• Korean Journal of Metals and Materials
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• v.48 no.12
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• pp.1056-1063
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• 2010

We present a new joining method for Pd-Cu membrane foils used as permeation tubes to collect $CO_2$. Since foils have poor mechanical strength, joining should be done at low temperatures to reduce residual stresses and without joining pressure. This contradicts the well known conditions for good contact between base materials that determines joint qualities. We selected Sn-Ag-Cu alloys that are highly reactive with Pd and Cu as a filler metal. As the filler melts at joining temperatures as low as $220{\sim}280^{\circ}C$, Pd and Cu are dissolved into the melt and react with the filler elements, which raises the melting temperature of the filler based on eutectic structures among the elements. Then, isothermal solidification progresses for the rest of the joining time. Intermetallic compounds (IMC) in the joints, one of the main factors for brittle joints, are inevitably formed. However, by optimizing both joining time and temperature, we balanced the wettability with IMC. Sealing test results confirmed that the joints are mechanically reliable during operation.

• Bulletin of the Korean Chemical Society
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• v.13 no.6
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• pp.620-624
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• 1992

The analytical performance of glow discharge mass spectrometer (GD-MS), using a flat type ion source is discussed. The efficiency of ion extraction was maximized at the distance between anode and cathode of 6 mm. At the operation condition of 4 mA, -1000 volt, and 1 mbar for the source, the optimum voltages for sampler and skimmer were40 volt and -280 volt, respectively. The intensities of Cu, Zn, and Mn were increased as a function of square root of current approximately. Korea standard reference materials (KSRM) were tested for an application study. The detection limits of most elements were obtained in the range of several ppm at the optimized operating condition. The peaks of aluminum and chromium were interfered by those of residual gases. The depth profile of nickel coated copper specimens (3, 5, 10 ${\mu}m$ thickness) were obtained by plotting time versus intensities of Ni and Cr after checking the thickness of nickel coated using a scanning electron microscope (SEM). At this moment, the sputtering rate of 0.2 ${\mu}m/min$ at the optimum operating condition was determined from the slope of the plot of time to the coating thickness. The roughness spectra of specimen's crater after 16 min, discharge were obtained using a Talysuf5m-120 roughness tester as well.

• Archives of Plastic Surgery
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• v.48 no.5
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• pp.528-533
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• 2021

Bladder acontractility affects several thousand patients in the United States, but the available therapies are limited. Latissimus dorsi detrusor myoplasty (LDDM) is a therapeutic option that allows patients with bladder acontractility to void voluntarily. Our goal was to conduct a systematic review of the literature to determine whether LDDM is a better option than clean intermittent catheterization (CIC) (standard treatment) in patients with bladder acontractility. On January 17, 2020, we conducted a systematic review of the PubMed/MEDLINE, Cochrane Clinical Answers, Cochrane Central Register of Controlled Trials, Embase, and ClinicalTrials.gov databases, without time frame limitations, to identify articles on the use of LDDM for bladder acontractility. Of 75 potential articles, 4 fulfilled the eligibility criteria. The use of LDDM to treat patients with bladder acontractility was reported in four case series by the same group in Europe. Fifty-eight patients were included, and no comparison groups were included. The most common cause of bladder acontractility was spinal cord injury (n=36). The mean (±standard deviation) operative time was 536 (±22) minutes, postoperative length of hospital stay ranged from 10 to 13 days, and follow-up ranged from 9 to 68 months. Most patients had complete response, were able to void voluntarily, and had post-void residual volume less than 100 mL. Although promising outcomes have been obtained, evidence is still weak regarding whether LDDM is better than CIC to avoid impairment of the urinary tract among patients with bladder acontractility. Further prospective studies with control groups are necessary.

