• Corrosion Science and Technology
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• v.22 no.3
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• pp.137-152
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• 2023

Polarization behavior and corrosion inhibition of copper in acidic chloride solutions containing benzotriazole were studied. Pourbaix diagrams constructed for copper in NaCl solutions with different BTAH concentrations were used to understand the polarization behavior. Open circuit potential (OCP) depended not only on chloride concentration, but also on whether a CuBTA layer was formed on the copper surface. Only when the (pH, OCP) was located well in the CuBTA region of the Pourbaix diagram, a stable corrosion inhibiting CuBTA layer was formed, which was confirmed by X-ray Photoelectron Spectroscopy (XPS) and a long-term corrosion test. The OCP for the CuBTA layer decreased logarithmically with increasing [Cl^-] activity in the solution. A minimum BTAH concentration required to form a CuBTA layer for a given NaCl concentration and pH were determined from the Pourbaix diagram. It was found that 320 ppm BTAH solution could be used to form a corrosion-inhibiting CuBTA layer inside the corrosion pit in the sprinkler copper tube, successfully reducing water leakage rate of copper tubes. These experimental results could be used to estimate water chemistry inside a corrosion pit.

• Journal of Chest Surgery
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• v.57 no.1
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• pp.87-91
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• 2024

Gunshot-induced chest trauma is exceedingly rare among civilians in South Korea due to strong firearm control policies. In contrast to military reports emphasizing the use of emergent open thoracotomy to increase chances of survival, most penetrating non-cardiac injuries in civilian settings are managed conservatively, such as through chest tube insertion, as they typically result from lower-energy bullets. However, early surgical intervention for penetrating gunshot wounds can help reduce delayed fatalities caused by septic complications from pneumonia or empyema. The advent of minimally invasive thoracic surgery has provided cost-effective and relatively non-invasive treatment options, aided in the prevention of potential complications from undrained hematomas, and facilitated functional recovery and reintegration into society. We successfully treated a patient with a penetrating gunshot wound to the chest using video-assisted thoracoscopic surgery.

• Journal of Intelligence and Information Systems
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• v.21 no.3
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• pp.19-36
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• 2015

Social media is an emerging issue in content services and in current business environment. YouTube is the most representative social media service in the world. YouTube is different from other conventional content services in its open user participation and contents creation methods. To promote a content in YouTube, it is important to understand the diffusion phenomena of contents and the network structural characteristics. Most previous studies analyzed impact factors of contents diffusion from the view point of general behavioral factors. Currently some researchers use network structure factors. However, these two approaches have been used separately. However this study tries to analyze the general impact factors on the view count and content based network structures all together. In addition, when building a content based network, this study forms the network structure by analyzing user comments on 22,370 contents of YouTube not based on the individual user based network. From this study, we re-proved statistically the causal relations between view count and not only general factors but also network factors. Moreover by analyzing this integrated research model, we found that these factors affect the view count of YouTube according to the following order; Uploader Followers, Video Age, Betweenness Centrality, Comments, Closeness Centrality, Clustering Coefficient and Rating. However Degree Centrality and Eigenvector Centrality affect the view count negatively. From this research some strategic points for the utilizing of contents diffusion are as followings. First, it is needed to manage general factors such as the number of uploader followers or subscribers, the video age, the number of comments, average rating points, and etc. The impact of average rating points is not so much important as we thought before. However, it is needed to increase the number of uploader followers strategically and sustain the contents in the service as long as possible. Second, we need to pay attention to the impacts of betweenness centrality and closeness centrality among other network factors. Users seems to search the related subject or similar contents after watching a content. It is needed to shorten the distance between other popular contents in the service. Namely, this study showed that it is beneficial for increasing view counts by decreasing the number of search attempts and increasing similarity with many other contents. This is consistent with the result of the clustering coefficient impact analysis. Third, it is important to notice the negative impact of degree centrality and eigenvector centrality on the view count. If the number of connections with other contents is too much increased it means there are many similar contents and eventually it might distribute the view counts. Moreover, too high eigenvector centrality means that there are connections with popular contents around the content, and it might lose the view count because of the impact of the popular contents. It would be better to avoid connections with too powerful popular contents. From this study we analyzed the phenomenon and verified diffusion factors of Youtube contents by using an integrated model consisting of general factors and network structure factors. From the viewpoints of social contribution, this study might provide useful information to music or movie industry or other contents vendors for their effective contents services. This research provides basic schemes that can be applied strategically in online contents marketing. One of the limitations of this study is that this study formed a contents based network for the network structure analysis. It might be an indirect method to see the content network structure. We can use more various methods to establish direct content network. Further researches include more detailed researches like an analysis according to the types of contents or domains or characteristics of the contents or users, and etc.

