• Title/Summary/Keyword: Dies

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F. H. Jacobi und Spinoza-Streit (야코비와 스피노자 논쟁)

  • Choi, Shin-Hann
    • Journal of Korean Philosophical Society
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    • v.129
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    • pp.315-339
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    • 2014
  • Diese Abhandlung untersucht Jacobis ${\ddot{U}}ber$ die Lehre Spinoza und den von diesem veranlassten Spinoza-Streit. Damit sie $enth{\ddot{u}}llt$ zuerst Jacobischen Zusammenhang zwischen transzent und immanent und folgt auf seine Wirkungsgeschichte in der Moderne. Ich rekonstruiere den Streit zwischen Jacobi und Lessing und danach interpretiere dessen Rezeption durch Hegel und Schleiermacher. Lessing stellt anstatt der traditionellen Begriffe der Gottheit ἑν ${\kappa}{\alpha}{\iota}$ ${\pi}{\alpha}{\nu}$ auf. $Demgegen{\ddot{u}}ber$ behauptet Jacobi Salto mortale um ihn ${\ddot{u}}berschreiten$ zu $k{\ddot{o}}nnen$, indem er Lessing als Pantheist und Atheist bestimmt. Salto mortale bei Jacobi ist der Sprung zu dem ${\ddot{U}}bernat{\ddot{u}}rlichen$ und dem Glaube. Der Streit zwischen Jacobi und Lessing ist der zwischen dem Naturalismus und ${\ddot{U}}bernaturalismus$ und $dar{\ddot{u}}berhinaus$ der zwischen dem Athismus und Theismus. $W{\ddot{a}}hrend$ die Natur der Inbegriff der Bedingten ist, ist Gott der absolute Anfang der Natur $au{\ss}erhalb$ des Naturzusammenhangs. $W{\ddot{a}}hrend$ Spinoza Gott im $nat{\ddot{u}}rlichen$ Zusammenhang begreift, $fa{\ss}t$ Jacobi den im ${\ddot{u}}bernat{\ddot{u}}rlichen$ auf. Deus sive natura bei Spinoza $ver{\ddot{a}}ndert$ sich Gott im Menschen bei Jacobi. Gott im Menschen ist nichts anders als das Prinzip des Lebens und das aller Vernuft. In diesem Zusammenhang $fa{\ss}t$ Hegel Gott als Geist denn Subjekt des Lebens auf und $h{\ddot{a}}lt$ das Wesen des Geistes $f{\ddot{u}}r$ die sich selbst vermittelnde Bewegung. Dies zeigt sich als die Spinoza ${\ddot{u}}berbietende$ Immanenzphilosophie. $Demgegen{\ddot{u}}ber$ behauptet Schleiermacher die Einheit des Endlichen und Unendlichen in der $religi{\ddot{o}}sen$ Anschuung. Die Verbindung von Mensch und Gott ist die im Endlichen immanent bleibende Anschauung der $g{\ddot{o}}ttlichen$ Eigenschaft. Dies zeigt das transzendente im immanenten.

Effect of abutment superimposition process of dental model scanner on final virtual model (치과용 모형 스캐너의 지대치 중첩 과정이 최종 가상 모형에 미치는 영향)

  • Yu, Beom-Young;Son, Keunbada;Lee, Kyu-Bok
    • The Journal of Korean Academy of Prosthodontics
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    • v.57 no.3
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    • pp.203-210
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    • 2019
  • Purpose: The purpose of this study was to verify the effect of the abutment superimposition process on the final virtual model in the scanning process of single and 3-units bridge model using a dental model scanner. Materials and methods: A gypsum model for single and 3-unit bridges was manufactured for evaluating. And working casts with removable dies were made using Pindex system. A dental model scanner (3Shape E1 scanner) was used to obtain CAD reference model (CRM) and CAD test model (CTM). The CRM was scanned without removing after dividing the abutments in the working cast. Then, CTM was scanned with separated from the divided abutments and superimposed on the CRM (n=20). Finally, three-dimensional analysis software (Geomagic control X) was used to analyze the root mean square (RMS) and Mann-Whitney U test was used for statistical analysis (${\alpha}=.05$). Results: The RMS mean abutment for single full crown preparation was $10.93{\mu}m$ and the RMS average abutment for 3 unit bridge preparation was $6.9{\mu}m$. The RMS mean of the two groups showed statistically significant differences (P<.001). In addition, errors of positive and negative of two groups averaged $9.83{\mu}m$, $-6.79{\mu}m$ and 3-units bridge abutment $6.22{\mu}m$, $-3.3{\mu}m$, respectively. The mean values of the errors of positive and negative of two groups were all statistically significantly lower in 3-unit bridge abutments (P<.001). Conclusion: Although the number of abutments increased during the scan process of the working cast with removable dies, the error due to the superimposition of abutments did not increase. There was also a significantly higher error in single abutments, but within the range of clinically acceptable scan accuracy.

