• The Journal of Korean Academy of Prosthodontics
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• v.43 no.3
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• pp.352-362
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• 2005

Statement of problem. Accurate impression is essential to success of implant prostheses. But there have been few studies about the accuracy of fixture-level impression techniques in internal connection implant systems. Purpose. The purpose of this study was to compare the accuracy of two fixture-level impression techniques in two conditions (parallel and divergent) and to assess the effect of tightening sequences and forces on stresses generated on superstructures in internal connection implant system (Astra Tech). Material and methods. Two metal master frameworks made from two abutments (Cast-to Abutment ST) each and a corresponding, passively fitting, dental stone master cast with four fixture replicas (Fixture Replica ST) were fabricated. Ten dental stone casts for each impression techniques (direct unsplinted & splinted technique) were made with vinyl polysiloxane impressions from the master cast. Strain gauges for each framework were fixed midway between abutments to measure the degree of framework deformation on each stone cast. Pairs of strain gauges placed opposite each other constituted one channel (half Wheatstone bridge) to read deformation in four directions (superior, inferior, anterior, and posterior). Deformation data were analyzed using one-way ANOVA and the Tukey test at the .01 level of significance. And the effect of tightening sequences (right-to-left and left-to-right) and forces (10 Ncm and 20 Ncm) were assessed with ten stone casts made from parallel condition by the splinted technique. Deformation data were analyzed using paired t-test at the .01 level of significance. Conclusions. Within the limitations of this study, the following conclusions could be drawn. 1. Frameworks bent toward the inferior side on all casts made by both direct unsplinted and splinted impression techniques in both parallel and divergent conditions. 2. There was no statistically significant difference of accuracy between the direct unsplinted and splinted impression techniques in both parallel and divergent conditions (P>.01). 3. There was no statistically significant difference of stress according to screw tightening sequences in casts made by the splinted impression technique in parallel condition (P>.01). 4. Greater tightening force resulted in greater stress in casts made by the splinted impression technique in parallel condition (P<.01).

• Korean Journal of Poultry Science
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• v.19 no.1
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• pp.47-53
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• 1992

This study was carried out to determine the plasma vitamin $D_3$($D_3$) of 3 weeks old broiler chicks (Hubbard line), whose dorsal skin was exposed to different dose of 310 m UV light. The irradiated doses were 0~0.79 J/$\textrm{cm}^2$(6 doses$\times$5 replica＝30 chicks). The blood samples were collected 2 days after exposure. The lipid in plasma isolated was extracted with ethyl acetate. The $D_3$ was purified by $C_{18}$ cartridge and analyzed by HPLC. The average $D_3$ content in plasma of control chicks was 20 ng /$m\ell$. When 0.32 J/$\textrm{cm}^2$ of dose was treated, the highest amount of 43 ng /$m\ell$ was found among those of chicks experimented, corresponding to 2.15 times that of control. However, When more doses than 0.32 J/$\textrm{cm}^2$ were exposed to the skin, D$_3$ contents were decreased gradually. The similar to control level of $D_3$ was observed when 0.79 J/$\textrm{cm}^2$ was applied.

• Journal of the Korean Vacuum Society
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• v.16 no.6
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• pp.463-467
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• 2007

Structure and optical properties of ZnO epilayers grown on oxygen- and hydrogen-plasma treated sapphire substrates by plasma-assisted molecular beam epitaxy (denoted as samples A and B, respectively) have been investigated by various techniques. The crystal quality and structural properties of the surface for the ZnO epilayers were investigated by high-resolution X-ray diffraction and atomic force microscope. For investigating the optical properties of excitonic transition of ZnO, we carried out photoluminescence experiments as a function of temperature. The free exciton, bound exciton emission and their phonon replicas were investigated as a function of temperature from 10 to 300 K, and the intensity of excitonic PL peak emission from the sample A is found to be higher than that of sample B. From the results, we found that sample A has better crystal structure quality and optical properties as compared to sample B. The number of oxygen vacancies may be decreased in sample A, resulting in an enhancement of the crystal quality and a higher intensity of excitonic emission band as compared to sample B.

• Archives of design research
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• v.18 no.1 s.59
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• pp.5-16
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• 2005

As for the public, it is hard to understand semiotics because of the scope of an enormous semiotics education. This study is making semiotics of Charles Sanders Peirce the subject. I thought that utilization can hold his semiotics study in a visual design field. First of all, this study considered design related papers related to the existing semiotics again and study found an error of the existing semiotics study and understanding did category concept with re-definition about semiotics of Peirce. Explained a symbol mark through understanding of semiotics of Peirce. This study was able to get the following conclusion through these results. 1) A symbol mark means one product, sonics, company oneself with a custom. Therefore, it is a rule symbol in the Representation side. 2) A symbol mark symbolizes an object with one symbol, so a symbol mark is a symbol in an object. 3) Because a symbol mark exists through a social rule, in semiotics definition of Peirce, this must become understanding with a Argument symbol. 4) A symbol mark is what a company or an organization field used from the past, and the public are recognizing this how. Therefore, it works as fact a company attaches a symbol mark to own product, and to show the public a symbol mark. A symbol mark is Dicent Sign in Interpretant. A rule and understanding about a lot of types which have various mutual relation, Peirce classification and understanding of a symbol mark tells to demand is holding that understanding a type of semiotics with the concept that is not an image to us.

