• 지역사회간호학회지
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• 제11권1호
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• pp.209-221
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• 2000

I began the study to identify the issues related to knowledge. attitude and behavior regarding smoking by sixth graders. which will ultimately lead to the development of a smoking prevention program that will not only help deter school-age children from smoking, but also make them aware of the more desirable behaviors and techniques for healthier life. The results are as follows: 1. Smoking Behavior: Of the focus group. 4.15% are current smokers and 18.23% are ever smokers. 2. Correlation between smoking knowledge and ever smoking: Ever smoking sample($11.10{\pm}3.66$) is less knowledge able than the never-smoking sample($12.17{\pm}3.95$), (t=3.23. p=.001). 3. Correlation between smoking attitude and ever smoking: Ever smoking sample($28.12{\pm}8.51$) was less desirable than the never-smoking sample($l2.17{\pm}3.95$). (t=8.24, p=.000). 4. Correlation between smoking Knowledge and smoking attitude: knowledge about smoking and attitude toward smoking are quantitatively correlated in such way that the more knowledgeable the child is about smoking. the more desirable the attitude toward smoking is(r=.17. p=.000). 5. Correlation between socio-anthropological characteristics and ever smoking: family . atmosphere($x^2$=16.49. p=.001), school life ($x^2$=l1.58, p= .003), grades in school( $x^2$=11.89. p=.003), gender($x^2$=8.97. p=.003). friends' gathering place($x^2$=13.19. p=.02), marital status of parents(p* =.03). and family's financial status($x^2$=6.71. p=.035). In addition, Correlation between somking-environmental characteristics and ever smoking: number of friends who smoke($x^2$=76.01. p=.001). information source for smoking($x^2$=48.03. p=.001), whether or not siblings smoke($x^2$=26.07, p=.001), whether or not female relatives smoke ( $x^2$= 15.65. p= .001), whether or not father smokes ($x^2$= 12.10. p= .007), errands to buy cigarettes for someone($x^2$=9.18. p=.010), and whether or not male relatives smoke ($x^2$=8.82. p=.35) 6. Results of the logistic analysis performed to identify the factors correlated to ever smoking show that: one point decrease in attitude score translates to 25.39 times' increase in ever smoking one person decrease in the number of friends who smoke translates to 0.66 times' decrease in ever smoking: the group where the father has quit smoking has 1.40 times more ever smoking than the group where the father does not smoke at all: and likewise, the group where the father currently smokes has 1.40 times more ever smoking than the group where the father has quit smoking. 7. The overall cause-and-effect relationship between the ever smoking and the related factors: attitude toward smoking caused ever smoking by -.43, smoking by friends, by .12, marital status of arents, by .05, school life. by .04, gender, by -.03, and smoking by father, by -.02. Knowledge about smoking (t=-1.67) did not cause significant effects on ever smoking.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제18권2호
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• pp.113-128
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• 2011

Let f : ${\mathbb{R}}{\rightarrow}{\mathbb{C}}$. We consider the Hyers-Ulam stability of Jensen type functional inequality $$|f(px+qy)-Pf(x)-Qf(y)|{\leq}{\epsilon}$$ in the half planes {(x, y) : $kx+sy{\geq}d$} for fixed d, k, $s{\in}{\mathbb{R}}$ with $k{\neq}0$ or $s{\neq}0$. As consequences of the results we obtain the asymptotic behaviors of f satisfying $$|f(px+qy)-Pf(x)-Qf(y)|{\rightarrow}0$$ as $kx+sy{\rightarrow}{\infty}$.

• 한국분말재료학회지
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• 제17권2호
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• pp.142-147
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• 2010

The ultrafine titanium carbonitride ($TiC_xN_y$) particles below 100 nm in mean size, including various carbon and nitrogen contents (x=0.55~0.9, y=0.1~0.5), were successfully synthesized by new Mg-thermal reduction process. Nanostructured sub-stoichiometric titanium carbide ($TiC_x$) particles were initially produced by the magnesium reduction of gaseous $TiCl_4+x/2C_2Cl_4$ at $890^{\circ}C$ and post heat treatments in vacuum were performed for 2 hrs to remove residual magnesium and magnesium chloride mixed with $TiC_x$. Finally, well C/N-controled $TiC_xN_y$ phases were successfully produced by nitrification heat treatment under normal $N_2$ gas atmosphere at $1150^{\circ}C$ for 2 hrs. The values of purity, mean particle size and oxygen content of produced particles were about 99.3%, 100 nm and 0.2 wt.%, respectively.

