leave a weak bonding layer and lead to lower bond strength. The purpose of this study was to evaluate te shear bond strengths(SBS) and the degree of conversion(DC) of 4 commercialy avilable dentin bonding systems which are composed of 2 multi-bottle systems [Scotchbond Multi-Purpose(SMP), AeliteBond(AB)] and 2 one-bottle systems [SingleBond(SB), One-Step(OS)]. For shear bond strength measurement, labial surfaces of freshly extracted bovine incisors were ground with #600 grit SiC paper to expose dentin. Four different groups of samples were formed, with 10 samples being made for each of the 4 commercial DBA in each group according to the curing sequences of DBA and overlayer thickness of composites:Group Ⅰ (standard cure and 1㎜ thick composites):The DBA was light cured and the composites of 1㎜ thickness was applied;Group Ⅱ (standard cure and 2㎜ thick composites):The DBA was light cured and the composites of 2㎜ thickness was applied;Group Ⅲ(simultaneous cure and 1㎜ thick composites):The DBA was not light-cured and simultaneously cured with composites of 1㎜ thickness;Group Ⅳ(simultaneous cure and 2㎜ thick composites):The DBA was not light-cured and simultaneously cured with composites of 2㎜ thickness. The SBS was measured immediately after the composites was bonded to the bovine dentin using an Instron machine. The DC of the DBA as examined in a thin film under simulated conditions of the experimental groups according to the curing sequences and overlayer thickness of composites in the SBS test. using a Fourier transform Infrared(FTIR) spectrometer. The following results were obtained from SBS tests and DC measurements 1. In SBS tests, the multi-bottle DBA(SMP, AB) had a generally higher bond strength values than the one bottle DBA(SB, OS). In DC measurements, the one bottle DBA(SB, OS) had a significantly higher DC than the multi-bottle DBA(SMP, AB). 2. In all DBAs except OS, there was no significant difference between the bond strength of group Ⅰ(standad cure and 1㎜ thick composites) and that of group Ⅲ(simultaneous cure and 1㎜ thick composites). SMP, SB in Group Ⅰ had a significantly higher DC than those in group Ⅲ, but AB, OS in group Ⅰ had a significantly lower DC than those in group Ⅲ 3. All DBAs in Goup Ⅱ(standard cure and 2㎜ thick composites) had significantly higher bond strength and DC than those in Group Ⅳ(simultaneous cure and 2㎜ thick composites). 4. In all DBAs, there was no significantly different SBS and DC between Group Ⅰ and Group Ⅱ, but all DBAs in Group Ⅲ had significantly higher SBS and DC than those in Group Ⅳ.

Ezen Good Orthotics 적용이 만성관절통증의 통증감소에 미치는 영향

김영빈,박병근,정동혁 圓光大學校 附設 體力科學硏究所 2005 體力科學硏究 Vol.28 No.-

The aim of the present study is to evaluate effects of Ezen Good Orthotics applied to 30 middle-aged patients with chronic joint pains around shoulders, waists and knees. The effects were measured and analyzed by means of MPQWL, VRS, VAS-I and VAS-U after 4, 8 and 12 weeks, respectively, during the 12-week application of the orthotics. From the findings of the measurement and analysis, following conclusion could be drawn: 1. Significant reductions in MPQWL were confirmed at each period of measurement since the use of Ezen Good Orthotics(p<.001). 2. Significant reductions were also revealed in VRS at each period of the measurement(p<.001). 3. VAS-I, too, turned out to be reduced significantly after 4-, 8- and 12-week use of Ezen Good Orthotics(p<.001). 4. The same reductions were found as well in VAS-U 4, 8 and 12 weeks after the application of the Ezen Good Orthotics(p<.00l). In sum, it may be concluded from the outcomes that the use of Ezen Good Orthotics may help reduce drastically chronic joint pains, mostly effective to remove them speedily and safely. Patients, rehabilitation therapists and health experts are, therefore, recommended to employ the products as safe and effective means to control pains. Continued researches and experiments should further be conducted to collect more data from the larger population of patients with particular diseases in clinical situation, though.

