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      • KCI등재

        도재소부용 비귀금속 합금의 표면처리가 금속과 도재간의 전단결합강도에 미치는 영향

        이청희,조성암,Lee, Cheong-Hee,Cho, Sung-Am 대한치과보철학회 1996 대한치과보철학회지 Vol.34 No.3

        도재 소부용 비귀금속합금의 표면처리가 금속과 도재간의 전단결합강도에 어떠한 영향을 미치는지 알아보기 위하여, 비귀금속 합금의 표면에 어떠한 처리도 하지 않는 대조군과 샌드브라스팅한 실험군, 스퍼트 에칭한 실험군, 그리고 샌드브라스팅후 스퍼트 에칭한 실험군으로 나눈 후에 각각의 시편에 통상적인 방법으로 도재를 소성한 후 인스트론 만능 시험기를 사용하여 전단결합강도를 측정하여 다음과 같은 결론을 얻었다. 1. 샌드브라스팅후 스퍼트 에칭한 실험군과 샌드브라스팅한 군은 대조군에 대해 높은 값을 나타내었다(P<0.05). 2. 스퍼트 에칭한 실험군은 대조군에 대해 차이가 없었다(P>0.05). A study of shear bond strength between porcelain and alloy pretreated with sandblasting, sputter etching, and sputter etching after sandblasting was established by Instron universal testing machine. 1. Sputter etched group after sandblasted(group IV) and sandblasted group(group II) were stronger than control group(group I) (P<0.05). 2. Sputter etched group(group III) and control group(group I) were not different(P>0.05).

      • KCI등재

        수종의 세멘트에 따른 주조금관의 유지력 및 세멘트 두께의 비교

        이청희,조광헌,Lee, Cheong-Hee,Jo, Kwang-Hun 대한치과보철학회 1994 대한치과보철학회지 Vol.32 No.1

        주조관에 대한 레진 세멘트의 유지력을 알아보기 위하여 상악소구치 30개를 일정한 크기로 삭제한 다음통상적인 방법으로 비귀금속 주조관을 제작한후, 각 군에 10개씩 나눈 후 I군에서는 인산 아연세멘트, II군에서는 Panavia-EX, 그리고 III군에서는 All-Bond & composite resin cement로 5kg의 정적인 압력하에서 세멘트한 후, 인스트론 만능시험기에서 cross head speed 1mm/min으로 유지력을 측정하였다. 레진 세멘트의 세멘트 두께를 측정하기 위해서 하나의 상악 소구치를 치아 형성한 후 인상을 채득하여 비귀금속의 치아 5개를 만들고 여기에서 각각의 비귀금속 주조관을 만든 후각 시편의 협, 설, 근, 원심 4면에 변연 가까이 표식을 만든 후, 세멘트하기전 및 Panavia-EX, All-Bond, 인산 아연 세멘트의 순으로 세멘트한 후의 주사전자 현미경 사진을 채득하여 세멘트 후의 두 표시 사이의 간격에 세멘트 하기 전의 간격을 제한 후 한 시편의 4면에서 나온 간격을 평균하여 그 해당 세멘트의 해당 시편에서의 세멘트 두께로 하여 5개의 시편에서 각각 세멘트의 세멘트 두께를 측정하였다. 1. III군에서 $4.34{\pm}1.08kg$으로 가장 파단하중이 높았고 II군에서 $3.34{\pm}1.22kg$, I군에서 $1.66{\pm}0.4kg$의 순으로 나타났다. 2. III군은 I군과 II군에 대해, 그리고 II군은 I군에 대해 통계학적 유의성 있는 차이를 나타내었다(p<0.05). 3. 세멘트 두께에 있어서 Z.P.C는 $45.4{\pm}16.6m$, Panavia는 $41.3{\pm}22.9m$, 그리고 All-Bond는 $151{\pm}82m$로 나타났다. 4. 인산 아연 세멘트와 Panavia는 All-Bond에 대해 통계학적 유의성 있는 차이를 나타내었으며(p<0.05)인산 아연 세멘트와 Panavia-EX사이에는 유의성 있는 차이가 없었다(p>0.05). The purpose of this study was to evaluate the effect of various cements on the retention of casting crown and the cement film thickness. To evaluate the retention of crown, thirty maxillary premolars were used and prepared to largely same dimension. According to the routine method, Non-precious metal crowns were made. The teeth and the metal crowns were divided into three groups and cemented under 5kg static pressure. Group I was composed of 10 teeth and 10 metal crowns and was cemented with zinc phohsphste cement. Group II was composed of 10 teeth and 10 metal crowns and was cemented with Panavia-EX cement. Group III was composed of 10 teeth and 10 metal crowns and was cemented with All-Bond & composite resin cement. After 5 days, the cemented specimens were mounted and the failure loads were measured by an Instron Universal Testing Machine. To evaluate the cement film thickness. 5 metal teeth and 5metal crowns from a prepared maxillary premolar were made. Two marks were flawed on the margin part of each surface at 4-surfaces of each specimen(one mark : crown, the other : metal tooth) and were measured the width with SEM photograph(80 sheets) before and after cementation(Panavia-EX, All-Bond cement, & ZPC) was made. Differences of the widths of marks between before and after were measured, and differences from 4-surfaces of a specimen cemented with a cement were measured and calculated. The results were as follows ; 1. There was a statistically significant difference between the failure loads of group III and the others(p<0.05). 2. There was a statistically significant difference between the cement film thickness of group III and the others(p<0.05).

