鑛山廢棄物을 骨材로 이용한 시멘트 모르터에 관한 實驗的 硏究

柳顯紀 忠州大學校 1996 한국교통대학교 논문집 Vol.31 No.2

To use the waste in complementing the insufficient amounts of natural aggregate resource the provides the great effect. So, this study analyzes and experiments the research on the actual condition, the productive amounts of mine--waste and the possibility to be applied, focused on mines in Chung-buk area as a basic research in using mine-waste for the aggregate of concrete. The results are as follow : In analyzing and experimenting mortar and concrete application of mine-waste, by suggesting the evaluation method called the index of flow, strength, we could evaluate the possibility for aggregate. But even though physical characteristics in some mine were good, it was evaluated as the faulty result by this method in some mines.

충남대학교 공업기술 계열 교사 연수 프로그램에 대한 만족도 분석

류창열,최유현,김판욱,김기수,김태훈,이창훈 忠南大學校 工業敎育硏究所 2005 論文集 Vol.27 No.1

The purpose of this study was to analyze the educated teachers' satisfaction of the in-service education programs of industrial technical and technology teachers in Chungnam National University. This study was carried out through survey to accomplish the purpose. The number of questionnaires collected was 86. This study used the SPSS program to conduct a descriptive analysis of the data. The results of this study were as follows: (1) The satisfaction about 'teachers' participation', 'utilization of audiovisual materials and instruments' and 'level of professor and lecture' was relatively high. (2) The satisfaction about 'environments of in-service education programs', 'evaluation of achievement', and 'efficacy of lectures' was relatively low.

상아질접착제에 대한 광조사가 접착에 미치는 영향

류현옥,김기옥,김성교 대한치과보존학회 2001 Restorative Dentistry & Endodontics Vol.26 No.5

The purpose of this study was to investigate the influence of light irradiation over self-priming adhesive on dentin bonding. After acid etching the exposed dentin, a self-priming adhesive (Prime&Bond□NT dental adhesive system, Dentsply DeTrey, GmbH, Konstanz, Germany) was applied and light irradiation was done for 20 sec with regular intensity (600 mW/㎠) in group I and for 3 sec with ultra-high intensity (1930 mW/㎠) in group III. No light irradiation was done over self-priming adhesive in groups II and IV. Composite resin was added on the self-priming adhesive and irradiated for 40 sec with regular intensity (600 mW/㎠) in groups I and II and for 3 sec with ultra-high intensity (1930 mW/㎠) in groups III and IV. To see the effect of light curing time on dentin bonding, another 3 group specimens were prepared. Without light-irradiation over self-priming adhesive, added composite resin was irradiated for 3, 6, or 12 sec with ultra-high intensity light. After bonded specimens were stored in 37℃ distilled water for 24 hours, shear bond strength were measured using a universal testing machine (4202, Instron, Instron Co., U.S.A.) and fractured surfaces were examined under a stereomicroscope (SZ-PT Olympus, Japan) . Statistical analysis were done with one-way, two-way ANOVA and chi-square test. The results were as follows: 1.The shear bond strengths from the groups irradiated over self-priming adhesive were significantly higher than those from the groups without irradiation (p<0.05). 2.There was no significant shear bond strength difference between regular intensity light irradiation groups and ultra-high intensity ones (p>0.05). 3. There was no significant shear bond strength difference among various irradiation time groups with ultra-high intensity ones (p>0.05). 4.In stereomicroscopic examination of fractured surfaces, adhesive-cohesive mixed failure mode was mostly seen in all groups, and there was no significant difference in failure mode among groups (p>0.05) . Key words : Light irradiation, Self-priming adhesive, Dentin bonding, Shear bond strength

무기질 혼화재를 이용한 시멘트 모르터의 특성에 관한 연구

柳顯紀 충주대 2001 한국교통대학교 논문집 Vol.36 No.2

The objective of this study is to analyze the fundamental groperties of fresh and hardened cement mortar with various addition rations of the inorganic admixtures and expansive additives.As the results of the test, the flow and air content increase with the addition of expansive additives.And as the replacement rates of fly ash and silica fume increase, the flow shows a decline.At hardened state, the compressive strength and flexual strength decrease with the addition of inorganic admixtures, expansive additives and zinc stearates.With the increase of silica fume's replacement, they show a little decrease at early age and then increase gradually.Also, absorption and permeability show a steep decrease when zinc stearates is added, and a slack decrease with the replacement of silica fume.

