• Journal of the Korean Geotechnical Society
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• v.37 no.10
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• pp.13-25
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• 2021

The most widely used method for determining the blast effects of explosives is the Trauzl test. This test is used to measure the explosive power (strength) of a substance by determining volume increase, which is produced by the detonation of a tested explosive charge in the cavity of a lead block with defined quality and size. In this paper, Trauzl lead block test and High speed 3D-DIC (Digital Image Correlation) system were conducted to evaluate the stemming effect of the blast hole. The effects of stemming materials can be expressed as the expansion of the cavity in a standard lead block through explosion of the explosives. The blasting experiment was conducted with emulsion explosives. The stemming material in the blast hole of lead block, which was adopted in this study, were using sand and stone chips. Results of blasting experiment and numerical analysis showed that the expansion rates of lead block were most affected by stone chips followed by sand. Also, as result of dynamic strain measurement on the lead block surface of High speed 3D-DIC system, the displacement and surface strain on the block were the highest in the experiment case of stone chips stemming.

• Journal of Chest Surgery
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• v.54 no.5
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• pp.377-382
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• 2021

Background: Subclavian vein (SV) catheterization is a method for the delivery of fluids, drugs, and blood products, venous blood sampling, and central vein pressure monitoring in cardiac surgery. Catheter occlusion is a serious complication of SV catheterization during cardiac surgery, especially after sternal retractor expansion. Methods: In this observational study, 303 patients who had successful right infraclavicular SV catheterization from September 2019 to April 2020 were enrolled to determine the incidence of catheter occlusion. After catheterization, the lumens of all catheters were checked for the ability to infuse and withdraw blood from the catheter before and after sternal retractor expansion. The patients' characteristics, cannulation approach, on-pump or off-pump technique, occlusion of the catheter and its lumens, and any associated complications were recorded. The data were analyzed using IBM SPSS ver. 22.0 (IBM Corp., Armonk, NY, USA). Results: Of the 303 patients studied, 205 were male (67.7%) and 98 were female (32.3%). Catheter occlusion occurred in 11 patients with on-pump cardiopulmonary bypass (CPB) (227 patients) and 4 patients with off-pump CPB (76 patients) (p=0.863). The incidence of catheter occlusion was 4.95% (15 of 303 patients) with no cases of simultaneous 3-lumen occlusion in a catheter. The most commonly occluded lumen was the distal lumen (57.92%). Simultaneous 2-lumen occlusion occurred in 4 patients. Catheter occlusion was found in 3 of 13 malpositioned catheters (23.07%). Conclusion: The current study showed that malpositioning of the catheter tip was a risk factor for catheter occlusion and that the distal lumen of a triple-lumen catheter was the most commonly occluded lumen.

• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.49-56
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• 2021

Liquefied Petroleum Gas is divided into liquefied gases containing propane (C₃H₈) and butane (C₄H₁₀). The quality of LPG varies greatly depending on the composition of the mixture, so it is important to measure the composition accurately. It is difficult to determine the composition of the mixture because liquid and gas coexist at room temperature. Therefore, the uncertainty in determining the concentration of hydrocarbons by component is high, and there are many problems that differ from the actual content standard. Therefore, it is necessary to develop a mixed liquid propane standard gas for the composition and accurate concentration of hydrocarbon substances. Mixed liquid propane standard gas is manufactured into bellows-type constant-pressure cylinders by ISO-6142 (2015). The homogeneity of the four standard gases manufactured was confirmed to be GC-FID. The manufacturer's uncertainty of expansion was 0.01 % to 0.30 % and homogeneity was 0.03 % to 0.25 %. In this mixed liquid propane standard gas, the relative expansion uncertainty of weight method, manufacturing consistency, cylinder adsorption and long-term stability was developed within 0.26 %-1.3 9% (95% of confidence level, k=2).

