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      • KCI등재

        불확실한 시공간 객체에 관한 위상 관계 알고리즘

        지정희,김대중,류근호,Ji, Jeong-Hui,Kim, Dae-Jung,Ryu, Keun-Ho 한국정보처리학회 2003 정보처리학회논문지D Vol.10 No.6

        지금까지 명확하게 정의된 경계를 갖는 공간 및 시공간 객체 모델 개발에 관한 많은 연구가 수행되어 왔다. 그러나, 이들 모델은 지리 분석과 이미지 해석에 관한 많은 응용에서 식별되는 불확실한 경계를 갖는 공간 및 시공간 객체에 직접적으로 적용될 수 없다. 따라서, 이 논문에서는 불확실한 공간 및 시공간 객체에 적용할 수 있는 불확실한 시공간 데이터 모델을 제안하고, 이 모델을 기반으로 불확실한 시공간 객체간의 위상 관계에 관한 연산자를 정의하고, 연산 알고리즘을 설계하였다. 제안된 모델은 기존 모델과의 호환성을 위해 개방형 GIS 명세서를 기반으로 하는 시공간 데이터 모델을 확장하여 설계하였다. 불확실한 시공간 객체는 시간에 따라 위치와 모양이 불연속적으로 변하는 객체와 시간에 따라 위치와 모양이 연속적으로 변하는 객체로 정의하였으며, 확장된 9-IM을 사용하여 이들 객체간의 위상 관계를 정의하였다. 제안된 모델은 천연자원 관리시스템, 날씨 정보 관리 시스템, 지리 정보 관리 정보 시스템 등에 효율적으로 적용될 수 있을 것으로 기대된다. So far, significant achievements have been studied on the development of models for spatial and spatiotemporal objects with indeterminate boundaries which are found in many applications for geographic analysis and image understanding. Therefore, in this paper we propose the spatiotemporal data model which is applicable for spatial and spatiotemporal objects with uncertainty. Based on this model, we defined topological relationships among the indeterminate spatiotemporal objects and designed the algorithm for the operations. For compatibility with existing spatial models, the proposed model has been designed by extending the spatiotemporal object model which is based on the open GIS specification. We defined indeterminate spatial objects, such as the objects whose position and the shape change discretely over time, and the objects whose shape changes continuously as well as the position. We defined topological relationships among these objects using the extended 9-IM. The proposed model can be efficiently applied to the management systems of natural resource data, westher information, geographic information. and so on.

      • SCOPUSKCI등재

        폐과오종(肺過誤腫)의 일치험례(一治驗例)

        박광훈,지정희,Park, Gwang-Hun,Ji, Jeong-Hui 대한흉부심장혈관외과학회 1976 Journal of Chest Surgery (J Chest Surg) Vol.9 No.2

        Since. its first description by Albrecht in 1904 that hamartoma (Greek. meaning "error" and "tumor")is tumor-like malformation characterized by abnormal mixture of normal constituent in any organ it arises, hamartoma involving the lung has assumed the following clinical features.: 1) all the pulmonary lesions presenting as "coin lesions", it occupies about 8% according to various reports. It also constitutes the most prevalent lesion of all the benign lung tumors, appearing in 0.25% of the general population. 2) Peak incidence of the lesion occurs in the 5th and 6th decade as the carcinoma patient do, and the occasional growing tendency and periperal location as in this presentation renders the differential diagnosis from the malignant disease difficult and surgical intervention inevitable for definite histological diagnosis and treatment. 3) Nearly all the clinical investigations such as history, physical exam, bronchoscopy, culture, and cytological exam of sputum sre likely to futile:the only tool for detecting the presence of the lesion is X-ray, butthat's short of telling the true nature of it. 4) Because of its age of presentation and growing tendency in middle-aged adult, it still controversial whether it is developmental anomaly as Albrecht described, or true neoplasm denovo of fibrous connective tissue origin. This is a case report of surgical experience of pulmonary hamartoma which had nearly all the typical clinical features above mentioned and was reviewed with related literatures.

