T.S. Eliot와 형이상시의 부활

홍기종 釜山大學校 1989 人文論叢 Vol.34 No.1

고환에 발생한 표피양낭

정기욱,정웅교,김재웅,이홍우,강성학 大韓泌尿器科學會 2001 Korean Journal of Urology Vol.42 No.9

경화방법에 따른 아크릴 레진 표면의 물리적 성질에 관한 연구

홍순호,이기대 慶北大學校 齒科大學 1987 慶北齒大論文集 Vol.4 No.1

Two principal techniques have been used in relining dentures: the direct intraoral application of acrylic resin and the indirect method which use heat cured acrylic resin. In this study, to observe the physical properties of acrylic resin surfaces by curing procedure in indirect methods which used heat cured acrylic resin and self cured ??erylic resin. The results were as follows: 1. In two types of resin, the surface hardness of heat cured specimen higher than self cured specimen. 2. In two of resin, there was difference in the surface roughness. 3. In two types of resin, the surface porosity of self cured specimen more larger and number than heat cured specimen.

配水管綱의 非線形 解釋

池洪基,朴埼鎬 嶺南大學校 工業技術硏究所 1993 工業技術硏究所論文集 Vol.21 No.2

This study deals with the analysis of pipe networks. The analysis of pipe network is normally done by computer programming. And the system are composed of as follows; elements, the pipes, connected with specified number of nodes. The pipe network system should be solved for the network system's solution. The element level, head losses for each elements are calculated from the head losses. From this process, the network solutions are completed. The critical step in this analysis is the determination of individual element behaviour. For this the method which is based on the Hazen-Williams formula and used Newton-Rapson technique is chosen. This non-linear analysis leads precise results.

Si 웨이퍼 내의 깊은 준위 분포 특성 파악에 관한 연구

홍창희,윤기정,안기형 동아대학교 공과대학 부설 한국자원개발연구소 1988 硏究報告 Vol.12 No.2

Distributions of deep levels are studied in the n-type Si wafer which are introduced during fabrication with e-beam deposition by using DLTS technique. Test is carried out on the Schottky diode. Metalization of the diode is done by e-beam deposition before of after electron irradiation. Deep levels of the defects are measured by using various metal such as Pd/Au, Au, Pd, Ti, Mo and Hf, and by changing the annealing temperature. It is approved that some defects are introduced in the neighbor of interface of silicon and metal by e-beam deposition, and main defect of them is E(0.42) level. In the resuts, two types of the deep level are observed ; one type is that is independent of electron irradiation, for example, E(0.42) level which is observed near the interface ; another type is that is observed only in the diode deposited by e-beam after electron irradiation, for example, E(0.18) level and so on which are observed farther from the interface. It may be the reason that interaction is presented between defects from Pd, at least, and prior defects.

쓰레기 소각재를 잔골재로 혼합한 콘크리트의 기초적 물성연구

홍기호,하상훈,김정규,어석홍 國立 昌原大學校 產業技術硏究院 2004 産技硏論文集 Vol.18 No.-

The purpose of this study is to investigate the material characteristics and strength properties of concrete mixed with waste incinerated bottom ash(BA), and to evaluate the leaching of environmentally harmful heavy metals from the bottom ash itself and from hardened concrete mixed with bottom ash. For this purpose, two reference mixed with W/C ratio of 0.45 and 0.55 were used, and the replacement proportion of BA was varied with ratios of 0, 30, 50, 70 and 100% by volume of fine aggregate in the reference mixes. The variation of compressive and splitting tensile strength, workability and unit weight of concrete were considered. Test results showed that the strengths, workability and unit weight decreased with increase in proportion of BA replaced. Leaching test results showed that there would be no environmentally harmful problem from using BA as substitutes of fine aggregates in concrete.