• 한국표면공학회지
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• 제52권6호
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• pp.316-320
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• 2019

The effect of boronizing on mechanical properties including wear behavior and hardness of Inconel 625 superalloy were investigated. The cross-section observation demonstrated that boronized samples were composed of multi-phase boride layer (Cr_xB_x, Ni₂B), diffusion layer, and substrate. The boride and diffusion layers were increased with increasing treatment temperature and holding time. However, Cr_xB_x layer was partially peeled off when it treated 1000℃. Subsequently, boride layer was completely separated from substrate with increasing temperature and time. A partial peeling of Cr_xB_x layer is not noticeably degraded mechanical properties. In particular, friction coefficient and wear resistance were enhanced in lack of Cr_xB_x phase. Therefore, these results suggest that a Ni₂B phase mainly contribute to wear behavior on boronized Inconel 625 superalloy.

• Toxicological Research
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• 제11권1호
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• pp.51-55
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• 1995

The present experiment was carried out to investigate whether X and Y chromosome dissociation in the primary spermatocytes of mice can be used as an in vivo assaying system that detect environmental mutagens. For this purpose, alkylating agents (EMS, MMS and MMC), which are strong mutagens, were administered to ICR male mice 12-15 weeks old. The mean frequencies of previously dissociated X-Y chromosomes and autosomes of the control group were 7.34-7.45% and 0.92-1.04%, respectively. The frequencies of X-Y dissociation in the mutagen-treated groups with 10.0 mM EMS and 5.0 mM MMS were about 3.3-4.6 times higher than that in the control group, but there were no significant differences in dissociation of autosomes in both the control and the mutagen-treated groups. These results suggest that X-Y dissociation in the primary spermatocytes of mice can be used as an in vivo short-term assaying system for environmental mutagens.

• Bulletin of the Korean Chemical Society
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• 제13권5호
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• pp.565-570
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• 1992

The 1,5-sigmatropic rearrangements involving group (X) migration in ${\omega}$(X)-substituted 1,3-pentadiene, $C^1H_2=C^2H-C^3H=C^4H-C^5H_2-X$, where X = H, $CH_3$, $BH_2$, $NH_2$, OH or F, are investigated MO theoretically using the AM1 method. For the migrating groups without lone pair electrons, X = H, $CH_3$, or $BH_2$, the suprafacial pathway is favored, whereas for the migrating groups with lone pair electrons participating in the TS, $X=NH_2$, OH, or F, the antarafacial pathway is favored electronically. However excessive steric inhibition in the antarafacial TS for $X=NH_2$ leads to subjacent orbital controlled suprafacial process. The antarafacial shift of F is relatively disfavored compared to that of OH due to smaller orbital overlap and larger interfrontier energy gap in the TS.

• Restorative Dentistry and Endodontics
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• 제29권1호
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• pp.66-72
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• 2004

