• Restorative Dentistry and Endodontics
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• v.35 no.6
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• pp.479-485
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• 2010

Objectives: The aim of this study was to compare the push-out bond strengths of resin cement/fiber post systems to post space dentin using different application methods of resin cement. Materials and Methods: Thirty extracted human premolars were selected and randomly divided into 3 groups according to the technique used to place the cement into root canal: using lentulo-spiral instrument (group Lentulo), applying the cement onto the post surface (group Direct), and injecting the material using a specific elongation tip (group Elongation tip). After shaping and filling of the root canal, post space was drilled using Rely-X post drill. Rely-X fiber post was seated using Rely-X Unicem and resin cement was light polymerized. The root specimens were embedded in an acrylic resin and the specimens were sectioned perpendicularly to the long axis using a low-speed saw. Three slices per each root containing cross-sections of coronal, middle and apical part of the bonded fiber posts were obtained by sectioning. The push-out bond strength was measured using Universal Testing Machine. Specimens after bond failure were examined using operating microscope to evaluate the failure modes. Results: Push-out bond strengths were statistically influenced by the root regions. Group using the elongation tip showed significantly higher bond strength than other ways. Most failures occurred at the cement/dentin interface or in a mixed mode. Conclusions: The use of an elongation tip seems to reduce the number of imperfections within the selfadhesive cement interface compared to the techniques such as direct applying with the post and lentulospiral technique.

• Korean Journal of Agricultural Science
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• v.39 no.1
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• pp.29-34
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• 2012

This study was carried out to identify the characteristics of 37 corn hybrids, which composed with 18 yellow colored kernel, 9 purple colored kernel, 8 white colored kernel. Days to silking of three colored waxy corn hybrids ranged from 61 to 73 days after sowing as midium-late ecotype. Ear length of hybrids ranged from 10.3 to 22.7 cm, and among them a total 22 waxy corn hybrids including CNU038 showed over 20 cm in ear length. The fresh weight per ear ranged from 58 to 289 g as the 32.9% of large coefficient of variance. In there results, we found yellow colored waxy corn hybrids showed relatively longer in ear length and heavier in fresh weight per ear compare to other colored waxy corn hybrids. In correlation relationships, plant height, ear height, stem diameter, ear length and ear weight showed positive correlation between themselves, while tip filling ratio did negative correlation with silking stage, plant height, ear length, ear weight and kernel thickness. Also, 100 kernel weight did positive correlation between traits related to ear and kernel.

• The Korean Journal of Pain
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• v.19 no.2
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• pp.175-180
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• 2006

Background: A transforaminal epidural steroid injection has been used for the treatment of radicular arm or leg pain, which has the advantage of ventral epidural spreading compared to either an interlaminar or caudal approach. However, several factors are known to affect the epidural spread pattern of contrast dye; therefore, the injected medication can not be delivered to the target site. The objective of our study was to observe any differences in the contrast flow patterns according to several factors. Methods: A total of 34 epidurographies in 29 patients, who underwent fluoroscopically guided transforaminal epidural steroid injections, were evaluated. After confirming the location of the needle tip within the anterior superior aspect of the neural foramen in the lateral view, and at the 6 o'clock position to the pedicle in the anteroposterior view, 2 ml of contrast dye was injected. The contrast flow patterns of ventral, ventral and dorsal, and dorsal epidural filling were analyzed, according to age, gender, magnetic resonance imaging finding and history of previous back surgery. Results: Ventral contrast flow occurred in 30 out of the 34 epidurographies (88%). Both ventral and dorsal contrast flow patterns were observed 13 out of 16 (81%) patients in the older age group. Also, both ventral and dorsal contrast flow patterns were observed in 16 out of 18 (88%) patients with spinal stenosis. Conclusions: Transforaminal epidural steroid injections, performed uner fluoroscopy, provide excellent nerve root filling and ventral epidural spreading. Patients with spinal stenosis or an old age have both ventral and dorsal epidural spreading patterns.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.5
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• pp.889-898
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• 2022

In this study, sand casting process was applied to manufacture a large aluminum turbo-type fan used for tank powerpack. To apply the sand casting method, the turbo fan was reverse engineered, and after designing three gating systems, the optimal gating system design was selected by performing casting simulation. In the case of the bottom up-gating system, there is a significant temperature loss of the molten alloy during blade filling. When the molten alloy is completely filled into the sand mold, the blade upper tip and front shroud are below the liquidus temperature. In the case of the top down-gating system, molten alloy scattering occurs, but the temperature loss while the blade is filled is smaller than that of the bottom up type. And after the inflow of molten alloy into the mold is completed, the blade upper tip and front shroud are higher than the liquidus temperature. A sand mold was manufactured with the top down-gating system and the casting process was performed. The fan was made perfectly in appearance without any unfilled parts.

• Journal of Information Display
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• v.5 no.4
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• pp.7-11
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• 2004

Effects of base vacuum level on the electrical and optical characteristics of the plasma display panel (PDP) were investigated. The relationship between efficiency and base vacuum level before filling discharge gas was analyzed. For the base vacuum level of $1{\times}10^{-4}$ torr, firing voltage of a 2-inch diagonal PDP panel was 232 V at the discharge gas pressure of 400 torr and luminous efficiency was 1.5 lm/W at 180V sustaining pulse. On the other hand for $1{\times}10^{-6}$torr, the firing voltage was reduced to 215 V and luminous efficiency was improved considerably to 2.5 lm/W. We successfully demonstrated the smooth operation of tip-less PDP fabricated using vacuum in-line sealing method.