鑛山廢棄物을 굵은 骨材로 이용한 콘크리트의 力學的 特性分析

柳顯紀 충주대학교 1997 한국교통대학교 논문집 Vol.32 No.2

This study analyzes and expriments the research on the actual condition, the productive amounts of mine-waste and the possibility to be applied, focused on mines in Chung-buk area as a basic research in using mine-waste for the aggregate of concrete. The results in concrete application of mine-waste by suggesting the evalution method called for the index of slump strength, and we could evaluate the possibility for coarse aggregate. But even though physical characteristics in some mines were good, it was evaluated as the faulty result by this method in some mines.

부순모래 置換率 變化에 따른 콘크리트의 力學的 特性分析

柳顯紀 忠州大學校 1998 한국교통대학교 논문집 Vol.33 No.2

This study aims to present the reference data in efficiency mixing design of concrete using the mixed fine aggregate of the river and crushed sand, through trial mixing. It also aims to analyse the mechanical properties and shrinkage in hardened state. By the test results, the formula of the unite water content is as follows. 1) Substitute Ratio of Crushed Sand 0% : w/c = 0.0909·F + 81.0242 2) Substitute Ratio of Crushed Sand 20% : w/c = -0.1104·F + 86.2807 3) Substitute Ratio of Crushed Sand 40% : w/c = -0.1170·F + 86.5635 And, in mechanical properties of concrete, the compressive strength of the concrete containing crushed sand compared with river sand is lower, tensile strength is higher, and bending strength is the same. Drying shrinkage is increased while the replacement ratio of crushed sand is increaded.

장기재령 경과에 따른 콘크리트의 수밀특성

柳顯紀 충주대학교 산업과학기술연구소 2002 産業科學論文集 Vol.10 No.-

The watertight of concrete can be controled by the characteristic of aggregate and how to construct. Generally, it is considered by resistance to hygroscopic property and water & vapour permeability. This study is about analyzing watertight during the process of constructing any structures and tries to analyze the watertight change according to passing time after pouring water and watertight change

배합 및 시공조건의 변화에 따른 고강도 콘크리트의 특성분석

류현기 忠州大學校 2003 한국교통대학교 논문집 Vol.38 No.2

This is a paper for the experiments to analyze the properties of watertight which is generated during the course of construction of High Strength concrete structure. The result which has been analyzed on the general properties for construction condition according to the pouring time, the effect of laitance, the mechanical concrete, the properties of watertight using water proofing agent, is summarized as the following. The more increasing W/C, the more passing time the absorption content and permeability content increase with the properties of watertight. The absorption content is low in the case of mixing water proofing agent compared to the plain concrete. According to the existence and nonexistence to the removing laitance the absorption and permeability content is lower in the case of removing laitance rather than in the case of not removing laitance.

산업부산물을 이용한 고성능 콘크리트의 특성에 관한 연구

류현기,윤승조 충주대 산업과학기술연구소 1999 産業科學論文集 Vol.7 No.2

This is study intended to develop the high performance concrete by using Fly Ash, Silica Fume and Expansive Additives in order to prevent the crack from caused by dry-shrinkage and get the economical efficiency. Form the test results, the optimum addition rate based on the fluidity, segregation resistibility, strength and length-change test can be achieved at 5% of Expansive Additives in the combination of 15:5 (Fly Ash : Silica Fume).

시공성의 변화요인이 콘크리트의 특성에 미치는 영향

柳顯紀 충주대 2003 産業科學論文集 Vol.11 No.-

An experimental work is performed to analyze the properties of watertight which is generated during the course of construction of concrete structure. The result which has been analyzed on the general properties for construction condition according to the pouring time, the effect of laitance, the mechanical concrete, the properties of watertight using water proofing agent, is summarized as the following. The more increasing W/C, the more passing time the absorption content and permeability content increase with the properties of watertight. The absorption content is low in the case of mixing water proofing agent compared to the plain concrete. The absorption and permeability content is lower in the case of removing laitance.