• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.189.2-189.2
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• 2010

The purpose of this study is fatigue damage assessment for large sized casting parts (hub and mainframe) of the 3MW offshore wind turbine by computer simulation. Hub and mainframe durability assessment is necessary because wind turbine have to guarantee for 20 years. Fatigue life evaluation must be considered all of fatigue load conditions as the components are wind load transmission path. Palmgren-Miner linear damage accumulation hypothesis is applied for fatigue life estimation with stress-life approach. S-N curve for the spheroid graphite cast iron EN-GJS-400-18-LT is derived according to durability guidelines. Reduction factors were applied for survival probability, surface roughness, material quality and partial safety factor according to Germanischer Lloyd rules. To calculate fatigue damage, stress tensors, extracted from the unity load calculation from ANSYS is multiplied with time track of fatigue loads extracted from GH bladed. Damage accumulation is performed with all of fatigue load conditions at each finite element nodes. In this study maximum nodal damage value is under 1.0. casted parts are safe. This research was financially supported by the Ministry of Knowledge Economy(MKE), Korea Institute for Advancement of Technology(KIAT) and Honam Leading Industry Office through the Leading Industry Development for Economic Region.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.3-4
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• 2009

As device process technology advances, effective channel length, the thickness of gate oxide, and supply voltage decreases. This paper describes a novel electrostatic discharge (ESD) protection device which has current feedback for high ESD immunity. A conventional Gate-Grounded NMOS (GGNMOS) transistor has only one ESD current path, which makes, the core circuit be in the safe region, so an GGNMOS transistor has low current immunity compared with our device which has current feedback path. To simulate our device, we use conventional $0.18\;{\mu}m$ technology parameters with a gate oxide thickness of $43\;{\AA}$ and power supply voltage of 1.8 V. Our simulation results indicate that the area of our ESD protection, device can be smaller than a GGNMOS transistor, and ESD immunity is better than a GGNMOS transistor.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권5호
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• pp.416-421
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• 2010

Purpose: The purpose of this study was to evaluate the incidence of intra- and postoperative complications of orthognathic surgery and their relevance. Materials and Methods: The clinical records and X-rays of 418 patients who underwent surgery at Chosun University Dental Hospital, Korea, over a 12-year period between 1998 and 2009 were examined. Results: The followings are some of the most common complications which happened during the oper-ations: Inadequate osteotomy in 25 cases, excessive bleeding in 11 cases, nerve injuries in 6 cases, soft tis-sue injuries in 8 cases, and tooth injury, and insertion of foreign bodies in 4 cases respectively. The most frequent complications which happened after surgery are shown below. Paraesthesia in 262 cases, dyspnea in 78 cases, pain in cervical region in 49 cases, open bite in 14 cases, plus 62 cases where other complications occurred. Despite the great variety of complications, severe life threatening complication frequency seems to be extremely low. Conclusion: Orthognathic surgery appears to be a relatively safe procedure but complications related to orthognathic surgery do still occur. Accurate evaluation and precise surgery are needed to minimize complications.

• Journal of Advanced Marine Engineering and Technology
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• 제28권6호
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• pp.993-999
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• 2004

The estimation of fatigue life at the design stage of membrane type LNG tank is very important in order to arrive at feasible and cost effective solutions considering the total lifetime of the tank. In this study, the practical procedure of fatigue life prediction by use of cumulative damage factors based on Miner-Palmgren hypothesis and probability density function has been shown with the corner region of Gaz Transport Membrane type LNG tank being used as an example. In particular the parameters of Weibull distribution that determine the stress spectrum are discussed. The main results obtained from this study are as follows: 1. The recommended value for the shape parameter of Weibull distribution for the LNG tank is 1.1 in case of using the direct calculation method proposed in this study. 2. The calculated fatigue life is influenced by the shape parameter of Weibull distribution and stress block. The safe fatigue design can be achieved by using higher value of shape parameter and the stress blocks divided into more stress blocks.

• Journal of Acupuncture Research
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• 제23권3호
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• pp.67-75
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• 2006

Objectives : The purpose of this study is to evaluate the clinical effect of moxibustion treatment for FBSS patients by VAS. Methods : This clinical study was carried out for 51 cases with FBSS, who had been treated from January, 2003 to October, 2005, in oriental medical clinic. The patients were treated by the moxibustion during 8 weeks on the pain region of lower back or legs. We measured the effects of treatment by VAS. SPSS( Statistical Program for Social Science) for Windows was used for statistical analysis and repeated measures ANOVA was performed to gauge the improvement of VAS. Results : 1. We investigated 25 female and 26 male patients. The age distribution was from early 20's to 70's, among which 50's were most common. 2. The worsening factors are usually overwork and heavy lifting, but the main reason is unknown. 3. According to VAS, The patients with FBSS were improved by moxibustion treatment. Conclusion : Through this research, moxibustion therapy is considered to be effective and safe method for FBSS(Failed Back Surgery Syndrome). Moxibustion treatment had some problems that should be overcome such as severe pain and burning. Therefore we should pay more attention.