• Clean Technology
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• v.24 no.4
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• pp.332-338
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• 2018

Currently graphite is used as an anode active material for lithium ion battery. However, since the maximum theoretical capacity of graphite is limited to $372mA\;h\;g^{-1}$, a new anode active material is required for the development of next generation high capacity and high energy density lithium ion battery. The maximum theoretical capacity of Si is $4200mA\;h\;g^{-1}$, which is about 10 times higher than the maximum theoretical capacity of graphite. However, since the volume expansion rate is almost 400%, the irreversible capacity increases as the cycle progresses and the discharge capacity relative to the charge is remarkably reduced. In order to solve these problems, it is possible to control the particle size of the Si anode active material to reduce the mechanical stress and the volume change of the reaction phase, thereby improving the cycle characteristics. Therefore, in order to minimize the decrease of the charge / discharge capacity according to the volume expansion rate of the Si particles, the improvement of the cycle characteristics was carried out by pulverizing Si by a dry method with excellent processing time and cost. In this paper, Si is controlled to nano size using vibrating mill and the physicochemical and electrochemical characteristics of the material are measured according to experimental variables.

• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.77-87
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• 2019

While the expansion of protected areas in accordance with Korea's National Biodiversity Strategy contributions to the conservation of biological diversity, it incurs economic losses and poses threats to the livelihoods of local residents. Payment for ecosystem services (PES) compensates local residents for their economic damages in a sustainable manner. To assess feasibility of PES, there is a need to estimate the general public's benefits from biodiversity conservation in protected areas. This study attempted to estimate visitors' willingness to pay (WTP) for biodiversity conservation in Mt. Jiri using the contingent valuation method (CVM). The WTP of respondents for the expansion of protected areas to increase biodiversity conservation was estimated at 16,103 KRW per household per year and this equates to a total of 316.8 billion KRW for all the households in Korea. The higher a respondent's age, education level and household income level, the more willing he or she is to pay for biodiversity conservation. Likewise, respondents who are aware of Mt. Jiri's designation as an Ecosystem and Landscape Conservation Area are more willing to pay for biodiversity conservation. Moreover, the higher the importance placed on biodiversity conservation policy, the higher the willingness to pay for biodiversity conservation. To enhance the feasibility of PES schemes, it is necessary to improve the general public's knowledge and awareness of biodiversity by providing opportunities for education and more information on biodiversity and biodiversity policies.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.107-116
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• 2020

The compaction grouting technique is widely used to improve the liquefaction resistance of loose sands that are liquefaction-prone. Particularly, the horizontal injection of compaction grout is proposed for the liquefiable ground with an overlying structure as it does not allow the vertical compaction grouting. However, there has been limited number of researches on the horizontal compaction grouting. Therefore, this study explores the grout bulb shape and expansion direction in loose sand. A series of scaled two-dimensional experiments on the horizontal compaction grouting was conducted varying the overburden stress. The results show that the grout bulb grows in an elliptical shape though its directivity of major axis changes with the overburden effective stress and relative density. The grout bulb expands faster in a horizontal direction under a low overburden stress with a small relative density. The higher overburden stress and the greater relative density cause the more circular shape with the faster expansion in a vertical direction. The presented finding is expected to contribute to accurate and efficient design of the horizontal compaction grouting method.

• Journal of Korean Library and Information Science Society
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• v.52 no.1
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• pp.109-128
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• 2021

