• 한국치위생학회지
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• 제7권4호
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• pp.569-582
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• 2007

The author aims at first securing basic material required for developing and operating proper oral health care education programs though making an investigation into the undergraduates of S College of Education on the actual status of oral health care and perceptions of oral health care education. The obtained results were as follows 1. In the actual status of oral care based on whether or not they have experiences in taking oral health care education, undergraduates with teeth brushing for more than three minutes a time were found to be 25.9% and 15.7% respectively according to the existence and nonexistence of experiences in the education(pM0.020), and undergraduates with teeth brushing in a circular motion was found to be 64.7% and 51.7% respectively, showing statistically significant differences(pM0.015). 2. In the actual status of preventative oral care according to whether or not they have experiences in taking oral care education, degrees of awareness of the usefulness of dental cleansers among the undergraduates were found to be 37.6% and 21.5% respectively according to the existence and nonexistence of experiences in the education(pM0.001), undergraduates with experiences in scaling were found to be 51.8% and 34.9% respectively(pM0.002) and undergraduates with experiences in having dental sealants were found to be 26.5% and 16.9%(pM0.031), showing statistically significant differences. 3. In the survey on perceptions of oral health care according to the existence and nonexistence of experiences in oral health care education, it was revealed that the case that they indicated 'the necessity of oral health care education' was 87.1% and 64.0% respectively according to the existence and nonexistence of the experience(pM0.000), and undergraduates intended to 'participate in oral care education for students(at mid and high schools and so on) after being teachers' were 77.6% and 65.7% respectively, showing statistically significant differences(pM0.011). 4. In general characteristics according to awareness of the necessity of cultivating oral health professionals, groups with awareness of the necessity consisted of 31.8% of freshmen and juniors(pM0.001), 55.69b of female undergraduates(pM0.001), 80.8% of non-smokers(pM0.012), 38.9% of large city residents(pM0.002) and 32.3% of undergraduates living in their own houses (pM0.028), showing statistically significant differences.

• 호남수학학술지
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• 제24권1호
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• pp.25-33
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• 2002

In this paper we have shown conditions of R for the existence of the solution to the problem of the type $-u''=ue^{{\varepsilon}u}$ on the interval (0, R) with boundary and other conditions as in $(1-{\varepsilon})-(4)$ for various ${\varepsilon}$.

• 한국가시화정보학회지
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• 제13권1호
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• pp.49-53
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• 2015

Recently, researches for droplet impact phenomena have been faced a new phase in the direction of studying the effect of complex external conditions (e.g. wettability, temperature, morphology, electric field, etc.) for depth understanding and precise controlling in various applications. Hence, here we investigated the electrified droplet impact phenomena, because there were few quantitative researches for electrified droplet impact when we considering many real applications such as electrospray, electrohydrodynamic (EHD) jet printing. To observe interaction effect of surface charge between substrate and droplet simultaneously, micro-droplets with various Reynolds number (Re) and Weber number (We) were dripped on super-hydrophobic surface with existence and nonexistence of electrical surface charge. It shows three kinds of impact behaviors, fully bouncing, partial bouncing, and splashing with different We. Also, charged droplet bounced higher on electrically charged surface than on non-charged surface. Additionally, transition regions of three impact behaviors were classified quantitatively with water hammer pressure value, which means instant pressure inside droplet at the impact moment.

• 한국의류산업학회지
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• 제11권1호
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• pp.147-155
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• 2009

This study has been made to examine the basic information, the preferences of material quality, and the demand performance of clothing for underwear materials between atopic patients and non-patients. The measurement tool was a questionnaire. For statistical analysis of data, crosstabs, ${\chi}^2$-test, t-test and ANOVA through SPSS for Windows(version 14.0) were used. The results obtained are as follows. The degree of the basic knowledge about clothing materials indicated that women was higher than men. The material decision method and the most considering part in case of selecting underwear products showed difference between men and women. The preference factors for underwear material quality were drawn with the five factors of sense of weight/pliability, lustering/see-through, tactility, and sense of cold and warmth. The preferred underwear material showed difference according to gender, existence and nonexistence of atopic determatitis, and degree of strength of skin itching caused by clothing materials. The demand performances of clothing in case of selecting underwear were drawn with the four factors of hygiene/practicality, skin protection, quality of materials, and aesthetic attribute. The demand performance of underwear showed difference according to gender, existence and nonexistence of atopic determatitis, degree of strength of skin itching caused by clothing materials.

