• Tunnel and Underground Space
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• v.22 no.4
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• pp.257-265
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• 2012

In this study, a series of CFD (Computational Fluid Dynamics) simulations carried out to evaluate the optimum design model of the internal flow path of drill bit. The Star-CCM+ code was adopted to simulate the multi-phase discharge flow of rock particles and flushing air during a drilling process. The input parameters for the flow simulation of rock particles and air were obtained from the in-situ drilling test results. After the three design factors were determined, the experimental design method (Taguchi method) was utilized to evaluate the optimum value of each factor.

• Journal of Biomedical Engineering Research
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• v.27 no.1
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• pp.30-37
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• 2006

Injecting currents into an electrically conducting subject, we may measure the induced magnetic flux density distributions using an MRI scanner. The measured data are utilized to reconstruct cross-sectional images of internal conductivity and current density distributions in Magnetic Resonance Electrical Impedance Tomography (MREIT). Injection currents are usually provided in a form of mono-polar or bi-polar pulses synchronized with an MR pulse sequence. Given an MRI scanner performing the MR phase imaging to extract the induced magnetic flux density data, the current source becomes one of the key parts determining the signal-to-noise ratio (SNR) of the measured data. Since this SNR is crucial in determining the quality of reconstructed MREIT images, special care must be given in the design and implementation of the current source. This paper describes a current source design for MREIT with features including interleaved current injection, arbitrary current waveform, electrode switching to discharge any stored charge from previous current injections, optical isolation from an MR spectrometer and PC, precise current injection timing control synchronized with any MR pulse sequence, and versatile PC control program. The performance of the current source was verified using a 3T MRI scanner and saline phantoms.

• Korean Journal of Social Welfare Studies
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• v.49 no.1
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• pp.297-334
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• 2018

This study focused on accomplishment of successful life development after discharge a child-care facility even though they had a variety of diversity in hard environment on their own past. Furthermore the research analyzed expression progress and detail information of resilience effect on twenty healthy members of society, who lived theirselves for more than 10 years at out of chid-care centers, based on grounded theory methodology participants. As written in the result section of the study, using the paradigm model analysis showed that it was caused by 'Practical planning for the future', 'Organization of positive meaning' and 'Understanding in another's shoe'. The contextual condition appeared as 'Self examination, 'Seeking anchor as ontology' and 'Natural intimacy among family members'. The centralization phenomenon came in 'Living philosophy of internal stabilities'. The intervention condition appeared as 'Rise up through the world' and 'faith all the world'. The action-interaction showed up as 'Strict self-discipline' and 'Growing up own family'. The consequence appeared as 'Making social family' and 'Being a someone's social mentor'. This research shows discussion in depth based on above analyzed result.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.5
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• pp.103-109
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• 2019

The pressure reducing valve for water is controlled by the load of the compression spring and the force of the fluid acting on the diaphragm of the stem. Repeated upward and downward reciprocation of the pressure-reducing valve stem damages the diaphragm, resulting in leakage. In this study, we designed a stem without a diaphragm and adjusted the stiffness of the compressing spring. In order to select the spring stiffness, springs offering a stiffness of -20%, -10%, 0%, and 10% with respect to the stiffness of the compression spring attached to the existing pressure reducing valve stiffness. A prototype for the pressure reducing valve was fabricated and the pressure change was evaluated for the target static pressure (6 bar) by testing the pressure characteristics after mounting the modified stem and each compression spring. Evaluation of the pressure characteristics was carried out using ASSE 1003 and KS B 6153. In addition, the flow rates were compared by internal flow analysis of the conventional pressure reducing valve and the pressure reducing valve using the modified stems, and the flow analysis was performed using Solidworks flow simulation 2018. The spring stiffness was constantly discharged at the target static pressure of 3.793 kgf/mm, and the flow rate was increased by about 15% compared with the conventional pressure reducing valve.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.34 no.4
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• pp.181-197
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• 2021