Hematite의 還元速度에 미치는 Al₂O₃, CaO, SiO₂의 影響

金東義,尹秉河,朴漢赫 경북대학교 공과대학 1985 工大硏究誌 Vol.14 No.-

Reduction of hematite by H_2 and CO-CO_2 gas was performed at 800℃, 900℃, 1000℃ after the addition of Al_2O_3, CaO and SiO_2 as an impurity substances. The reduction rate was appeared maximum by CaO and minimum by Al_2O_3 addition, when their amounts were equal at any temperatures, and regardless of the kinds of foreign oxides, the effects on the reduction rate revealed maximum, when the amount was about 1.0wt%. The reduction rate by the mixed control rate equation was showed straight lines by adopting the values of De and Kr from those experimental data. As the results, effects on the reduction rate when hematite contains foreign oxides, such as Al_2O_3, CaO and SiO_2, at high temperature, it was controlled by chemical reaction, and at low temperature it was controlled by interparticle pore diffusion.

부산지역 일부 산업장 근로자들의 유병률에 관한 연구

김광혁,윤병재 THE KOREAN SOCIETY FOR BIOMEDICAL LABORATORY SCIEN 1997 Journal of biomedical laboratory sciences Vol.3 No.2

1993년 1월 1일부터 1995년 12월 31일까지 부산시내 324개 사업장 16,453명의 근로자를 대상으로 성별, 연령별, 업종별 유병률을 조사하여 다음과 같은 결과를 얻었다. 조사대상자의 성별 비는 1.9:1.0이고 평균 연령은 남자가 43±17세, 여자는 38±15세로 나타났다. 전체 대상자 16,453명중 1,932명 (11.7%)이 질병을 앓고있는 사람이며 남자가 1,521명 (14.0%), 여자가 411명 (7.3%)으로 나타났다. 성별에 따른 유병률은 폐결핵, 간장질환, 소음성 난청은 남자가 여자보다 유의하게 높았고 빈혈증, 유기용제 중독은 여자가 남자보다 유의하게 높았다 (p<0.001). 연령별 유병률은 29세 미만과 30∼39세, 40∼49세에서 간장질환이 높았고 50세 이상에서 순환계 질환이 높았다 (p<0.001). 업종별 유병률은 전기 건설업, 신발 고무제조업에서 순환계 질환이 가장 높았고 1차금속, 운수 정비업, 섬유 피혁, 화학 석유제조업, 기타 제조업에서 간장질환이 가장 높게 나타났다. 음료 및 식료품 제조업과 기계제조업에 종사하는 사람은 소음성 난청이 가장 높았다. 근무 기간별 유병률은 연중독을 제외한 모든 질환에서 근무기간이 길수록 높았다 (p<0.001). This study was performed to investigat the prevalence rates disease in industrial workers (16,453) in Pusan city from Jan. 1, 1993 to Dec. 31, 1995. The results were as follows: The male to female ratio was 1.9:1.0 and average age was 43±17 in male, 38±15 in female of subjects. The percentage value of patients was 14.0% in male, 7.4% in female of total patients 1,932 (11.0%). The prevalence rates of pulmonary tuberculosis, hepatic disease, and occupational hearing loss were significantly increased in male than females (p<0.001). But anaemia and organic solvent poisonings significantly increased in females than males (p<0.001). The prevalence rates of hepatic disease increased significantly in below 29, 30-39 and 40-49 age groups, that of cardiovascular disease increased significantly in the age group over 50 years (p<0.001). According to industrial types, the prevalence rate of cadiovascular disease increased in electricity and constration and shoes and rubber in disease, there of hepatic disease increased in primary metal, transportation and maintenance and other industrial, those of occupational hearing loss in drink and food and machinery. The prevalence rate of disease increased significantly long working duration in all diseases except lead poisoning.