All-in-one adhesives were recently developed for reducing the technique sensitivity and chair time, but lots of concerns were made on bondability, longevity, and microleakage. The object of this study was to evaluate microleakage and marginal quality of all-in-one adhesives using electrochemical method and SEM analysis quantitatively. After making Class V cavities, they were bulk filled with Heliomolar(#A1 after surface treatment with three adhesives: Adper Prompt (Group A), One up bond F (Group O), Xeno III (Group X) Electrical conductivity (microamphere, ${\mu}A$) was checked two times: before and after cavity filling. Percentage of leaky margin was estimated from SEM image (${\times}1,000$). The data were statistically analysed: ANOVA and Paired T test for electrical conductivity, Kruskal-Wallis and Mann-Whitney test for marginal quality, Spearman s rho test for checking of relationships between 2 methods. The result were as follows: 1. There was no difference in microleakage between adhesive systems and every specimen showed some of microleakage after filling. 2. Microleakage was reduced about 70% with composite resin filling. 3. Marginal quality was the best in group A. decreasing among groups in the following order: group O, followed by group X. There were significant differences between group A and group X (p=0.015), and between group 0 and group X (p=0.019). 4. There was no relationship between the microleakage measured by electrochemical method and marginal quality measured by SEM analysis. Within the results of this study, there was no difference in microleakage among groups by electrical conductivity. However, significant difference in marginal quality was seen among groups. It was believed that these dissimilar results might be induced because of their own characteristics. Analysis of microleakage needs various methods for accuracy.

• 지역사회간호학회지
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• 제5권2호
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• pp.181-202
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• 1994

This study was conducted in order to grasp the condition of the student's knowledge and attitude about tuberculosis. And to offer the basic materials for the prevent tuberculosis in elementary school. The objects were comprised 395 of volunteered 6th grade students who study in two elementary schools. The material of this study was the questionaire(chronbach $\alpha=.9016$) suited to the purposed of this research which has been made through studying references. All the questionaire were collected immediately without explanation. The data was collected from 13rd to 25th of May on 1994. Analysis of the data was done utilizing SPSS for percentage, mean, ANOVA and pearson-Correlation Coefficient. The Result are as follows; 1. General features of the objects of study. Sex distribution was similar. Salary of 1000-1500 thousand won were highest (40.2%), nuclear family was highest (87.1%), fathers of graduated high school were the highest(44.0%), mothers of graduated high school were the highest(56.8%). And there was nobody about tuberculosis patient in one's close relatives were highest(95.4%). 2. The conditions of attitude about tuberculosis. Having experience of tuberculin test were highest(59.0%). Less than 9mm indulation among the tuberculin tested group were 85.1%, more than indulation were 14.9%. Have a B. C. G. injection among the less than 9mm indulation were 83.2%. Leave alone among the more than 10mm indulation were 56.0%. Think it too much trouble to do not tuberculine test were 63.0%. Do not take a chest X-ray in the past were 60.3%. And take a chest X-ray in the past were 39.7%. Health educated group was 74.3%. If tuberculosis sign was developed, notified to parent was 73.8%. 3. The condition of knowledge about tuberculosis. When 5 points was given to 'very affiming' and 1 point was given to 'very deny', the total average was 3.54. And symptom of tuberculosis secion was 3.67, vaccination of tuberculosis section was 3.66, tuberculine test section was 3.56, epidemiology of tuberculosis section was 3.54, infection of tuberculosis section was 3.38. And every section showed affirmative correlation(P<.001). 4. Correlation between the general features and attitude variables. High incomed group may have more attitude on tuberculin test than low incomed group($x^2=16.$ 190, P<.01). High educated group may have more attitude on tuberculin test than low educated group(Father : $x^2=28.530$, P<.001, Mother: $x^2=26.060$, P<.001). High educated group may have more attitude on health education than low educated group(Father: $x^2=20.$ 767, P<.000, Mother: $x^2=10.639$, P<.05). Nuclear family may have more attitude on notify to parent than others($x^2=51.45$, P<.000). Tuberculosis patient in one's close associates have more attitude on notify to parent than others($x^2=51.$ 45, P<.000). 5. Difference between the general features and knowledge of tuberculosis. High incomed group were highest score in knowledge (F=3.99, P<.01). High educated group were highest score in knowledge(Father : F=8.81, P<.000, Mother: F=9.09, P<.000). 6. Difference between the attitude and knowledge of tuberculosis. Tuberculin tested group were highest score in knowledge(t=9.88, P<.000). Taken chest X-ray group were highest score in knowledge (t=2.07, P<.05). Received health education group were highest score in knowledge(t=6.83, P<.000). Notified symptoms to teachers and parent group were highest score in knowledge(F=3.89, P<.01).