Enamel Microabrasion을 시행한 법랑질과 복합레진의 전단결합강도

홍기상,이상훈,이상대 大韓小兒齒科學會 2000 大韓小兒齒科學會誌 Vol.27 No.1

Enamel microabrasion은 염산과 연마제를 사용하여 치아의 착색을 제거하는 술식으로서, 그 효과는 법랑질 표층에 국한된다. Enamel microabrasion으로 모든 착색이 치료 가능한 것은 아니므로, 착색이 깊을 경우에는 microabrasion후에도 제거되지 않고 남은 착색부위를 광중합 복합레진을 사용해 수복할 것이 권장된다. 본 연구의 목적은 enamel microabrasion의 방법과 시간이 법랑질에 대한 복합레진의 전단결합걍도에 미치는 영향을 조사하는 것이었다. 아무런 처치도 하지 않은 대조군을 1군으로 하였고, 18% 염산과 fine pumice의 혼합물을 hand applicator로 치면에 5초씩 5,10회 적용시킨 것을 각각 2,3군으로 하였다. 10% 염산과 연마제의 혼합물인 기성품 PREMA를 10:1 gear reduction handpiece로 20초씩 5, 10회 적용시킨 것을 각각 4,5군으로 하였다. 여기에 37% 인산으로 부식 후 복합레진을 결합시켜 thermocycling 후 전단결합강도를 측정하여 다음과 같은 결론을 얻었다. 1. 2군이 가장 높은 결합강도(24.36±3.34MPa)를 나타내었고, 3군이 가장 낮은 결합강도 (19.35±3.43MPa)를 보였다. 전단결합강도는 2>4>5>1>3군의 순서로 감소하였다. 2. 2군은 1군과 3군보다 통계학적으로 유의성있게 높은 결합강도를 나타내었다(p<0.05). 3. 염산과 pumice로 enamel microabrasion을 시행한 2,3군과 PREMA를 사용한 4,5군 사이에는 유의한 결합강도의 차이가 없었다 (p<0.05) 4. 파절면 검사에서, adhesive failure는 3,4군에서 나타났고, cohesive failure는 1,2,3,4군에서 관찰되었다. 5군에서는 mixed failure만이 관찰되었다. 5. SEM관찰에서, 염산과 pumice로 enamel microabrasion을 시행한 2,3군에서는 인산으로 부식한 것과 비슷한 표면양상이 관찰되었고, PREMA로 처리한 4,5군에서는 1군과 흡사한 매끈한 표면양상이 관찰되었다. 각 군의 시편을 인산으로 부식시킨 다음에는 전형적인 산부식 후의 표면양상이 관찰되었고, 군간 별다른 차이가 없었다. Enamel microabrasion is a means by which superficial enamel discoloration is removed using hydrochloric acid and fine pumice. As enamel microabrasion alone may not by sufficient in cases of deeper discoloration, composite resin restoration is recommended in areas where there is remaining discoloration. The purpose of this study was to investigate the effects of different methods and number of applications of enamel microabrasion on the shear bond strength of composite resin to enamel. Untreated control was designated as groups1,5-second applications of a mixture of 18% HCI and fine pumice were performed 5 and 10 times on groups 2 and 3, respectively. A commercially available mixture of 10% HCI and abrasives (PREMA) was appliedusing a 10:1 gear reduction handpiece 5 and 10 times on groups 4 and 5, respectively, with each application lasting 20 seconds. After etching with 37% phosphoric acid, composite resin was bonded. Thermocycling was performed and shear bond strength was measured. The following results were obtained: 1. Group 2 showed the highest bond strength(24.36±3.34), while group 3 showed the lowest (19.35±3.43). Shear bond strength decreased in the following order: 2>4>5>1>3. 2. Group 2 showed bond strength significantly higher compared to groups 1 and 3(p<0.05). 3. There were no significant differences between groups 2 and 3, which had been microabraded using HCI and pumice, and groups 4 and 5, to which PREMA had been applied, when bond strengths were compared(p>0.05) 4. When modes of fracture were examined, adhesive failure was observed in groups 3 and 4, while cohesive failure was observed in groups 1,2,3 and 4. Only mixed failures were found in group 5. 5. When viewed using a SEM, groups 2 and 3, which had been microabraded using HCI and pumice, showed surface appearances similar to that of enamel etched with phosphoric acid. Groups 4 and 5, treated with PREMA, exhibited a smooth surface similar to that of group 1. All groups showed similar, typical surface characteristics following phosphoric acid etching.