• Journal of Chest Surgery
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• v.35 no.11
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• pp.812-816
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• 2002

Pericardial effusions result from various conditions such as inflammation, malignancies, open heart surgery and uremia. Recently, video assisted thoracic surgery (VATS) has been used for diagnostic and therapeutic purposes in the management of pericardial effusion and intrathoracic lesions due to its ability to provide outstanding visibility of intrathoracic structures with less pain, superior cosmetic effects, and shorter hospital stay Material and Method: From April 1995 to October 2001, 51 patients received pericardial window operation via either thoracoscopic(Group A, n＝37, m:f＝18:19, mean age＝56.4 yrs)or thoracotomy approach(Group B, n＝14, m:f＝8:6, mean age=58.4 yrs). Result: In group A, the operation time, duration of chest tube insertion, recurrence rate of pericardial effusion, and postoperative hospital stay were 61.2 minutes, 9.3 days, 2.7%, 16.2 days, respectively while in group B these values were 58.4 minutes, 12.2 days, 7.1, and 17.3 days. The number of injections for pain control in group A were 4.2 times, whereas in group B it was 6.3 times. Although there was a tendency for the mean hospital stay and duration of chest tube insertion to be shorter in group A than in group B, these differences did not reach statistical significance. There was also no significant difference in the operation time and recurrence rate between the two groups. Conclusion: The safety and effectiveness of VATS in the management of pericardial effusion is comparable to the open thoracotomy method. It allows for a shorter hospital stay, duration of chest tube insertion, lesser postoperative pain and a smaller skin incision.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.702-708
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• 2011

There are considerable areas of wet paddy fields in Korea that requires improvement of its drainage system. In poorly drained sloping paddy fields, upland crops can be damaged by either rainfall or capillary rise of the water table caused by percolating water beneath the upper fields during summertime rainy season. The purpose of this study is to evaluate excess water stress of soybean yield by drainage systems. Four drainage methods namely open ditch, vinyl barrier, pipe drainage and tube bundle were installed within 1-m position at the lower edge of the upper paddy fields. Stress Day Index (SDI) approach was developed to quantify the the cumulative effect of stress imposed on a soybean yield throughout the growing season. SDI was determined from a stress day factor (SD) and a crop susceptibility factor (CS). The stress day factor is a measure degree and duration of stress of the ($SEW_{30}$). The crop susceptibility factor (CS) depends of a given excess water on crop stage. The results showed that SDI used to represent the moisture stress index was most low on the pipe drainage 64.75 compared with the open ditch 355.4, vinyl barrier 271.55 and tube bundle 171.55. Soybean grain yield increased continuously with the rate of 3% in Vinyl Barrier, 32% in Pipe Drainage and 16% in Tube Bundle.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.3
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• pp.135-145
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• 2019

Analysis of a long cycle or a trend of time series data based on a long-term observation would require comparability between data observed in the past and the present. In the present study, we proposed an approach to ensure the compatibility among the instruments used for the long-term observation, which would allow to secure continuity of the data. An open-path gas analyzer (Model LI-7500, LI-COR, Inc., USA) has been used for eddy covariance flux measurement in the Gwangneung deciduous forest for more than 10 years. The open-path gas analyzer was replaced by an enclosed-path gas analyzer (Model EC155, Campbell Scientific, Inc., USA) in July 2015. Before completely replacing the gas analyzer, the carbon dioxide ($CO_2$) and latent heat fluxes were collected using both gas analyzers simultaneously during a five-month period from August to December in 2015. It was found that the $CO_2$ fluxes were not significantly different between the gas analyzers under the condition that the daily mean temperature was higher than $0^{\circ}C$. However, the $CO_2$ flux measured by the open-path gas analyzer was negatively biased (from positive sign, i.e., carbon source, to 0 or negative sign, i.e., carbon neutral or sink) due to the instrument surface heating under the condition that the daily mean temperature was lower than $0^{\circ}C$. Despite applying the frequency response correction associated with tube attenuation of water vapor, the latent heat flux measured by the enclosed-path gas analyzer was on average 9% smaller than that measured by the open-path gas analyzer, which resulted in >20% difference of the sums over the study period. These results indicated that application of the additional air density correction would be needed due to the instrument heat and analysis of the long-term observational flux data would be facilitated by understanding the underestimation tendency of latent heat flux measurements by an enclosed-path gas analyzer.

