• Journal of Powder Materials
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• v.25 no.6
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• pp.459-465
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• 2018

Most commercially available detonation nanodiamonds (DNDs) require further processing to qualify for use in biomedical applications, as they often contain many impurities and exhibit poor dispersibility in aqueous media. In this work, DNDs are modified to improve purity and impart a high colloidal stability to the particles. The dispersive and adsorption properties of modified DNDs are evaluated in terms of the suitability of DNDs as carriers for non-steroidal anti-inflammatory drugs (NSAIDs) in transdermal delivery. The study of adsorption on strongly positively and strongly negatively charged DNDs showed their high loading capacity for NSAIDs, and a pronounced relationship between the drugs and the particles' charges. Experiments on long-term desorption carried out with DND/NSAID complexes indicate that the nanoparticles exert a sustained effect on the drug release process.

• Korean Journal of Materials Research
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• v.28 no.11
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• pp.671-679
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• 2018

Finite element analyses are carried out to understand the piezoelectric behaviors of ZnO nanowires. Three different types of ZnO nanowires, with aspect ratios of 1:2. 1:31, and 1:57, are analyzed for uniaxial compression, pure bending, and buckling. Under the uniaxial compression with a strain of $1.0{\times}10^{-4}$ as the reference state, it is predicted that all three types of nanowires develop the same magnitude of the piezoelectric fields, which suggests that longer nanowires exhibit higher piezoelectric potential. However, this prediction is not in agreement with the experimental results previously reported in the literature. Such discrepancy is understood when the piezoelectric behaviors under bending and buckling are considered. When only the strain field due to bending is present in bending or buckling, the antisymmetric nature of the through-thickness stain distribution indicates that two piezoelectric fields, the same in magnitude and opposite in sign, develop along the thickness direction, which cancels each other out, resulting in a zero net piezoelectric field. Once additional strain contribution due to axial deformation is superposed on the bending, such field cancelling is compensated for due to the axial component of the piezoelectric field. Such numerical predictions seem to explain the reported experimental results while providing a guideline for the design of nanowire-based piezoelectric devices.

• Journal of Home Health Care Nursing
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• v.25 no.3
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• pp.215-223
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• 2018

Purpose: The purpose of this study was to investigate effects of nurse managers' conflict management styles on nurses' levels of leader trust and organizational commitment. Methods: For this study, a descriptive survey design was used. The participants were 165 nurses who had worked more than 1 year in a university hospital. Data were collected from September 1 to September 10, 2016, using a self-report questionnaire. The collected data were analyzed using descriptive statistics, t-tests, ANOVA, Scheffe's tests, Pearson's correlation coefficients, and multiple regression analysis. Results: Among the nurse managers' conflict management styles, the problem-solving style was positively correlated with both leader trust and organizational commitment. Concession-avoiding and control-leading styles were negatively correlated with both variables. Furthermore, the problem-solving style was found to have significant influence on both leader trust and organizational commitment. Conclusion: In order to more actively cope with conflict situations occurring in the nursing work environment, nursing managers need to exhibit more effective attitudes of conflict management. This study suggests that the problem-solving style is a desirable conflict management style in terms of increasing leader trust and organizational commitment.

• Journal of the Korean Society of Safety
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• v.34 no.1
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• pp.53-61
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• 2019

This study performs reliability analysis of three-dimensional temporary shoring structures with three different models. The first model represents a field model which does not have diagonal bracing members. The installation of bracing members is often neglected in the field for convenience. The second model corresponds to a design model which has the bracing members with the hinge connection of horizontal and bracing members at joints. The third model is similar to the second model but the hinge connection is replaced with partial rotational stiffness. The reliability analysis results revealed that the vertical members of the three models are safe enough in terms of axial force, but the vertical and horizontal members exhibit a big difference among the three models in terms of combination stress of axial force and bi-axial bending moments. The field model showed significant increase in failure probability for the horizontal member, and thus the results demonstrate that the bracing member should be installed necessarily for the safety of the temporary shoring structures.

• The Journal of Industrial Distribution & Business
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• v.12 no.5
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• pp.27-36
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• 2021

Purpose: This study empirically investigates the effect of collaborative communication and information sharing on the supply chain performance of South Korean pharmaceutical companies. Specifically, it understands the importance collaborative communication and suggests a method for investigating communication in academic research on the pharmaceutical industry. Investigating this sector is crucial because the importance of the pharmaceutical industry is increasing globally against the background of the Covid-19 pandemic. Research design, data, and methodology: A questionnaire was administered to employees of South Korean pharmaceutical companies and 244 valid responses were used for the statistical analysis. Additionally, structural equation modeling was used to measure the relationships between the observed and latent variables. Results: Collaborative communication has a positive effect on information sharing. However, information sharing, unlike collaborative communication, does not exhibit a significant positive relationship with supply chain performance. These results indicate that it is important to communicate effectively in the supply chain rather than strive for the right type of information sharing. Conclusions: Consumers and retailers within the supply chain should continue to strive for candid communication. This study is meaningful, as it empirically tests the relationships between collaborative communication, information sharing, and supply chain performance in the South Korean pharmaceutical industry.

