• Restorative Dentistry and Endodontics
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• v.45 no.4
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• pp.50.1-50.11
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• 2020

Objectives: In this study, we investigated the potential of amoxicillin-loaded polymeric microspheres to be delivered to tooth root infection sites via a bioactive reparative cement. Materials and Methods: Amoxicillin-loaded microspheres were synthesized by a spray-dray method and incorporated at 2.5% and 5% into a mineral trioxide aggregate cement clinically used to induce a mineralized barrier at the root tip of young permanent teeth with incomplete root development and necrotic pulp. The formulations were modified in liquid:powder ratios and in composition by the microspheres. The optimized formulations were evaluated in vitro for physical and mechanical eligibility. The morphology of microspheres was observed under scanning electron microscopy. Results: The optimized cement formulation containing microspheres at 5% exhibited a delayed-release response and maintained its fundamental functional properties. When mixed with amoxicillin-loaded microspheres, the setting times of both test materials significantly increased. The diametral tensile strength of cement containing microspheres at 5% was similar to control. However, phytic acid had no effect on this outcome (p > 0.05). When mixed with modified liquid:powder ratio, the setting time was significantly longer than that original liquid:powder ratio (p < 0.05). Conclusions: Lack of optimal concentrations of antibiotics at anatomical sites of the dental tissues is a hallmark of recurrent endodontic infections. Therefore, targeting the controlled release of broad-spectrum antibiotics may improve the therapeutic outcomes of current treatments. Overall, these results indicate that the carry of amoxicillin by microspheres could provide an alternative strategy for the local delivery of antibiotics for the management of tooth infections.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.495-507
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• 2023

The purpose of this study is to identify the current status of legal disputes that occur while firefighters are performing their duties and to suggest efficient response measures. To investigate awareness of legal disputes, a survey was conducted on 3,500 firefighters, and the responses of 505 people who participated in the survey were analyzed. As a research method, frequency analysis and cross-analysis were conducted based on the demographic characteristics of the participants and a survey of firefighters' awareness of the law, and through this, basic statistics and status were analyzed. As a result of the analysis, it was found that firefighters feel a lot of burden, including time and material losses, as well as disadvantages and mental anxiety in the workplace when legal disputes occur while performing their duties. The need for an organizational response in the workplace as an efficient response to this was statistically confirmed. Therefore, based on the results of this study, we propose the permanent establishment and operation of a professional legal support team within each city/provincial fire department headquarters so that firefighters can concentrate on their duties free from legal disputes.

• Journal of the Korean Society for Library and Information Science
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• v.58 no.2
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• pp.33-56
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• 2024

In this study, we analyzed the current situation of court libraries and aimed to propose a future-oriented strategy for preserving and managing their collections. Based on literature and status analysis, the study presents the future preservation strategy of court library collections in three main categories: First, securing space for the long-term preservation of court library collections; second, establishing a system for collecting and preserving court library collections; and third, performing digital archiving for the permanent preservation and utilization of court records, valuable legal volumes, administrative materials, and other judiciary-specific resources. Through this, court libraries, including those in various courts, should resolve the issue of insufficient collection storage space, preserve holdings systematically and efficiently, and activate library use.

• Korean Journal of Environment and Ecology
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• v.37 no.3
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• pp.209-220
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• 2023

Over the past few centuries, widespread changes to natural ecosystems caused by human activities have severely threatened biodiversity worldwide. Understanding changes in ecosystems is essential to identifying and managing threats to biodiversity. In line with this need, the IUCN Council formed the IUCN Global Ecosystem Typology (GET) in 2019, taking into account the functions and types of ecosystems. The IUCN provides maps of 10 ecosystem groups and 108 ecological functional groups (EFGs) on a global scale. According to the type classification of IUCN GET ecosystems, Korea's ecosystem is classified into 8 types of Realm (level 1), 18 types of Biome (level 2), and 41 types of Group (level 3). GETs provided by IUCN have low resolution and often do not match the actual land status because it was produced globally. This study aimed to increase the accuracy of Korean IUCN GET type classification by using land cover maps and producing maps that reflected the actual situation. To this end, we ① reviewed the Korean GET data system provided by IUCN GET and ② compared and analyzed it with the current situation in Korea. We evaluated the limitations and usability of the GET through the process and then ③ classified Korea's new Get type reflecting the current situation in Korea by using the national data as much as possible. This study classified Korean GETs into 25 types by using land cover maps and existing national data (Territorial realm: 9, Freshwater: 9, Marine-territorial: 5, Terrestrial-freshwater: 1, and Marine-freshwater-territorial: 1). Compared to the existing map, "F3.2 Constructed lacustrine wetlands", "F3.3 Rice paddies", "F3.4 Freshwater aquafarms", and "T7.3 Plantations" showed the largest area reduction in the modified Korean GET. The area of "T2.2 Temperate Forests" showed the largest area increase, and the "MFT1.3 Coastal saltmarshes and reedbeds" and "F2.2 Small permanent freshwater lakes" types also showed an increase in GET area after modification. Through this process, the existing map, in which the sum of all EFGs in the existing GET accounted for 8.33 times the national area, was modified so that the total sum becomes 1.22 times the national area using the land cover map. This study confirmed that the existing EFG, which had small differences by type and low accuracy, was improved and corrected. This study is significant in that it produced a GET map of Korea that met the GET standard using data reflecting the field conditions. 

