• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.2982-2989
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• 2021

One of the consequences of the 475 ℃ embrittlement of duplex stainless steels is the reduction of the resistance to localized corrosion. Therefore, the detection of this type of embrittlement before the material exhibits significant loss in toughness, and corrosion resistance is important to ensure the structural integrity of critical components under corrosion threats. In this research, conductivity measurements are performed using the alternating current potential drop (ACPD) technique with using a portable four-point probe as a nondestructive evaluation (NDE) method for detecting the embrittlement in a 2507 (UNS S32750) super duplex stainless steel (SDSS) aged at 475 ℃ from as-received condition to 300 h. The electric conductivity results were compared against two electrochemical tests namely double loop electrochemical potentiokinetic reactivation (DL-EPR) and critical pitting temperature (CPT). Mechanical tests and the microstructure characterized using scanning electron microscopy (SEM) imaging are conducted to track the progress of embrittlement. It is shown that the electric conductivity correlates with the changes in impact energy, microhardness, and CPT corrosion tests result demonstrating the feasibility of the four-point probe as a possible field-deployable method for evaluating the 475 ℃ embrittlement of 2507 SDSS.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.395-400
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• 2021

In this paper, the wideband patch antenna is simulated and manufactured for the wireless LAN of 5GHz band that is defined in IEEE 802.11a. In the 802.11a, 200 channels of 675MHz are defined. Therefore, the bandwidth is needed more than 12.3%. For the wideband characteristics, low dielectric constant is realized with the multi-layer of 2 teflon substrates and the air dielectric layer and the feeding method of the coupled-line is used. Optimized wideband patch antenna is simulated with the return loss of 38.99dB at the center frequency of 5.43GHz and the bandwidth of 12.9%. The gain of manufactured patch antenna is 4.38, 4.52, and 5.12dBi at the channel number of 46, 56, and 153, respectively.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.599-604
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• 2021

In the information age, internet was developed from the wired access to the wireless Internet access. When a surge in demand for wireless Internet access, efficiency and performance of 2.4 and 5GHz band which leads to saturation of the communication was significantly fall. In this paper, we studied the design and fabrication of slot patch antenna to be used in wireless communication systems operating at around 10GHz band. To obtain optimal antenna parameters such as patch size, inter patch space, sL, sW, feed L, feed w, slot patch antenna was simulated by HFSS(High Frequency Structure Simulator). From these parameters, slot and patch antenna is fabricated using FR-4 substrate of dielectric constant 4.4. The characteristics of fabricated antenna were analyzed by network analyzer. The fabricated slot patch antenna showed a center frequency as 10.23GHz, the minimum return loss as -32dB, and -10dB bandwidth as 420MHz respectively.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.2
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• pp.105-108
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• 2021

Background : Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is a rare, autosomal recessive metabolic disorder which is caused by genetic mutations that disrupt the urea cycle. It is characterized by variable clinical presentation and the age of onset. Patients may present with gait disturbance and progressive paraplegia and muscle tightness in the lower extremities. The use of botulinum toxin in metabolic disease has rarely been discussed. We describe a case of a 14-year-old-boy with HHH syndrome, who presented with a several - month history of gait disturbance and lower extremity weakness. Case presentation : A 14-year old male had a history of recurrent upper respiratory tract infections, occasional vomiting, loss of appetite, and general weakness, all of which started since he was 10 months old. He was diagnosed with HHH syndrome at one year of age. At the age of 14, he was referred for the assessment and treatment of his gait disturbance and aggravated weakness of the lower extremities. Brain MRI, electrodiagnostic study and blood test were performed to exclude any lesions related to neurologic dysfunction. Botulinum toxin type A were injected into muscles of adductor longus, adductor magnus, lateral and medial hamstring, and lateral and medial gastrocnemius muscle heads under needle electromyography guidance to reduce lower limb spasticity. Intensive physical therapy including gait training and stretching exercise of adductor and calf muscles were also provided. After intensive physical therapy and botulinum toxin injection to reduce lower limb spasticity, he was able to ambulate for 20 meters independently without any walking aids. There were no adverse events after the injection. Conclusion : Botulinum toxin injection is a safe and effective therapy for patients with HHH syndrome who suffer from gait disturbance.

• Journal of Korean Neurosurgical Society
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• v.64 no.3
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• pp.447-459
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• 2021

Objective : Oblique lateral interbody fusion (OLIF) is becoming the preferred treatment for degenerative lumbar diseases. As beginners, we performed 143 surgeries over 19 months. In these consecutive cases, we analyzed the learning curve and reviewed the complications in our experience. Methods : This was a retrospective study; however, complications that were well known in the previous literature were strictly recorded prospectively. We followed up the changes in estimated blood loss (EBL), operation time, and transient psoas paresis according to case accumulation to analyze the learning curve. Results : Complication-free patients accounted for 43.6% (12.9%, early stage 70 patients and 74.3%, late stage 70 patients). The most common complication was transient psoas paresis (n=52). Most of these complications occurred in the early stages of learning. C-reactive protein normalization was delayed in seven patients (4.89%). The operation time showed a decreasing trend with the cases; however, EBL did not show any significant change. Notable operation-induced complications were cage malposition, vertebral body fracture, injury to the ureter, and injury to the lumbar vein. Conclusion : According to the learning curve, the operation time and psoas paresis decreased. It is important to select an appropriately sized cage along with clear dissection of the anterior border of the psoas muscle to prevent OLIF-specific complications.