      • KCI등재

        지르코니아 표면의 미세구조 변화가 레진 시멘트와의 인장결합강도에 미치는 영향

        강정규(Jeong-Gyu Kang),김태연(Tae-Yeon Kim),이정환(Jung-Hwan Lee),지정희(Jeong-Hui Ji),이민호(Min-Ho Lee),배태성(Tae-Sung Bae),안승근(Seung-Geun Ahn) 대한치과재료학회 2021 대한치과재료학회지 Vol.48 No.3

        This study was performed to evaluate the effects of microstructural change of zirconia surface on tensile bond strength with resin cement. The zirconia partially sintered block was cut into a size of 18 × 18 × 7 mm, and then the Zirface slurry (DMAX, Daegu, Korea) containing 15% and 30% zirconia was applied and followed by sintering at 1530 ℃ for 2 hours. Resin cement (PermaCem 2.0, DMG, Hamburg, Germany) was applied on zirconia specimen and polymerized to prepare an 18 × 18 × 14 mm block. In addition, for comparison of bond strength, specimens were prepared for the group that was polished and the group that was blasted at 3 atm using 110 μm alumina. Thereafter, all blocks were cut into a cross-sectional area of 1.0 × 1.0 mm to prepare 12 specimens. The specimens were immersed in distilled water at 37 ℃. for 10 days for aging treatment. A holder for tensile testing was attached to each of the specimens, and then a tensile force was applied at a crosshead speed of 0.5 mm/min to measure the fracture load. The fracture surfaces of each test piece was observed with a high-resolution field emission scanning electron microscope. Through the above tests, the following results were obtained. 1. On the blasted surface, zirconia grains were locally removed but on the Zirface treated surface, a porous microstructure was created on the zirconia surface. 2. Arithmetical mean deviation from the mean line ra was the highest in the blasted group and the lowest in the polished group, and as a result of Tukey analysis, there were statistically significant differences between all test groups (P<0.05). 3. The maximum tensile bond strength was 18.8±5.4 MPa in the Zirface 30% group, and as a result of Tukey analysis, there was a statistically significant difference from the other test groups (P<0.05). 4. As a result of observing the fracture surface after the tensile test with a high-resolution field emission scanning electron microscope, in the Zirface 30% group, cohesive fracture and interfacial fracture in the resin was observed, but the other test groups showed the interfacial fracture pattern. In conclusion, within the limits of this study, treating the zirconia surface with Zirface 30% to form a porous microstructure can contribute to the improvement of the bond strength between zirconia and resin cement.

      • KCI등재

        글레이즈 처리한 다색 리튬 디실리케이트와 지르코니아의 색조비교

        황별(Byeol Hwang),지정희(Jeong-Hui Ji),박철수(Cheol-Soo Park),신재우(Jaewoo Shin),이정환(Junghwan Lee),이민호(Min-Ho Lee),배태성(Tae-Sung Bae) 대한치과재료학회 2021 대한치과재료학회지 Vol.48 No.1

        The purpose of this study was to investigate the effect of glazing treatment of multi-colored zirconia disc and lithium disilicate block on the optical properties. From an Ultra Translucent Multi-Layered (UTML) disc containing 50% cubic crystal and a lithium disilicate-based Amber Mill Direct (AMD) block, the 1.2 mm thick specimens of the upper layer (T), the center (M), and the lower layer (B) were prepared. Three types of paste glaze of InSync Glaze Paste, IPS E.max Ceram Glaze Paste, and Amber Ceram G7 Glaze Paste were applied and fired to a uniform thickness on the surface of the specimen. CIE L<SUP>*</SUP>, a<SUP>*</SUP>, b<SUP>*</SUP> values were measured using a spectrophotometer and contrast and translucency were calculated. The bonding interface with the glaze layer was observed using HR FE-SEM. In the glazed groups, L<SUP>*</SUP> value increased, but a<SUP>*</SUP> value and b* value decreased. The translucency value measured in the untreated group was statically higher in the AMD groups than in UTML groups (P<0.05). The translucency did not show a significant difference before and after glazing treatment in the UTML group (P>0.05), but significantly decreased compared to the untreated group after glazing treatment in the AMD group (P<0.05). The contrast ratios generally increased after glaze treatment compared to the untreated group. Since the glaze treatment can affect the optical properties of ceramic restorations, the choice of glaze should be considered important for the desired color by the dental technician.