매복된 상악 중절치의 교정적 처치를 통한 치험례

김남혁,김성오,송제선,손흥규,최병재,이제호,최형준 大韓小兒齒科學會 2010 大韓小兒齒科學會誌 Vol.37 No.1

매복은 임상 검사나 방사선 사진 검사 상에서 인식 가능한 맹출 경로 상에 장애물이나 이소 위치에 의한 치아 맹출의 정지를 의미한다. 상악 중절치의 치아 매복의 원인으로는 과잉치, 치아종, 치배의 이소위치, 외상 후 연조직 치유에 의한 폐쇄, 만곡치, 정지된 치근 발육 등이 있다. 매복된 치아는 인접치의 근심이동으로 인한 공간 상실, 부정교합, 인접치의 치근 흡수, 낭종의 형성 등을 유발할 수 있으므로 맹출장애에 대한 주의 깊은 관찰과 조기 진단이 중요하며 적절한 치료가 시행되어야 한다. 매복된 치아의 치료방법으로는 유치의 발거나 외과적 노출을 통한 맹출 유도, 경과관찰, 외과적 방법이나 교정력을 이용한 매복치의 재위치, 매복치의 외과적 발거 등이 있다. 이 중 교정적 견인은 매복된 치아가 원인을 제거한 후 또는 외과적으로 치관을 노출시킨 후에 일정기간의 관찰에도 맹출하지 않거나, 맹출경로가 정상에서 많이 벗어나 맹출이 기대되지 않을 경우 적용될 수 있다. 본 증례는 매복된 상악중절치를 교정적 견인을 통해 정상적인 맹출 방향으로 유도한 치험례들로 양호한 치료 결과를 보였기에 이를 보고하고자 하는 바이다. Impaction is defined as a cessation of the eruption of a tooth caused by a clinically or radiographically detectable physical barrier in the eruption path or by an ectopic position of the tooth. The reasons for impaction of the maxillary central incisor are supernumerary tooth, odontoma, ectopic position of tooth germ, dilacerated tooth and so force. Impacted tooth cause space loss due to proximal movement of adjacent tooth, malocclusion, root resorption of adjacent tooth, cyst formation, so careful observation and early detection is important and exact treatment should be applied to prevent these results. The treatment options of impacted tooth include induction an eruption through extraction of deciduous tooth or surgical exposure, reposition of impacted tooth by surgical method or orthodontic treatment. Orthodontic traction is recommended when an eruption does not happen after removal of barrier or surgical exposure, when eruption path is too transpositioned to be corrected spontaneously so eruption does not expected. In these cases, traction of impacted maxillary central incisor was carried out using orthodontic method with closed eruption technique and it showed good clinical results so we report these cases.

요소 및 포도당 동시 측정용 ISFET다기능 바이오센서

김창수,권대혁,손병기 경북대학교 센서기술연구소 1990 센서技術學術大會論文集 Vol.1 No.1

A multi-biosensor for simultaneous detection of urea and glucose was fabricated by using ISFETs and Immobilized enzyme membrane and its performance characteristics were investigated. Detection of urea and glucose was possible in urea concentration range of 1~100mg/dl and glucose concentration range of 5~100mg/dl respectively. The ISFET multi-biosensor with strong advantages, very small size and fast response, showed high Potentials for in-situ measurements.

DC/DC 승압 컨버터의 출력 특성 개선을 위한 스너버 회로 설계

김성종,김인혁,정구종,손영익,한병문 明知大學校 産業技術硏究所 2009 産業技術硏究所論文集 Vol.28 No.-

Applications of DC!DC boost converters are increasing recently in many industrial areas including renewable energy sources. High switching frequency of the power semiconductor devices including MOSFET, IGBT causes the EMI noise owing to the large values of dv/dt and di/dt. Since the EMI noises degrade power efficiency and reliability of the system many researches have been made to reduce the noise. This paper presents a passive snubber circuit to improve the tum-on and turn-off transients of the pulsewidth modulated (PWM) DC/DC boost converters. The noises in the output voltage of the DC!DC converter are reduced by adding a resistor and an inductor to the circuit. Experimental results show the effectiveness of the proposed snubber circuit to improve the output characteristics of the boost converter.

