• Journal of Technologic Dentistry
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• v.38 no.4
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• pp.281-290
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• 2016

Purpose: The increased aesthetic requirements and demands of patients have resulted in the developments of coloring liquid for zirconia. Methods: In this study, zirconia block was dipped into $Fe(NO_3)_3$solution, which showed a color and then concentration of $Fe(NO_3)_3$and zirconia's color and physical properties depending on the dipping time were observed and compared with exclusive coloring solutions. As the result, the following conclusions were obtained. Results: When compared with the specimens that were colored using exclusive solutions, $L^*$ value rose overall depending on the concentration of $Fe(NO_3)_3$and $a^*$ value was red in the form of (+) in all the specimens. Also, $b^*$ value was in the form of (+) at 0.5 to $1{\ss}fl$, but was in the form of (-) at 1.5 to $2{\ss}fl$. The dipping time did not highly influence $L^*$ value, but $a^*$ value and $b^*$ value were directly opposite to the specimens, which were not colored, except the sample that was dipped for only 2 seconds. When compared with exclusive coloring solutions, $Fe(NO_3)_3$had the most similar color at 0.5 to $1{\ss}fl$ and the longer the coloring time, the higher the rate of color change became. In relation to the density change depending on the addition of $Fe(NO_3)_3$, there was the lowest density at $2{\ss}fl$ and the density was increased in the specimens that were not colored. Conclusion: These results show that $Fe(NO_3)_3$solution can be used to make colored zirconia. It is expected that newly made colored zirconia can be used in clinical practice because the colored zirconia not only possesses the mechanical properties that all ceramic core material should have but also was biocompatible to a living cells.

• Journal of the Korea Society for Simulation
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• v.20 no.2
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• pp.59-66
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• 2011

In this paper, a method to allocate a submarine search mission to an ASW(Anti-Submarine Warfare) helicopter is proposed. The aim of the proposed method is to increase the submarine detection capability. For this purpose, we modeled the behaviors that the ASW helicopter conduct during the search mission, and the relations between the behaviors are also modeled. To measure quantitatively the effectiveness of ASW search mission, the measure of effectiveness(MOP) is defined. Scenarios are designed to analyze the effectiveness utilizing the ASW mission model. We conducted simulations applying the designed scenarios and some parameters concerned with the friendly ship and the enemy submarine interacting each other in the ASW missions. We analyzed the result of simulation depending on the dipping interval and the pattern of dipping positions in the situation that the helicopter operates for a long time and should resupply several times on the friendly ship. From the analyzed data, we suggested the practical value of ratio between the detectable range of the sonar and the dipping interval to improve the effectiveness of ASW mission.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.2
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• pp.190-200
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• 2021

Purpose. The aim of this study was to evaluate biaxial flexural strength and hardness of colored monolithic zirconia after dipping in different time intervals of coloring solution. Materials and Methods. Disk shaped specimens were prepared from monolithic zirconia (Eclipse V2.0, AMS, Gimpo, Korea). Four experimental groups were categorized (n = 12) due to coloring time (PU (0s); ST (8s); OV (1 min); PS (preshade)), to evaluate biaxial flexural strength and Vickers hardness. After fracture, X-ray diffraction analysis was performed using fractured specimens. Results were analyzed with one-way ANOVA test. Results. There was no significant difference between groups in the biaxial flexural strength test. However, in the Vickers hardness test, the group with standard dipping time (ST) showed significantly higher value than the group without dipping in coloring liquid (PU)(P=.038). Also, there was no significant difference in the rest of the groups (P>.05). As a result of X-ray diffraction analysis, specific peaks of tetragonal phase were shown and the volume of monoclinic phase fraction was lower than 25%. Conclusion. Although this study has several limitations, coloring liquids had no significant effect on biaxial flexural strength. Vickers hardness was significantly different between the group to which the coloring liquid was applied and the group to which the coloring solution was not applied, but there was no significant difference between the other groups. Also, the flexural strength of monolithic zirconia corresponds to Class 5 of the minimal flexural strength standard according to the use of dental ceramics.

