• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1734-1739
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• 2014

In this paper, microstrip low pass filter using transmission line with the modified DCRLH structure is designed and fabricated to be removed a spurious resonant mode, and a deep attenuation in stop band. The low pass filter is composed of shunt open-stub to get a deep attenuation and series short-stub to eliminate the spurious harmonics in stop band. In this way, the spurious harmonics occurring on the higher order frequency are suppressed and the filter performance is improved. Insertion loss and VSWR of the fabricated microstrip low pass filter in the passband from DC to 1.5 GHz is 1.26 dB and 1.65, and attenuation on the stopband from 1.84 GHz to 2.18 GHz is less than -100 dB. And also this filter has a good performance for 20 watt power test.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.1
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• pp.63-70
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• 2021

Using computer-aided design and manufacturing technique improve quality of treatment in many aspect. This case reports the complete mouth rehabilitation of a patient with amelogenesis imperfecta utilizing digital technology. Clinical examination revealed loss of mastication due to insufficient occlusal stop, missing teeth, interdental spacing due to microdontia, insufficient overbite, and etc. Full veneer crowns for teeth were selected, followed by a fixed partial denture and implant placement was done using CAD-CAM guide template with bone graft for partially edentulous space. Definitive restorations were duplicated by double scanning provisional restorations and successfully delivered to the patient. These full mouth rehabilitation procedures resulted in satisfactory outcomes for the patient functionally and aesthetically.

• Journal of Advanced Navigation Technology
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• v.5 no.2
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• pp.141-148
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• 2001

This paper describe the development of narrow-band passband filter with small package and low loss, high selectivity performance. This filter is placed between power amplifier and frequency mixer of IMT-2000 mobile equipment. The elliptic-function narrow-band passband filter is designed with new architecture using the microstrip line. This package is very small by $3.2cm{\times}1.25cm$ and have the 3 % 3 dB bandwidth. Also in the passband the insertion loss is about 2.5 dB and is better than older RF SAW filter(insertion loss: 3.2 dB). In the stop-band it has the two deep notch under the -56 dB.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.3
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• pp.1-9
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• 2003

In this paper, we designed a highly suppressed sidelobe ladder type RF SAW bandpass filter based on 1-port resonator, for 800 MHz mobile communication system. In order to get the highest device characteristics, we optimized some important parameters such as the electrode thickness, electrode lambda weghting of the reflectors, and static capacitance ratio. Furthermore, we fabricated the Tx and Rx. filter using optimized parameters. Implemented filters can be used in 800 MHz mobile communication system and external impedance matching circuits are not needed. RF filter was fabricated on 36$^{\circ}$LiTaO$_3$ substrates with Al-Cu (W 3 %)and mounted 3.8mm$\times$3.8mm$\times$1.5mm SMD package. Developed filters has 2.3 dB insertion loss in the 25 MHz pass-band, 33MHz with 3-dB insertion loss, stop-band rejection of 30 dB, passband ripple is less than 0.5 The power durability of the filters measured about 3.5W and the maximum temperature variation within -2$0^{\circ}C$~8$0^{\circ}C$ was 0.09 dB/$^{\circ}C$ of 3-dB insertion loss.

• Journal of Periodontal and Implant Science
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• v.52 no.3
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• pp.194-205
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• 2022

Purpose: This study aimed to determine the long-term outcomes after peri-implantitis treatment and the factors affecting these outcomes. Methods: This study included 92 implants in 45 patients who had been treated for peri-implantitis. Clinical data on the characteristics of patients and their implants were collected retrospectively. The change in the marginal bone level was calculated by comparing the baseline and the most recently obtained (≥3 years after treatment) radiographs. The primary outcome variable was progression of the disease after the treatment at the implant level, which was defined as further bone loss of >1.0 mm or implant removal. A 2-level binary logistic regression analysis was used to identify the effects of possible factors on the primary outcome. Results: The mean age of the patients was 58.7 years (range, 22-79 years). Progression of peri-implantitis was observed in 64.4% of patients and 63.0% of implants during an observation period of 6.4±2.7 years (mean±standard deviation). Multivariable regression analysis revealed that full compliance to recall visits (P=0.019), smoking (P=0.023), placement of 4 or more implants (P=0.022), and marginal bone loss ≥4 mm at baseline (P=0.027) significantly influenced the treatment outcome. Conclusions: The long-term results of peri-implantitis treatment can be improved by full compliance on the part of patients, whereas it is impaired by smoking, placement of multiple implants, and severe bone loss at baseline. Encouraging patients to stop smoking and to receive supportive care is recommended before treatment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.5
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• pp.111-116
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• 2022

The causes of motor burnout include overload, phase loss, restraint, interlayer short circuit, winding ground fault, instantaneous overvoltage, and the rotor contacting the stator, leading to insulation breakdown, leading to breakdown or electrical accidents. Therefore, equipment failure causes not only loss due to cost required for equipment maintenance/repair, but also huge economic loss due to productivity decrease due to process stop because the process itself including the motor is stopped. The current level of technology for diagnosing motor failures uses vibration, heat, and power analysis methods, but there is a limit to analyzing the problems only after a considerable amount of time has passed according to the failure. Therefore, in this paper, a device and algorithm for measuring insulation resistance using DC AMP signal was applied to an industrial motor to solve this problem. And by following the insulation resistance state value, we propose a diagnosis of deterioration and failure of the motor that cannot be solved by the existing method.

