자가 산부식 프라이머의 적용시간이 상아질의 미세인장 결합강도에 미치는 영향

조영곤,이영곤,김종욱,박병철,김종진,최희영,진철희,유상훈 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.5

This study evaluated the influence of application time of self-etching primers on microtensile bond strength (μTBS) to dentin using three self-etching primer adhesive systems. Dentin surfaces were exposed from forty-eight human molars. They were conditioned with three self-etching primers (Clearfil SE Bond [SE], Unifil Bond [UF], Tyrian SPE + One Step Plus [TY]) and different primining times (10s, 20s, 30s and 40s). Composite resins were bonded to dentin surfaces and specimens were made. μTBS was tested and statistically compared using by one-way ANOVA and Tukey's Test. The results of this study presented that priming time for 10s in SE and UF groups and for 30s and 40s in TY group was highly decreased μTBS to dentin.

초음파 반사 패턴과 주파수 대역 분할 신호처리를 이용한 다층구조인 노내 간극 측정

구길모,심철무,김종환,김상백,김희동,박치승 한국비파괴검사학회 2000 한국비파괴검사학회지 Vol.20 No.4

모의 원자로내 용융물 냉각 실증 실험 결과 용융물 Al₂O₃/Fe themite 와 lower head vessel사이에 간극이 발생된다. 간극을 정량적으로 측정하기 위한 기존의 초음파 방법은 구조물의 복잡성과 2300℃ 에서 용융되는 thermite Al₂O₃/Fe, Al₂O₃의 영향으로 발생되는 lower head의 열영향부위(HAZ)의 금속학적인 결정입자 크기의 변화로 결정 계면으로부터 발생되는 잡음신호와 초음파 산란, 감쇠, 모드 변환 등이 발생되어 신뢰성이 떨어지고 있다. 간극을 정량적으로 측정하기 위해서 thermite와 lower head 사이에 물이 체워진 형태의 즉 고체, 액체, 고체의 다층구조에서 초음파의 진행 및 반사 형태를 분류 및 분석하였다. 결정립의 잡음을 억제하기 위하여 주파수대역의 확률 처리 방식인 PT(polarity threshold) 알고리즘을 이용하여 약 6dB 신호 대 잡음비의 개선효과를 가져왔다.

법랑질 접착에 대한 습윤 효과

고근호,조영곤,진철희,유상훈,김종욱,박병철,기영재,최희영,김종진 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.3

This study evaluated the microleakage and interfacial gap between enamel and composite resin under the dry and wet condition of the enamel surface, V shaped class 5 cavities were prepared on the occlusal portion of extracted human molars. Samples were divided into three groups: D group (air dry for 10-15s), BD group (blot dry with moist cotton pellet), and DR group (air dry for 10-15s and rewet with Aqua-Prep F for 20s). Cavities were filled using Aelitefil composite resin after applied One-Step. Microleakage was tested by 2% methylene blue dye solution and the data were statistically analysed by Kruskal-Wallis test and Mann-Whitney test. Also Enamel-resin interface was observed under SEM. Group BD showed statistically lower microleakage than group D (p〈0.05). but there was no statistically significant difference between group BD and DR (p)0.05). At the enamel-resin interface, group D showed the gap of 2 ㎛ thickness, but group BD and DR showed close adaptation. In conclusion, the use of blot dry and rewetting agent (Aqua-Prep F) resulted in decreased microleakage and improved adhesion between enamel and resin when using One-Step.

복합레진의 지연충전이 미세인장 결합강도에 미치는 영향

박현식,조영곤,박병철,김종욱,최희영,김종진,진철희,유상훈,기영재 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.3

The purpose of this study was to evaluate the effect of immediate or delayed composite resin filling on dentinal microtensile bond strength (μTBS) after applied the adhesive. The coronal dentin of human third molars was exposed. Single-Bond or One-Step was applied on the dentin surfaces, and composite resin were constructed immediately (group 1) or 5 min., 10 min., 15 min., 20 min. and 30 min. (groups 2-6) after an adhesive was applied. The specimens were sectioned and made bar-shaped. Each surface area of them was about l ㎟. The RBS test was performed by EZ test. The results were analysed by One-way ANOVA and Tukey's test at 95 % significance level. The results suggested that the μTBS of Single-Bond to dentin was decreased when the composite resin was constructed 20 min. and 30 min. after Single-Bond was applied. But the μTBS of One-Step was not affected by delayed composite resin filling.