• Cross-Cultural Studies
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• v.39
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• pp.309-328
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• 2015

This study is a consideration of Xu Xiao-Bin(徐小斌)'s Sounds of nature(天?) in the mutual text point of view of Lee Cheong-jun's Sopyonje series. Xu Xiao-Bin's Sounds of nature shows similar motive to Lee Cheong-jun's Sopyonje series that is a story of a mother who damages her daughter's eyes and the daughter. however, it is accepted in totally different ways that the action of father/mother who damage their daughter's eyes. the mother in Sounds of nature is a composer as well as singer and the father in Sopyonje is a singer. The mother's behavior is not able to have duty in Sounds of nature due to it is focused in 'mother's action' rather than a singer but the father's behavior is focused in 'singer's action' in Sopyonje. therefore the action of the father, who is a singer, is considered not merely personal desire of father but also desire to preserve 'singing' as a national culture in public status. the length between two novels are clear in the two daughter's point of views. the daughter in "Sounds of nature" refuses her destiny made from her mother. The daughter's behavior of recovering her own volition, becomes frankly showing the falsehood of 'mother's love. In comparison, the daughter's voice is under the shade in Sopyonje. she surrenders herself to the fate made by her father, and she does not show her desire. This is the point that the difference is created by gender of writers.

• Asian Spine Journal
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• v.12 no.6
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• pp.1028-1036
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• 2018

Study Design: Single-center, observational, case-control study. Purpose: Comparison and analysis of the metabolic and coagulative profiles in patients with idiopathic scoliosis, patients with congenital scoliosis, and healthy controls. Overview of Literature: Serum melatonin deficiency has been a controversial topic in the etiopathogenesis of scoliosis. Low bone mineral density, low vitamin D3 levels, and high parathyroid hormone levels are common metabolic abnormalities associated with scoliosis that may be responsible for its pathogenesis. In addition to metabolic defects, several studies have shown coagulation defects that either persist from the preoperative period or occur during surgery and usually lead to more than the expected amount of blood loss in patients undergoing deformity correction for scoliosis. Methods: The study population (n=73) was classified into those having congenital scoliosis (n=31), those with idiopathic scoliosis (n=30), and healthy controls (n=12). After detailed clinicoradiological evaluation of all the subjects, 10-mL blood samples were collected, measured, and analyzed for various metabolic and coagulation parameters. Results: The mean serum melatonin levels in patients with idiopathic scoliosis were significantly lower than those in the healthy controls. Although the mean serum melatonin level in the congenital group was also low, the difference was not statistically significant. Serum alkaline phosphatase and parathyroid hormone levels were higher in the scoliosis groups, whereas the vitamin D level was lower. No differences were observed in the coagulation profiles of the different groups. Conclusions: Low serum melatonin levels associated with scoliosis can be a cause or an effect of scoliosis. Moreover, low bone mineral density, high bone turn over, and negative calcium balance appear to play an important role in the progression, if not the onset, of the deformity.

• Composites Research
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• v.32 no.2
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• pp.113-119
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• 2019

The objective of this research is to study the mechanical and vibration characteristics of vibration damping aluminum panels for automotive parts. For this purpose, the test and simulation results of aluminum-resin hybrid materials and aluminum sheet materials were compared. Tensile strength and elastic modulus of the hybrid material were approximately 10% lower than aluminum sheet. Also, it was showed that the hybrid material have lower natural frequency than aluminum sheet, and it was confirmed that loss factor increases as the thickness of resin increases. Finally, it is confirmed that the test results and the analysis results are similar with each other and the performance prediction of the materials are possible by FEA.

• Integrative Medicine Research
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• v.6 no.3
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• pp.317-324
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• 2017

Background: Bu-Zhong-Yi-Qi-Tang (BZYQT) has long been used for the treatment of severe weakness caused by general fatigue, loss of appetite, or indigestion. The aim of this feasibility study is to assess the effectiveness and safety of BZYQT for the treatment of functional dyspepsia (FD) with spleen qi deficiency. Methods: This study will be conducted at a single center as a prospective, nonrandomized, nonblinded, single-arm feasibility study. A total of 30 participants diagnosed with FD in accordance with the Rome III criteria will be enrolled. All patients will receive BZYQT for 4 weeks. The primary outcome is the change in the Nepean Dyspepsia Index-Korean version (NDI-K) scores between the baseline and 4-week images. The secondary outcomes include the tongue coating thickness, blood parameters, and BZYQT Questionnaire score. The NDI-K score will be acquired four times, at Weeks 0 (baseline), 2 (during treatment), 4 (after treatment), and 8 (after follow-up). Written informed consent will be obtained from all study participants prior to enrollment. This study has been approved by the Institutional Review Board of Kyung Hee University Korean Medicine Hospital. This study protocol is registered with the national clinical trial registry of the World Health Organization International Clinical Trials Registry Platform. Results will be published in a journal and will be disseminated both electronically and in print. Discussion: The results of this study may serve as a guide for researchers seeking to effectively evaluate the effects of BZYQT.

• Journal of Climate Change Research
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• v.2 no.3
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• pp.143-159
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• 2011

Projects applying the CDM methodology AM0035 of the $SF_6$ Emission Reductions in Electrical Grids should provide direct monitoring of all the key parameters that are related to estimation of baseline and project emissions including detailed explanations of key operating conditions and procedures, and an explanation addressing uncertainty as the result of EB meeting 41. Through this study, recovery ratio during maintenance, purity of $SF_6$ before and after disposal, replacing, loss rate of $SF_6$ before and after reclamation, leakage emission from electricity consumption and fossil fuel combustion, considered conservatively the key parameter of various monitoring. Consequently, confirmed the reduction in the amount of reduction due to the baseline emission decrease, project emission increase.