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.269-269
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• 2012

A new ion source has been designed, fabricated, and installed at the NBTS (Neutral Beam Test Stand) at the KAERI (Korea Atomic Energy Research Institute) site. The goalis to provide a 100 keV, 2MW deuterium neutral beam injection as an auxiliary heating of KSTAR (Korea Super Tokamak Advanced Research). To cope with power demand, an ion current of 50 A is required considering the beam power loss and neutralization efficiency. The new ion source consists of a magnetic cusp bucket plasma generator and a set of tetrode accelerators with circular copper apertures. The plasma generator for the new ion source has the same design concept as the modified JAEA multi-cusp plasma generator for the KSTAR prototype ion source. The dimensions of the plasma generator are a cross section of $59{\times}25cm^2$ with a 32.5 cm depth. The anode has azimuthal arrays of Nd-Fe permanent magnets (3.4 kG at surface) in the bucket and an electron dump, which makes 9 cusp lines including the electron dump. The discharge properties were investigated preliminarily to enhance the efficiency of the beam extraction. The discharge of the new ion source was mainly controlled by a constant power mode of operation. The discharge of the plasma generator was initiated by the support of primary electrons emitted from the cathode, consisting of 12 tungsten filaments with a hair-pin type (diameter = 2.0 mm). The arc discharge of the new ion source was achieved easily up to an arc power of 80 kW (80 V/1000 A) with hydrogen gas. The 80 kW capacity seems sufficient for the arc power supply to attain the goal of arc efficiency (beam extracted current/discharge input power = 0.8 A/kW). The accelerator of the new ion source consists of four grids: plasma grid (G1), gradient grid (G2), suppressor grid (G3), and ground grid (G4). Each grid has 280 EA circular apertures. The performance tests of the new ion source accelerator were also finished including accelerator conditioning. A hydrogen ion beam was successfully extracted up to 100 keV /60 A. The optimum perveance is defined where the beam divergence is at a minimum was also investigated experimentally. The optimum hydrogen beam perveance is over $2.3{\mu}P$ at 60 keV, and the beam divergence angle is below $1.0^{\circ}$. Thus, the new ion source is expected to be capable of extracting more than a 5 MW deuterium ion beam power at 100 keV. This ion source can deliver ~2 MW of neutral beam power to KSTAR tokamak plasma for the 2012 campaign.

• Fire Science and Engineering
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• v.34 no.2
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• pp.110-119
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• 2020

The National Fire Safety Code (NFSC) sets forth the installation methods and technical standards of firefighting facilities. This information is stipulated in the attached Table 1 of the Enforcement Decree of the Act on Fire Prevention and Installation, Maintenance and Safety Control of Fire-Fighting Systems. The NFSC serves as a foundation for fire prevention and public safety. However, the current version of the NFSC has been under scrutiny due to its delayed enactment and revision process. This is because of its structural inflexibility, time-consuming procedures, and mixed usage of both performance and technical standards. Furthermore, there are difficulties with keeping its unique specialties due to the absence of a specialized, permanent independent entity that enacts, revises, and maintains its standards. Moreover, the NFSC lacks collectivity, openness, and consistency. Therefore, to overcome the aforementioned obstacles, this study investigates the operational and legal status of the NFSC and the problems regarding its enactment and revision process. Further, it presents suggestions for system improvement by analyzing and comparing the information with domestic and foreign counterparts dedicated to managing their similar technical NFSC standards. First, the study recommends that the legal performance and technical standards mixed within the current NFSC should be separated. Second, the enactment and revision of technical standards should be implemented by the private sector and not by the government. Third, technical standards should adopt a user-oriented approach for the code system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.15-28
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• 1992

