용해실리카의 기준경도를 이용한 나노 압입시스템의 실험적 교정

이윤희 ( Yun Hee Lee ),안승민 ( Seung Min Ahn ),김주영 ( Ju Young Kim ),박찬평 ( Chan Pyung Park ),장희광 ( Hee Kwang Jang ) 대한금속재료학회(구 대한금속학회) 2015 대한금속·재료학회지 Vol.53 No.3

Indirect calibration of a nanoindentation system was performed by deriving a reference loading curve. This reference load-depth relationship was accomplished by assuming a perfect nanoindentation test on an ideal reference material; if all components in a nanoindentation system are well calibrated and the reference material has unique hardness and Young’s modulus, the indentation depth can be formulated with a function of the indentation load having two parts of contact and surrounding elastic depths. Substituting both the hardness and Young’s modulus of a fused silica into the derived function, the reference loading curve was plotted and directly compared with experimental data of the fused silica measured by two commercial nanoindenters. All indentation loading curves showed leftward shifts compared to the reference loading curve, and this is discussed, offering two reasons for the result, system compliance and indenter apex geometry.(Received January 6, 2014)

수냉쿨러의 냉각 효율 향상을 위한 플레이트 부품의 형상에 관한 연구

성윤호,김형찬,김선민,윤석영,이영웅,이상욱 순천향대학교 부설 산업기술연구소 2021 순천향 산업기술연구소논문집 Vol.27 No.2

This study investigates changes in cooling efficiency for heat sink plate width, perforated width, and chamfer angle as part of a parameter study to maximize cooling efficiency of heat sink by setting various variables on plates. The width of the plate is set to 16, 20, 24, 28 mm, perforated width 1.5, 2.0, 2.5 mm, chamfer angles 5, 10, 15 and 20°. By conducting a computational study with Ansys Fluent, the sink plate with plate width of 16mm, perforated width of 3mm and chamfer angle of 10° is shown to be the best cooling efficiency.

색상 측정 기기를 이용한 복합레진 적층 수복과 단일 수복의 색상 비교 분석

송영상,김자현,이빈나,장지현,장훈상,황윤찬,오원만,황인남 大韓齒科保存學會 2012 Restorative Dentistry & Endodontics Vol.37 No.2

Objectives: This study analyzed the difference in color caused by different thickness in enamel layer of composite resins when applied with single and layering placement technique, and evaluated if the results agreed with the shade guide from the manufacturers to verify reliability of the color matching process of the manufacturers. Materials and Methods: For single composite resin samples, 6 mm diameter and 4 mm thickness cylindrical samples were fabricated using Ceram-X mono (DENTSPLY DeTrey) and CIE L*a*b* values were measured with spectrophotometer. Same process was done for layering compositie resin samples, making 3 dentinal shade samples, 4 mm thickness, for each shade using Ceram-X duo (DENTSPLY DeTrey) and enamel shade resins were layered in 2 mm thickness and CIE L*a*b* values were measured. These samples were ground to 0.2 mm thickness each time, and CIE L*a*b* values were measured to 1 mm thickness of enamel shade resin. Results: Color difference (△E*) between single and layering composite resin was 1.37 minimum and 10.53 maximum when layering thicknesses were between 1 mm and 2 mm and 6 out of 10 same shade groups suggested by manufacturer showed remarkable color difference at anythickness (△E* > 3.3). Conclusion: When using Ceram-X mono and duo for composite resin restoration, following the manufacturer's instructions for chossing the shade is not appropriate, and more accurate information for Ceram-X duo is needed on the variation and expression of the shades depending on the thickness of the enamel. (Restor Dent Endod 2012;37(2):84-89)