• Journal of Ocean Engineering and Technology
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• v.33 no.5
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• pp.435-446
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• 2019

Because offshore structures are affected by various environmental loads, the risk of damage is high. As a result of ever-changing ocean environmental loads, damage to offshore structures is expected to differ from year to year. However, in previous studies, it was assumed that a relatively short period of load acts repeatedly during the design life of a structure. In this study, the residual life of an offshore wind turbine support structure was evaluated in consideration of the timing uncertainty of the ocean environmental load. Sampling points for the wind velocity, wave height, and wave period were generated using a central composites design, and a transfer function was constructed from the numerical analysis results. A simulation was performed using the joint probability model of ocean environmental loads. The stress time history was calculated by entering the load samples generated by the simulation into the transfer function. The damage to the structure was calculated using the rain-flow counting method, Goodman equation, Miner's rule, and S-N curve. The results confirmed that the wind speed generated at a specific time could not represent the wind speed that could occur during the design life of the structure.

• Journal of Environmental Science International
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• v.28 no.3
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• pp.291-301
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• 2019

This study was conducted to investigate the effect of salt concentration and turbidity on the inactivation of Artemia sp. by electrolysis, UV photolysis, electrolysis+UV process to treat ballast water in the presence of brackish water or muddy water caused by rainfall. The inactivation at different salt concentrations (30 g/L and 3 g/L) and turbidity levels (0, 156, 779 NTU) was compared. A decrease in salt concentration reduced RNO (OH radical generation index) degradation and TRO (Total Residual Oxidant) production, indicating that a longer electrolysis time is required to achieve a 100% inactivation rate in electrolysis process. In the UV process, the higher turbidity results in lower UV transmittance and lower inactivation efficiency of Artemia sp. Higher the turbidity resulted in lower ultraviolet transmittance in the UV process and lower inactivation efficiency of Artemia sp. A UV exposure time of over 30 seconds was required for 100% inactivation. Factors affecting inactivation efficiency of Artemia sp. in low salt concentration are in the order: electrolysis+UV > electrolysis > UV process. In the case of electrolysis+UV process, TRO is lower than the electrolysis process, but RNO is more decomposed, indicating that the OH radical has a greater effect on the inactivation effect. In low salt concentrations and high turbidity conditions, factors affecting Artemia sp. inactivation were in the order electrolysis > electrolysis+UV > UV process. When the salt concentration is low and the turbidity is high, the electrolysis process is affected by the salt concentration and the UV process is affected by turbidity. Therefore, the synergy due to the combination of the electrolysis process and the UV process was small, and the inactivation was lower than that of the single electrolysis process only affected by the salt concentration.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.1
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• pp.64-78
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• 2019

The background concentrations of heavy metals in Korean coastal sediments were estimated using heavy metal data for 495 sediments obtained from 'National Marine Ecosystem Survey (Coastal ecosystem) in 2016-2017' and the extent of contamination was assessed. Al, Cs, and Li are chosen as appropriate indicators for sediment grain size. In the relationships between heavy metal and indicators concentrations, the lowest slope data were selected through the outlier removal and residual analysis, and the background concentrations were presented as a linear regression line between metal and indicator. Comparing the previous studies for the background concentrations of heavy metals in Korean coastal sediments, concentration levels were generally consistent but those for As and Cd were presented for the first time, and the background concentration using Li as the indicator was presented for the first time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.104-107
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• 2019

Modern people have abundant food and various forms of life compared to the past, but they have come to form an unhealthy diet, such as skipping breakfast and not eating in time in a busy life. When these eating habits are maintained for a long time, it leads to digestive trouble. The most easily occurring symptoms are called reflux esophagitis and dysphagia. Among them, dysphagia requires quick and accurate diagnosis as they develop into various forms of complications or are also identified as presymptoms of gastric and laryngeal cancers. The result of the diagnosis is still passively judged by the doctor and each of results are different depending on the doctor. The result of the diagnosis here means the severity. When they identify treatment or complications following the results of the diagnosis, the wrong diagnosis may lead to excessive or insufficient treatment. In this paper, to figure out the severity of dysphagia in the diagnosis of dysphagia, we studied the development of a program using the K-means algorithm in the processing of X-ray images for identifying residual food in epiglottic vallecula and pyriform sinus in the section leading to esophagus.

