에폭시 배합비에 따른 내열성 복합재료 최적조건

신평수 ( Pyeong Su Shin ),왕작가 ( Zuo Jia Wang ),권동준 ( Dong Jun Kwon ),최진영 ( Jin Yeong Choi ),성일 ( Ill Sung ),진달샘 ( Dal Saem Jin ),강석원 ( Suk Won Kang ),김정철 ( Jeong Cheol Kim ),박종만 ( Joung Man Park ) 한국복합재료학회 2014 Composites research Vol.27 No.4

2개 이상의 에폭시 기지재의 배합비를 이용하여 최적의 에폭시 복합재료를 제조하였다. 이 실험에서 노볼락계 에폭시 및 아이소시아네이트계 에폭시를 기지재로 사용하였다. 그에 따라 화학적 조성의 변화를 이용하여 다양한 실험을 통한 최적의 에폭시 배합비를 유추하였고, 에폭시의 내열성 및 계면을 파악하기 위하여 열중량측 정기를 이용하여 유리전이온도의 변화를 파악하였고 정적 접촉각을 측정하였다. 기계적 물성을 파악하기 위하여 에폭시 배합비에 따른 유리섬유/에폭시 복합재료의 인장, 압축, 굴곡강도를 상온에서 및 노화시간에 따라 파악하였다. 에폭시와 유리섬유간 계면을 개념도로 나타냈다. 시험 결과 에폭시 배합비에 따른 적외선 피크 및 유리전 이온도 변화를 확인하였다. 서로 다른 에폭시의 배합비가 1:1일 때 기계적물성이 상대적으로 좋은 것을 확인하였다. Composites Research : The optimum condition of glass fiber/epoxy composites was investigated according to mixing ratio of two epoxy matrices. Novolac type epoxy and isocyanate modified epoxy were used as composites matrix. Based on chemical composition of mixing matrix, optimum mixing ratio of epoxy resins was obtained through various experiments. In order to investigate thermal stability and interface of epoxy resin, glass transition temperature was observed by DSC instrument, and static contact angle was measured by reflecting microscope. Change of IR peak and Tg was conformed according to different epoxy mixing ratio. After fabrication of glass fiber/epoxy composites, tensile, compression, and flexural properties were tested by UTM by room and high temperature. The composites exhibited best mechanical properties when epoxy mixing ratio was 1:1.

임신중기 태반조기박리 임부에서 기대요법에 의한 생존분만

하민숙 ( Min Sook Ha ),황태기 ( Tae Gi Hwang ),이상경 ( Sang Kyeong Lee ),이인하 ( In Ha Lee ),박연진 ( Yeon Jin Park ),지일운 ( Ill Woon Ji ),정은환 ( Eun Hwan Jeong ),김학순 ( Hak Soon Kim ),성노현 ( Ro Hyun Sung ) 대한산부인과학회 2004 Obstetrics & Gynecology Science Vol.47 No.9

Prognosis of placental abruption depends on gestational age and the status of the mother and the fetus, and perinatal mortality was almost entirely attributable to prematurity. A midtrimester women with placental abruption was successfully treated by expe

풍촌석회석을 원료로 한 경질 탄산칼슘 제조에 대한 연구

성일용,엄제현,신강호 三陟大學校 産業科學技術硏究所 1999 産業科學技術硏究論文集 Vol.4 No.-

본 연구는 삼척지역 석회석의 부가가치 향상을 목적으로 수행되었다. 석회석의 부가가치 향상 방법에는 여러 가지가 있을수 있으나 본 연구에서는 중질탄산칼슘과 경질탄산칼슘의 제조에 역점을 두었다. 따라서 삼척지역 석회석을 중질탄산칼슘 또는 침강성 탄산칼슘 제조용 원료로 사용할 경우 발생되는 문제점들을 파악하고 그 해결방안을 제시하고자 하였다. 연구내용은 광물학적특성조사, 소성특성조사, 수화특성조사, 탄산화반응특성조사, 경탄제조특성조사, 중탄제조특성조사로 이루어진다. 광물학적특성조사에서는 현미경관찰, XRD분석, XRF분석, 산용해실험, 수선 등을 행하였고, 소성특성조사에서는 TG-DTA 분석, 온도 및 시간에 따른 소성율 변화를 조사하였다. 수화특성조사에서는 소성조건에 따른 수화반응속도와 습식사분에 의한 불순물제거율을 조사하였고, 경탄제조실험에서는 주로 방추형탄산칼슘과 교질탄산칼슘을 입방형탄산칼슘, 침상탄산칼슘을 제조하였고, 중질탄산칼슘제조 실험에서는 분쇄시간에 따를 입도변화, 입도에 따른 백색도 변화를 조사하였다. 얻어진 실험 결과들을 종합하면 아래와 같다. 본 연구에 사용된 석회석 시료를 중질탄산칼슘용으로 사용하고자 할 경우 백색도 향상을 위한 보다 많은 연구가 필요하며, 경질탄산칼슘용으로 사용하고자 할 경우는 800∼1000℃ 범위에서 소성→수화→습식 입도분급에 의한 탈철 →H₂O₂→(CH₃)₂CHCH₂CH₂OH-H₃PO₄+NH₂OH·HCI또는 알루민산염을 사용하는 표백 처리 →탄산화반응의 순서에 따라 경질탄산칼슘을 제조 하는 것이 적당할 것으로 생각 되며 이 때 생산되는 경질탄산 칼슘의 품질을 기존에 생산되는 국내산 경탄의 품질과 비교하면 DY39, DY48, DY50, DY58을 사용한 경우는 중품위 정도의 경탄을 얻을 수 있고, DY38, DY49, DY60을 사용하면 고품위의 겅탄을 제조 할 수 있을 것으로 사료된다. 그러나 외국산 경탄의 백색도(97∼99)에는 다소 떨어지는 경향이 있다.