Changes in occlusal force depending on the movement of the adjacent and opposing teeth after loss of lower first molar: comparative study by using a strain gauge (하악 제1대구치 상실 시 인접 및 대합 치아들의 이동양상에 따른 교합력 변화: 스트레인게이지를 이용한 비교 연구)

  • Song, Myoung-Ja;Park, Ji-Man;Chun, Youn-Sic
    • Journal of Dental Rehabilitation and Applied Science
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    • v.32 no.1
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    • pp.47-59
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    • 2016
  • Purpose: The aim of this study was to investigate the changes in occlusal force after loss of the lower first molar depending on the inclination and extrusion of the adjacent and opposing teeth by using a strain gauge. Materials and Methods: Anatomic teeth were used to reconstruct the normal dental arch with loss of the lower right first molar. A uniformly thick layer of silicone was applied to the root to mimic the periodontal ligament. Four stages of dies with varying degrees of inclination and extrusion of the adjacent and opposing teeth were constructed and attached to master model interchangeably by using a CAD/CAM fabricated customized die system. The strain gauges were attached to teeth and a universal testing machine was used to determine the changes in occlusal force. An independent t-test and one-way ANOVA were performed (${\alpha}=.05$). Results: While simulating chewing food, the upper first, second premolar and lower second molar showed greater occlusal force than before extraction. When the change of adjacent teeth's occlusal force with their progressive movement after molar loss was evaluated, the difference among four die models was significant and was in the decreasing aspect (P < 0.05). Conclusion: When the lower first molar was lost and the adjacent teeth did not move yet, the occlusal force in adjacent teeth was higher than that when the lower first molar still existed. In addition, the occlusal force in the upper premolars and lower second molar decreased significantly with the progressive movement of adjacent teeth.

Fabrication and densification of magnetic α-Fe/Al2O3 nanocomposite by mechanical alloying (기계적합금화에 의한 α-Fe/Al2O3 자성 나노복합재료의 제조 및 치밀화)

  • Lee, Chung-Hyo;Kim, Han-Woong
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.23 no.6
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    • pp.314-319
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    • 2013
  • Fabrication of nanocomposite material for the $Fe_2O_3-Al$ system by mechanical alloying (MA) has been investigated at room temperature. It is found that ${\alpha}-Fe/Al_2O_3$ nanocomposite powders in which $Al_2O_3$ is dispersed in ${\alpha}-Fe$ matrix are obtained by mechanical alloying of $Fe_2O_3$ with Al for 5 hours. The change in magnetization and coercivity also reflects the details of the solid state reduction process of hematite by pure metal of Al during mechanical alloying. Densification of the MA powders was performed in a spark plasma sintering (SPS) machine using graphite dies at $1000^{\circ}C$ and $1100^{\circ}C$ under 60 MPa. Shrinkage change after SPS of MA'ed sample for 5 hrs was significant above $700^{\circ}C$ and gradually increased with increasing temperature up to $1100^{\circ}C$. X-ray diffraction result shows that the average grain size of ${\alpha}-Fe$ in ${\alpha}-Fe/Al_2O_3$ nanocomposite sintered at $1100^{\circ}C$ is in the range of 180 nm. It can be also seen that the coercivity (Hc) of SPS sample sintered at $1000^{\circ}C$ is still high value of 88 Oe, suggesting that the grain growth of magnetic ${\alpha}-Fe$ phase during SPS process tend to be suppressed.

