표면처리가 장석도재의 굴곡강도에 미치는 영향

정성화,임범순,김철위 서울대학교 치과대학 치과생체재료학교실 1995 치과생체재료학 논문집 Vol.3 No.1

Dental ceramics exhibits excellent esthetic, compressive strength and chemical durability, good tissue compatibility and transulcency comparable to natural teeth. Dental ceramics, however, have brittleness as ell as low tensile and shear strength and are extremely sensitive to brittle fracture initiated at surface defects. Glazing and polishing treatments can reduce the influence surface flaws, which lead to an increase in strength of the porcelain. And the other method of strengthening the porcelain is to generate a state of residual compression in the surface, which can be accomplished either by ion exchange treatment or thermal tempering. The object of this study was to compare the effect of various surface treatments on the flexural strength of feldspathic porcelain. Bars of feldspathic porcelain specimen (3×3×30㎜) were prepared from Vintage (Shofu) body procelain by condensing slurries into a platinum foil mould , then sintered in a furnace (Master Splint 120) according to the manufacturer's recommendations under vacuum. The bars were divided into the seven groups : self-glazing (control), over glazing subsequent to ion exchange, and ion exchange subsequent to over-galzing. The ion exchange treatment consisted of applying Ceramicoat past (GC) as evenly as possible to the porcelain using a paintbursh. The coating material was dried for 20 minutes at 150℃, followed by firing at 450℃ for 30 minutes. To evaluate the effect of ion exchange temperature, the same drying cycle was followed by 30-minute heat treatments at 350℃, 400℃, 500℃, and 550℃. Each specimen was loaded to failure on a universal testing machine with a crosshead speed of 0.02 ㎝/min. 7∼10 specimens in each groups were test and the mean value for flexural strength was calculated. The fracture surfaces were examined by a scanning electron microscope. For qualitative analysis of the relative changes in potassium and sodium concentrations after ion exchange treatment, energy dispersive x-ray analysis was performed on the surface and bulk section of the fractured surface. Quatitative chemical analyses were performed on the cross section of the specimen after ion exchange treatment by a scanning elecron microscope equipped with a wavelength dispersive x-ray analyzer. Analyses were made in 10∼20 ㎛ below the treated surface. From the experiment, the following results were obtained: 1. The flexural strength was increased by 37% using over-laze treatment, but polishing or heat treatments of feldspathic did not show significant difference (p>0.05) relative to the self-glaze control group. 2. Relative to the control group (self-glaze), the mean flexural strengths of specimen were increased by ion exchanged treatment : 20% at 350℃, 28% at 400℃, and 56% at 450℃ and 500℃. 3. The effect of ion exchange treatment was lost if the porcelain was subsequently treated by self-glaze. The group with ion exchange treatment subsequent to over-glaze treatment showed the highest flexural strength among the experimental groups. 4. The fracture surface of the specimen with ion exchange treatment showed the hackle region, which could imply the degree of fracture resistance in the ion exchanged layer. 5. The chemical analysis (EDX and WDX) results showed that the effect of ion exchange was extended to 50 ㎛ below the ion treated surface.

뜻의 성숙으로서 의지와 뜻 : 의지

김위성 釜山大學校 韓國民族文化硏究所 2003 한국민족문화 Vol.22 No.-

Fixation of meaning brings about will's rise. Negation of meaning by will is associated with nihilism We can pass though nihilism and overcome it by thorough examination of will's nature. Will is known through human body, but its autonomy makes it independent from the body. And the autonomy gives the power to overwhelm nihilism. Will to power is originated from the radical nihilism. The ultimate form of will to power is changed into will to will and the way to sense.

空間의 唯一性에 관한 考察

金渭星 釜山水産大學校 1973 論文集 Vol.11 No.-

The present paper concerns itself primarily with the problem whether there must be only one space. The absolute space of Newton and the space of pure intuition of Kant as the examples were examined on their uniqueness. Newtonian space was not the necessary condition in explaning the phenomena of motions. It could be replaced by another space, for example Mach's, which also made it possible to systematize the mechanics, even though it denied inertia as the property of things. Inertia depended rather upon the other matters than on the essential quality of a thing. Kantian space was investigated in connection with its infinity and the certainty of Euclidean geometry. Its uniqueness did not follow from the infinity. Euclidean geometry as the probable ground of the uniqueness did not follow from the pure intuitive space and not hold a priori. And we could suppose a space of dream with non-contradiction and publicity. It opened the possibility of multi-spaces. Therefore there is nowhere the necessity of the uniqueness of space.