      • KCI등재

        위상이동 형상측정법을 이용한 의치 중합 방법에 따른 적합도 검사

        이청희,조광헌,최부병,Lee, Cheong-Hee,Jo, Kwang-Hun,Choi, Boo-Byung 대한치과보철학회 1999 대한치과보철학회지 Vol.37 No.4

        According to repeated measurements and correction procedures, the accuracy of the phase-shifting profilometry was developed. At first, after 20 final models for maxillary complete denture were duplicated , the mucosa sur-faces of models were measured with the phase-shifting proflometry and each mirror view of these was calibrated. Maxillary casts were divided into 4 groups of 5 casts per each, and wax dentures with 2 sheets of baseplate wax and artificial teeth were made and then cured according to the curing method of each group. Group I ; quick curing with QC-20 acrylic resin Group II ; 9 hour curing with QC-20 acrylic resin Group III ; SR-Ivocap system Group IV ; metal base and quick curing with QC-20 acrylic resin. After curing, polishing, and storing at $37^{\circ}C$ in saline for 30 days, the forms of the impression surface of the dentures were measured with the phase-shifting profilometry. Then, the impression surface form of each denture was placed in the optimal position of com-parison with the mirror view of the same final cast. The amount and direction of distortion of each denture was analyzed and the effects of polishing and storage in each denture were compared, The obtained results were as follows : 1. In Group I, the denture was observed as the appearance distorted in the opposite direction of the mucosa and the postero-lateral part of palatal portion of the denture was observed as the appearance separated from the mucosa. Also, the buccal flanges of the denture were observed as the appearance distorted in the direction of the mucosa. 2. In Group II, the postero-lateral part of palatal portion of the denture was observed as the appearance separated slightly from the mucosa. The bilateral buccal flanges of denture were observed as the appearance distorted severely in the direction of the mucosa. 3. In Group III the bilateral part of the residual ridge crest portions and the buccal flanges of the denture were observed as the appearance distorted in the direction of the mucosa, and specially, the buccal flanges of the maxillary tuberosities were distorted severely. 4. In Group IV, the acrylic resin base of the buccal portion of the denture was observed as the appearance distorted in the opposite direction of the mucosa. 5. The phase-shifting profilometry, done with repeated measurements and correction procedures, was effective in comparing the amount and direction of distortion at every position after the laboratory work and the delivery of maxillary complete denture.

      • KCI등재
      • KCI등재

        지대치 유도면의 기울기에 따른 응력 분포에 대한 연구

        이청희,Lee, Cheong-Hee 대한치과보철학회 1998 대한치과보철학회지 Vol.36 No.2

        The purpose of this study was to investigate the effects of load on root that was applied to edentulous area in three simulated situation, in each case the guiding planes of abutment were right vertical, 95 degrees, or 100 degrees to residual ridge. The 2-dimensional finite element method was used and the finite element model was prepared as fellows. Right mandibular 1st and 2nd molar was lost and the 2nd premolar with distal rest was used as primary abutment which had three different degrees of guiding plane. Then 150N of compressive force was applied to central fossae of the 1st and 2nd molars and von Mises stress and displacement was measured. The results were as follows; 1. Irrespective of slopes of guiding planes, the stress was concentrated on mesial side of root apex and distal side of coronal portion of root, in particular on junction with distal alveolar bone. As slopes of guiding planes were increased. stress on root and compact bone surrounding abutment was increased but no considerable effect was seen on compact bone of residual ridge. 2. Distal side of coronal portion of root limited by periodontal ligament was displaced distally and mesial side of apical portion was mesially. With slope of guiding plane increasing, the pattern of displacement was similar with one another but the quantity was increased. 3. Both abutment & alveolar bone were displaced downward and root of abutment, especially distal side of coronal portion, was displaced severely. As the guiding plane was tiffed more mesially over $90^{\circ}$, the degree of displacement was also increased.