• Geophysics and Geophysical Exploration
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• v.1 no.1
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• pp.19-24
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• 1998

This paper deals with tomographic travel time inversion of three dimensional seismic refraction survey conducted over a dipping interface. The slowness, and thus velocity as its reciprocal, distribution on the subsurface interface is to be determined applying an ART with under-relaxtion parameter. The models chosen are realistic, i.e., most likely to be met in engineering seismics, and the interface includes anomalous zones. It is found that, generally speaking, the inversion could be misleading or meaningless without the correction of the dip of the interface. This is rather surprising when we recall that usual assumption for the interpretation of refraction seismics data is the horizontal attitude of structures within the limit of $15^{\circ}$ dip or so. To make the present method tenable for a new means of routine seismics, some practical ways of identifying head wave arrivals are to be devised.

• Journal of Fisheries and Marine Sciences Education
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• v.22 no.4
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• pp.501-507
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• 2010

The ceramic contained paint was made to replace the lead sinker for gill-net with coated lead sinker. The ceramic contained paints were coated in various conditions on the lead sinker with 19g of weight and the optimal coating condition was studied. The adaptability of the coated lead sinker was checked through the anti durability test and fishing operation with gill-net. The case of "Main material 70 wt% + Urethane thinner 30 wt% (Main material 700 $m{\ell}$ + Thinner 300 $m{\ell}$)" showed the best in the coating characteristics depending on the combination ratio of the ceramic paint contained. The coated lead sinker dried at $100^{\circ}C$ inside oven was superior to the drying in the room temperature in its surface glossiness and anti durability and faster drying time than the one dried in normal temperature. The quadruple layers of coating on lead sinker with 4 times of dipping and drying application showed the super anti durability in the coating characteristics depending on the frequency of dipping. When press is applied to the coated lead sinker, the coated layer is not detached from the sinker. In addition, the coated lead sinker was not damaged or peeled at the fishing operation about 2 months in various depths within 50m and by the materials at the bottom (sand, stone and gravel stone) and it was in good condition.

• Food Science and Preservation
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• v.6 no.3
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• pp.276-280
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• 1999

To maintain the quality characteristics of vegetables, produce was dipped in Korean medical herb extracts (KMHE) such as Rheum palmatum L. or Coptis chinensis Franch with different concentration. Dipping in 500 ppm KMHE solution was suitable for the reduction or microbial load on cucumber, and 100 ppm KMHE solution was appropriate for others. Dipping time was suitable for produce about 10 minutes, and the temperature of dining solution had a limited effect cm the microbial load reduction. Antimicrobial activity of Coptis chinensis Franch and Rheum palmatum L. was maintained for cucumber and zucchini wrapped with polyvinylchloride film during storage at 10$^{\circ}C$.

• Journal of the Korean institute of surface engineering
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• v.50 no.6
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• pp.523-530
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• 2017

In this study, we developed the h-BN interphase for ceramic matrix composites (CMCs) through a wet chemical coating method, which has excellent price competitiveness and is a simple process as a departure from the existing high cost chemical vapor deposition method. The optimum condition for nitriding an h-BN interphase using boric acid and urea as precursors were derived, and the h-BN interphase coating through a wet method on a carbon preform of 2.5 D was conducted to apply the optimum conditions to the CMCs. In order to control the coating property via the wet coating method, four parameters were investigated such as dipping time of the specimen in the precursor solution, the ratio of boric acid and urea in the precursor, the concentration of solution where the precursor was dissolved, and the cycle of dipping and dry process. The CMCs was fabricated through polymer impregnation and pyrolysis (PIP) processes and a three-point flexural strength test was conducted to verify the role of the coated h-BN interphase.