순수 논리학의 이념

김위성 釜山大學校 1985 人文論叢 Vol.27 No.1

This paper deals with the problems about the ideas of pure logic in order to find clues to disentangle the embarrassing recent situations in the views of the nature of logic. As the first forerunner, Kant contributes to the distinction between pure logic and applied logic, but he does not explain the ways of grasping the former's essence. In that matter, Hegel's logic is excellent in the dynamic process of consciousness. Its circular movement from pure knowledge to pure being, creates the synthesis between thought and being. But it lacks the convincing arguments. Husserl's phenomenological method overcomes the defects of Hegel, by describing the givenness of consciousness, although it does not reach the concrete results of pure logic.

인식이론에 있어서 자기반성의 문제 : 하버마스의 '인식과 관심'을 중심으로

김위성 釜山水産大學校 1976 論文集 Vol.17 No.-

시차열분석기를 이용한 치과용 콤포짓트레진의 중합열 측정

김성철,김철위 대한구강생물학회 1986 International Journal of Oral Biology Vol.10 No.2

In this study, seventeen kinds of composite resins, lately used in Korea, were devied into three groups and used. Seven of them were light curing composite resins for anterior teeth, four of them were light curing composite resins for posterior teeth and the rest six were chemical curing composite resins for anterior and posterior teeth. In respective samples, heat of reaction, th highest point of temperature and the time to reach the highest point of heat liberation were measured by using DSC under 37℃ isothermal condition. Including the filler content, the correlation of the data were analyzed and the characteristics of three groups were compared one another. From the experiment the following results were obtained ; 1 In light cured resins, as the content of filler increased, heat of reaction and the highest point of temperature were decreased. 2. In chemical cured resins. as the highest point of temperature and the heat of reaction increased, the time to reach the peak heat liberation was decreased. 3. The heat of reaction from light cured composite resins for anterior teeth is higher than that of light cured composite resins for posterior teeth. 4. The light cured composite resins set faster than the chemical cured composite resins but the highest point of temperature and the heat of reaction of the light cured composite resins for anterior teeth were greater than the other two groups.

뜻의 길 : 의미의 철학적 해명(뜻의 구조)

김위성 釜山大學校 1992 人文論叢 Vol.41 No.1

The concept of Korean 뜻 has both the element of meaning and the one of will. Therefore the illumination of its structure is aided by the comparison between the philosophical systems of meaning and will, e.g. Schlick's philosophy of meaning and Nietzsche's philosophy of will. Meaning and will must be comprehended through 뜻, and can have their proper place and be united into one. 뜻. -is and 뜻, does are the results of the process, and they are the moments which show various forms of 뜻.

칸트의 선험적 변증론 : -이율배반을 중심으로-

김위성 釜山水産大學校 1977 論文集 Vol.19 No.-

幾何學의 性格에 관한 認識論的 및 論理的 考察

金渭星 釜山水産大學校 1974 論文集 Vol.13 No.-

This paper is concerned with the problem of the nature of geometry as knowledge. It analyzes the nature from epistemological and logical viewpoints. According to the dichotomy of knowledge into the empirical and the a priori, firstly the systematization of geometry on the foundation of the former is pursued in vain for inseparable non-empirical elements within the axioms and definitions. And then the way of the latter is followed in Kantian Philosophy of Mathematics, which sees geometrical knowledge as synthetic judgment a priori. He presupposes the a priori and synthetic character of geometry as the fact found in our knowledge and seeks its source in the pure intuition. Another dichotomy of analytic-synthetic distinction in Kant contributes to the a priori geometry, but becomes outdated because it disregards that subject-predicate relation is not universal in the judgments. It comes out that explicit definitions are ambiguous and confounded in facing the adequate definitions. They are revealed as implicit definitions which Formalism uses in making geometry strict and consistent. Formalism makes it possible to comprehend non-Euclidean geometries in compatible way with the Euclidean in their formal logical structures. Pure geometry is uninterpreted and founded only on Formalism. But the choice of geometry asks criteria by which a geometry is found most adequate to explain and describe the world of experience. Conventionalism holds that all systems of geometry are only conventions and they are chosen only by the principle of simplicity in application to the facts. But it fails to make strict distinction between mathematical geometry as pure and physical geometry as applied.

서양철학의 파악과 연구에 있어서 일본의 영향

김위성 부산대학교 한국민족문화연구소 2000 한국민족문화 Vol.16 No.-

From the 17th century, Korea accepted Western Philosophy on its own right. But Japan's occupation of Korea in the beginning of 20th century has threatened its acceptance into false image of philosophy, After the Liberation of Korea from Japan in 1945, Korea could develop the correct understanding and digestion, and absorb it into Korea's own philosophy. Now Korea has been paving the secure way to the independent Korean Philosophy in cooperation with the assistance of Western Philosophy.