금 합금 보철물의 교합면 삭제로 인한 임플란트-골 계면으로의 열전달에 관한 연구

조재영,강선녀,정창모,윤미정,허중보,전영찬 대한치과보철학회 2012 대한치과보철학회지 Vol.50 No.1

연구 목적: 임플란트-골 계면에서 발생하는 과도한 열은 골유착을 저해하여 임플란트의 실패를 유발한다. 이에 이번 연구에서는 임플란트 금 합금 보철물의 교합면 삭제시 임플란트-골 계면으로의 열전달 양상과 냉각 방식의 효율성을 알아 보고자 하였다. 연구 재료 및 방법: 온도 감지 장치 제작을 위하여 Internal cone 연결형태의 임플란트에 16개의K형 열전대를 부착하여 아크릴릭 레진에 포매하였다. 치과용 금 합금과 주조용 abutment를 사용하여 교합면에 3개의 요철을 가지는 시편을 10개 제작하였고, 연결 나사를 이용하여 임플란트와 연결한 뒤 온도 감지 장치를 37℃로 유지되는 수조에 위치시켰다. 저속 핸드피스와 green stone bur를 이용하여 30초 동안 보철물의 요철을 삭제하였는데, 무냉각군, 공기 냉각 군, 물 분사 냉각 군으로 나누어 요철을 삭제하였다. 보철물이 삭제 되는 동안 임플란트의 부위별로 온도가 0.05초 간격으로 기록되었고, 삭제를 멈춘 뒤에도 무 냉각 군의 경우 임계 온도인 47℃ 이하로 온도가 하강할 때까지, 공기 냉각군과 물 분사 냉각군의 경우 삭제 중단 후 30초 동안 추가로 온도를 기록하였다. 냉각 방식에 따른 임플란트-골 계면의 온도를 알아보고, 임플란트의 부위별 온도변화의 유의차를 알아보기 위하여 one-way ANOVA를 실시하였고, Turkey HSD 이용하여 95% 유의수준에서 사후 검증하였다. 결과: 무 냉각 군은 임플란트-골 계면의 온도가 47℃ 이상으로 상승하였으며, 임플란트의 경부에서 유의하게 높은 열이 측정되었다(P>.05). 공기냉각군과 물분사 냉각군은 임플란트-골 계면의 온도가 47℃ 이하로 유지되었다. 무 냉각 군에서 임플란트 경부의 온도가 47℃에 도달되는 데는 약 10.8 ± 1.5초가 소요되었다. 공기 냉각 군과 물 분사 냉각 군 사이에서는 임플란트-골 계면 온도의 유의차가 없었다(P>.05) 결론: 이상의 결과로부터 임플란트 금 합금 보철물의 교합면 삭제 시, 임플란트 주위 조직에 위해를 가할 수 있는 임계 온도 이상의 열이 발생했음을 알 수 있었으며, 냉각방식은 공기 냉각과 물 분사 냉각 모두 효과적이라고 생각된다. PURPOSE. The purpose of this study was to analyze temperature change along the implant-bone interface induced by grinding the occlusal surface of implant gold prosthesis and to compare the temperature generated by grinding of prosthesis with different cooling methods. MATERIALS AND METHODS. The experimental gold prostheses were fabricated with dental gold alloy and castable abutment. The prostheses had 3 cylindrical protrusions on the occlusal surface with 1mm in height. Temperature was measured using 16 thermocouple wires attached to the implant fixture surface and the fixture was embedded in an acrylic resin block inside the 37℃ water bath. Cylinders were grinded for a period of 30 second with a low-speed handpiece with green stone point. One cylindrical protrusion was grinded without cooling, the second one was grinded with air blow, and the third one was grinded with water-spray. RESULTS. The mean maximum temperature was measured more than 47℃ of the implant and the maximum temperature was measured at the cervical portion of the implant in the group without cooling. There was statistically significant difference between the group without cooling and the groups with cooling (P<.05). However, there was no significant difference at all portion of implant in the groups with cooling (P>.05). CONCLUSION. The results of this study support that the grinding of implant gold prosthesis without cooling may damage the peri-implant tissue. The continuous use of air blow and water-spray adjacent to prosthesis during the grinding of implant gold prosthesis may prove to be beneficial for cooling of the implant.

Piracetam이 마우스의 기억력 및 대뇌피질내 Acetylcholine량 변화에 미치는 영향

尹再順,申精姬,李容筍,劉永瓚 梨花女子大學校 韓國生活科學硏究院 1991 韓國生活科學硏究院 論叢 Vol.47 No.-

The central cholinergic synapse is known to be closely connected with memory. Previously, piracetam has been reported to improve the intellectual ability. We used a scopolamine-induced amnesiac mouse to study the effects of piracetam on memory retrieval by passive avoidance learning test and on the acetylcholine level of cerebral cortex. The amnesia was produced in mouse by the intraperitoneal injection(i.p.) of scopolamine at a dose of 1 ㎎/㎏ body weight(b.w.). Upon administration of piracetam to amnesiac mouse at doses of 100 and 200 ㎎/㎏ b.w., i.p., 30 min, prior to retrieval test, the significant improvement on memory impairment was observed by examination 24 hr after training. The level of acetylcholine in cerebral cortex of mouse was decreased by the scopolamine treatment, however, this decrease was attenuated by piracetam. These results suggest that the effect of piracetam on memory may be attributed to activation of cholinergic nerve.

테르펜과 1,2-디메틸싸이클로펜텐의 기체상 오존화반응

윤의중,구본석,정인수,정인찬,이영훈,신혜숙 한서대학교 산학협력연구원 부설 환경연구소 2000 환경연구소 논문집 Vol.3 No.-

Gas phase Ozonolyses have been examined with particular emphasis on the question whether are produced. The following results were obtained. 1) In contrast to previous reports, Ozonolyses of the terpense β-pinene and sabinene provided the corresponding ozonides as minor products. Major products were the corresponding ketones, respectively. In addition, β-pinene afforded the lactones, while sabinene gave the lactones. 2) Ozonolyses of 1, 2-dimethylcyclopentene provided the corresponding ozonide as a minor and diketone as the major product, along with small proportions, each, of nine additional products. 3) Ozone treatment of diketone provided small amounts of Ozonide in a hitherto unprecedented reaction of diketiones with ozone.