• Journal of Korea Foundry Society
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• v.28 no.3
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• pp.119-123
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• 2008

Wear test on two die steels for aluminum die casting was carried out by dipping and rotating the specimens into the molten aluminum maintained $680^{\circ}C{\sim}780^{\circ}C$. The rotating speed of the specimen was $4.5rpm{\sim}20.0rpm$. Diffusion layer was formed between the die steel and molten aluminum, and became thicker with dipping time. Wear rate was not proportional with the thickness of the diffusion layer, but was closely related to the density of the diffusion layer. Wear rate was little affected by the kind of die steel and by the microstructure such as martensite, tempered martensite, and pearlite. Specimen with nitrided surface showed good wear resistance, and its wear rate was decreased with increase in the thickness of nitrided layer. While whole surface was worn in heat treated specimens, wear of nitrided specimens was proceeded by pitting partially.

• Journal of the Korean institute of surface engineering
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• v.20 no.4
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• pp.144-153
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• 1987

In the case of dipping the Ni-Resist cast iron into molten aluminum with iron content, the thickness of intermetallic compound was remarkably increased with increasing iron content. The thickness was shown by following equation in the range of 1-3% iron content; $x=22.5t^{1/2}+4.47{\cdot}t{\cdot}(Fe%)$. where, x is thickness(${\mu}m$), t the time (minute), Fe% the iron w/o. When the Ni-Resist cast iron was dipped into the molten aluminum containing zinc content, the intermetallic compound thickness was also increased with increasing zinc contents. And thickness was represented by the following equation in the range of 2-10% zinc content; $x=3.46t^{1/2}+0.27{\cdot}t{\cdot}(Zn%)$. However, in the case of dipping the Ni-resist cast iron into molten aluminum with silicon content, the thickness of intermetallic compound was decreased with increasing silicon content, as shown in the following equation; $x=7.17t^{1/2}-0.15{\cdot}t{\cdot}(Si%)$. The intermetallic compound formed onto Ni-Resist cast iron was identified to be $FeAl_3\;and\;Fe_3Al$. As the result of hardness measurement, the peak hardness appeared in the intermetallic compound at near interface of the cast iron and the compound.

• Journal of fish pathology
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• v.20 no.2
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• pp.139-145
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• 2007

To decrease stress in eel (Anguilla japonica) during its culture or transportation, aspirin (ASA) known as analgesic, antiinflammatory and antithrombic agent was administrated by dipping or oral routes. Concentrations of aspirin (ASA) and salicylic acid (SA) in eel plasma were simultaneously measured by a high performance liquid chromatography (HPLC). The plasma was acidified with 0.2 M HCl and 0.2 M orthophosphoric acid, and mixed with acetonitrile. ASA and SA extracted with acetonitrile were analyzed by the HPLC equipped with reversed phase Novapak C18 column (4 ㎛ silica, 150×4 mm) and UV detector(237 nm). The mobile phase consisted of 740 ㎖ water, 900 ㎕ orthophosphoric acid (85%) and 180 ㎖ acetonitrile. The retention times of ASA, SA and 2-methylbenzoic acid(MBA) were 4.8 min, 8.4 min and 11.5 min, respectively. The limit of quantification was 0.01 ㎍/㎖ for SA and 0.05 ㎍/㎖ for ASA. The mean recovery from eel plasma was 70.8～99.6% for ASA and 95.2～100.3% for SA. This HPLC method was applied to analyze ASA and SA of eel plasma after either dipping in a concentration of 20 ppm or feeding the feed supplemented with 50 ㎎/kg BW. Only SA was detected in eel plasma after the administration of ASA by dipping or oral routes because the drug was quickly decomposed into SA in eel plasma. The amount of SA in eel plasma reached the highest value at 3hr in dipping and 7 days in oral administration. When the ASA-administrated eel were kept in ASA free aquaria, 0.02-0.03 ㎍/㎖ of SA were detected 48 hr after the administration in both routes.