Objectives : This study reports a 42-year old female inpatient who visited for recurrent herpes zoster on the right hand and right side of the face on 5 days after coronavirus disease 2019 (COVID-19) vaccination. She already had 2 times of herpes zoster prior to this outbreak. Methods : During 10 days of hospitalization, both treatments were simultaneously applied to her. For Korean medical treatment, acupuncture, herbal medicine including Sipjeondaebo-tang, and Hominis Placenta pharmacopuncture were mainly used. Collaborating with internal medicine of our hospital, essential medications for herpes zoster including antihistamine, corticosteroid, and acyclovir were administered. To assess symptoms, taking photos and numerical rating scale(NRS) were used. Results : On the 3rd day of hospitalization, erythema on the right hand disappeared. On the 4th day, discomfort arisen by zoster lesions dropped from NRS 8, which was initially evaluated, to NRS 0. Facial lesion also steadily improved. At the moment of discharge, erythema on the right side of oral angle disappeared and mild traces of vesicular lesions remained on the right hand. Conclusions : Considering her medical history, the recent recurrent herpes zoster was suspected as an adverse event of COVID-19 vaccination. Unlike general course of herpes zoster, the skin lesions and discomfort were rapidly improved owing to the collaborated treatment during the 10 days. This study may be the first literature on herpes zoster following COVID-19 vaccination in Korea.

• Journal of the Korean Society of Safety
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• v.35 no.6
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• pp.85-92
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• 2020

Wet Scrubber reacts the incoming pollutant gas with cleaning water (water + absorbent) to absorb pollutants and release the clean air to the atmosphere. Wet scrubbers and packed tower scrubbers using this principle are widely used in businesses that emit acid gases. In particular, in the etching process using hydrochloric acid (HCl), alkaline washing water (NaOH) having a pH of about 8 to 11 is used to absorb a large amount of acid gas. However, These salts are attached to the injection nozzle (nozzle), filling material (packing), and the demister (Demister), causing air pollution, human damage, and inoperability due to clogging and acid gas discharge. Therefore, In this study, an improvement plan was proposed to manage the washing water with pH 3~4 acidic washing water. The test method takes samples from the Wet Scrubber flue measurement laboratory twice a month for 1 year. Hydrogen chloride (HCl) concentration (ppm) was measured, and nozzle clogging and scale conditions were measured, compared, and analyzed through a differential pressure gauge and a pressure gauge. As a result of the check, it was visually confirmed that the scale was reduced to 50% or less in the spray nozzle, filler, and demister. In addition, the emission limit of hydrogen chloride in accordance with the Enforcement Regulation of the Air Quality Conservation Act [Annex 8] met 3 ppm or less. Therefore, even if the washing water is operated in an acidic pH range of 3 to 4, it is expected to reduce air pollution and human damage due to clogging of internal parts, and it is expected to reduce maintenance costs such as regular cleaning or replacement of parts.

• Korean Journal of Veterinary Service
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• v.45 no.3
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• pp.145-153
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• 2022

Pathogens such as feline herpesvirus, feline calicivirus, Bordetella bronchiseptica, Chlamydia felis, Mycoplasma felis and Pasteurella multocida usually cause feline upper respiratory tract disease (URTD). Real-time PCR was used to analyze the detection and prevalence of the most common respiratory pathogens in cats with (n=69) and without respiratory signs (n=31). Pathogens were detected in 53 cats, divided into 37 (69.8%) with a single pathogen, 15 (28.3%) with two pathogens, and 1 (1.9%) with three pathogens. M. felis had the highest detection rate in 29 (42.0%) cats, P. multocida was detected in 18 (26.1%), FHV in 10 (14.5%), FCV in 7 (10.1%), B. bronchiseptica in 3 (4.3%), and C. felis in 2 (2.9%). M. felis was the most frequently detected pathogen in cats living outdoors without vaccination. Of the 37 cats infected with single pathogen, nasal discharge was observed in 13 (35.1%), ocular signs in 6 (16.2%), drooling in 5 (13.5%), dyspnea in 3 (8.1%), and asymptomatic in 10 (27.0%). In 51 outdoor and 49 indoor cats, pathogens were detected in 35 (68.6%) and 18 (36.7%) cats, respectively. Of the 29 cats infected with M. felis, 22 (75.9%) showed respiratory signs, and 7 (24.1%) were healthy. In the age of the 53 positive cats, 10 (18.9%) were under the age of 1 year, 26 (49.1%) were aged 1~3 years, and 17 (32.1%) were aged 3 years or older. Although the number of cats in the study was small, the results can provide valuable data on the prevalence of URTD in Korean cats.

