• Journal of Power System Engineering
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• v.18 no.1
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• pp.76-83
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• 2014

This study was carried out an experimental and finite element analysis on the fracture behavior of straight pipes with local wall thinning under internal pressure. Local wall thinning was machined on the pipes in order to simulate erosion/corrosion metal loss. The configurations of the eroded area has an eroded ratio of d/t=0.80~0.92 and an eroded length of l=25, 50 and 102 mm. Three-dimensional elastic-plastic analyses were also carried out using the finite element method, which is able to accurately simulate failure behaviors. In regards to the relation ship between pressure and eroded ratio, the criterion that can be used safely under operating pressure and design pressure were obtained from this calculation. The results of this calculation were in relatively good agreement with that of the experiment.

• The Journal of the Acoustical Society of Korea
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• v.37 no.1
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• pp.31-38
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• 2018

Based on the measured data in the south western sea of Jeju Island during the SAVEX15(Shallow Water Acoustic Variability EXperiment 2015), the effect of internal waves on the PPD (Predictive Probability of Detection) of a sonar system was analyzed. The southern west sea of Jeju Island has complex flows due to internal waves and USC (Underwater Sound Channel). In this paper, sonar performance is predicted by probabilistic approach. The LFM (Linear Frequency Modulation) and MLS (Maximum Length Sequence) signals of 11 kHz - 31 kHz band of SAVEX15 data were processed to calculate the TL (Transmission Loss) and NL (Noise Level) at a distance of approximately 2.8 km from the source and the receiver. The PDF (Probability Density Function) of TL and NL is convoluted to obtain the PDF of the SE (Signal Excess) and the PPD according to the depth of the source and receiver is calculated. Analysis of the changes in the PPD over time when there are internal waves such as soliton packet and internal tide has confirmed that the PPD value is affected by different aspects.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.311-315
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• 2012

Diaphragm type noncontact automatic control valve is a valve for controling acidic PR(Photo Resist) liquid used in the semiconductor process. PR is photosensitive liquid that changes phases depending on light transmittance. PR is very toxic and expensive; the purpose of this paper is to address methods that prevent loss due to leaks. The design of noncontact precise automatic control valve is expected to play an important role in controlling fluid flow, therefore influencing energy conservation and environmental improvement. In this paper, diaphragm type automatic control valve's part design, assembly and simulation are introduced. Also, through the analysis of fluid flow the valve's internal velocity, pressure, and turbulent intensity are interpreted. This paper proposes to contribute to the improvement of the valve's performance.

• Journal of the Korean institute of surface engineering
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• v.38 no.4
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• pp.156-162
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• 2005

Nickel-iron nanocrystalline alloys with different compositions and grain sizes were fabricated by electro-plating for MEMS devices. The iron content of the deposits was changed by varying the nickel/iron ion ratio in the electrolyte. X-ray diffraction (XRD) analysis was applied for measuring the strength of the texture and grain size of the deposits. The nickel/iron atom ratio of the deposits was analyzed by EDS. The hardness of the alloys was evaluated by Vickers hardness indenter. The internal stress of the deposits was measured by Thin Film Stress Measurement using Stoney's formula. Surface morphology and roughness were investigated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The results of this study revealed that at a grain size of approximately $17\~24$nm the hardness, internal stress and roughness depend strongly on the iron content. With increasing the iron content, the hardness and internal stress of the deposits increased. An excellent correlation between the increase in the internal stress and the loss of (200) texture was found.

• Journal of Veterinary Clinics
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• v.23 no.2
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• pp.183-185
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• 2006

Four pigeons which lived together of same cage were referred due to excessive feather loss, severe itching, and erythema on the head, neck and flank regions. They had behavioral problem with feather bloating and plucking. Although they were mildly depressed, appetite was normal. On microscopic examination of feather picking, prominent external parasite infection was found. Mite infection was diagnosed with morphological confirmation. On analysis of complete blood count (CBC), eosinophilia was evident. The patients were treated with ivermectin (apply 200 mcg/kg topically two times per every other week and spray 200 mcg/ml solution every week). Clinical signs of four, pigeons were improved 45 days following first therapy. This case report indicates that mite infection is accompanied with severe feather loss, itching, and generalized erythema on the skin and behavioral problem with feather bloating and plucking. And this infection can be managed with topical and spray application of Ivermectin without injection.