Meso-Dihydroguaiaretic Acid Isolated from Saururus chinensis Inhibits Cyclooxygenase-2 and 5-Lipoxygenase in Mouse Bone Marrow-Derived Mast Cells

Tae Chul Moon,Chang Seob Seo,Kyungmi Haa,Jin Cheul Kim,Nam Kyung Hwang,Tae Gyun Hong,Jee Hyeun Kim,Do Hun Kim1,손종근,장현욱 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.5

Meso-dihydroguaiaretic acid (MDGA) is a medicinal herbal product isolated from the aerial parts of Saururus chinensis that inhibits the cyclooxygenase-2 (COX-2)-dependent phase of prostaglandin D2 (PGD2) generation in bone marrow-derived mast cells (BMMC) (IC50 9.8 μM). However, this compound did not inhibit COX-2 protein expression in BMMC at concentrations up to 30 μM, indicating that MDGA directly inhibits COX-2 activity. In addition, this compound consistently inhibited the production of leukotriene C4 (IC50 1.3 μM). These results demonstrate that MDGA inhibits both COX-2 and 5-lipoxygenase. Furthermore, this compound strongly inhibited the degranulation reaction in BMMC (IC50 11.4 μM). Therefore, this compound might provide a basis for novel anti-inflammatory drug development.

응급실 환아에 대한 임상통계적 관찰

김진헌,박철원,나창수 朝鮮大學校 附設 醫學硏究所 1986 The Medical Journal of Chosun University Vol.11 No.1

The studies were carried out to analyze the emergency patient visited to the emergency room of Chosun University Hospital under 15years of during the four-year period from Jan., 1982 to Dec., 1985. The results were obtained as below. 1) During the 4 year periods, the total number of emergency patients under the 15years of age was 5,122. 2) Fifty two percents of the total patient were admitted. 3) Deaths bsfore arrival to emergency room were 41 cases and deaths during managements at emergency room were 8 cases. 4) The total number of the male patients was 3,299 and that of the female, 1,823. 5) The most popular time of visiting to emergency room was between 4 : 00 PM and 12 : 00 PM 6) Monthly distribution of visits revealed higher incidence in Aug. and Sep. and lower incidence in Jan. and Feb. 7) Weekly distribution of visits revealed higher incidence on Sunday relatively. 8) Distribution of age showed peak incidence was below 2years of age(36.6%) 9) The number of patients received urgent management was 910 and the content was as below : O₂ inhalation(36.9%), Dressing(17.4%), Primary suture(13.9%), G-tube and lavage(7.9%), Barium reduction (6.9%). 10) Distribution of diseases and injury in according to the WHO's International Classification of Diseases was as below in order : Injury and poisoning'(28.6%), Ill-defined symptoms and signs(25.5%) .Infectious disease(13.7%), Respiratory disease(ll.6%), Perinatal problems(7.4%), Nervous system disorder(5.0%), Digestive discase(4.5%). 11) Distribution of patient's address was as below : Kwangju(57.0%), Rural(38.3%). 12) Most frequent primary diagnosis of emergency cases were as below : Injury and poisoning, diarrhcal disorder, URI, pneumonia.

스위치드 릴럭턴스 전동기의 속도제어에 관한 연구

김창현,권영안,김철우 부산대학교 1994 生産技術硏究所論文集 Vol.47 No.

Switched reluctance motor has several advantages as a variable speed motor. This paper studies a speed control of SRM with widely slotted opto interrupter. A low resolution of the position sensor is compensated through additional counters. The variable structure system with feedforward control and PI control of turn on angle and turn off angle is proposed as a control method. This control method is verified through the experiment in this paper. 스위치드 릴럭턴스 전동기(SRM)는 제작의 용이성, 구동회로의 안정성등 여러가지 장점으로 가변속 전동기로서 많은 주목을 받고 있다. 본 논문에서는 위치센서로서 광폭 광센서를 사용하는 SRM의 속도제어에 관하여 연구한다. 저 해상도의 위치신호는 카운터 보조회로를 부가하여 보상하였고, 속도제어방식으로는 점호각과 소호각을 피드포워드제어 또는 PI제어를 수행하는 가변구조 시스템으로써 응답속도 및 속도추종 성능이 양호하게 이루어지는 제어알고리즘을 제시하였다. 또한 본 연구에서 SRM 구동시스템을 제작하고 실험을 통하여 본 제어알고리즘의 우수성을 입증하였다.

균일 마이크로 스트립 선로에서 디지털 펄스 신호의 시간영역 전송 특성 해석

김기래,노철우 신라대학교 자연과학연구소 1999 自然科學論文集 Vol.7 No.-

Recently the necessity of MMIC is increasing because clock frequency goes up by digital data transmission of Gbps class being demanded and the density of circuits gets high for the purpose of lightening and miniaturizing system, owing to the development of ultra high speed. In this paper, the distortion of square pulse and Gaussian pulse caused by dispersion as it propagates along a uniform microstrip line is investigated. A model dispersion of the phase constant proposed by Kirchning-Jansen is used to meet the frequency, accuracy, and microstrip parametric requirements. Numerical integration technique which has high accuracy and is easily simulated, is used to obtain the time domain response of pulse signals. The dispersion of pulse signals is analyzed regarding to the relative permittivity, substrate height, strip width of the microstrip line and pulse width of signal pulse. The simulation results show that small relative permittivity and small w/h ratio are advantageous for the dispersion of the pulse signals, and that pulse signals bandwidth cause smaller dispersion. The results of this paper are compatible to the trade-off determination of relative permittivity, substrate height, strip width and pulse width of signal pulse when a design of MIC and MMIC is necessary.