• 상하수도학회지
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• 제24권6호
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• pp.675-682
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• 2010

Groundwater is an essential drinking water source in Gyungbuk, South Korea. The primary source of nitrate in groundwater is from nitrogen fertilizers. Efficient management of a small drinking water plant requires a good understanding of its status such as the objective and the cognition of users. The objective of this study is to understand user situation and produce useful user-friendly policy based on user cognition. Most people who participated in this study, should take their groundwater from a good quality source. Even though they would like to have a good facility for getting safe water, they were reluctant to do it due to the cost used. It means that people who drink groundwater have no idea that health safety is affected by groundwater quality. The volume used depended upon personal activities such as agriculture and stockbreeding. We can easily find groundwater with nitrate that exceeds drinking water standards. Therefore, we have to carry out groundwater management with two categories ; 1) drinking water only and 2) others according to objectives in small drinking water systems.

• 한국소음진동공학회논문집
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• 제24권6호
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• pp.476-482
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• 2014

The stress analysis of the pipeline is required in any kind of plant for its safe operation. For this, the displacement vibration data measured at many locations of the pipeline should be provided. In reality, the installation of the non-contact type displacement sensors such as laser displacement sensors or eddy current type proximity sensors in a narrow and confined region in the vicinity of the pipeline is almost impracticable. In this work, the general purpose piezo-ceramic accelerometers were attached on the measuring points on the pipeline and the acceleration vibration signal was acquired. The measured acceleration signal was low pass filtered and then downsampled. The resulting acceleration signal was transformed into both the time-domain and frequency-domain displacement signal utilizing the fast Fourier transform techniques. All the procedures are presented in detail. It is demonstrated that the measurement of the pipeline acceleration by using contact type accelerometers can be made for the purpose of providing the required displacement data for the stress analysis of the pipeline.

• Journal of Chest Surgery
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• 제34권5호
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• pp.426-429
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• 2001

Superior sulcus or pancoase tumor refers to any primarty lung cancer locating in thoracic inlet and causing pain in the periscapular region or aim. These originate inperipheral, and involve th extrapulmonary structures more than parenchyma of the lung. We experienced l case of superior sulcus tumor radically resected via anterior transcervical approach, which provide more safe exposure of cervical structures of thoracic inlet than classis posterolateral thoracotomy. Therefore were report this case with review of literature.

• Journal of Korean Neurosurgical Society
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• 제40권1호
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• pp.6-10
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• 2006

Objective : The purpose of this study is to evaluate the surgical outcomes of bifrontal interhemispheric[BIH] approach and compare them to those of the pterional approach for the treatment of craniopharyngioma. Methods : Seventeen patients had their first operation for the resection of craniopharyngiomas between 2000 and 2004 at our medical center. Eleven patients who had the pterional approach and 6 with the BIH approach were enrolled. The age range at the time of surgery was 5 to 80 years [mean age 35.6 years old]. The presenting symptoms were visual disturbance increased intracranial pressure in 5 patients. Results : The tumors were totally removed in 3 [27 %] and subtotally in 8 [73 %] patients with the pterional approach. Total tumor removal was achieved in 5 out of 6 [83%] patients by the BIH approach, except improved in 4 [36 %] patients treated with the pterional approach and in all patients treated by the BIH approach. Conclusion : The BIH approach for craniopharyngioma surgery may be an effective and safe approach for tumors that extend outside of the sellar-suprasellar region with acceptable outcomes.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권4호
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• pp.373-377
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• 2010

Vascular anomalies are common birthmarks. A eight-month-old male infant had a small size, bright red swelling on the lower lip since birth. On cutaneous examination there was a small brightly erythematous, lobulated, soft plaque on the left side of the lower lip of $10{\times}8{\times}5$ mm. Ultrasonogram examination revealed the lesion and confirmed the diagnosis of capillary hemangioma. The decision to initiate treatment is based on many factors, including size, location and risks and benefits of the proposal therapy. Systemic corticosteroids are decided to prevent the scarring and deforming. Prednisolone was given at a dose of 2 mg/kg/day for 2 weeks followed by tapering for 6 weeks for treatment. After eight weeks there was 80% reduction in the size of the lesion and the left lower lip almost completely cleared without intraoral bleeding. Furthermore, intervention by way of systemic steroids, laser therapy or surgical debulking is appropriate and safe in a select group of patients presenting with a proliferating hemangioma. This report describes a case that was sucessfully treated by systemic steroid therapy for hemangima in intraoral region.