코칭 관리의 과정 모델 분석

육조영,김희수,윤찬호 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.5

The purpose of this study is to examine the process of 'coaching(administration)' .For that purpose, this study brought in the concept of the management process (VanderZwaag, H.J.) and the administrative process(Hodgkinson, C.) and examined the process model of 'coaching(administration)' . As the result of this study, the process of coaching (administration)' was characterized as follows. 1. The process model of 'coaching(administration)' consists of philosophy, planning, organizing, managing and valuating. 2. At the stage of philosophy and planning, the policy of 'coaching(administration)' is made. 3. At the stage of organizing and managing, the policy of 'coaching(administration)' is implemented and the process of 'coaching(administration)' goes on toward the purpose effectively. 4. The last stage of process (valuating) feeds back to the stage of philosophy. 5. The stage of philosophy has the possibility for changing the direction of process through the consideration of value.

Lipase를 이용한 (S)-3-acetoxy-2-methylpropanol의 제조

서영배,서연찬,이갑득 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.2

Captopril, α-tocopherol, erythromycin A, muscone과 같은 의약품, 향료등 생리활성물질의 합성에 있어서 유용한 중간원료로 이용되는 광학활성인 D-(-)-β-hydroxyisobutyric acid를 제조하기 위하여 그 전구체로 (S)-3-acyloxy-2-methylpropanol을 선정하여 lipase의 부제가수분해반응을 이용하여 이의 개발을 시도하였다. 대칭성 기질 2-methyl-1,3-propanediol diacetate 2를 다양한 lipase를 사용하여 부제가수분해(asymmetric hydrolysis)시킨 결과 lipase PS(Amano 제약, Pseudomonas sp.)의 경우는 phosphate buffer pH 7.0 조건하에서 광학순도(optical purity) 95% e.e.의 (R)-(-)-3-acetoxy-2-methylpropanol을 80% 수율로 생산하였으며, lipase AY(Candida rugosa)의 경우는 phosphate buffer pH 6.5/isobutyl alcohol (1/1), O℃의 조건하에서 목적으로 한 (S)-3-acetoxy-2-methylpropanol 3을 광학순도 약 60% e.e.로 생산하였다. Optically active carboxylic acid, D-(-)-β-hydroxyisobutyric acid {(D)-(-)-HIBA} is a useful chiral starting material for the preparation of enantiomerically pure bioactive compounds which have a chiral methyl carbon center in the molecule such as captopril, α-tocopherol, erythromycin A, muscone and so on. (S)-3-Acetoxy-2-mthylpropanol can be used as the precursor of (D)-(-)-HIBA, that is, chemical oxidation of the hydroxyl group and subsequent hydrolysis of acyl group in (S)-3-acetoxy-2-methylpropanol affords D-(-)-β-hydroxyisobutyric acid. (S)-3-acetoxy-2-methylpropanol was prepared by lipase-catalyzed asymmetric hydrolysis. In the enzymatic hydrolysis system, lipase AY (Candida rugosa) provided the expected (S)-3-acetoxy-2-methylpropanol in 60% e.e. of the enantiomeric purity under the phosphate buffer and organic co-solvent system.

항공사의 컴퓨터 예약시스템과 국내 여행업의 유통 네트워크에 관한 연구

김찬영,이윤철 한국항공대학교 경영연구소 2002 경영연구 Vol.9 No.1

본 연구는 항공사의 컴퓨터 예약 시스템의 발전과 여행시장의 유통경로 변화를 고찰하여 여행업의 유통전략과 유통경로의 방향성을 제시해 보려는 데 그 목적이 있다. 항공사 컴퓨터 예약시스템은 발전을 지속하였으나 1990년대에 들어와서는 Internet이 등장하여 항공사는 인터넷 시스템으로 고객과 직접 접촉하는 직접거래가 증가하고 있다. 이러한 상황에서 여행업은 항공사와 고객사이에서 유통경로의 역할을 할 분야를 찾아야 하며 관광업계가 같이 발전하기 위해서는 업무여행자 시장과 관광여행자 시장을 구분하여 여행업의 유통경로를 설정하는 방안을 제시하였다. The purpose of this study is to present a distribution strategy for traveling business and directivity of distribution channels by examining the development of the computerized reservation system for airline companies and the changes of distribution channels for traveling markets. The computerized reservation system for airline companies has been continued to develop, however, with the appearance of the internet in 1990s airline companies are making more transactions through direct contacts with clients by the internet system. It has been presented that in such circumstances a traveling business should find out the sectors in which they can play a role of the distribution channel between airline companies and their customers and in order that they may be developed together with the business circles of tourism the distribution channel of a traveling business should be set by dividing the travelers markets and leisure traveler markets.

백반증 병변에 국한되어 발생한 건선 1예

김윤전,강희영,이은소,김유찬 대한피부과학회 2006 대한피부과학회지 Vol.44 No.4