• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.2
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• pp.149-153
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• 2011

Purpose: The aim of the present study was to evaluate the clinical outcome of resorbable blasting media surface tapered implant. Methods: 169 Osstem$^{(R)}$ GS III dental implants in 73 patients who received implant treatments at Seoul National University Bundang Hospital, were included in this study. The incidence of biological and prosthetical complications has been carefully analysed for each implant. Results: The short-term implant survival rate was 97.63%, success rate 94.7%. The prevalence of biological complications was 15.38% and the prevalence of prosthetic complications was 13.04%. The mean value of crestal bone loss was $0.28{\pm}0.57$ mm. The relationship between loading periods and marginal bone loss was small and not statistically significant. In mandible, marginal bone loss was larger than in maxilla, no statistically significant. Also, length and diameter of implant had no relationship with marginal bone loss. Conclusion: We suggest that this implant system could achieve successful and stable results.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.2
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• pp.1965-1970
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• 1970

The experiment was carried out in order to improve the leakage stopping work in the irrigation canal founding on the porous soil. But the experiment had many problems to be studied more owing to the insufficient time and facilities. The results obtained are summarized as follows; 1. Polyethylene film is estimated not to make strength decrease owing to buring in the subsoil, but to make owing to the sunlight. 2. Coated nylon shows the tendency to deteriorate strength when it is buried in the earth or exposed to the sun for long time, but leakage is all but impermeability generally. 3. Leakage loss rates for one hour show some differences in the canal to be full with water in accordance with operating methods, that is, the clay lining section is 12.6%, the coated nylon lining section is 1.7%, the polyethylene film lining section is 1.3%, respectively. 4. Leakage quantities per wetted perimeter unit area show $3.556cc/cm^2/hr$. in the clay lining section, $1.574cc/cm^2/hr$. in the coated nylon section, $0.695cc/cm^2/hr$. in the polyethylene film lining section, respectively. 5. When the construction fund make the clay lining section as a standard, the polyethylene film section is 92.1%, the coated nylon section is 174.2%, respectively. But, the unit cost of execution may be low when the polyethylene film and the coated nylon will enable to mass-produce for the purpose of execution.

• Journal of Korea Foundry Society
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• v.6 no.1
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• pp.27-35
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• 1986

The gating design of gray cast iron was programmed in a Personal computer. By this program, casting test was done. The results obtained are as follows. 1. Gating design that can calculate the velocity of metal flow and size in each gate section by knowing the loss coefficient caused by friction loss and bend loss was programmed. 2. In the test casting, the gating ratio was changed into 1.1:1.3:1, 1:2:2, 1:4:4. And sound casting, free of sand washing defect, was obtained at the velocity of 35.5cm/sec in ingate.

• Tunnel and Underground Space
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• v.28 no.1
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• pp.111-124
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• 2018

The purpose of this study is to analyze ventilation design factor for network-type double-deck road tunnel that have been developed actively around the world. A numerical analysis was carried out through computational fluid dynamics (CFD) to derive shock loss coefficient that occurs due to the change in cross sectional area at both merging section and diverging section. The model used for the numerical analysis is real-scale model and the reliability of the result is secured by comparing with the coefficient of the previous studies. As a result of this study, shock loss coefficient was calculated depending on the change in cross-sectional area ratio and was higher than the result of previous studies in case of both merging section and diverging section. It is considered that the characteristics of the geometrical structure of network-type double-deck road tunnel have a great impact on shock loss coefficient. Therefore, the result of this study is expected to be helpful for more accurate ventilation design of network-type double-deck road tunnel.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.3
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• pp.259-269
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• 2013

In this paper, we propose an SIW(Substrate Integrated Waveguide) multi-section E-plane transformer using air-holes for an SIW system with variable thicknesses. Air-holes are inserted into a SIW E-plane quarter wavelength transformer for matching an E-plane impedance discontinuity. A PSIW(Punched Substrate Integrated Waveguide) consisted of air-holes has an SIW characteristic impedance tunability because of reducing a equivalent shunt capacitance of the SIW. And, a PSIW multi-section E-plane transformer is implemented for improving a matching bandwidth by using the Chebyshev polynomial. The measurement results of PSIW double-section E-plane transformer show that the insertion loss($S_{21}$) is $1.57{\pm}0.11$ dB and input return loss($S_{11}$) is more than 15 dB from 11.45 GHz to 13.6 GHz.