      • KCI등재

        접착성가공의치에서 세멘트 종류가 전단결합강도에 미치는 영향

        이청희,Lee, Cheong-Hee 대한치과보철학회 1996 대한치과보철학회지 Vol.34 No.4

        교정치료을 위해 발거된 소구치를 사용하며 레진에 고정한 후 직경 4mm이상의 법랑질 평면을 얻었다. 직경 4mm의 아크릴릭 봉을 길이 5mm로 해서 Ni-Cr 비귀금속 합금으로 주조한 후, 사용될 표면을 전기화학적 식각처리 하였다. 각 실험군당 시편 42개를 I군은 Panavia 21, II군은 Superbond, III군은 All-Bond로 세멘트 한 후 1일, 15일, 그리고 30일에 각 군당 14개의 시편을 임의로 취득하여 인스트론 만능시험기에 특별히 만든 Jig를 사용하여 거상하고 cross-head speed 1mm/min으로 전달결합강도를 측정하였다. 세멘팅한 후 1일에 측정한 전달결합강도는 Panavia-21의 I군에서 $32.7{\pm}9.9kg$중, Super-bond의 II군에서 $25.9{\pm}5.9kg$중, 그리고 All-Bond의 III군에서 $23.5{\pm}7.2kg$중의 순으로 나타났으며, I군이 II군과 III군에 대하여 통계학적인 유의성이 있었다(P<0.01). 세멘팅후 15일에 측정한 전단결합강도는 II군이 $34.6{\pm}10.4kg$중, I군에서 $23.1{\pm}8.7kg$중, 그리고 III군에서 $10.9{\pm}7.2kg$중으로 II군이 I과 III군에 대해, I군은 III군에 대해 통계학적 유의성이 있었다(P<0.01) 세민팅후 30일에 측정한 전달결합강도는 II군에서 $33.0{\pm}12.9kg$중, I군에서 $31.0{\pm}8.6kg$중, 그리고 III군에서 $13.6{\pm}6.6kg$중으로 II군과 I군이 III군에 대해 통계학적인 유의성이 있었다(p<0.01). 저장기간에 따른 전달결합강도 비교에서 III군에서 1일에서의 전단결합강도가 15일과 30일에서의 전단결합강도보다 통계학적으로 유의성 있게 높았다(P<0.01). The purpose of this study was to compare the shear bond strength of adhesion bridge by various resin cements. One hundred and foully 1st premolars were used. The teeth were cut below 2mm from CEJ and the coronal portions were used. The coronal portions were embeded with the acrylic resin and trimmed with sic paper until the flat plane with ${\phi}$ 4mm above acrylic resin sticks in height 5mm were casted with nonprecious metal and the using surfaces were treated with sic paper from #200 to #1200 and polished with alminum oxide paste. And then, the using surfaces were sandblasted and treated with the electrochemical etching. The teeth were divided into three groups of fourty two each. In group I, teeth and specimens were cemented with Panavia 21 In group II, teeth and specimens were cemented with Superbond In group I, teeth and specimens were cemented with All-Bond & composite resin cement Each group was subdivided into three subgroups according to the storage period ; one-day storage, fifteen-day storage, and thirty-day storage. The special jig was made. Then, the specimen and jig were mounted to Instron Universal Testing Machine and the failure were measured. The results were as follows. 1. There was statisfically significant difference between the failure loads of group I and group II and III after one day storage(P<0.01), 2. There was statisfically significant difference between the failure loads of group II and group I and III and between group I and group III at fifteen day storage(P<0.01). 3. There was statisfically significant difference between the failure loads of group I and II and group III after thirty day storage(P<0.01). 4. There was statisfically significant difference between the failure loads of one day storage and fifteen and thirty days storages in group III (P<0.01).

      • KCI등재후보

        비수 유화법을 이용한 아스코르빅산의 안정화

        이청희,신재동,배수현,강기춘,표형배 大韓化粧品學會 2012 대한화장품학회지 Vol.38 No.4

        아스코르빅산(비타민 C)은 수용액상에서 공기와 빛, 알칼리 등에 의해 쉽게 불안정화되는 성질이 있어 화장품에 적용에 있어서 제한적이다. 아스코르빅산은 수용액상에서 불안정성에 영향을 주는 가장 중요한 인자인 공기, 특히 산소와 열, 빛 등의 외부환경에 민감하게 반응하여 산화에 의해 쉽게 분해되는 문제점이 있다. 본 연구에서는 이러한 아스코르빅산의 안정성을 증가시키고자 폴리올과 유화방법을 변화시켜 안정화하는 연구를 수행하였고 실온과 고온에서 색상과 아스코르빅산의 함량변화를 HPLC로 측정하여 비교하였다. 그 결과 실험한 조건들 중 폴리올은 글리세린을 사용한 경우 아스코르빅산의 안정화 가장 좋았으며 비수유화방법을 사용한 경우에 있어서 가장 안정하였다. 이러한 결과들로부터 아스코르빅산이 본 실험의 비수유화로 안정성이 증가하며 안정한 화장품을 만드는 데 적용이 가능하다. Ascorbic acid (Vitamin C) becomes unstable in the aqueous phase by oxygen, light and alkali, etc. The properties are limited in application to cosmetics. The most important factor that determines the destabilization of ascorbic acid in the aqueous phase was tried to understand considering its molecular deformation and degradation. In this study, we changed the polyols and emulsification technique for the stability of ascorbic acid. Then we observed the color and concentration change of ascorbic acid at room temperature and high temperature (42 ℃) for 6 weeks and identified the stability using HPLC regularly. As a result, we found that glycerin was the most appropriate polyol for stability of the ascorbic acid. Also the technique of nonaqueous emulsification stabilized ascorbic acid than P/S emulsification. Also, P/S emulsification, glycerin was more stable than propylene glycol. By the results we suggest that ascorbic acid could be stabilized by nonaqueous emulsification method and this data could be applied to stabilization methods for cosmetic products.

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