• Progress in Superconductivity and Cryogenics
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• v.18 no.4
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• pp.15-20
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• 2016

The effects of electron beam (EB) irradiation on the superconducting critical temperature ($T_c$) and critical current density ($J_c$) of YBCO films were studied. The YBCO thin films were irradiated using a KAERI EB accelerator with an energy of 0.2 MeV and a dose of $10^{15}-10^{16}e/cm^2$. A small $T_c$ decrease and a broad superconducting transition were observed as the EB dose increased. The value of $J_cs$ (at 20 K, 50 K and 70 K) increased at doses of $7.5{\times}10^{15}$ and $2.2{\times}10^{16}e/cm^2$. However, $J_cs$ decreased as the dose increased further. The X-ray diffraction (XRD) analysis showed that the c axis of YBCO was elongated and the full width at half maximum (FWHM) increased as the dose increased, which is strong evidence of the atomic displacement by EB irradiation. The transmission electron microscopy (TEM) showed that the amorphous layer formed in the vicinity of the surfaces of the irradiated films. The amorphous phase was often present as an isolated form in the interior of the films. In addition to the formation of the amorphous phase, many striations running along the a-b direction of YBCO were observed. The high magnification lattice image showed that the striations were stacking faults. The enhancement of $J_c$ by EB irradiation is likely to be due to the lattice distortion and the formation of defects such as vacancies and stacking faults. The decrease in $J_c$ at a high EB dose is attributed to the extension of the amorphous region of a non-superconducting phase.

• Journal of Korean Critical Care Nursing
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• v.14 no.2
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• pp.1-11
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• 2021

Purpose : The aim of this study was to propose appropriate nurse staffing of adult intensive care units considering patients' nursing care needs according to the Workload Management System for Critical Care Nurses (WMSCN). Methods : In a cross-sectional survey conducted in September 2017, 1,786 patients' WMSCN scores, surveys from 2,145 nurses, and administrative data from 118 units in 41 hospitals were analyzed. The means (standard deviations) of the aforementioned scores and nursing hours per patient day were presented. Nurse-to-patient ratios and nurse-to bed ratios for staffing to meet patients' nursing care needs were calculated. Results : The mean WMSCN scores were 109.50±17.17 in tertiary hospitals and 96.38±19.26 in general hospitals. Nursing hours per patient day were 12.47±2.80 in tertiary hospitals and 11.01±2.45 in general hospitals. Nursing hours per patient day correlated with WMSCN scores. Nurse-to-bed ratios required for the provision of ICU nursing care ranged from 1: 0.36 to 1: 0.48. Conclusion : Our findings provide evidence that current ICU nurse staffing is insufficient for meeting patients' nursing care needs. We suggest adjusting the legal standards for adequate nurse staffing considering these needs.

• The Journal of Pediatrics of Korean Medicine
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• v.36 no.1
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• pp.65-77
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• 2022

Objectives The purpose of this study was to understand the public's perception of Korean medical treatment for growth disorders to develop Korean medicine clinical practice guidelines and critical pathways for growth disorders in children and adolescents. Methods A survey was conducted using an online platform targeting 252 adults aged 19 years from May 16, 2021 to May 17, 2021. The questionnaire consisted of questions about the demographic characteristics of respondents; overall perception, experience, and satisfaction with Korean medical treatment for growth disorders; willingness to use or recommend Korean medical treatment for growth disorders; and points for improvement. Results The overall perception of treatment for growth disorders was 3.30 ± 0.892 on a 5-point scale. Concerning the negative reasons, 54.4% of the respondents were concerned about safety; regarding the positive reason, expectations for overall health as well as height growth were the highest at 46.5%. Additionally, there was a high demand for information, such as providing safety information on treatment, presenting evidence for the efficacy of treatment, and standardized clinical process, as points requiring improvement. Conclusions To raise public perception of Korean medical treatment for growth disorders, it is necessary to satisfy the opinions of the public identified through this survey. Therefore, the development and utilization of Korean medicine clinical practice guidelines and critical pathways for growth disorders would play an important role.

• Clinics in Shoulder and Elbow
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• v.27 no.1
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• pp.26-31
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• 2024

Background: The coracoacromial ligament (CAL) is frequently observed to be damaged during arthroscopy and it is unclear how demographic, anatomic, and radiographic factors are related to CAL degeneration in full-thickness rotator cuff tears. Methods: A prospective study was conducted of patients at a single institution undergoing shoulder arthroscopy for first-time, full-thickness rotator cuff tears. We evaluated preoperative anteroposterior radiographs to obtain critical shoulder angle, glenoid inclination, acromial index, acromiohumeral distance, lateral acromial angle, and acromial morphology. We documented CAL quality, rotator cuff tear size and pattern during arthroscopy. Multiple logistic regression was used to identify predictive factors for encountering severe CAL fraying during arthroscopy. Results: Shoulders had mild CAL degeneration in 58.1% of cases, whereas severe CAL degeneration was present in 41.9% of shoulders. Patients with severe CAL attrition were significantly older (62.0 years vs. 58.0 years, P=0.042). Shoulders with severe CAL attrition had large rotator cuff tears in 54.1% of cases (P<0.001), and tears involving the infraspinatus (63.2% vs. 29.6%, P=0.003). The severe degeneration group was more likely to have a larger critical shoulder angle measurement on preoperative radiographs than those in the mild attrition group (36.1°±3.6° [range, 30°-45°] vs. 34.1°±3.8° [range, 26°-45°], P=0.037). Conclusions: While the clinical impact of CAL degeneration remains uncertain, increased severity of CAL degeneration is associated with older age, larger rotator cuff tear size, presence of infraspinatus tearing, and increased preoperative critical shoulder angle. Level of evidence: III.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.5
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• pp.111-118
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• 2011