      • KCI등재

        리튬 디실리케이트 크라운의 제작방법이 적합도에 미치는 영향

        최수연(Su-Yeon Choi),김세하(Seha Kim),지정희(Jeong-Hui Ji),이민호(Min-Ho Lee),배태성(Tae-Sung Bae) 대한치과재료학회 2020 대한치과재료학회지 Vol.47 No.3

        The purpose of this study was to evaluate the influence of fabrication methods of lithium disilicate reinforced glass-ceramic crown on marginal and internal fit. Lithium disilicate reinforced glass-ceramic crowns were fabricated using ingots for heat press forming and blocks for CAD/CAM milling manufactured by Hass and Ivoclar/Vivadent. Dentiform of maxillary central incisor was prepared with a 6°taper and 1 mm deep chamfer margin and duplicated with silicone. Then the polyurethane resin was poured at silicone mold to produce working model. Marginal and internal fit were measured by the silicone replica technique. Each silicon replica was cut into labio-lingual and mesio-distal sections and the thickness of the light body silicon was measured. Fourteen reference points were determined and measured using a microscope. As a result of calculating and comparing the average value of 14 points in all groups, the measured value was within 120 μm, the clinically acceptable range suggested by previous literatures. In all groups, the marginal fit was smaller than the internal fit. At the margin area, significant differences were identified only between the ECM group and the EPM group, and there was no statistically significant difference between the remaining groups. At the deep chamfer area, the ECM and ABM group produced by the CAD system had excellent compatibility. In the axial wall and incisal area, ECM was superior to both EPC and EPM. Also, both ABM and APC groups were statistically significantly superior than APM.

      • KCI등재

        열가압성형 지르코니아 코어의 굴곡강도에 대한 매몰재의 영향

        김태연(Tae-Yeon Kim),김세하(Seha Kim),지정희(Jeong-Hui Ji),임병구(Byoung gu Lim),오성근(Sung Geun Oh),신재우(Jaewoo Shin),이정환(Junghwan Lee),이민호(Min-Ho Lee),배태성(Tae-Sung Bae) 대한치과재료학회 2020 대한치과재료학회지 Vol.47 No.4

        The purpose of this study was to evaluate the effect of the reaction between investment material and zirconia on the strength of zirconia in the application of heat-pressing method. Sixty specimens were cut (24 mm×4 mm×0.5 mm) into plates from Zirtooth™ Multi O-9814 block (∅98×14T, HASS, Gangwondo, Korea) and sintered at 1450℃. Specimens were divided into 6 subgroups according to the depending on the investement material; (a) UN group (Control), (b) PH group (Prime vest HS), (c) CP group (Calibra-press), (d) BV group (BC-Vest), (e) MH group (Microstar-HS), (f) F1 group (Formula 1). Five investment materials were buried according to the procedure recommended by the manufacturer and left at room temperature for 30 minutes. The investment mold was dried and maintained at an elevated temperature of 850℃ for 50 minutes. Then, Amber Lisi-POZ LT (HASS) was placed in a thermoformed electric furnace (Programat EP3000/G2, Ivoclar Vivadent, Schaan, Liechtenstein) together with the mold, heated to 915℃ at an elevation temperature of 45℃/min, and moored for 15 minutes. The specimens were loaded to fracture in a universal testing machine and the fracture surface was examined by a field-emission scanning electron microscopy (FE-SEM). The surface of the zirconia specimen with the investment material was analyzed by energy dispersive X-ray spectroscopy (EDS). The 3-point flexural strength test showed the highest value (1265.5 MPa) in the UN group and the lowest value (756.1 MPa) in the F1 group. As a result of EDS analysis, the largest amount of Si was detected in the F1 group, and the most interfacial changes occurred as a result of FE-SEM analysis. It was concluded that when the zirconia is buried with the investment material and the heat press molding is performed, the state of the interface is changed due to the investment material at the bonding interface while the strength is lowered.