• Journal of the Korean GEO-environmental Society
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• v.8 no.6
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• pp.5-12
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• 2007

Mudstone has characteristics that it has high enough strength and stiffness in a dry condition, but the strength and stiffness decrease in a wet condition with groundwater infiltration. The sliding of cut slope frequently encountered in Pohang area has been reported due to the rapid reduction of shear strength in mudstone after being exposed to the air. The study in this paper shows that mudstone having enough strength in a boring stage has lost the strength after installing PRD (percussion rotary drill) steel pipe pile inducing an insufficient bearing capacity. Field test has been performed to investigate the most favorable method for increasing a pile bearing capacity in mudstone with various methods such as MSG (Micro Silica Grouting) around the tip and side of a pile, the perimeter grouting combined with Micro pile reinforcement, and concrete filling after tip reinforcing grouting. MSG has been turned out to be the most favorable method for increasing a pile bearing capacity in mudstone, confirmed by the static load test.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.13-13
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• 2010

Switching an elementary excitation by injecting a single carrier would offer the exciting opportunity for the ultra-high data storage technologies. However, there has been no methodology available to investigate the interaction of low energy discrete carriers with nano-structures. In order to map out the spatial dependency of such single carrier level interactions, we developed a pulse-and-probe algorithm, combining with low temperature scanning tunneling microscopy. The new tool, which we call single carrier spectroscopy, allows us to track the interaction with the target macrostructure with tunneling carriers on a single carrier basis. Using this tool, we demonstrate that it is possible not only to locally write and erase individual bi-solitons, reliably and reversibly, but also to track of creation yields of single and multiple bi-solitons. Bi-solitons are pairs of solitons that are elementary out-of-phase excitations on anti-ferromagnetically ordered pseudo-spin system of Si dimers on Si(001)-c(42) surfaces. We found that at low energy tunneling the single bisoliton creation mechanism is not correlated with the number of carriers tunneling, but with the production of a potential hole under the tip. An electric field at the surface determines the density of the local charge density under the tip, and band-bending. However a rapid, dynamic change of a field produces a potential hole that can be filled by energetic carriers, and the amount of energy released during filling process is responsible for the creation of bi-solitons. Our model based on the field-induced local hole gives excellent explanation for bi-soliton yield behaviors. Scanning tunneling spectroscopy data supports the existence of such a potential hole. The mechanism also explains the site-dependency of bi-soliton yields, which is highest at the trough, not on the dimer rows. Our study demonstrates that we can manipulate not just single atoms and molecules, but also single pseudo-spin excitations as well.

• Genomics & Informatics
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• v.12 no.3
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• pp.80-86
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• 2014

Foldback intercoil (FBI) DNA is formed by the folding back at one point of a non-helical parallel track of double-stranded DNA at as sharp as $180^{\circ}$ and the intertwining of two double helixes within each other's major groove to form an intercoil with a diameter of 2.2 nm. FBI DNA has been suggested to mediate intra-molecular homologous recombination of a deletion and inversion. Inter-molecular homologous recombination, known as site-specific insertion, on the other hand, is mediated by the direct perpendicular approach of the FBI DNA tip, as the attP site, onto the target DNA, as the attB site. Transposition of DNA transposons involves the pairing of terminal inverted repeats and 5-7-bp tandem target duplication. FBI DNA configuration effectively explains simple as well as replicative transposition, along with the involvement of an enhancer element. The majority of diverse retrotransposable elements that employ a target site duplication mechanism is also suggested to follow the FBI DNA-mediated perpendicular insertion of the paired intercoil ends by non-homologous end-joining, together with gap filling. A genome-wide perspective of transposable elements in light of FBI DNA is discussed.

• The Korean Journal of Pain
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• v.10 no.2
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• pp.285-290
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• 1997

Horner's syndrome is a well-recognized complication of regional analgesia of neck and shoulder region, and not often a complication of lumbar or low thoracic epidural block. Recently we experienced right Horner's syndrome accompanying paralysis of right upper extremity following lumbar epidural block in for an obstetric patient. Epidurography and MRI was performed to clarify the cause of unilateral high epidural block and cervical sympathetic block. Radiologic study demonstrated a loop formation of the epidural catheter and tip of catheter was located in right anterior epidural spaced(L1-2). The initial epidurogram revealed unilateral spreading of dye in the cervical region in right epidural space. A second epidurogram, 10 minutes following, showed dye filling in left epidural space, however spread of dye in left side was limited to lumbar and low thoracic region. We concluded the most probable cause of this unilateral high epidural block was due to misplacement of the catheter into the anterior epidural space.

• Journal of the Korean Geotechnical Society
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• v.30 no.12
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• pp.51-61
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• 2014

This paper presents an experimental study of the plugging effect on the capacity of open-ended piles installed in sandy soil. Full-scale tests, including dynamic and static axial-compression load tests, were carried out on three instrumented piles with different diameters (508.0, 711.2 and 914.4 mm). To measure the outer and inner shaft resistances acting on the piles, a double-walled system was utilized with instrumented strain gauges on the outside and inside walls of the pile. The results of field tests show that the inner shaft resistance was mostly mobilized at the location between the pile tip and 18-34% of the total plug length. It was found that the soil plugging in the lower portion has influence on the inner shaft resistance. In addition, it can be also demonstrated that the ratio of inner shaft resistance plus annulus load resistance to total resistance decreased with increasing pile diameters. The results of these tests show that the relationship between the degree of plugging and pile diameter is clearly established. Direct observations of the soil plugs were made and used to quantify both the plug length ratio (PLR) and the incremental filling ratio (IFR). Based on this result, it was found that the N value of the standard penetration test (SPT) is highly correlated with the IFR.