• 한국방사선학회논문지
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• 제14권3호
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• pp.271-277
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• 2020

본 연구에서는 질병의 진단 및 치료에 가장 많이 사용되는 X선을 노출시켜 장수풍뎅이 유충의 체중과 생존율의 변화를 알아보고자 하였다. 2019년 4월 초 장수풍뎅이 유충 1령 41마리를 구입하여 적응을 위해 3일 사육 후, 대조군 11마리, 조사군 (10 Gy, 20 Gy, 30 Gy 각 10마리)으로 분류하여 대전 소재 대학병원 방사선종양학과에서 선형가속기(Clinac IS, VERIAN, USA)를 이용하여 조사(6MV X-ray, Source-surface distance 96cm, field size 18 × 10cm, dose rate 600MU/min) 하였다. 조사 후 1주 간격으로 생존율, 체중을 측정하였다(사육 온도 20.6℃, 습도 64.3%). 모든 통계분석은 SPSS ver 22.0(Chicago, IL, USA)을 사용하여 체중은 평균과 표준편차로 나타내어 대조군과 X선 조사군 간에 독립 표본 T-검정(Independent t-test)을 실시하였고, 생존율은 교차분석으로 비교 하였다. 또한, 선량과 체중의 상관성을 Spearman 으로 분석하였다. 조사 후 3주차에서는 모근 군이 체중이 증가하였고, 대조군에 대해 10 Gy군과 20 Gy군은 통계학적인 유의한 차이를 보였고(p<0.05), 특히 30 Gy군과는 더 큰 차이를 보였다(p<0.01). 14주차에서 체중에서 대조군은 증가를 보였지만 조사군은 감소를 보였고, 대조군에 대해 10 Gy 군과 30 Gy 군(p<0.05), 20 Gy군(p<0.01) 간에 통계학적인 유의한 차이를 보였다. 조사 후 3주차에는 10 Gy군을 제외한 모든 군에서 급격한 생존율 감소를 보였고, 조사군에서 4주차까지 급격한 생존율 감소를 보였다. 대조군은 3주차부터 14주차까지 생존율의 변화(54.5%)가 없었다. 조사 후 3주차부터 조사에서 선량이 높을수록 낮은 생존율을 보였다. 조사 후 19주차에는 대조군 45.4%, 10 Gy군 30.0%의 생존율을 보였고, 20 Gy군과 30 Gy군에서는 모두 사망하였다. 조사 후 기간이 길어질수록 선량과 체중은 높은 음의 상관성을 보였다. X선은 장수풍뎅이 유충의 체중과 생존율에 영향을 미쳤고, 선량이 높을수록 체중과 생존율의 감소는 더 크게 나타났다.

• 청정기술
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• 제28권2호
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• pp.117-122
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• 2022

본 연구는 80 kW 연소로에서 초 저 NO_x 버너를 개발하고 실험한 결과를 나타낸 것이다. 실험은 80 kW 단일 버너 연소로에서 진행되었으며, swirl number 변화, 총 당량비, 1차 / 2차 산화제 비율을 변경하여 진행하였다. 본 연구에서는 가스(LNG)를 보조연료로 사용하여 NO_x 생성량을 크게 감소 시킬 수 있었다. 화력발전소에서 석탄 연소 시 발생하는 NO_x의 양은 약 300 ppm이다. 그러나 본 연구에서 사용된 버너는 LNG를 혼소하여 NO_x의 양을 40 ppm까지 감소 시킬 수 있었다. 1차 산화제의 투입량이 보조 연료인 가스가 연소될 만큼만 사용하여 가스와 석탄을 동시에 투입하면 연소가스가 버너 출구에서 고온영역을 형성하여 석탄을 휘발시키므로 N 탈휘발에 포함되어 배출된다. 그러므로 이 후 석탄이 연소 되면 석탄내 포함된 N이 거의 없기 때문에 NO_x 생성량이 감소하는 것이다. 본 연구 결과를 바탕으로 실제 화력발전소 버너를 개발한다면 NO_x 생성을 연소 초기에 대량 감소시킬 수 있을 것으로 예상된다.