• 한국산학기술학회논문지
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• 제14권6호
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• pp.2760-2766
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• 2013

서론 : 본 논문은 전방 잠금형 금속판을 이용한 요골 원위부 골절 수술 후 나사못(screw)의 요골구 관통 유무를 확인하기 위한 방법으로 방사선 요골구 접선방향촬영법의 새로운 검사법을 제시하고자 한다. 재료 및 방법 : 요골구 접선방향 촬영 시 요골 원위부 거상 각도는 2.5, 5, 7.5, 10도와 전완골과 방사선 검출기와의 각도를 60, 70, 80도로 각각 변화시켜 촬영한 방사선영상에서 나사못의 요골구 관통유무를 분석하였다. 결과 : 요골구 접선방향 영상에서는 요골구를 관통하지 않은 경우와 요골구 내관통, 요골구 외관통인 경우가 각각 55명(63.95%), 9명(10.47%), 22명(25.58%)으로 분석 되었고, 요골구를 관통한 나사못의 길이는 0.43~2.72mm의 범위로 평균 1.06mm이었다. 요골구가 잘 묘사되는 방사선 촬영법은 요골 거상각도 2.5~7.5도에서 90%이상, 전완골과 방사선 검출기의 각도 70도에서 요골구가 80%이상 잘 묘사되는 것으로 분석 되었다. 결론 : 요골구 접선방향 촬영법은 요골 원위부 거상 각도 5도, 전완골과 검출기의 각도는 70도를 추천 한다.

• Journal of applied mathematics & informatics
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• 제25권1_2호
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• pp.363-374
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• 2007

In this paper, we consider the discrete nonlinear delay model which describe the control of a single population of cells. We establish a sufficient condition for oscillation of all positive solutions about the positive equilibrium point and give a sufficient condition for the global attractivity of the equilibrium point. The oscillation condition guarantees the prevalence of the population about the positive steady sate and the global attractivity condition guarantees the nonexistence of dynamical diseases on the population.

• 대한수학회지
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• 제43권4호
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• pp.829-843
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• 2006

We propose a cubic differential system, which can be considered a generalization of the predator-prey models, studied by many authors recently (see [18, 20], for instance) The properties of the equilibrium points, the existences, nonexistence, the uniqueness conditions and the relative positions of the limit cycles are investigated. An example is used to show our theorems are easy to be used in applications.

• 대한수학회지
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• 제39권1호
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• pp.77-89
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• 2002

In this paper, we define for a component $X_{0}$ of a nonsingular compact real algebraic surface X the complex genus of $X_{0}$, denoted by gc($X_{0}$), and use this to prove the nonexistence of nonzero degree entire rational maps f : $X_{0}$ Y provided that gc(Y) > gc($X_{0}$), analogously to the topological category. We construct connected real surfaces of arbitrary topological genus with zero complex genus.

• 대한수학회논문집
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• 제29권1호
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• pp.37-50
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• 2014

Using variational methods, we prove some results on the nonexistence and multiplicity of weak solutions for a class of semilinear elliptic systems of two equations involving Grushin type operators with sign-changing nonlinearities. We also shows that the similar results can be obtained for systems of m equations, where m is arbitrary.

• 대한수학회보
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• 제51권6호
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• pp.1697-1710
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• 2014

The initial-boundary value problem for a class of nonlinear higher-order wave equations system with a damping and source terms in bounded domain is studied. We prove the existence of global solutions. Meanwhile, under the condition of the positive initial energy, it is showed that the solutions blow up in the finite time and the lifespan estimate of solutions is also given.