Temporal variations of the path of the East Korea Warm Current(EKWC) which flows northward along the east coast of Korea were analysed to investigate whether the EKWC directly influences the existence of the so-called Warm Core in the Ulreung basin. From the 13 years(1975-1987) data of the Fisheries Research and Development Agency(FRDA), the $10^{\circ}C$ isotherm at the 100m depth and the depth of $2^{\circ}C$ isotherm and the temperature field at the 200m depth were used for identification of the path and the central position of the Warm Core. Sea surface winds computed from the surface pressure charts gave the monthly-averaged wind stress curl over the East Sea which was used for determination of the Sverdrup transport. And the mass transport stream functions were computed by use of the Sverdrup balance. The variations of the path show that the EKWC does not always have a fixed path and fluctuates with time. And the existence of the Warm Core is independent upon the presence of the EKWC even when the EKWC doesn't flow northward along the east coast of Korea. In view of the mass transport stream functions, the influences of the sea surface winds on the branching of the Tsushima Warm Currents and the presence of the EKWC were investigated. The presence of the EKWC may be hindered by the southward flow driven by the sea surface winds when the Tsushima currents are rather weak. A very weak correlation exists between the north-south component of the Sverdrup transport and the position of the Warm Core. However, a small but significant part of the southward transport across the latitudinal line of $38^{\circ}N$ indicates that cold water from the northern part of the East Sea may be driven and be forced to flow beneath the permanent thermocline in such a way that the thermal structure of the Warm Core and its position might be changed.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.24 no.4
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• pp.259-280
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• 2013

There has been a dramatic increase in the proportion of temporary employees in LIS fields, due to current trends of restructuring, automation, complete personnel systems, and complete wage systems. This research, therefore, conducted a survey exploring the current status and working environment of the temporary posts in LIS fields, in order to understand and direct the employment prospects of potential librarians. Results show that the average working period of more than half of temporary librarians are between 1-3 years. The total working period as a temporary librarian, including former experiences in their career, were evenly distributed between 1-5 years. Among those, being temporary often persisted, as 32% of temporary librarians stayed in their temporary status for more than 5 years. Second, temporary librarians perceived themselves as working the same hours as regular librarians, having independent or assistant tasks to regular librarians, and having a neutral or larger amount of tasks than regular librarians. Third, temporary librarians are employed and contracted from the work place, generally having contracts of less than 2 years or an open contract, which shows a serious level of job instability. Therefore, we should consider the following: proper remuneration for work of equal value, professional contractors, the supplementation of the total wage system and the number of public employees in the system as well as changing temporary positions to permanent positions and so on.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.635-643
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• 2018

This paper propose a method to identify the motor parameters and improve input voltage error which affect the low speed position error of the back-emf(back electromotive force) based sensorless algorithm and to secure the operation reliability and stability even in the case where the load fluctuation is severe and the start and low speed operation frequently occurs. In the model-based observer used in this paper, stator resistance, inductance, and input voltage are particularly influential factors on low speed performance. Stator resistance can cause resistance value fluctuation which may occur in mass production process, and fluctuation of resistance value due to heat generated during operation. The inductance is influenced by the fluctuation due to the manufacturing dispersion and at a low speed where the change of the current is severe. In order to find stator resistance and inductance which have different initial values and fluctuate during operation and have a large influence on sensorless performance at low speed, they are commonly measured through 2-point calculation method by 2-step align current injection. The effect of voltage error is minimized by offsetting the voltage error. In addition, when the command voltage is used, it is difficult to estimate the back-emf due to the relatively large distortion voltage due to the dead time and the voltage drop of the power device. In this paper, we propose a simple circuit and method to detect the voltage by measuring the PWM(Pulse Width Modulation) pulse width and compensate the voltage drop of the power device with the table, thereby minimizing the position error due to the exact estimation of the back-emf at low speed. The suitability of the proposed algorithm is verified through experiment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1483-1491
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• 2010

The purpose of this study was to examine current status of the types of dental filling materials and preventive materials among Korean children in mixed dentition. Seven elementary schools were randomly selected from four metropolitan regions in South Korea. The total of 711 children aged 9-10 years old were examined with their parents’ informed consents. Oral examination was conducted by one trained dentist. The mean number of dfs was $7.9{\pm}8.0$ ($ds=1.3{\pm}2.5,\;fs=6.6{\pm}7.6$) and DMFS was $1.4{\pm}2.2$ ($DS=0.2{\pm}0.8,\;FS=1.1{\pm}2.1$). The average of filled surfaces using amalgam, composites, sealants, and others were $2.8{\pm}3.9,\;1.6{\pm}2.8,\;2.9{\pm}3.2$, and $4.5{\pm}7.0$, respectively. The use of dental filling material according to region, the amalgam was the highest in Daegu and the resin was the highest in Pusan. In permanent teeth, about 70% of total filling surfaces had sealant and about 20% was resin fillings, and the proportion of amalgam filling surfaces was less than 10%.