건조기에서 Amino수지 성형재료의 경화특성에 관한 연구

최재욱,최일곤,목연수,김상렬 釜慶大學校 1998 釜慶大學校 論文集 Vol.3 No.2

We studied the effect of mass transfer in a dryer on the condensation of amino resin mould material and the curing characteristics, and investigated the drying rate, the moisture and the curing fluidity according th the variations of the temperature and the drying media recycle volume which affects the mass transfer in the drying process. So, the result are summarized as follows: ① As the drying temperature increased to 70℃, 80℃ and 90℃ respectively, the drying rate became fast. ② In the same final drying time, the higher the drying temperature became, the more the moisture content of the urea resin mould material inceased. ③ Accordingly as the drying temperature increased, the moisture content of the drying material suddenly decreased in short drying time, but the moisture content increased when the drying time was between 80 minute and 120 minutes. ④ As the drying temperature increased, the curing fluidity of amino resin mould meterial decreased. ⑤ As the recycle volume of the drying media increased, the curing fluidity decreased.

수리된 복합레진 수복물의 전달결합강도 연구

최수영,정선와,황윤찬,김선호,윤창,오원만,황인남 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.6

This study was performed to evaluate the interfacial shear bond strength of base (direct and indirect) and repair composites with aging and surface treatment methods. Direct composites resin specimens (Charisma®, Heraeus Kulzer, Germany) were aged for 5 min, 1 hour, 24 hours, and 1 week in 37℃ distilled water before surface treatment, and then divided into five groups: Group 1, grinding; Group 2, grinding and application of bonding agent; Group 3, grinding, etching with 37% phosphoric acid for 30sec, and application of bonding agent; Group 4, grinding, etching with 37% phosphoric acid for 30sec, silane treatment, and application of bonding agent; Group 5, grinding, etching with 4% hydrofluoric acid for 30sec, silane treatment, and application of bonding agent. Indirect composite resin specimens (Artglass®, Heraeus Kulzer, Germany) were aged for 1 week in 37℃ distilled water and divided into seven groups: Group 1 - Group 5, equal to Charisma specimens; Group 6, grinding, etching 37% phosphoric acid for 60sec, silane treatment, and application of bonding agent; Group 7, grinding, etching with 4% hydrofluoric acid for 60 sec, silane treatment, and application of bonding agent. The repair material(Charisma®) was then added on the center of the surface (5mm in diameter, 5mm in height). The shear bond strength was tested and the data was analyzed using one-way ANOVA and the Student-Newman-Keuls test. The following conclusions were drawn. 1. The shear bond strength of Charisma® specimens aged for 1 hour was significantly higher in Group 2 and Group 5 than in Group 1 (p<0.05), and that of Charisma® specimens aged for 1 week was significantly higher in Group 3 and Group 5 than in Group 1 (p<0.05). No significant difference was found in the bond strength of specimens aged for 5 min and 24 hours. 2. In Group 2 of the Charisma® specimens, there was significant difference between the bond strength of 24 hours and that of 1 week (p<0.05). 3. In Group 4 of the Charisma® specimens, the shear bond strength of specimens aged for 24 hours was significantly higher than the others(p<0.05). 4. There was no significant diiference between the shear bond strength of the Artglass® specimens. 5. Most of the Charisma® specimens showed cohesive fractures. Artglass® specimens that were etched with acid(phosphoric or hydrofluoric) for 30 sec showed more cohesive fractures.

영구형 항서맥 심박조율기 환자의 장기추적관찰

최현석,이무용,최영진,최성준,김효수,손대원,오병희,이명묵,박영배,최윤식,이영우,이명용 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.5

가연성물질의 인화점에 관한 연구 : Ⅰ. 순수성분 및 2성분계 혼합물 Ⅰ. Pure Substances and A Mixture of Binary System