A Study for the Improvement of the Life Cycle of Press Die using Wire Cut Discharge Machining (와이어 컷 방전가공 시 프레스금형 수명 향상에 대한 고찰)

  • Yun, Jae-Woong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.9
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    • pp.61-67
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    • 2017
  • Research into the selection of suitable materials and the development of fast processing methods for press die manufacturing is absolutely necessary to reduce the production time and cost. In particular, knowledge of its heat properties must be considered whendeveloping a long press die. Generally, as the main component materials of press dies, Cr, W low alloy tool steel, high carbon-high chrome steel, high speed steel, etc., are used as thetooling steel for the cold die. Machine tools and wire-cut electric discharge machining are mainly used for processing the press die parts. There are many differences in the machining time and life cycle of die parts depending on the machining process. The parts produced by milling and grinding have a high manufacturing time and cost with a long life cycle, while thosemade by milling and wire-cut discharge machining have areduced manufacturing time and cost,whereastheir die life cycle is reduced. Therefore, in this study, we will discuss amethod of improving the life cycle of the die parts by using heat treatment as a processing method that reduces the manufacturing time and cost. SEM, EDS analysis and the surface roughness analysis of the surface and center of the workpiece are used for analyzing the specimens produced by three machining methods, viz. milling - grinding, milling - wire cut discharge, and milling - wire cut discharge - heat treatment. A method of making die parts having the same life cycle as those produced by milling - grinding is developed with the milling - wire cut discharge - high temperature tempering method.

Evaluation of marginal and internal gaps of Ni-Cr and Co-Cr alloy copings manufactured by microstereolithography

  • Kim, Dong-Yeon;Kim, Chong-Myeong;Kim, Ji-Hwan;Kim, Hae-Young;Kim, Woong-Chul
    • The Journal of Advanced Prosthodontics
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    • v.9 no.3
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    • pp.176-181
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    • 2017
  • PURPOSE. The purpose of this study was to evaluate the marginal and internal gaps of Ni-Cr and Co-Cr copings, fabricated using the dental ${\mu}-SLA$ system. MATERIALS AND METHODS. Ten study dies were made using a two-step silicone impression with a dental stone (type IV) from the master die of a tooth. Ni-Cr (NC group) and Co-Cr (CC group) alloy copings were designed using a dental scanner, CAD software, resin coping, and casting process. In addition, 10 Ni-Cr alloy copings were manufactured using the lost-wax technique (LW group). The marginal and internal gaps in the 3 groups were measured using a digital microscope ($160{\times}$) with the silicone replica technique, and the obtained data were analyzed using the non-parametric Kruskal-Wallis H test. Post-hoc comparisons were performed using Bonferroni-corrected Mann-Whitney U tests (${\alpha}=.05$). RESULTS. The mean (${\pm}$ standard deviation) values of the marginal, chamfer, axial wall, and occlusal gaps in the 3 groups were as follows: $81.5{\pm}73.8$, $98.1{\pm}76.1$, $87.1{\pm}44.8$, and $146.8{\pm}78.7{\mu}m$ in the LW group; $76.8{\pm}48.0$, $141.7{\pm}57.1$, $80.7{\pm}47.5$, and $194.69{\pm}63.8{\mu}m$ in the NC group; and $124.2{\pm}52.0$, $199.5{\pm}71.0$, $67.1{\pm}37.6$, and $244.5{\pm}58.9{\mu}m$ in the CC group. CONCLUSION. The marginal gap in the LW and NC groups were clinically acceptable. Further improvement is needed for CC group to be used clinical practice.

THE FRACTURE RESISTANCE AND STRESS DISTRIBUTION OF ALL CERAMIC CROWNS WITH TWO TYPES OF FINISH LINE ON MAXILLARY CENTRAL INCISOR (상악중절치에서 전부도재관의 finish line형태에 따른 파절강도와 응력 분포에 관한 연구)

  • Ki Tae-Seok;Kim Kyea-Soon;Lee Jin-Han;Kim Yu-Lee;Dong Jin-Keun
    • The Journal of Korean Academy of Prosthodontics
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    • v.41 no.4
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    • pp.405-420
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    • 2003
  • Purpose : The purpose of this study was to compare the fracture resistance of the IPS Empress ceramic crown with 1.0mm width rounded shoulder, which is usually recommended in all ceramic crown. and 0.5mm width chamfer finish lines on the maxillary central incisor. Material and method : After 15 metal dies were made for each group, the IPS Empress all ceramic crowns were fabricated and cemented with resin cement(Bistite resin cement, Tokuyama Soda Co. LTD., Japan) on the metal die. The cemented crowns were mounted on the positioning jig and the universal testing machine(Zwick Z020, Zwick Co. Germany)was used to measure the fracture strength with loading on the incisal edge. And also, three-dimensional finite element stress analysis was used to measure the stress distribution with the various types of the finish lines(1.0mm width rounded shoulder, 0.5mm width chamfer), the loading site(incisal edge, incisal $\frac{1}{3}$) and the type of loading(concentration loading, distribution loading). Results and conclusion : 1. In the fracture resistance experiment according to the finish line, the mean fracture strength of rounded shoulder(876N) and the mean fracture strength of chamfer(882N) did not skew any significant difference between each other(p>0.05). 2. The stress distribution of all ceramic crown in three dimensional finite element analysis showed concentration aspect at loading point and cervical area or labial surface. 3. In metal die, there were no differences in stress distribution between finish lines, but in natural teeth model, chamfer finish line showed higher stress than rounded shoulder finish line. 4. When force was loaded on the incisal edge the stress was concentrated on the incisal edge and the cervical area of labial surface. When force was loaded on the incisal $\frac{1}{3}$, the stress concentrated on the cervical area of labial surface and the cingulum area. 5. Generally, natural teeth model showed higher and various stress than the metal die.