WBI 교수모형을 이용한 페트리 네트 학습의 설계 및 구현

김경민,노철우 신라대학교 교육과학연구소 1999 교육과학연구 Vol.- No.4

利益變動原因分析의 모델

金喆鎬 弘益大學校 1982 弘大論叢 Vol.14 No.1

This paper provides some tools to analyze variation factors is a firm's normal profit. For the purpose of developing these, this abstract begins with the analysis of variation causes in sales, cost of goods sold, operating expenses and the other revenues. and expenses, and finally concentrates on the correlation analysis of cost-volume-profit. 1. Analysis of variation in sales Increase of market price & decrease of quantity: ΔS_a=(P'-P)Q'+P(Q'-Q)={P(1+r₁)-P}Q'+P{Q(1-r₂)-Q} Decrease of market price & increase of quantity: ΔS_b=(P'-P)Q+P'(Q'-Q)={P(1-r₁)-P}Q+P'{Q(1+r₂)-Q} Increase (or Decrease) of market price & quantity: ΔS_c={(P'-P)Q+½(P'-P)(Q'-Q)}+{P(Q'-Q)+½(P'-P)(Q'-Q)}={[P(l±r₂)-P)Q+½P(1±r₁)-P)][Q(l±r₂)-Q]}+{P[Q(1±r₂)-Q)+½P(1±r₁)-P][Q(l±r₂)-Q]} (S:sales, P:previous market price, P':current market price Q:previous. quantity, Q':current quantity, r₁:rate of variation in price, r₂:rate of variation in quantity) 2. Analysis of variation in CGS. Increase in CGS per unit & decrease in quantity: ΔC_(pa)=(p'-p)Q'+p(Q'-Q) Decrease in CGS per unit & increase in quantity: ΔC_(pb)= (p'-p)Q+p'(Q'-Q) Increase (or Decrease) in CGS per unit & quantity: ΔC_(pa)={(p'-p)Q+½(p'-p)(Q'-Q)}+{p(Q'-Q)+½(p'-p)(Q'-Q)} (p : previous CGS per unit, p' : current CGS per unit) 3. Analysis of variation in operating expenses Increase in the rate of operating variable expenses per unit &decrease in quantity: ΔC_(o₁)=(f_0'-f_0)+(p'·r₄'-p·r₄)Q'+p·r₄(Q'-Q) Decrease in the rate of operating variable expenses per unit & increase in quantity: ΔC_(o₂)=(f_0'-f_0)+(p'·r₄'-p·r₄)Q+p'·r₄'(Q'-Q) Increase (or Decrease) ,in the .rate of operating variable expenses per unit & quantity: ΔC_(o₃)=(f_0'-f_0)+{(p'·r₄'-p·r₄)Q+½p'·r₄'-p·r₄)(Q'-Q)}+{p·r₄(Q'-Q)+½p'·r₄-p·r₄)(Q'-Q)} (f_0 : previous operating fixed expenses, f_0' : current operating fixed expenses, r₄ : previous rate of operating variable expenses, r₄' : current rate of operating variable expenses) 4. Analysis of variation in the other revenues & expenses. Other revenues: ΔN₁=(I₁'-I₁)+(A₁'-A₁)+(M₁'-M₁) Other expenses: ΔN₂=(I₂'-I₂)+(D'-D)+(A₂-A₂)+(M₂'-M₂) (I₁ : receivable interest, I₂ : payable interest, A₁ : valuation income, A₂ : valuation expense, D : depreciation, M₁ : miscellaneous income, M₂ : miscellaneous expenses) :5. Analysis of the correlation of cost-volume-profit. Gross Margin (G₁) : ΔG₁=ΔS-ΔC Operation Margin (G₂) : ΔG₂=ΔS-(ΔC+ΔC_0) Normal profit (Earning before special gains or losses & income taxes)(G₃) : ΔG₃=(ΔS+ΔN₁)-(ΔC+ΔC_0+ΔN₂) (N₁ : non-operating income, N₂:non-operating expenses) 'Since the ultimate purpose of analysis of variation in profit is to provide some informations for management, the further analysis for each product, region & customer in sales has to be included in the study on the variation in margin. Therefore, I think,. a more careful and sufficient study on this field should be forthcoming.