This paper is to explore considerations in authority control to accommodate LRM nomen entities through the literature reviews, the analysis of RDA rules, and the opinion survey of domestic catalog experts. As a result, for authority control, considerations were proposed in the aspect of nomen's attribute elements, catalog description, and MARC authority format. First, it is necessary to describe in as much detail as possible the category, the scheme, intended audience, the context of use, the reference source, the language, the script, the script conversion as the attributes of the nomen with the status of identification, note, and indifferentiated name indicators added in RDA. Second, the description method of attribute elements and relational elements of nomen can be unstructured, structured, identifier, and IRI as suggested in RDA, and vocabulary encoding scheme (VES) and string encoding scheme (SES) should be written for structured description, Also, cataloging rules for structuring authorized access points and preferred names/title should be established. Third, an additional expansion plan based on Maxwell's expansion (draft) was proposed in order to prepare the MARC 21 authority format to reflect the LRM nomen. (1) The attribute must be described in 4XX and 5XX so that the attribute can be entered for each nomen, and the attributes of the nomen to be described in 1XX, 5XX and 4XX are presented separately. (2) In order to describe the nomen category, language, script, script conversion, context of use, and date of usage as a nomen attribute, field and subfield in MARC 21 must be added. Accordingly, it was proposed to expand the subfield of 368, 381, and 377, and to add fields to describe the context of use and date of usage. The considerations in authority control for the LRM nomen proposed in this paper will be the basis for establishing an authority control plan that reflects LRM in Korea.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.1
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• pp.29-38
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• 2022

Recently, seismic design for anchors is required, which are used for connecting structural members and non-structural and structural members. In this study, pull-out tests on the new expansion anchors which have been developed for cracked concrete. The anchors of 12 mm and 20 mm diameters were tested which are commonly used. Experiments were conducted on non-cracked concrete and cracked concrete to evaluate the seismic performance of the post-installed anchor. The experimental method complies with the specified test protocol (KCI, 2018). Three experimental variables are included in this study: presence of cracks, concrete compressive strength, and effective embedment depth. The strength of the anchors was evaluated with the characteristic capacity K_5% determined from the test results incorporated with the safety of 5% fractile. The characteristic capacity K_5% of the non-cracked and cracked concrete specified in KDS 14 20 54 are 9.8 and 7.0, respectively. Test results show that all groups except the three groups have higher characteristic capacity K_5% than the KDS code and the nominal strengths of the tested anchors can be determined with the obtained characteristic capacity K_5%.

• Journal of Korea Entertainment Industry Association
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• v.15 no.2
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• pp.179-189
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• 2021

As the school was in crisis due to the COVID-19, e-Learning was extended. Although it was difficult for everyone, e-Learning were stabilized with the enthusiasm and efforts of school teachers. Online education in Korea, called 'K-edu' is being promoted by school teachers in COVID19, and is considered an important area of future education beyond the post corona. Therefore, analyze the meaning of K-edu experienced by school teachers, studying changes in the educational paradigm in the Post-COVID era is very important in establishing the direction and content of future education. In this study described the K-edu experienced by school teachers in response to Corona 19 as 'changed daily life of school teachers', 'changes in schools', 'difficulties felt by teachers' and 'proposals for K-edu' through the qualitative research method FGI. Based on this, the characteristics of K-edu that changed through COVID-19 were analyzed as 'expansion of educational space', 'expansion of educational form' and 'highlighting the importance of face-to-face education'. Through this study, we hope that K-Edu led by school teachers will serve as a cornerstone for leading the world beyond Korea.

• Journal of Korea Entertainment Industry Association
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• v.15 no.2
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• pp.83-97
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• 2021

This study started with curiosity about theatre without its three elements and would reveal its possibility through performance and experiment and promote the expansion of each element and the development of a new form at the same time. After the occurrence of COVID-19, theatre has come up against a big limitation of contact-free, untact communication due to its inherent characteristic of 'presence.' For the survival of theatre in the rapidly changing world, it is desperately necessary to check the existing performance method and to be concerned about its development for the future. Thus, this researcher started from a more fundamental exploration of theatre focused on an "experiment of theatre without its three elements" and would sort out the three elements (actors, audience, and a play) from a macroscopic perspective. Also, the researcher would investigate the impacts of these elements on the performance and the possibility of theatre even after removing the elements through performance and experiment. This study consists of one performance and two experiments and is based on the interviews and progress details conducted by the planner and experimenter and the survey with the experiment participants. The significance of this study is its reflection on the essence of the genre, theatre, and the roles of all elements constituting that, not from a narrow perspective that would simply define the concepts of the elements but through the expansion and change of them. Furthermore, hopefully, it will be connected to the discovery of a new theatrical format that has not been considered through its combination with another genre.