• Journal of Institute of Convergence Technology
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• v.7 no.1
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• pp.1-6
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• 2017

The Heat exchanger for deep geothermal system is very important to enhance the efficiency of the system. The co-axial heat exchanger is used due to the limitation of digging space. The heat transfer on the external surface of outer pipe should be high to receive a large amount of heat from the ground. However, the inner pipe should be insulated to reduce the heat loss and increase the temperature of discharge water. This study made experiment apparatus to describe the co-axial heat exchanger and measure the heat transfer coefficients on the internal and external surface. And the pin-fin was designed and fixed on the internal surface to increase the efficiency of heat exchanger. Finally, we calculated the temperature of discharge water using the heat transfer circuit of co-axial heat exchanger and heat transfer coefficient which from experimental results. The water temperature was reached the ground temperature at -500 m and following the ground temperature. When the water return to the ground surface, the water temperature was decreased due to heat loss. As the pin-fin case, the heat transfer coefficient on the internal surface was decreased by 30% and it mean that the pin-fin help to insulate the inner pipe. However, the discharge water temperature did not change although pin-fin fixed on the inner pipe.

• Journal of Veterinary Clinics
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• v.39 no.3
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• pp.144-148
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• 2022

A one-year-old spayed female Korean Shorthair cat presented to Kangwon National University Veterinary Hospital with vomiting, weight loss, lethargy, loss of appetite, and polyuria that lasted for more than two weeks. The body condition score, blood pressure, heart rate, and body temperature were abnormally low, and the physical examination findings were consistent with moderate dehydration. Hematological and biochemical tests demonstrated mild azotemia and a low Na:K ratio. Additional abdominal ultrasound imaging revealed reduced size of both adrenal glands. The adrenocorticotropic hormone (ACTH) stimulation test showed decreased post-ACTH cortisol and aldosterone levels and increased endogenous ACTH levels, confirming a diagnosis of primary hypoadrenocorticism. The cat was treated with subcutaneous injections of desoxycorticosterone pivalate (DOCP) and oral prednisolone supplementation, and subsequent electrolyte analysis showed a normal Na:K ratio. Clinical symptoms were also improved in response to treatment. Hypoadrenocorticism in cats is a very rare disease, but it should not be excluded as a potential diagnosis in favor of kidney diseases or other conditions, especially when the Na:K ratio is low. In addition, the prognosis for the disease and the response to DOCP treatment should be further evaluated in cats.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.6
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• pp.15-21
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• 2022

This study considered the internal flow considering the internal shape of the CNG filling nozzle, which is widely distributed in Korea. The CNG filling nozzle is the last part to pass through in the CNG filling process and has a significant influence on the filling efficiency. The mechanism was identified by disassembling the CNG filling nozzle and performing a flow analysis according to the mechanism. Consequently, the energy loss owing to eddy currents in the flow was determined, and modeling was proposed to reduce the energy loss by simplifying the shape and parts.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1548-1553
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• 2003

The design of a high speed axial piston pump for hydrostatic transmission systems requires specific understanding on where and how much its internal frictional and flow losses are generated. In this study, the frictional loss of a bentaxis type hydraulic piston pump was analyzed in order to find out which design factors influence the mechanical efficiency most significantly. To this end, the friction coefficients of the sliding components were experimentally identified by a specially constructed tribometer. Applying them to the three-dimensional dynamic model of the pump presented by Doh and Hong [1], the friction torques generated by the sliding components such as piston head , bearing and valve plate were theoretically computed. The accuracy of the computed results was confirmed by the comparison with the experimentally measured mechanical efficiency. In this paper, it is shown that the viscous friction on the valve plate and the drive shaft bearing is the primary sources of the frictional losses of the bent-axis type pump, while the friction forces on the piston contribute to them only slightly.

• Clinics in Shoulder and Elbow
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• v.18 no.2
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• pp.75-79
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• 2015

Background: This retrospective comparative study aims to evaluate the surgical outcomes and complications of two surgical methods for simple fractures of the humeral shaft; minimally invasive anterior plating and open reduction combined with internal fixation. Methods: A total of 26 patients with humeral shaft simple fractures, who had surgery between June 2009 and September 2013 and were followed-up at least 12 months, were included in our analysis. They were divided into two groups; group 1 comprised of 12 patients who underwent minimally invasive anterior plating and group 2 comprised of 14 patients who underwent an open reduction and internal fixation. The clinical outcomes, radiological results, and complications were compared and analyzed. Results: We found that bone union was achieved in all patients, and the mean union periods were $20.7{\pm}3.34$ and $20.3{\pm}3.91$ weeks for groups 1 and 2, respectively. In most patients, we found that shoulder and elbow functions were recovered. At 12 months post-operation, we found that the Korean Shoulder Scoring system, the University of California at Los Angeles score and Mayo elbow performance score were $91.4{\pm}7.97$, $33.4{\pm}1.15$, and $90.8{\pm}2.23$ for group 1, and $95.2{\pm}1.53$, $33.3{\pm}1.43$, and $90.17{\pm}1.85$ for group 2. In terms of complications, we found that 2 patients had radial nerve palsy after open reduction and internal fixation, but all cases spontaneously resolved within 6 months. Complications such as infection and loss of fixation were not reported. Conclusions: Both minimally invasive anterior plating and open reduction with internal fixation produced satisfactory outcomes in the treatment of simple fractures of the humeral shaft.