• Journal of the Korea Convergence Society
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• v.11 no.2
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• pp.53-60
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• 2020

The purpose of this paper is to evaluate the image of the Styrofoam Wedge that can minimize the position change by supporting the wrist during the True PA and lateral examination of the wrist. In 50 people, the gap between the distal radius joint facet and the wrist bone was measured after the wrist True PA and lateral images were obtained using a general examination(vertical), tube angle(vertical:10°, lateral:20°) and Styrofoam Wedge(vertical). When joint spacing was measured in the True PA and lateral images of the wrist, general examination(5.54mm, 9.42mm), tube angle(2.05mm, 5.07mm) and Styrofoam Wedge(1.79mm, 5.46mm) were shown to be small. The smaller the joint spacing, the easier it is to observe that is open. Therefore, True PA and lateral imaging of the wrist Styrofoam Wedge can reduce the distortion of the image and thus acquire images of high diagnostic value. In addition, it may be possible to reduce the deviation caused by the change of patient's position during re-projection.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.361-366
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• 2017

As the recent development of computing architecture and application software technology, real world simulation, which is the ultimate destination of computer simulation, is emerging as a practical issue in several research sectors. In this paper, metal plate motion in a square shock tube for small time interval was calculated using a supercomputing-based fluid-structure-combustion multi-physics simulation tool called Illinois Rocstar, developed in a US national R amp; D program at the University of Illinois. Afterwards, the simulation results were compared with those from experiments. The coupled solvers for unsteady compressible fluid dynamics and for structural analysis were based on the finite volume structured grid system and the large deformation linear elastic model, respectively. In addition, a strong correlation between calculation and experiment was shown, probably because of the predictor-corrector time-integration scheme framework. In the future, additional validation studies and code improvements for higher accuracy will be conducted to obtain a reliable open-source software research tool.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.20 no.2
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• pp.29-33
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• 2014

Active air flushing mini-pumps were installed in a rigid polypropylene container ($32cm{\time}23cm{\time}18cm$) containing 900 g of fresh green peppers for effectively controlling its $O_2$ concentration on real time basis to preserve the product quality. The performance of the constructed system was compared to that of the modified atmosphere (MA) container system with gas diffusion tube controlled in close/open cycles responding to real time $O_2$ concentration at 10 and $20^{\circ}C$. In the control logic, the $O_2$ concentration was programmed to be located exactly at 13% or stay in the range of 13-15%. The active air flushing system could control the $O_2$ concentration in the desired level or range at both temperatures, while the passive diffusion system could work only under the low temperature condition of $10^{\circ}C$. At higher temperature of $20^{\circ}C$, the passive diffusion system could not manage the produce respiration increased more highly than the gas transfer through the diffusion tube, resulting in too low $O_2$ concentration and too high $CO_2$ concentration which would be injurious to the green pepper. When tested at $20^{\circ}C$, the MA container system could preserve the green pepper better than the perforated air package in terms of weight loss, ascorbic acid and chlorophyll contents and firmness.

• Science of Emotion and Sensibility
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• v.21 no.1
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• pp.83-90
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• 2018

The purpose of this study is for fundamental research of meditation smart wear for physical and mental healing, and researching method for monitoring phase of meditation through textile by measuring the number of abdominal respiration when meditating. For this purpose, the research implemented Single Wall Carbon Nano-Tube (SWCNT) based strain gauges type textile sensor, considered reliability and validity of respiratory sensing, and analyzed efficiency of respiratory sensing based on body parts comparatively. The first preliminary experiment was to evaluate the performance of textile sensor through abdominal model dummy which open and shut of 5 cm repeatedly for 2 minutes at the rate of 0.1Hz in order to simulate abdominal respiration. It concluded signal efficiency between reference sensor(BIOPAC) and textile respiratory sensor appears statistically significant (p<0.001). The second experiment were conducted with 4 subjects doing abdominal respiration under same conditions, and after comparing the signal values between two sensors from 4 attached locations(around center and sides of omphali and phren), center of omphali and sides of phren were selected as suitable location for measuring meditational breathing as they showed large and stable signals. In result, this research aimed for implementing of the textile sensor for sensing meditational breathing of long respiration cycle, review of reliability and validity for sensing number of meditational respiration with the sensor and consideration of sensing efficiency by sensing location on body parts.