• Journal of Agricultural Extension & Community Development
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• v.28 no.2
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• pp.85-98
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• 2021

This study aims to examine consumer types based on pet food selection attributes and to analyze the differences in consumer characteristics by those types. In this study, the researcher uses k-means cluster analysis and crossover analysis to determine market segmention, and then analyzes the resultant characteristics by categorizing consumers. A total of 202 cases are used for this study. First, the selection attributes are classified into the six factors of credibility, quality, design, convenience, information, and price. Second, the clusters are categorized into the four clusters, which are designated pet food lower-involvement type, pet food information- and price-seeking type, pet food convenience-seeking type, and pet food higher-involvement type. Third, these four groups exhibit statistically significant differences in terms of occupational variables, number of pets, and purchase frequency. The results of this study may provide helpful information in establishing customized, market-based marketing strategies based on the characteristics of pet food consumers.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.5
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• pp.125-132
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• 2019

Ultra-high performance concrete (UHPC) has high compressive and tensile strengths due to the particle packing, and its ductile behavior can be ensured by utilizing steel fibers. However, since the UHPC members exhibit different characteristics of crack behavior and tensile behavior from normal concrete, the tension stiffening and cracking characteristics of the UHPC should be accurately modeled for the design and analysis of the UHPC members. In this study, uniaxial tension tests was conducted on the UHPC members with strands, where the test variables were diameter and reinforcing ratio of strands. Detailed analyses were also conducted to identify the tensile characteristics and crack behavior of the UHPC members. By comparing the test results with current code provisions and other models proposed by existing researchers, their applicability for estimation of crack behavior of the UHPC members was examined.

• Steel and Composite Structures
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• v.37 no.6
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• pp.679-693
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• 2020

This paper investigates the seismic response of buildings equipped with Self-Centering Energy Dissipating (SCED) braces. Two-dimensional models of 3, 6, 12 and 16-story SCED buildings considering both material and geometric nonlinearities are investigated by carrying out pushover and nonlinear time-history analyses. The response indicators of the buildings are studied for weight-scaled ground motions to represent the Design Basis Earthquake (DBE) level and the Maximum Considered Earthquake (MCE) event. The fragility curves of the buildings for two Immediate Occupancy (IO) and Life Safety (LS) performance levels are developed using Incremental Dynamic Analysis (IDA). Results of the nonlinear response history analyses indicate that the maximum inter-story drift occurs at the taller buildings. The mean peak inter-story drift is less than 2% in both hazard levels. High floor acceleration peaks are observed in all the SCED frames regardless of the building height. The overall ductility and ductility demand increase when the number of stories reduces. The results also showed the residual displacement is negligible for all of case study buildings. The 3 and 6-story buildings exhibit desirable performance in IO and LS performance levels according to fragility curves results, while 12 and 16-story frames show poor performance especially in IO level. The results indicated the SCED braces performance is generally better in lower-rise buildings.

• Journal of Korean Association for Spatial Structures
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• v.21 no.1
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• pp.71-78
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• 2021

The U-flanged truss hybrid beam is a new composite beam made by pouring concrete into the U-flanged truss beam. In this study, an experimental study was performed to verify the shear capacity of U-flanged truss hybrid beams with the newly developed end reinforcement details. For all specimens, the maximum shear strength was determined by shear failure of concrete in the loading point The detail reinforced with stirrups at the end zone can exhibit the greatest shear strength, but the method of reinforcing the end zone using vertical steel plates, which is a relatively easy method to manufacture, is considered to be the most effective detail in terms of shear strength and ductility. Also, in the case of U-flanged truss hybrid beams reinforced with vertical steel plates at the end zone, the shear strength can be evaluated on the safety side by using the Korea Design Standard formula.

• Tribology and Lubricants
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• v.37 no.1
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• pp.1-6
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• 2021

This paper presents the experimental results of hydrophobic surfaces developed using a stereolithography-based additive-manufacturing technique. The additive manufacturing technique can be used to manufacture objects with complex geometries from computer-aided design data. Several additive manufacturing methods, such as selective laser sintering, fused deposition modeling, stereolithography apparatus (SLA), and inkjet-based system, have been developed. The SLA is a form of three-dimensional printing technology used to create prototypes, patterns, and production parts in successive layers through photochemical processes. Light causes chemical monomers and oligomers to cross-link together to form objects composed of polymers. Moreover, this method is economical for fabricating surfaces with high output resolution and quality. Here, we fabricate various surfaces using different shapes using an SLA. The surfaces with micro-patterns are fabricated for 10 cases, including the biomimetic surface. The fabricated surfaces with various micro-patterns are evaluated for hydrophobicity performance based on the static contact angle. The contact angle is measured three times for each case, and the averaged value is used. The results indicate that the arrangements in a staggered structure have a larger contact angle than those in a line when the same micro-pattern is applied. Moreover, the mimetic surfaces exhibit more hydrophobic characteristics than those of artificial micro-patterns.