• The Journal of Art Theory & Practice
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• no.2
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• pp.169-190
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• 2004

The purpose of this article is to delve into the problems of originality of the artwork by examining issues of reproduction within the contemporary art market. In contemporary arts, especially in terms of art production and consumption, we can't overlook society and its economic structure and its connection with of capitalism. As the purity of art creation has turned into an exchange value, art, especially an object as artwork, has fallen into the status of production in an economic marketing system. Walter Benjamin mainly referred to that point in his thesis Das Kunstwerk im Zeitalter seiner technischen Reproduzierbarkeit, which originated the sociology of plastic arts. This thesis, published in 1936, traced how the artistic functions of photograph and movie had been changed through the social development. His main concerns were movie and photograph but what I am concentrating from his point of view, is that even in the field of plastic arts, the manufacture of reproduction has been practiced as a primary method within the social and political contexts and development. Though I am referring to this in the main body of this article, reproduction in contemporary art strongly needs a new definition since it has been spread all over like a newest virus, not only by collector's personal taste or hut also by commercial circulations of these reproductions to the public. This relates to Benjamin's argument about the value of an exhibition at a museum(Ausstellungswert). Since the function of an artwork has been one of cultural industry, the manufacturing of reproduction raises unexpected problems, such as, the originality of the artwork, the value of an exhibition at a museum, its achievement as documentary and as a territory of art criticism. In this point of view, I want to inquire into the value and criteria of an exhibition in contemporary art through the review of the definitions and the intrinsic attributes of reproduction. Somehow in a broad sense, the reproduction is a product coming out of representation or copy (replica) of an original art work or an model. Therefore, the problems it presents differ from the Simulacre, which is an image without an original one. In terms of the Meanings of reproduction, we can distinguish it as reproductions, copies, and productions. These types of reproductions are not the original artworks reflected by the creative intention of the artists. For example, a publishing company reproduced some of lithographs of Salvador Dali in the 1960s. They are commercial copies in the form of representation or reproduction with no artistic and creative intention of the artist. However, In despite of this theoretical basis, reproductions of the famous artists are still displayed without any verification for of the public's quest for the artworks. Moreover, many commercial companies that are planning to exhibit art works of the world-famous artists only for their profits keep trying to speak ill of and judging by the law the honest art critics' articles which discuss the true values of exhibition. If freedom of expression is one of the ideals of democracy, even the judgment of the originality of the artworks should be freely expressed.

• The KIPS Transactions:PartC
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• v.15C no.3
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• pp.157-166
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• 2008

The ubiquitous service environment is poor in reliability of connection and also has a high probability that the intrusion against a system and the failure of the services may happen. Therefore, It is very important to guarantee that the legitimate users make use of trustable services from the viewpoint of security without discontinuance or obstacle of the services. In this paper, we point out the problems in the standard Jini service environment and analyze the Jgroup/ARM framework that has been developed in order to help fault tolerance of Jini services. In addition, we propose a secure Jini service architecture to satisfy the security, availability and quality of services on the basis of the analysis. The secure Jini service architecture we propose in this paper is able to protect a Jini system not only from faults such as network partition or server crash, but also from attacks exploiting flaws. It provides security mechanism for dynamic trust establishment among the service entities. Moreover, our secure Jini service architecture does not incur high computation costs to merge the user service states because of allocation of the replica based on each session of a user. Through the experiment on a test-bed, we have confirmed that proposed secure Jini service architecture is able to guarantee the persistence of the user service states at the level that the degradation of services quality is ignorable.

• Korean Journal of Materials Research
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• v.22 no.1
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• pp.46-53
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• 2012

In this study, mechanical tests and microstructural analyses including TEM analyses with EDX of precipitates in modified 9Cr-1Mo steel were carried out to determine the cause of embrittlement observed after heat-treatment, which limits the usage of the alloy for power plants. Mod. 9Cr-1Mo steel specimens at austenite temperature were quenched to the molten salt baths at $760^{\circ}C$ and $700^{\circ}C$, in which the specimens were kept for 10 min ~ 10 hr with subsequent air-cooling. Impact tests showed that the impact value dropped abruptly when the specimens were kept longer than 30 min at $\sim760^{\circ}C$ reaching to minima in about 1 hr, and then increasing at further retention. The tensile strength of the specimens reached the minimum value without much change afterward, whereas the values of elongation showed the same trend as that of the impact value. The isothermally heat-treated steel at $700^{\circ}C$ also showed a minimum impact value in about 1 hr. These results suggest that the isothermal heattreatment at 760 and $700^{\circ}C$ for about 1 hr induces temporal embrittlement in Mod. 9Cr-1Mo steel. The microstructural examination of all the specimens with extraction replica of the carbides revealed that the specimens with temporal embrittlement had $Cr_2C$, indicating that the cause of the embrittlement was the precipitation of the $Cr_2C$. In addition, TEM/EDX results showed that the Fe/Cr ratio was 0.033 to 0.055 for $Cr_2C$, whereas it was 0.48 to 0.75 for $Cr_{23}C_6$, making the distinction of the $Cr_2C$ and $Cr_{23}C_6$ possible even without direct electron diffraction analyses.

