• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.6
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• pp.43-49
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• 2004

Electric pulp test is a method to examine the vitality of dental pulp using physical and chemical stimulation. During the pulp test, the current stimulates intradental nerve, and it makes patients painful. In this paper, we measured each activating response EMG in anterior belly of digastric muscle, voice, and finger movement during the pulp test by increasing stimulus intensity gradually. We also measured excessive stimulus time from the activating responses (EMG, voice, and finger movement) to the end of the stimulation. We measured and analyzed excessive stimulus time for each stimulus detecting method. As a result, we developed automatic stimulus breaker using the human responses to stimulus during electric pulp test. We reduced the excessive stimulus time by disconnecting the pulp tester stimulus output rapidly in 10 ms after activating human response.

• The Journal of Advanced Prosthodontics
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• v.1 no.1
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• pp.41-46
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• 2009

STATEMENT OF PROBLEM. The poor chemical bonding of a denture base resin to cast titanium framework often introduces adhesive failure and increases microleakage. PURPOSE. This study evaluated the shear bond strengths of a heat cure denture base resin to commercially pure titanium, Ti-6Al-4V alloy and a cobalt-chromium alloy using two adhesive primers. MATERIAL AND MATHODS. Disks of commercially pure titanium, Ti-6Al-4V alloy and a cobalt-chromium alloy were cast. Specimens without the primer were also prepared and used as the controls. The shear bond strengths were measured on a screw-driven universal testing machine. RESULTS. The primers significantly(P < .05) improved the shear bond strengths of the heat cure resin to all metals. However, the specimens primed with the Alloy $primer^{(R)}$(MDP monomer) showed higher bond strength than those primed with the MR $bond^{(R)}$(MAC-10 monomer) on titanium. Only adhesive failure was observed at the metal-resin interface in the non-primed specimens, while the primed specimens showed mixed failure of adhesive and cohesive failure. CONCLUSIONS. The use of appropriate adhesive metal primers makes it possible not only to eliminate the need for surface preparation of the metal framework before applying the heat cure resins, but also reduce the need for retentive devices on the metal substructure. In particular, the Alloy $primer^{(R)}$, which contains the phosphoric acid monomer, MDP, might be clinically more acceptable for bonding a heat cure resin to titanium than a MR $bond^{(R)}$, which contains the carboxylic acid monomer, MAC-10.

• Clinical and Experimental Reproductive Medicine
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• v.38 no.2
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• pp.75-81
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• 2011

Objective: Bisphenol A (BPA) is a chemical used extensively to manufacture plastics and epoxy resin liners for food and beverage cans. BPA, with properties similar to estrogen, has endocrine-disrupting effects. In the present study, we examined the effects of early prepubertal BPA exposure on the onset of puberty and reproductive parameters such as estrous cycle and reproductive organ weights in female mice. Methods: Female mice were injected subcutaneously at postnatal day (PND) 8 with BPA (0.1, 1, 10, 100 mg/kg) in sesame oil or with sesame oil alone. Body weight was measured from PND 10 to 70. Vaginal opening and estrous cycle were monitored from PND 20 to 29. Animals were sacrificed at PND 25, 30, and 70, and the ovary and uterus weights were measured. Results: Early prepubertal exposure to BPA (10 and 100 mg/kg) significantly decreased body weight from PND 18 to 30. BPA treated mice at testing dose levels showed early opening of the vagina compared to the control group. The number of estrous cycle and days of estrus were significantly decreased in high dose (100 mg/kg) BPA treated mice. The ovary weight at PND 25 and 30 was significantly decreased in all BPA treatment groups. Conclusion: Early prepubertal exposure to BPA accelerated the onset of puberty but decreased reproductive parameters in female mice.

• Korean Journal of Materials Research
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• v.24 no.1
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• pp.48-52
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• 2014

The Mg-enriched magnesium aluminum silicate (MAS) glass is known for its higher mechanical strength and chemical resistance. Among such glasses, cordierite ($Mg_2Al_4Si_5O_{18}$) is well known to have a low thermal expansion and low melting point. Polycrystalline engineering ceramics such as alumina can be strengthened by a surface modification with low thermal expansion materials. The present study involves the synthesis of cordierite by a sol-gel process and investigates the effect of glass penetration on the surface of alumina. The cordierite powders were prepared from $Al(OC_3H_7)_3$, $Mg(OC_2H_5)_2$ and tetraethyl orthosilicate by hydrolysis and condensation reaction. The cordierite powders were characterized by X-ray diffraction (XRD, Rigaku), scanning electron microscope (SEM, JEOL: JSM-5610), energy dispersive spectroscopy (EDS, JEOL: JSM-5610), and universal testing machine (UTM, INSTRON). The X-ray diffraction patterns showed that the synthesized particles were ${\mu}$-cordierite calcined at $1100^{\circ}C$ for 1 h. The shape of synthesized cordierite was changed from ${\mu}$-cordierite to ${\alpha}$-cordierite with increasing calcination temperature. Synthesized cordierite was used for surface modification of alumina. Cordierite powders penetrated deeply into the alumina sample along grain boundaries with increasing temperature. The results of surface modification tests showed that the strength of the prepared alumina sample increased after surface modification. The strength of a surface modified with synthesized cordierite increased the most, to about 134.6MPa.