      • KCI등재

        반복성형이 2 종류 열가압 성형용 글라스-세라믹의 기계적 성질에 미치는 영향

        임청하(Chung-Ha Lim),신재우(Jae-Woo Shin),석정진(Jung-Jin Seok),지정희(Jeong-Hui Ji),이민호(Min-Ho Lee),배태성(Tae-Sung Bae) 대한치과재료학회 2014 대한치과재료학회지 Vol.41 No.1

        The purpose of this study was to evaluate the effect of repeat processing on the mechanical properties of two pressable glass-ceramic dental materials. IPS e.max ZirPress of apatite-reinforced glass-ceramic material and IPS e.max Press of lithium disilicate-reinforced glass-ceramic material were used in this study. Twenty disc specimens (13.0 mm × 1.5 mm) for each material were prepared by 4 times repeated heat-pressing. Sprue and button parts were reused to make specimens for every repeated heat-pressing. This study compared the biaxial flexural strength, Vickers hardness, fracture toughness, and the X-ray diffraction response. Microstructures were examined using a scanning electron microscope (SEM). IPS e.max Press showed the decrease of the biaxial flexural strength and fracture toughness values and the increase in sizes of the lithium disilicate crystals after repeat processing for 3 times. IPS e.max ZirPress showed the decrease in Vickers hardness value after repeat processing for 2 times. Based on these results of this study, clinically acceptable limits of the repeat number of heat-pressing were twice in the case of the IPS e.max Press and to be once in the case of the IPS e.max ZirPress.

      • KCI등재

        니오븀함량에 따른 치과용 Ti - xNb 합금의 물리적 성질

        박일송(Il-Song Park),박정은(Jung-Eun Park),지정희(Jeong-Hui Ji),Jin Guang-Chun,윤동주(Dong-Joo Yoon),박주미(Ju-Mi Park) 대한치과재료학회 2011 대한치과재료학회지 Vol.38 No.1

        The materials currently used for surgical implants include 316L stainless steel (316LSS), cobalt chromium (Co-Cr) alloys and titanium and its alloys. Elements such as Ni, Cr and Co are found to be released from the stainless steel and cobalt chromium alloys due to the corrosion in the body environment. The materials currently used for surgical implants include 316L stainless steel (316LSS), cobalt chromium (Co-Cr) alloys and titanium and its alloys. Elements such as Ni, Cr and Co are found to be released from the stainless steel and cobalt chromium alloys due to the corrosion in the body environment. The relative intensity o f β phase increased according to t he increase of niobium contents. Also the dendrite structures were changed to globular structures with increasing niobium contents. The microhardness values and corrosion resistance of all the Ti-xNb alloys were significantly higher than that of pure Ti and the Ti-37Nb alloy showed the best corrosion resistance among the other groups.