최재욱,목연수,하동명 韓國火災 ·消防學會 1999 한국화재소방학회논문지 Vol.13 No.1

基準點 間隔이 블럭調整의 精密度에 미치는 影響에 관한 硏究

崔在和,崔允秀,千翼卿 成均館大學校 科學技術硏究所 1989 論文集 Vol.40 No.2

Up to now, analyses of the precision in A.T, have been dealt with hypothesis of error-free on ground control coordinates. In fact, it is not error-free but the precision of ground control surveying is higher than the precision of aerotriangulation. In this investigation, it has, therefore, given weight corresponding to precison of the ground control surveying, and it has analyzed the influence which the precision of ground control coordinates exerts upon the absolute error of check points with the change of the control spacing. Then, the results of this investigation can be concluded as follows: (1) In weight 10^1 case, it has known that ground control coordinates have been permitted error-free. (2) It is thought that it will be desirable to give the corresponding weight when the precision of ground control surveying is had. (3) The absolute error goes to bad with the change of control spacing from 2 models to 4 models. Therefore, it is known that the control spacing influences the absolute error.

Board drain 工法에 關한 實驗的 硏究

崔允秀,具滋甲 안성산업대학교 1991 論文集 Vol.23 No.-

The drain capacity of drain board depends on the circumference length rather than the cross section of drain board. This paper based on the fact written above, throuth the vacuum consolidation test about "+" type board increased circumference lengh and existing "-" type board, intends to compare the cnsolidation effect between two types of board. 1. consolidation time of the "+" type board is shorten than "-" type board by 1.6 times. 2. The "+" type board is more effective improving the soil than "-" type board. 3. When 4 sheets board with 5cm breath is disposed in the form of "+" type, it seems to be good to use 0.65 as conversion coefficient.

난소암에서 CA125의 임상적 의의

윤병일,김수녕,손인숙,유연웅,최원석 건국대학교 의과학연구소 2000 건국의과학학술지 Vol.10 No.-

The concentration of the tumor marker CA125 in serum from patients with ovarian tumor was measured to define the usefulness of them in differentiating malignant ovarian tumor from benign ovarian mass. In the study of 105 patients with gynecologic neoplasm, of whom 38 were myoma uteri, 42 benign ovarian tumor, and 25 ovarian cancer, the level of serum CA125 were measured. CA125 was greater than 35 U/ml in 2.6% of myoma uteri, in 2.4% of benign ovarian tumors and 68.0% of ovarian cancers. Using a cut-off level of 35 U/ml, the results can be characterized by a 68.0% of sensitivity and 97.5% of specificity in detecting an ovarian cancer. Among 25 patients with ovarian cancer, 11 of 14 (78.6%) patients with serous cystadenocarcinoma, 4 of 6 (66.7%) patients with mucinous cystadenocarcinoma and 2 of 5 (40.0%) patients with endometrioid carcinoma had CA125 values greater than 35 U/ml. In relation to a higher tumor stage, there was an increasing incidence of elevated levels of CA125. As a result, it is likely that the measurement of CA125 is useful for early diagnosis of ovarian cancer.