• Nuclear Engineering and Technology
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• v.18 no.2
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• pp.97-106
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• 1986

System thermal-hydraulic parameters and simulated, using the best-estimate system code(RELAPS/MODl/NSC), based upon the sequence of events for the KNU1 (Korea Nuclear Unit 1) loss of offsite power transient at 77.5% power which occurred on June 9,1981. The results are compared with the actual plant transient data and show good agreements. After the flow coastdown following the trips of both reactor coolant pumps, the establishment of natural circulation by the temperature difference between the hot and the cold legs is confirmed. The calculated reactor coolant flowrate closely approximates the plant data indicating the validity of relevant thermal-hydraulic models in the RELAP5/MOD1/NSC. Results also show that the sufficient heat removal capability is secured by the appropriate supply of the auxiliary feedwater without the operation of S/G PORVs. In addition, a scenario accident at full power, based upon the same sequence of events described above, is also analysed and the results confirmed that the safety of KNU1 is secured by the appropriate operation of the S/G PORVs coupled with the supply of auxiliary feedwater which ensures sufficient heat removal capability. The characteristics of the non-safety related components such as the turbine stop valve closing time, S/G PORV settings etc. are recognized to be important in the transient analyses on a bestestimate basis.

• Journal of dental hygiene science
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• v.13 no.4
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• pp.418-425
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• 2013

This study was investigated in order to provide basic data for prevention of periodontal disease and maintenance through proper lifestyle by finding the relevance of periodontal health with lifestyle habits. Data were collected from total of 326 subjects in their forties and fifties by using questionnaire and examination of periodontal health status. Results were analyzed by using IBM SPSS Statistics 19.0. The smoking status were statistically significant to gingival index (p<0.01), pocket depth (p<0.001), and clinical attachment loss (p<0.001). Smoking amount per day were statistically significant to gingival index (p<0.05), pocket depth (p<0.01), and clinical attachment loss (p<0.001). Duration of smoking were statistically significant to gingival index (p<0.05), pocket depth (p<0.01), and clinical attachment loss (p<0.001). Drinking cycle were statistically significant to gingival index (p<0.05), and clinical attachment loss (p<0.05). It is investigated that smoking (p<0.05) influence on clinical attachment loss. Dental care institute needs to make patients be aware of the fact that excessive smoking and drinking affect the periodontal health status for prevention of periodontal disease and maintenance of oral health. Therefore systematic educational programs to stop smoking and drinking should be prepared.

• The Journal of Fisheries Business Administration
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• v.37 no.3 s.72
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• pp.45-63
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• 2006

A number of public loans with lower interests and other tax benefits have been provided for farmers and fishermen. However, much of those loans have been accumulated as non-performing. The result is that a large part of fisheries debts are now on the verge of default, Those loans, that fail to pay interests, keep rapidly growing like a time bomb. Now something has to be done before it burst. Firstly, the government must clean up the debts caused by government's mismanagement in the past. The past debt must be repaid or written off by the government since its guarantee was committed several times in guidelines regarding public loans. As such a measure, the government can greatly enlarge its capital contribution to the Credit Guarantee Fund for Farmers and Fishermen and Loss Guarantee fund for Policy Loan. It would greatly help to compensate local branches of fisheries cooperatives for their loss incurred from carrying public loans. In the past, the government used to roll over old debts of fishermen with new debts whenever maturity came. It ends up growing the size of non - performing loans. For this reason, it is not delay of the debt payment, but its write - off that fishery society needs a lot. Secondly, the loan authorities must lower overall risk in providing public loans for fishermen in the future. The whole process must be thoroughly reviewed and changed to provide and manage government loans. To facilitate this, fisheries cooperative must stop being just a public agent, rather take a bigger responsibility in selecting, and checking loan beneficiaries, and securing debt repayment. Incentives must be arranged properly enough to induce fisheries cooperatives to treat public loans just like their own business. Finally, the so - called 'special account of policy loan in fisheries industry' must be set up to enhance the transparency and to check the performance of public loans programs.

• Tribology and Lubricants
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• v.22 no.6
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• pp.314-319
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• 2006

In this paper, the friction and wear characteristics of contact type sealing unit far a water turbine have been presented. The sealing unit for a small hydropower generation is to stop a leakage of circulating water from an outside of an impeller to an inside of a rolling bearing. The friction heating between a seal ring and a seal seat may radically increase a surface temperature in which increase a power loss and wear on the rubbing surface. The surface wear strongly affect to the seal life of a mechanical face seal. In this study, the hardness of a stainless steel in which is a heat-treated is 892.8 in Victors hardness and the hardness of silicone carbide of SiC is 714.1 in Victors hardness. The surface hardness of a heat-treated stainless steel is 25% high compared with that of a ceramic material of SiC. The contact modes of rubbing surfaces are a dry friction, a water film friction and a mixed friction that is contaminated by a dust, silt, and moistures, etc. These two factors of a contact rubbing modes and a material property are very important parameters on the tribological performance such as a friction and wear between a seal ring and a seal seat in primary sealing unit. The experimental result shows that the surface hardness of a seal material is very important on the friction coefficient and a wear volume. Thus, the results recommend higher hardness of a seal material, which may reduce a friction loss and increase a wear life of primary seal components.