MARGINAL FIT RELATED TO MARGIN TYPES OF GLASS INFILTRATED ALUMINA CORE FABRICATED FROM AQUEOUS-BASED ALUMINA TAPE

  • Oh, Nam-Sik;Yu, Byeung-Su;Kim, Il-Kyu;Choi, Jin-Ho;Kim, Dae-Joon;Park, Il-Seok;Lee, Myung-Hyun;Lee, Keun-Woo
    • The Journal of Korean Academy of Prosthodontics
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    • v.40 no.3
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    • pp.262-268
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    • 2002
  • Statement of problem. In-Ceram system is one of the all-ceramic crowns that can be used in anterior 3 unit fixed partial dentures and posterior single crowns. The alumina core used in In-Ceram system is manufactured using slip-casting technique. The slip-casting technique is difficult and technique sensitive. To improve this problem, tape-casting method was introduced into dentistry. There were no studies to examine the effect of margin design on the margin fitness of all-ceramic crowns fabricated from alumina tape. Purpose. The purpose of this study was to compare the marginal fitness of glass infiltrated alumina core fabricated from aqueous-based alumina tape according to different margin types ($90^{\circ},\;110^{\circ},\;135^{\circ}$ shoulder margin). Material and method. Three upper central resin incisors were prepared with $90^{\circ},\;110^{\circ}$, and $135^{\circ}$ shoulder margins for all-ceramic crowns, respectively. The resin teeth were duplicated and master die and special plaster die were made as usual. After alumina cores were fabricated from aqueous-based alumina tape, cores were cemented to each 15 epoxy dies replicated from three resin teeth with resin cement. These cemented cores were embedded in epoxy resin. Specimens were cut mesiodistally and buccolingually. Marginal gap and discrepancy were measured under microscope. Results. The marginal gap and discrepancy of $90^{\circ}$ marginal angle was $75.1{\mu}m,\;86.6{\mu}m,\;110^{\circ}$ marginal angle was $41.5{\mu}m,\;50.7{\mu}m$ and $135^{\circ}$ marginal angle was $51.7{\mu}m,\;54.2{\mu}m$, respectively. The smallest value was seen in 110 (angle, which was statistically significant compared to that of $90^{\circ}$ angle (p<0.05). Conclusion. Marginal fitness of alumina cores made of alumina tape with $110^{\circ}$ shoulder margin was best and others were clinically acceptable.

Effects of temperature on the growth and ingestion rates of the newly described mixotrophic dinoflagellate Yihiella yeosuensis and its two optimal prey species