작업장 누적소음 노출과 혈압과의 관련성

이상윤, 김재용*, 임형준, 윤기정, 최홍렬*, 고상백**, 강대희, 조수헌 대한산업의학회 2001 대한직업환경의학회지 Vol.13 No.2

목적 : 작업장에서의 누적소음노출값과 혈압의 변화 사이의 관계를 관찰하기 위한 단면 연구를 시행하였다. 방법 : 소음발생 제조업체의 남성근로자 중 건강진단 자료, 설문지 자료, 인사기록이 모두 갖추어진 852명을 연구대상으로 하였다. 작업장 소음측정값은 34개 지점에서 측정된 작업환경 측정 보고서 값을 사용하였고, 혈압은 건강진단시 측정한 수축기 혈압과 이완기 혈압 각각의 평균을 이용하였다. 가능한 교란변수들을 건강진단시 설문조사를 통하여 조사하였다. 근로자의 근무기간과 근무했던 작업부서의 소음노출값을 이용하여 누적소음노출값을 추정하였고, 이에 따라 전체 연구대상 근로자를 저소음노출군, 중등도소음노출군, 고소음노출군, 과다소음노출군으로 구분하였다. 누적소음노출값으로 구분한 소음노출군 사이에 평균 수축기 혈압 및 이완기 혈압의 차이가 있는 지를 나이, 비만도지수, 혈중 콜레스테롤값, 고혈압의 가족력, 흡연력, 음주력 등의 가능한 교란변수들의 영향을 통제한 상태에서 비교하였다. 결과 : 가능한 교란변수들을 보정한 상태에서 저소음노출군에서 과다소음노출군으로 갈수록 수축기 혈압 및 이완기 혈압의 증가가 있는지를 관찰하기 위해 일반선형모델을 이용하여 분석하였을 때, 수축기 혈압 및 이완기 혈압 모두 소음노출군이 혈압 변화의 유의한 설명변수였고, 수축기 혈압 및 이완기 혈압 모두 저소음노출군에 비해 과다소음노출군이 각각 2.1 mmHg, 2.7 mmHg 만큼 높았다. 결론 : 이는 만성적으로 누적된 고소음에의 노출로 인하여 혈압 상승의 가능성이 있음을 시사한다. Objectives : The association of workplace cumulative noise exposure and blood pressure was investigated in this study using cross-sectional design. Methods : The study population comprised 852 manufacturing male workers of whom occupational health examination data, questionnaire and personnel records were available. Workplace ambient noise monitoring data was used for calculating individual cumulative noise exposure level. Mean of each systolic and diastolic blood pressure of occupational health examination data was used for individual systolic and diastolic blood pressure level. Possible confounding variables including family history of hypertension, smoking habit, alcohol drinking habit were collected by questionnaire. On the basis of job location and duration of work at the location, a cumulatlve time-weighted average noise level was calculated for each workers. According to this cumulative noise exposure level, each study subject was categorized as low noise exposure group, moderate noise exposure group, high noise exposure group, very high noise exposure group. Among noise exposure groups, mean of systolic and diastolic blood pressure was compared after adjusting possible confounding variables such as age, body mass index, serum cholesterol level, family history of hypertension, smoking history, alcohol drinking habit. Results : After adjusting possible confounding variables, noise exposure group was signnificant explanatory variables for both systolic and diastolic blood pressure, and mean of both systolic and diastolic blood pressure of very high exposure group was higher than that of low exposure group. Conclusions : These findings suggested that the high cumulative noise exposure might elevate the blood pressure.

Hydroxy Propyl Methyl Cellulose의 자연발화에 관한 연구

최재욱,목연수,하동명 한국화재소방학회 2001 한국화재소방학회논문지 Vol.15 No.4

HPM의 자연발화는 일정한 주위온도에서 자연발화의 연구와 Godbret-Greenwald가 고안한 전기로에서 운상상태의 최소발화온도를 구하였으며, 시료를 용기에 충전했을 경우 용기의 크기가 클수록 발화한계온도는 낮아졌으며, 겉보기활성화에너지는 Frank-Kamenetskii의 열발화이론으로부터 계산하였고, 운상상태의 발화온도는 21%의 산소농도하에서 최소발화온도를 구하였으며, 산소농도 변화의 실험결과 산소농도 10%에서 발화되지 않았으며 한계산소농도를 구할 수 있었다. The spontaneous ignition of hydroxypropyl methyl cellulose(HPMC) was investigated at constant ambient temperature in the oven and minimum ignition temperature of dust clouds with Godbret-Creenwald Furnace respectively, In the experiments of the vessel filled with sample, the larger the vessel was the lower the spontaneous ignition temperature and ambient temperature was calculated from the Frank-Kamenetskii thermal ignition theory, The minimum ignition temperature for the dust cloud state was found under 21% oxygen concentration. At the experiment with the change of oxygen concentration, HPMC was not ignite at 10% O2 and so the limiting oxygen concentration was obtained at 10%. Keywords : Spontaneous ignition, Ambient temperature, Minimum ignition temperature Frank-Kamenetskii thermal ignition theory

산지하천의 강우특성에 의한 부유물질 유출에 관한 연구

윤인규,박수진,최한규 강원대학교 산업기술연구소 2007 産業技術硏究 Vol.27 No.A

In this research, we have selected the region of Jawoon river that is the area of high land vegetable growing in the upper Soyang Reservoir and we have observed actual floating materials that generate negative nutrition and turbidity of the Reservoir water and the changes of water quality by raining of each month for one year of 2005 in order to monitor the relationship of pollution sources by the outflow of rain water. In addition, we also have conducted statistical inspection methods such as correlation analysis and regression analysis on strength of raining force and rain continuance time among the elements affecting the outflow of floating materials.