유전치의 전장피개수복 : 증례보고

홍기상,이상훈,장기택 大韓小兒齒科學會 1999 大韓小兒齒科學會誌 Vol.26 No.2

치아우식증, 외상, 발육성 결함으로 광범위한 수복이 필요한 유전치의 치료는 소아치과의사에게 있어서 매우 까다로운 문제이다. 이상적인 수복수술은 강도, 내구성, 심미성과 장착의 효율성을 모두 갖추어야 한다. 이에 행동조절문제가 있는 어린이를 치료하는 기술적 문제를 더하면, 여러 가능한 수복 방법 중에서 적절한 술식을 선택하는 것은 어려운 일이다. 현재 사용되는 수복술식에는 복합레진의 접착을 사용한 celluloid strip crown, conventional stainless steel crown, open-faced stainless steel crown, commercially 및 chairside veneered stainless steel crown과 epoxy-coated stainless steel crown 등이 있다. 이 모든 술식이 나름대로의 기술적, 기능적 또는 심미적 단점을 갖고 있어 각각의 효율적이고 효과적인 사용을 위해서는 적절한 선택이 중요하다. 이에 저자는 이러한 여러 가지의 전장피개수복 방법을 사용해 유전치를 치료하여 그 결과를 보고하는바이다. Primary anterior teeth requiring extensive restorative therapy due to caries, trauma or developmental defects can present a particularly challenging problem for the pediatric dentist. The ideal restorative technique would combine strength, durability, esthetics and efficiency in placement. Couple these concerns with the technical difficulties of operating on children with behavior management problems, and the dentist is left with the difficult tack of choosing from a variety of restorative options. Restorative modalities currently in use to treat primary anterior teeth include bonding with composite resin as in celluloid strip crowns, conventional stainless steel crowns, open-faced stainless steel crowns, commercially and chairside veneered stainless steel crowns and epoxy-coated stainless steel crowns. Each of these techniques presents technical, functional or esthetic compromises that complicate their efficient and effective usage. This is a report of the results obtained at the Department of Pediatric Dentistry. College of Dentistry, Seoul National University, through the use of these various methods of treating primary anterior teeth.

(±)-6a, 7-Dihydro-1-hydroxy-6, 6-dimethyl-3-pentyl-6H-dibenzo [b,d] pyran-9(8H)-one의 염소화 반응에 관한 연구

홍기운,육찬남,백승화 圓光大學校 1991 論文集 Vol.25 No.2

(±)-6a, Dihydro-1-hydroxy-6, 6-dimethyl-3-pentyl-6H-dibenzo[b,d] pyran-9[8H]-one의 염소화 반응은 metal halide와 함께 18-crown-6존재하에m-chloroperbenzoic acid에 의해 산화반응이 일어났다. 이 반응계에서는 염소화 반응이 방향족 고리에만 선택적으로 일어났다. (±)-6a, 7-Dihydro-1-hydroxy-6, 6-dimethyl-3-pentyl-6H-dibenzo [b, d]pyran-9(8H)-one has been chlorinated in the aromatic ring with metal halide in the presence of 18-crown-6 on oxidation with m-chloroperbenzoic acid. This reagent system effects the regiospecific chlorination of activated aromatic ring over olefinic double bond.

폐수슬러지를 혼입한 콘크리트의 재료특성 및 강도특성

홍기호,하상훈,김정규,어석홍 國立 昌原大學校 產業技術硏究院 2004 産技硏論文集 Vol.18 No.-

The purpose of this study is to investigate the material characteristics and strength properties of concrete mixed with wastewater sludge, and to evaluate the leaching of environmentally harmful heavy metals from the wastewater sludge itself and from hardened concrete mixed with wastewater sludge. For this purpose, a reference mix with W/C ratio of 0.45 was used and the replacement proportion of wastewater sludge was varied with ratios of 0, 30, 50, 70 and 100% by volume of coarse aggregate in the reference mix. The variations of compressive and splitting tensile strength, workability and unit weight of concrete were considered. Test results showed that the strengths and unit weight decreased with increase in proportion of wastewater sludge replaced, but workability increased. Leaching test results showed that there would be no environmentally harmful problem from using wastewater as substitutes of coarse aggregates in concrete.