• Journal of Acupuncture Research
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• v.39 no.3
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• pp.151-158
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• 2022

Changes in symptoms and dysfunction related to meniscus tears following the use of Korean medicine for ≥ 4 days were studied. The medical charts of 53 cases of diagnosed meniscus tears (magnetic resonance imaging) with an admission Numeric Rating Scale (NRS) score ≥ 4, between 2017 and 2022 were retrospectively reviewed. Treatments included acupuncture, pharmacopuncture, herbal treatment, Chuna therapy, and physiotherapy. The NRS, Western Ontario and McMaster Universities Osteoarthritis Index, and European Quality of Life 5 Dimensions were performed at admission and discharge. There were 42 females and 11 males in this study. Patients were more likely to be in their 60s (38.18%), have an unknown etiology (81.13%), and have complex tears (50.94%). After receiving a combination of alternative Korean medicine during hospitalization, the mean NRS score improved from 6.82 ± 1.19 to 3.66 ± 1.83 (p < 0.001), the Western Ontario and McMaster Universities Osteoarthritis Index score improved from 46.47 ± 20.99 to 37.98 ± 19.23 (p < 0.001), and the mean European Quality of Life Five Dimensions score improved from 0.61 ± 0.18 to 0.68 ± 0.14 (p < 0.001) after treatment. These results suggest that Korean medicine treatment of meniscus tears alleviated pain and improved physical function.

• Tribology and Lubricants
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• v.37 no.6
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• pp.246-252
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• 2021

Among the engine components of an internal combustion engine, the valve train is a series of systems that supply intake gas to the combustion chamber and operate intake and exhaust valves that discharge exhaust gas. If excessive wear occurs in the valve train system, the suction and exhaust valves do not open and close on time, which leads to abnormal combustion and exhaust gas. In this study, we conduct experiments and analyses on friction and wear characteristics of the valve train system. Moreover, we experimentally study the correlation between the pinball and pinball cap on engine oil lubrication, friction experiment, wear amount analysis, and surface analysis. Specifically, we experiment using Ball on reciprocating tribo-tester and apply commercial engine oil sold on the market engine oil. We construct the experimental conditions for each new oil and oil. Accordingly, the completed specimen was subjected to a confocal microscope to check the wear volume, observe the surface of the specimen, and confirm the elemental components using a scanning microscope (SEM) and an energy dispersion X-ray spectrometer (EDS). Through this experiment, we analyze the friction and wear characteristics of valve train components according to engine oil grade, and the obtained data serve as an effective engine oil management method.

• Journal of Yeungnam Medical Science
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• v.40 no.3
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• pp.283-288
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• 2023

Severe chronic neutropenia is classified as severe congenital, cyclic, autoimmune, or idiopathic. However, there is a lot of uncertainty regarding the diagnosis of severe congenital neutropenia (SCN) and chronic idiopathic neutropenia, and this uncertainty affects further evaluations and treatments. A 20-year-old man presented with fever and knee abrasions after a bicycle accident. On admission, his initial absolute neutrophil count (ANC) was 30/µL. He had no medical history of persistent severe neutropenia with periodic oscillation of ANC. Although his fever resolved after appropriate antibiotic therapy, ANC remained at 80/µL. Bone marrow (BM) aspiration and biopsy were performed, and a BM smear showed myeloid maturation arrest. Moreover, genetic mutation test results showed a heterozygous missense variant in exon 4 of the neutrophil elastase ELANE: c597+1G>C (pV190-F199del). The patient was diagnosed with SCN. After discharge, we routinely checked his ANC level and monitored any signs of infection with minimum use of granulocyte colony-stimulating factor (G-CSF), considering its potential risk of leukemic transformation. Considering that SCN can be fatal, timely diagnosis and appropriate management with G-CSF are essential. We report the case of a patient with SCN caused by ELANE mutation who had atypical clinical manifestations. For a more accurate diagnosis and treatment of severe chronic neutropenia, further studies are needed to elucidate the various clinical features of ELANE.