      • KCI등재

        4 종류의 다른 버로 형성된 지대치에서 제작한 지르코니아 코어의 변연 및 내면 적합도 평가

        오상훈(Sang-Hoon Oh),석홍병(Hong-Bing Shi),노형록(Hyeong-Rok Noh),지정희(Jeong-Hui Ji),이민호(Min-Ho Lee),배태성(Tae-Sung Bae) 대한치과재료학회 2016 대한치과재료학회지 Vol.43 No.3

        Marginal shape of abutment is one of the factors to effect on the fitness of zirconia crown. The aim of this study was to help clinicians set up specific guidelines on preparation for CAD/CAM zirconia crown by evaluation of marginal and internal fitness of CAD/CAM zirconia core using abutment model reflecting tip design of diamond burs to be used in a dental clinic. 4 groups consisting of 10 specimens of abutment made of photo-polymerized resin(RC 31;EnvisionTEC;Germany) were fabricated with 3D printer(Ultra 2, EnvisionTEC, Germany). The margin shape of each group’s abutment is designed to reflect 4 types of tip design of diamond burs(torpedo bur, deep chamfer bur, sloped shoulder bur, shoulder bur) to be used in a dental clinic. And then, zirconia cores for abutments of 4 groups were fabricated by same technician with same CAD/CAM system. 5 zirconia cores of each group were adapted on the abutment without cement, and 5 zirconia cores were cemented on abutment with ZPC. After embedding the specimens in resin, we observed marginal and internal fitness on the cross-section of the resin block by recording 200~500 fold magnification. When experiments without cement, the measured value of the gap in the margin, internal line angle and occlusal surface of torpedo group and deep chamfer group were smaller than sloped shoulder nd shoulder group. All result of ZPC cemented groups showed larger values than non-cemented group, especially shoulder group. Torpedo and deep chamfer bur are clinically acceptable for CAD/CAM zirconia crown. However, sloped shoulder and shoulder bur showed relatively large gap in the finish line and occlusal surface, having large variations within the group.

      • KCI등재

        교정용 미니스크류의 cutting flute 형성이 삽입 및 제거 토크에 미치는 영향

        박철수(Cheol-Soo Park),임병구(Byoung-Gu Lim),원은규(Eun-Kyu Won),황조연(Jo-Yeon Hwang),황별(Byeol Hwang),지정희(Jeong-Hui Ji),전우용(Woo-Yong Jeon),이민호(Min-Ho Lee),배태성(Tae-Sung Bae) 대한치과재료학회 2021 대한치과재료학회지 Vol.48 No.1

        The purpose of this study was to evaluate the structural characteristics of the thread length of orthodontic mini-screws and the effects of insertion and removal torques according to the formation of the cutting flute. Two types of mini-screws were made, with a thread length of 6.0 mm and a thread length of 3.3 mm. In order to examine the effect of flute formation, the experiment group was divided into a miniscrew test group with flute formation and an experiment group without flute formation. To evaluate the effect of flute formation, two flutes were formed at 180° on the circumference, and at the tip of the mini screw, up to 4 mm for thread length of 6.0 mm and 2.4 mm for thread length of 3.3 mm. A biomechanical test block formed of 2 mm cortical bone and 10 mm cancellous bone was used to eliminate the influence of the difference in cortical bone thickness and bone density according to the insertion site. 1 mm diameter guide hole was drilled on the test block and the mini-screw was placed vertically. Using a 0.1 N·cm precision digital torque gauge, the maximum torque value was recorded at this time by embedding it to the top of the screw under a static load of 1.2 kg and the value when it was removed in the opposite direction. The insertion torque values for the 6.0 mm and 3.3 mm length mini screws were (29.53±1.84) N·cm and (26.84±2.15) N·cm, and the removal torque values are (14.50±1.37) N·cm and (13.15±2.89) N·cm, respectively. There were no statistically significant differences (P>0.05). The flute of 6.0 mm mini-screws had no statistically significant difference in both insertion and removal torque values and increased to (30.13±1.97) N·cm and (18.65±1.10) N·cm (P>0.05). In experiments with 3.3 mm mini-screws, the insertion and removal torque values decreased to (20.99±3.94) N·cm and (11.32±2.03) N·cm, respectively, showing a statistically significant decrease only in the insertion torque values (P<0.05). The insertion and removal torque values of the mini-screw were not significantly increased even when the screw length was doubled, and the flute formation effect was different with the screw length.

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