• The Journal of Advanced Prosthodontics
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• v.8 no.5
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• pp.396-403
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• 2016

PURPOSE. Early loading of implant can be determined by excellent primary stability and characteristic of implant surface. The implant system with recently improved surface can have load application 4-6 weeks after installing in maxilla and mandible. This study evaluated the effect of healing period to the stability of hydrophilic tapered-type implant at maxillary posterior area. MATERIALS AND METHODS. This study included 30 patients treated by hydrophilic tapered-type implants (total 41 implants at maxilla) and classified by two groups depending on healing period. Group 1 (11 patients, 15 implants) was a control group and the healing period was 12 weeks, and Group 2 (19 patients, 26 implants) was test group and the healing period was 6 weeks. Immediately after implant placement, at the first impression taking, implant stability was measured using Osstell Mentor. The patients also took periapical radiographs after restoration delivery, 12 months after restoration and final followup period. The marginal bone loss around the implants was measured using the periapical radiographs. RESULTS. All implants were survived and success rate was 97.56%. The marginal bone loss was less than 1mm after 1 year postoperatively except the one implant. The stabilities of the implants were not correlated with age, healing period until loading, insertion torque (IT), the diameter of fixture and the location of implant. Only the quality of bone in group 2 (6 week) was correlated with the stability of implant. CONCLUSION. Healing period of 6 weeks can make the similar clinical prognosis of implants to that of healing period of 12 weeks if bone quality is carefully considered in case of early loading.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.4
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• pp.442-450
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• 2014

This paper is a study of the propagation characteristic of matching liquids in the skin-covered breast model. In order to evaluate the matching liquids, we investigated six kinds of matching liquids applied to proposed 1-D breast model from frequency range of 3~6 GHz. A uniform plane wave is projected / transmitted inside the multi-layered breast model. Then the propagation characteristics inside the model and the transmission loss of each matching liquids were analyzed. The studying method presented in the paper can be used in the breast cancer detection system, the field of cancer detection using human tissue and the field of other medical devices. This paper was applied to the breast cancer detection system. Consequently, these studies could be used to determine the suitable type of matching liquids for breast cancer detection system and to apply useful for performance analysis.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.6
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• pp.8-12
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• 2008

A ring resonator based band-pass filter enabling enhanced sideband suppression was proposed and demonstrated. It is composed of a single-ring based band-pass section combined with a band-rejection section based on two different coupled rings. The sideband region of the transfer characteristics of the first band-pass filter section was selectively suppressed by means of the band-rejection section without causing any excessive insertion loss. As a result, the overall transfer characteristics of the proposed filter was unproved so that its sideband suppression was elevated to allow for sharper roll-off and narrower bandwidth. In this work, a conventional single-ring band-pass filter and a proposed filter including the band-rejection section were designed and fabricated. As for the achieved device performance, with the center frequency at about 4 GHz, the sideband suppression ratio was increased as much as 8 dB and the 3-dB bandwidth was reduced from 98 MHz to 48 MHz by about 51% with no remarkable excessive insertion loss as expected. And the quality factor of the device was increased by about 105%.

• The korean journal of orthodontics
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• v.51 no.3
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• pp.199-216
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• 2021

Objective: The aim of this systematic review was to evaluate the complications and side effects associated with the clinical use of orthodontic miniscrews by systematically reviewing the best available evidence. Methods: A survey of articles published up to March 2020 investigating the complications associated with miniscrew insertion, in both the maxilla and mandible, was performed using 7 electronic databases. Clinical studies, case reports, and case series reporting complications associated with the use of orthodontic miniscrew implants were included. Two authors independently performed study selection, data extraction, and risk-of-bias assessment. Results: The database survey yielded 24 articles. The risk-of-bias assessment revealed low methodological quality for the included studies. The most frequent adverse event reported was root injury with an associated periradicular lesion, vitality loss, pink discoloration of the tooth, and transitory loss of pulp sensitivity. Chronic inflammation of the soft tissue surrounding the miniscrew with mucosal overgrowth was also reported. The other adverse events reported were lesion of the buccal mucosa at the insertion site, soft-tissue necrosis, and perforation of the floor of the nasal cavity and maxillary sinus. Adverse events were also reported after miniscrew removal and included secondary bleeding, miniscrew fracture, scars, and exostosis. Conclusions: These findings highlight the need for clinicians to preliminarily assess generic and specific insertion site complications and side effects.

• Journal of Magnetics
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• v.17 no.1
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• pp.36-41
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• 2012

The transcranial magnetic stimulation recharges the energy storing condenser, and sends the stored energy in the condenser to the pulse shaping circuit, which then delivers it to the stimulating coil. The previous types of transcranial magnetic stimulation required a booster transformer, secondary rectifier for high voltages and a condenser for smooth type. The energy storing condenser is recharged by switching the high-voltage direct current power. Loss occurs due to the resistance in the recharging circuit, and the single-pulse output energy in the transcranial magnetic stimulation can be changed because the recharging voltage cannot be adjusted. In this study a booster transformer, which decreases the volume and weight, was not used. Instead, a current resonance inverter was applied to cut down the switching loss. A transcranial magnetic stimulation, which can simultaneously alter the recharging voltage and pulse repeats, was used to examine the output characteristics.