• Journal of Technologic Dentistry
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• v.39 no.2
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• pp.75-82
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• 2017

Purpose: This study provided the basic data for selection the zirconia block and CAM by means of marginal fitness observations, flexural strength test and hardness test. Methods: Three dental zirconia blocks(ABCera, NaturaZ, ST98) and two dental milling machines(CAD/CAM MS, DWX-50) were used in this study. Metal abutment(diameter 10 mm, height 5 mm, inclined angle $3^{\circ}$ taper, 1 mm chamfer margin) was fabricated by Ti customized abutment, and then zirconia copings were fabricated for each ten specimens. Silicone replica technique was used to observe the marginal fitness of cross-sections with a stereomicroscope at ${\times}50$ magnification. The dental zirconia blocks was cut into 10 pieces each having a size of $25mm{\times}5mm{\times}1mm$, and fabricated according to the manufacturer's instructions, and flexural strength was measured using a universal testing machine. For hardness test, a micro Vickers hardness tester was used as it was in the flexural strength test. Statistical analysis was performed by one way ANOVA and post-test was performed by Scheffe test. Results: For marginal fitness of bucco-lingual axial, ZU group($59.7{\pm}10.3{\mu}m$) was the lowest, followed by RA, ZA, ZD, RD, RU. For marginal fitness of mesio-distal axial, ZU group($59.3{\pm}10.2{\mu}m$) was the lowest, followed by RA, ZA, RD, ZD, RU. One-way ANOVA showed statistically significant difference between groups(p<0.05). For flexural strength, ABCera block($718.0{\pm}57.2MPa$) was the highest, followed by NaturaZ, ST98. For hardness, ABCera block($1550.3{\pm}19.8Hv$) was the highest, followed by ST98, NaturaZ. There was no significant difference in flexural strength and hardness between blocks(p>0.05). Conclusion: Based on the results of this study, the type of dental zirconia block did influence the marginal fitness, and all dental zirconia blocks are expected to be suitable for clinical application. The highest flexural strength and hardness were ABCera block, and no statistically significant difference was observed.

• Journal of fish pathology
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• v.11 no.2
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• pp.143-150
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• 1998

Characteristics and distribution of the natural commensal flora in the surrounding environment and tissues of clam in Hadong area were studied under varying conditions of growth media and incubation temperatures. Total numbers of bacteria present in intestinal tract, gill, body fluid and surrounding mud were found to be not influenced by the used BHIA, STA and SNA media. Although the growth rate of bacteria at the condition of $15^{\circ}C$ incubation temperature was slower than that of $25^{\circ}C$ and $35^{\circ}C$, it showed the highest number of total bacteria compared with other two different conditions of incubation temperature. Interestingly, the proportion of bacteria able to form colony on several selective media was higher in replica analysis from nutrient media to selective media than that in direct smearing from samples. The generic diversity of bacteria isolated from the tissues and analyzed by API 20E and API 20NE kit showed similar pattern with each other and distinct from that of environment. The distribution of bacteria in the surrounding mud or mantle fluid of clam indicated a high diversity comparable to that found for the gill or intestinal tract microflora, with Pseudomonas being the prevalent group. It implies that the tissues of clam may probide a selective habitat for a commensal microflora.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.448-453
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• 2017

The purpose of this study was to compare the marginal discrepancy of coping crowns according to manufacturing method and materials by using the CAD/CAM system to compare the optimum manufacturing method and materials. The coping crowns were fabricated by using manufacturing methods and materials, and marginal fit was measured using the replica technique. For comparative analysis of manufacturing methods and materials, analysis of variance was performed. One-way ANOVA was performed to compare and analyze different mean values. For the milling method of the alloy, 114.6 was obtained for the MM group, 111.4 for the MS group, 67.2 for the MSC group, and 50.9 for the MSS group, respectively, using the milling/sintering method. In the milling/sintering method of ceramic, 35.6 and 36.3, respectively, were obtained for the SLME group and SLMR group, respectively. However,there was a significant difference according to the material. The milling/sintering method of the ceramic material gave the lowest value, and it was verified by the optimal method. However, marginal discrepancy of coping crowns fabricated using the CAD/CAM system is applicable to the clinic since it corresponds to acceptable numerical values in clinical practice.