With increasing interest in health promotion and quality of life, growing attention has been focused on the beneficial effects of urban green area. However, very few evidence-based approaches have been conducted on the health-related benefits of urban greenery. Therefore, this study examined the health-related benefits of green areas using physiological and psychological indices to obtain evidence-based data on these benefits. Twenty male university students were selected as subjects. Data were collected when participants viewed landscapes in a green area or an urban area for fifteen minutes. This research was reviewed and approved by the Ethics Committee of School of Medicine, Chungnam National University. Physiological data in the green area revealed significantly decreased heart rates, significantly increased high-frequency value of heart rate variability, an index of parasympathetic activity, and reduced salivary cortisol concentration, a stress hormone, compared to the urban area. Psychological tests showed the green area significantly reduced the negative mood state and psychological symptoms, and significantly increased the positive mood state. Our data provided evidence for the health-related benefits of green areas, and the findings of this study support that green areas can play a critical role in health promotion for urban residents, by positively affecting autonomic nervous and endocrinal activities.

• Journal of Mechanical Science and Technology
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• v.20 no.1
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• pp.59-65
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• 2006

A half-scaled large test model for the main components of the real annular structure was built and the thermal behaviors were experimented and obtained by thermal cyclic loads. The model design and the test conditions for the thermal loads were determined to take into consideration the thermal and mechanical loads acting on the real annular structure by finite element analyses. Temperature profiles and strains of the main components of the model were measured at an early stage of the test and periodically throughout the test in the given test conditions. After completion of the thermal cyclic tests, no evidence of crack initiation and propagation were identified by a dye penetration test. The measured strains at the critical parts were slightly increased proportionally with the increase in the number of the thermal cycles.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.5
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• pp.341-347
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• 2003

This paper presents an improved escalator dynamic model so as to reflect the experimental observation on the pseudo-resonance affected by load applied. The experimental evidence reveals that backlash on gearbox as well as sag of driving Chain are most critical factors to the pseudo-resonance in escalators. The dynamic model effectively reflects vibration characteristics measured in real escalators with respect to different conditions of driving chain and the number of passengers. For validation of the dynamic model developed. numerical results from the model are compared with experimental results. The developed model and its simulation results are used rigorously for the design of escalator systems in enhancing the ride comfort.

• 한국논리학회:학술대회논문집
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• 2008.07a
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• pp.73-92
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• 2008

Describing a physical system in idealized terms involves making literally false claims about the system. Given this, it is puzzling that justified beliefs about physical systems can be formed by starting with idealized descriptions and then performing mathematical calculations. I argue that this puzzling aspect of idealizations cannot be easily removed by introducing talk of approximations. I go on to develop an account of how this curious feature of idealizations is to be understood. My account requires us to reassess what precisely we take the laws of physics to be saying, and also has consequences concerning the kind of evidence we can have for thinking that mathematics is the 'language of nature'. Finally, some critical comparisons are made with the so-called model-based account of scientific laws developed by Cartwright and Giere.

• The Journal of Information Systems
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• v.11 no.2
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• pp.47-72
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• 2002

In the beginning of new millennium, Business-to-Business(B2B) Electronic Commerce(EC) is a hot issues of the world business and economic communities. The market of B2B EC is increasing rapidly, and become a more complex and competitive because many participants and intermediaries are play on their own objectives and strategies. To cope with the situation, participants of B2B EC market should make play with a competitive strategies. So, the participant enterprises must know the critical success factors of their own EC market. This study identifies B2B EC success factor measurement sets, and explores several success factors based on the perceived importance of B2B EC practitioner in the manufacturing enterprises. The study tests the differences of success factors by IS level, EC business model characteristics, and EC introduction and operating characteristics.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.593-596
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• 2004

We introduce a method of identifying evidence of shocks in the X-ray emitting gas in clusters of galaxies. Using information from synthetic observations of simulated clusters, we do a blind search of the synthetic image plane. The locations of likely shocks found using this method closely match those of shocks identified in the simulation hydrodynamic data. Though this method assumes nothing about the geometry of the shocks, the general distribution of shocks as a function of Mach number in the cluster hydrodynamic data can be extracted via this method. Characterization of the cluster shock distribution is critical to understanding production of cosmic rays in clusters and the use of shocks as dynamical tracers.