실리콘 고무印象의 寸法精度에 關한 比較 實驗

金在一,成在鉉 慶北大學校 齒科大學 1984 慶北齒大論文集 Vol.1 No.1

A new class of elastomeric impression materials, the highly filled silicones, had recently been introduced. The purpose of this study was to evaluate the effect of pouring time on the accuracy of the silicone rubber base impressions. After the standard silicone rubber base impression and the putty & wash impression were made with the brass master die, the impressions were separated and poured with stone at the several time interals. Following results were obtained by comparing the distances between the post on the brass master die and on the stone replicas; Overall, the accuracy of the putty & wash impression was superior to that of the standard silicone rubber base impression. It was desirable in dimensional accuracy in both methods to pour impression as soon as possible. The standard silicone had statistically significant shrinkage at 24 hours or later, but the putty & wash impression did not differ significantly from the master die throughout all time intervals. In both impressions, no signifcant difference was found in accuracy between 1st & 2nd pours at the same time intervals.

외환위기전 한국제조기업의 환위험노출 평가에 관한 연구

최성용,성일진 서울여자대학교 대학원 1999 論文集 Vol.- No.7

This article examines firstly the exposure of Korean manufacturing firms with high export ratio to foreign currency risk. Evidence is presented that the relationship between stock returns and exchange rates differs systematically across those firms. We find that about 27 percent of our sample of 155 Korean Manufacturing firms' stock returns experienced economically significant contemporaneous negative exposure effects and lagged positive exposure effects for the period August 1993 to October 1997. The extent to which a firm is exposed to exchange-rate fluctuations can be explained by the level of its size, export ratio, and book to market ratio.

Ball Mill 분쇄에 對한 硏究

박동기,성일용,엄제현,김익수,김승혁 三陟大學校 1998 論文集 Vol.31 No.1

In the field of study on 'comminution' there appear some kinds of polarizition, i.e. macro-micro, software-hardware and practice-theory and so on. For instance, numerous papers are available on mathematical modelling or simulation of practical ball mill grinding circuits. Few discussion, however, has been made in those papers from the viewpoint of energy consumption on the basis of its quantitative measurement. On the other hand so-called 'fracture of a single particle' phenomena have been investigated exclusively from this point of view in other papers concerned. The authors, therefore, are trying to fill the gap of this type nad conducted so far some experimental work on a laboratory scale ball mill system facilitating precise measurements of torgue.

Mn-nodule의 선광에 관한 연구(제1보)

김익수,박동기,성일용,김승혁,엄제현 三陟大學校 2000 論文集 Vol.33 No.1

For the purpose of reserching the floatability of Managanese-nodule, the test was proformed by means of Zeta potential measuring and the flotation experiment for 10Å Manganite. The flotation condition in the flotation experiment were as follow. sample : Todorokite (0.3gr) sample size : 65 mesh ~ 200 mesh condition size : 10 min flotation time : 4 min air amount : 20 ㎖/min promoter : D.A.cl, S.D.S. PH regular : Hcl, CaO From the test the flotation result were summerized as follow. 1. The isoelectric point of 10Å Manganite in the Zeta potential measuring was pH 4.3. 2. The floatability of 10Å Manganite was 80% as a function of pH5 using 10mg/ℓ of D.A.cl. 3. The recovery of 10Å Manganite was best when the floatability of 10Å Manganite was 90% as using D.A.cl 80mg/ℓat PH 2.7.

Micromanganese-Nodule의 選鑛에 관한 硏究(제1보)

엄제현,박동기,김익수,성일용,김종윤,김진석 三陟大學校 産業科學技術硏究所 2002 産業科學技術硏究論文集 Vol.7 No.4

For the purpose of researching of the manganese recovery from the micromanganese-nodule, the test was performed by means of the ζ-potential measuring and of the floatation experiment for manganese recovery of the micromanganese nodule obtained from siliceous deep sea clay. The floatation condition in the floatation experiment were as follow. Sample size : 65mesh∼200mesh. Condition time : 10 min. Flotation time : 4 min. Air amount : 20㎖/min. Promoter : DAS, NaDS. Kerosene Dpresser : Na_2SiO_3(Water glass) PH regulator : HCl, CaO From the above test the flotation results were summerized as follow. (1) ζ-potential of micromanganese-nodule was minus(-) in the pH 3∼12. (2) The manganese recovery from the micromanganese- nodule was the best at pH 7. (3) The manganese recovery from the micromanganese- nodule was the best using DACI 50㎎/ℓ + kerosene 200㎎/ℓ in the promoter at pH 7. (4) The best manganese recoverv of the micromanganese-nodule was 80% using DACI 50㎎/ℓ + kerosene 200㎎/ℓ in the promoter and water glass 500㎎/ℓ in the depresser at pH 7. In the futurity, continuous study of the micromanganese-nodule in many kinds of site should be required.

황산화 부선법에 의한 방연광의 억제에 관한 연구

엄제현,박동기,김익수,성일용,김종윤,김진석 三陟大學校 産業科學技術硏究所 2003 産業科學技術硏究論文集 Vol.8 No.1

The applicability of a sulphation-floatation process was considered in order to depress of galena in a mineral processing process of complex sulphide ores. The galena will be depressed in the floatation step because of the formation of a PbSO₄ film on the surface of galena. when a PbS bulk concentrate is treated with sulphuric acid. The optimum conditions of the sulphation treatment for depressing galena were found to be 30%. and about 5 minutes of retention, with 18 Vol. % H₂SO₄. under these conditions. galena was sulphated only slightly and thus in complete depression in the floatation.