  • Kang, Hee Chang;Jeong, Hae Jin;Lim, An Suk;Ok, Jin Hee;You, Ji Hyun;Park, Sang Ah;Lee, Sung Yeon;Eom, Se Hee
    • ALGAE
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    • v.35 no.3
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    • pp.263-275
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    • 2020
  • Water temperature is known to affect the growth and feeding of marine dinoflagellates. Each dinoflagellate species grows well at a certain optimal temperature but dies at very cold and hot temperatures. Thus, changes in water temperatures driven by global warming and extremely high or low temperatures can affect the distribution of dinoflagellates. Yihiella yeosuensis is a mixotrophic dinoflagellate that can feed on only the cryptophyte Teleaulax amphioxeia and the chlorophyte Pyramimonas sp. Furthermore, it grows fast mixotrophically but rarely grows photosynthetically. We explored the direct and indirect effects of water temperature on the growth and ingestion rates of Y. yeosuensis feeding on T. amphioxeia and the growth rates of T. amphioxeia and Pyramimonas sp. under 7 different water temperatures (5-35℃). Both the autotrophic and mixotrophic growth rates of Y. yeosuensis on T. amphioxeia were significantly affected by temperature. Under the mixotrophic and autotrophic conditions, Y. yeosuensis survived at 10-25℃, but died at 5℃ and ≥30℃. The maximum mixotrophic growth rate of Y. yeosuensis on T. amphioxeia (1.16 d-1) was achieved at 25℃, whereas the maximum autotrophic growth rate (0.16 d-1) was achieved at 15℃. The maximum ingestion rate of Y. yeosuensis on T. amphioxeia (0.24 ng C predator-1 d-1) was achieved at 25℃. The cells of T. amphioxeia survived at 10-25℃, but died at 5 and ≥30℃. The cells of Pyramimonas sp. survived at 5-25℃, but died at 30℃. The maximum growth rate of T. amphioxeia (0.72 d-1) and Pyramimonas sp. (0.75 d-1) was achieved at 25℃. The abundance of Y. yeosuensis is expected to be high at 25℃, at which its two prey species have their highest growth rates, whereas Y. yeosuensis is expected to be rare or absent at 5℃ or ≥30℃ at which its two prey species do not survive or grow. Therefore, temperature can directly or indirectly affect the population dynamics and distribution of Y. yeosuensis.

SCANNING ELECTRON MICROSCOPIC STUDY OF THE JUNCTION BETWEEN GOLD INLAYS AND GINGIVAL CAVOSURFACE MARGINS (금인레이의 치은변연적합도에 관한 주사전자 현미경적 연구)

  • Park, Joon-Il;Kown, Hyuk-Choon
    • Restorative Dentistry and Endodontics
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    • v.16 no.2
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    • pp.43-61
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    • 1991
  • Present - day inlay casting procedures have been developed for more than 100 years and experimentation has focused on the perfect adaptation to the cavity preparation. Marginal adaptation is considered to be an important indicator of the acceptability of the cast restotration, especially on the gingival margin. The purpose of this study was to evaluate the effects of a dissecting microscope and burnishing on vertical discrepancies, horizontal discrepancies, and cement thicknesson master die. Extracted premolars were prepared for class II gold inlays and master dies were made with conventional techniques. The experiments consisted of 4 groups. Group 1 : unaided eye, no burnishing on master die. Group 2 : unaided eye, burnishing on master die. Group 3 : microscope, no burnishing on master die. Group 4 : microscope, burnishing on master die. Cemented inlays were embedded in the hard resin and sectioned with microcutter through the gingival margins. The sectioned surfaces were polished with emery paper and finally with aluminum oxide powders. The results of the experiments were measured for vertical discrepancies, horizontal discrepancied and cement thickness under the scanning electron microscpe at the beveled gingival margin. The results of the study were summarized as follows. 1. Group 1 showed the vertical discrepancies of $81.6{\mu}m({\pm}48.6{\mu}m)$, horizontal discrepancies of $60.1{\mu}m({\pm}41.1{\mu}m)$, and cement thickness of $59.6{\mu}m({\pm}24.6{\mu}m)$. 2. Group 2 showed the vertical discrepancies of $78.6{\mu}m({\pm}30.9{\mu}m)$, horizontal discrepancies of $36.9{\mu}m({\pm}20.7{\mu}m)$, and cement thickness of $54.0{\mu}m({\pm}21.6{\mu}m)$. 3. Group 3 showed the vertical discrepancies of $57.5{\mu}m({\pm}26.4{\mu}m)$, horizontal discrepancies of $28.4{\mu}m({\pm}17.5{\mu}m)$, and cement thickness of $37.2{\mu}m({\pm}17.4{\mu}m)$. 4. Group 4 showed the vertical discrepancies of $56.7{\mu}m({\pm}35.0{\mu}m)$, horizontal discrepancies of $31.8{\mu}m({\pm}24.2{\mu}m)$, and cement thickness of $45.6{\mu}m({\pm}19.8{\mu}m)$. 5. Vertical discrepancies were not significantly different at any groups(p>.050). 6. Microscope groups(Group 3, 4) showed significantly improved horizontal marginal adaptation (p<.050). 7. Although cement thickness showed the subset of Group 3. 4, 2 and Group 4, 2, 1. Group 3 showed significantly smaller thickness than Group l(p<.050). 8. Finishing and polishing by means of a microscope produced significantly smaller discrepancies than doing so with the unaided eye(p<.050).

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