계류기구로 관측한 대구시 야간 안정층 특성에 관한 사례연구

김희종,윤일희,권병혁,허만천 한국환경과학회 2002 한국환경과학회지 Vol.11 No.3

Using measured data at Daegu by tethersonde for the period or 1984~1987, we have investigated the lower atmospheric boundary layer structure including relationships between inversion layer and meteorological factor(wind and temperature), and the inversion strength and inversion height. The inversion layer was defined from the vertical temperature profile and its strength was analyzed with the wind shear as well as the vertical temperature gradient. From October to January, measured inversion layer isn't destroyed, however, in June, after sun rise, it is destroyed by surface heating and mixed layer is developed from surface. According to pasquill stability classes, the moderately stable cases dominated. It's the larger vertical temperature gradient, the lower SBL height. We have introduced B(bulk turbulence scale) which indicated SBL height. It's larger B, the higher SBL height and vice versa. It was noted that the bulk turbulence scale (B) is appropriated to determine the stable boundary layer height.

광섬유를 이용한 고감도 압력센서의 개발

김창원,권대혁,김진섭,이정희,손병기 경북대학교 센서기술연구소 1995 연차보고서 Vol.1995 No.-

KOH 수용액을 이용하여 실리콘 식각공정기술을 확립하였으며, 이를 이용하여 실리콘 기판 위에 스트레스 균형이 이루어진 150 ㎚-Si_3N_4/300 ㎚-SiO_2/150 ㎚-Si_3N_4 두께를 가지는 구조의 평탄한 3층 유전체 멤브레인을 제작하였다. 본 실험에서 사용되는 파장인 1.3 ㎛ 근방에서 다이아프레임의 광투과도는 약 50 %로 광반사막으로 사용이 불가능하였다. 따라서, 다이아프레임 뒷면에 약 1000 Å의 금을 증착하여 N/O/N/Au박막의 광투과도를 수 %정도로 감소시킴으로써, 센서의 광반사막으로 사용할 수 있었다. source fiber를 단일모드로 했을 때 다이아프레임의 크기에 따라 감도는 각각 0.52㎻/torr(3×3 ㎟), 0.65 ㎻/torr(4×4 ㎟), 0.77 ㎻/torr(5×5 ㎟)였다. 광손실을 최소화하기 위해 광전송용 다모드 광섬유를 사용하였을 때는, 2×2 ㎟의 다이아프레임의 크기에 대해 0∼800 torr의 넓은 측정범위에서 거의 선형적인 압력특성을 나타내었다. Using KOH solution, silicon etching technology has been established and stress-balanced flat 600 ㎚ thick triple dielectric membrane(150 ㎚-Si_3N_4/300 ㎚-SiO_2/150 ㎚-Si_3N_4) on silicon substrate has been fabricated. At the wavelength of the sensor light source near 1.3 ㎛, the optical transmittance of the diaphragm was about 50 %, it was impossible to be used as a reflecting film. To decrease to a few percents, the back-side of the diaphragm was deposited 1,000 Å thick gold layer, which is sufficient enough to be used as a light reflection layer of the sensor. When was used 8/126 ㎛ single-mode fiber, the respective sensitivities for diaphragm size were 0.52 ㎻/torr(3×3 ㎟), 0.65 ㎻/torr(4×4 ㎟), 0.77 ㎻/torr(5×5 ㎟). When was used 62/126 ㎛ multi-mode fiber for the light transmission to minimize optical loss, the pressure characteristics was showed almost linearly curve in a wide pressure range, 0 torr∼800 torr, for the 2×2 ㎟ diaphragm in dimensions.

Si Bulk Micromachining을 위한 Wafer Rolling Etching 및 그 특성

김건년,이보나,박효덕,신상모,공경준,장동근,김병철,권혁채,이봉희 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

A wafer rolling etching system for the silicon bulk micromachining has been designed and fabricated. The silicon diaphragms were anisotropically etched in a 24.5 weight percent KOH solution. Compared to the conventional KOH etching systems, pyramidal hillocks, and wave-shaped structures on the etched surfaces were greatly reduced by using this system. After etching for time of 438 minutes, the average etched depth and the etch-rate were measured to be 537μm and 1.22μm/min, respectively. The average etching uniformity of etching depth was 0.87% in 5-inch wafer. Our results showed that the wafer rolling method enhanced etch uniformity and etch rate.