• Journal of Convergence for Information Technology
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• v.7 no.4
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• pp.75-81
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• 2017

The design trend of information technology is quickly changed with the times. The design trend of information display is a bezel-less display, recently. The bezel-less display or edge-less display is a new trend of mobile phone display. In this study, the shading tape was manufactured for assembling process of touch panel display with the high screen-to-body ratio so-called bezel-less display. The shading tape was fabricated on PET film with the UV curable acrylic pressure sensitive adhesive(PSA) by roll-to-roll process. The UV curable PSA was synthesized with the eco-friendly toluene-less manufacturing method. The adhesive power of manufactured shading tape was investigated by motorized tensile testing machine. The thixotropic, maintaining property of cutting shape, was characterized by field emission scanning electron microscope. As results, the shading tape exhibits high adhesive power and good thixotropic performance suitable for assembly process of touch panel display. The functional shading tape will be expected to improve productivity of assembly process of touch panel display.

• Journal of the Semiconductor & Display Technology
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• v.10 no.2
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• pp.115-119
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• 2011

A tip-type carbon nanotube(CNT)-based field emitter was studied to consider it as electron source for micro-focused x-ray tube. The CNT was grown directly on a metal (tungsten) substrate by using an inductively coupled plasma-chemical vapor deposition (ICP-CVD) method. Prior to CNT growth, the metal substrate was etched to have various tip angles from $10^{\circ}$ to $180^{\circ}C$ (flat-type). The morphologies and microstructures of all the grown CNTs were analyzed via field-emission SEM. Furthermore, the effects of substrate tip-angles on the emission properties of CNT-based field emitters were characterized to estimate the maximum current density, the turn-on voltage, and the spatial distribution of electron beams. Prolonged long-term stability testing of the CNT emitters was also performed. All the experiment results obtained from this study indicated why a tip-type CNT emitter, compared with a flat-type CNT emitter, would be more desirable for a micro-focused x-ray system, in terms of the emission current level, the focused beam area, and the emission stability.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.684-689
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• 2003

In previous paper, we isolated the bacteria, Bacillus subtilis JM-3, with proteolytic and fibrinolytic activity for candidate microorganisms that have rapid fermenting and physiological functions from anchovy sauce. This study was carried out to search physiological functions of Bacillus subtilis JM-3, such as antimicrobial, antioxidative, antimutagenic, angiotensin-converting enzyme inhibition, and anticarcinogenic activity in vitro. The cell free culture of Bacillus subtilis JM-3 showed strong antibacterial activity against Listeria monocytogenes, antioxidative activity with 87% of inhibition rate against linoleic acid, 50% of antimutagenic activity against N-nitrosodimethylamine and N-nitrosomorpholine, and 88.9% of growth inhibition rate against SNU-1 cell line (stomach cancer cell of human). However, Bacillus subtilis JM-3 did not show angiotensin-converting enzyme inhibition activity.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.4
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• pp.245-254
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• 2018

Impact of tropospheric correction techniques on accuracy of the GPS (Global Positioning System) derived ellipsoidal heights has been experimentally assessed in this paper. To this end, 247 baselines were constructed from a total of 88 CORS (Continuously Operating Reference Stations) in Korea. The GPS measurements for seven days, acquired from the so-called integrated GNSS (Global Navigation Satellite Systems) data center via internet connection, have been processed by two baseline processing software packages with an application of the empirical models, such as Hopfield, modified Hopfield and Saastamoinen, and the estimation techniques based on the DD (Double-Differenced) measurements and the PPP (Precise Point Positioning) technique; hence a total number of the baseline processed and tested was 8,645. Accuracy and precision of the estimated heights from the various correction schemes were analyzed about baseline lengths and height differences of the testing baselines. Details of these results are summarized with a view to hopefully providing an overall guideline of a suitable selection of the modeling scheme with respect to processing conditions, such as the baseline length and the height differences.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3587-3595
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• 2015

Low-carbon eco-friendly precast concrete (PC) box structure has been recently was developed as an low-cost infrastructure of near-surface transit system. The concrete of PC box was manufactured by industrial byproducts such as ground granulated blast furnace (GGBF) slag, flyash and rapid-cooling electric arc furnace (EAF) oxidizing slag, its mechanical property and durability were estimated in this study. Based on the mechanical and durability tests, it is found that low-carbon eco-friendly concrete shows high initial compressive strength, more than 90% of design strength (35MPa), and high resistance to salt-attack, chemical- attack and freeze-thaw. Therefore, low-carbon eco-friendly PC box concrete technology is expected to contribute to the railway with low environmental impact.

• Resources Recycling
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• v.23 no.4
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• pp.69-74
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• 2014

Slags generated in the smelting reduction of deep sea manganese nodule could be utilized as an additional materials for making Fe-Si-Mn alloys by mixing with cokes and re-smelting at an arc furnace. In this re-melting process slag is also generated, and the secondary slag is treated as waste. In this survey, recycling of the waste slag of Mn nodule was studied. It is tried to utilize the waste slag as ceramic materials or construction materials. However, it is difficult to use the waste slag directly as an additional material to ceramics such as portland cement or castable refractory material due to the much difference of chemical compositions. As an altercation road constructing material is considered, and toxicity on the soil of the waste slag was tested according to Korean Standard for testing permissible amount of toxic substances. The test result was satisfied with the requirements on the standard. So, it should be suggested that the waste slag of the Mn nodule could be utilized as constructing materials such as road filler or base materials.