• Applied Chemistry for Engineering
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• v.22 no.3
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• pp.286-290
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• 2011

Syngas was produced out of pellet refuse derived fuel (RDF) produced from an RDF production facility of W city, Korea. A two-stage gasification system was developed to use the RDF char as an auxiliary heat source for gasification reaction. The composition and heating value of syngas as well as the heating value of residual product (char) were measured at a different residence time to investigate the optimal operating condition of the two-stage gasification system for syngas production. The optimal char residence time to minimize the energy cost due to an external heat source supply was also deduced.

• Journal of Gastric Cancer
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• v.22 no.1
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• pp.47-55
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• 2022

Purpose: The use of direct oral Xa inhibitors (DXaIs) to prevent venothrombotic events is increasing. However, gastrointestinal bleeding, including that related to endoscopic resection, is a concern. In this study, we evaluated bleeding and coagulation times during the perioperative period of gastric endoscopic submucosal dissection (ESD). Materials and Methods: Patients who consecutively underwent gastric ESD from August 2016 to December 2018 were analyzed. Bleeding rates were compared among the 3 groups (antiplatelet, DXaIs, and control). DXaI administration was discontinued on the day of the procedure. Prothrombin time (PT), activated partial thromboplastin time, and the ratio of inhibited thrombin generation (RITG), which was based on dilute PT, were determined before and after ESD. Results: During the study period, 265 gastric ESDs were performed in 239 patients, where 23 and 50 patients received DXaIs and antiplatelets, respectively. Delayed bleeding occurred in 17 patients (7.4%) and 21 lesions (7.1%). The bleeding rate in the DXaI group was significantly higher than that in the other groups (30.4%, P<0.01), and the adjusted odds ratio of bleeding was 5.7 (95% confidence interval, 1.4-23.7; P=0.016). In patients using DXaIs, there was a significant (P=0.046) difference in the median RITG between bleeding cases (18.6%) and non-bleeding cases (3.8%). Conclusions: A one-day cessation of DXaIs was related to a high incidence of bleeding after gastric ESD, and monitoring of residual coagulation activity at trough levels might enable the predicted risk of delayed bleeding in patients using DXaIs.

• Korean Journal of Remote Sensing
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• v.38 no.1
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• pp.111-126
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• 2022

Land use and land cover (LULC) mapping is an important factor in geospatial analysis. Although highly precise ground-based LULC monitoring is possible, it is time consuming and costly. Conversely, because the synthetic aperture radar (SAR) sensor is an all-weather sensor with high resolution, it could replace field-based LULC monitoring systems with low cost and less time requirement. Thus, LULC is one of the major areas in SAR applications. We developed a LULC model using only KOMPSAT-5 single co-polarized data and digital elevation model (DEM) data. Twelve HH-polarized images and 18 VV-polarized images were collected, and two HH-polarized images and four VV-polarized images were selected for the model testing. To train the LULC model, we applied the conditional generative adversarial network (cGAN) method. We used U-Net combined with the residual unit (ResUNet) model to generate the cGAN method. When analyzing the training history at 1732 epochs, the ResUNet model showed a maximum overall accuracy (OA) of 93.89 and a Kappa coefficient of 0.91. The model exhibited high performance in the test datasets with an OA greater than 90. The model accurately distinguished water body areas and showed lower accuracy in wetlands than in the other LULC types. The effect of the DEM on the accuracy of LULC was analyzed. When assessing the accuracy with respect to the incidence angle, owing to the radar shadow caused by the side-looking system of the SAR sensor, the OA tended to decrease as the incidence angle increased. This study is the first to use only KOMPSAT-5 single co-polarized data and deep learning methods to demonstrate the possibility of high-performance LULC monitoring. This study contributes to Earth surface monitoring and the development of deep learning approaches using the KOMPSAT-5 data.