• Industry Promotion Research
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• v.9 no.3
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• pp.87-100
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• 2024

This study approached the factors affecting companies's sustainable growth by overcoming the valley of death after starting a business from the perspective of technology, market, location, cluster, and INC model, and conducted a case study on success and failure companies in Daedeok Cluster to explore the adequacy and suitability of the main factors of previous studies. The results of this study suggest that location accessibility-based collaboration between innovators is important for the growth of companies in the cluster, and balanced growth such as innovative ideas, market needs, and capability to meet needs is necessary for companies' products and services to create innovative value in the market. This study is worth in that it presents factors for sustainable corporate growth through the analyses of success and failure cases for companies in the Daedeok Cluster. In addition, the research is successful in that it proposed a policy support plan based on collaboration among companies to foster companies in the cluster.

• Geomechanics and Engineering
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• v.38 no.3
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• pp.319-334
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• 2024

The current theories on the interaction between surrounding rock and support in deep-buried tunnels do not consider the form of pre-reinforcement support or the flexibility of primary support, leading to a discrepancy between theoretical solutions and practical applications. To address this gap, a comprehensive mechanical model of the tunnel with pre-reinforced rock was established in this study. The equations for internal stress, displacement, and the radius of the plastic zone in the surrounding rock were derived. By understanding the interaction mechanism between flexible support and surrounding rock, the three-dimensional construction analysis solution of the tunnel could be corrected. The validity of the proposed model was verified through numerical simulations. The results indicate that the reduction of pre-deformation significantly influences the final support pressure. The pre-reinforcement support zone primarily inhibits pre-deformation, thereby reducing the support pressure. The support pressure mainly affects the accelerated and uniform movement stage of the surrounding rock. The generation of support pressure is linked to the deformation of the surrounding rock during the accelerated movement stage. Furthermore, the strength of the pre-reinforcement zone of the surrounding rock and the strength of the shotcrete have opposite effects on the support pressure. The parameters of the pre-reinforcement zones and support materials can be optimized to achieve a balance between surrounding rock deformation, support pressure, cost, and safety. Overall, this study provides valuable insights for predicting the deformation of surrounding rock and support pressure during the dynamic construction of deep-buried weak rock tunnels. These findings can guide engineers in improving the construction process, ensuring better safety and cost-effectiveness.

• Microbiology and Biotechnology Letters
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• v.52 no.2
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• pp.141-151
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• 2024

Isochrysis sp. is a sea microalga that has become a species of interest because of the extreme lipid content and rapid growth rate of this organism indicating its potential for efficient biofuel production. Using genome sequencing/genome-scale modeling for the prediction of Isochrysis sp. metabolic utilities there is high scope for the identification of essential pathways for the extraction of byproducts of interest at a higher rate. In our work, we design and present iIsochr964, a genome-scale metabolic model of Isochrysis sp. including 4315 reactions, 934 genes, and 1879 metabolites, which are distributed among fourteen compartments. For model validation, experimental culture, and isolation of Isochrysis sp. were performed and biomass values were used for validation of the genome-scale model. OptFlux was instrumental in uncovering several novel metabolites that influence the organism's metabolism by increasing the flux of interacting metabolites, such as Malonyl-CoA, EPA, Protein and others. iIsochr964 provides a compelling resource of metabolic understanding to revolutionize its industrial applications, thereby fostering sustainable development and allowing estimations and simulations of the organism metabolism under varying physiological, chemical, and genetic conditions. It is also useful in principle to provide a systemic view of Isochrysis sp. metabolism, efficiently guiding research and granting context to omics data.

• Journal of Advanced Navigation Technology
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• v.28 no.4
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• pp.436-441
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• 2024

Urban air mobility (UAM) is an innovative air traffic management system that utilizes electric vertical take off and landing aircraft(eVTOL) to transport passengers and cargo in urban areas. The corridor can be defined as the airspace that the vehicle operates in and must be collaboratively managed. For the stable operation of UAM, it is essential to have strategic separation and a collaborative decision-making(CDM) system for cooperation and coordination among stakeholders. This study examines the application of time-based milestones from traditional air traffic flow management to the UAM system to ensure safe traffic volume and optimize air traffic flow. For traffic flow management, the milestone time information is categorized into a total of 13 key milestone time indicators based on the UAM movement status, and the sharing entities providing each time indicator and the flow of milestones are defined. Emphasizing the need for a CDM to balance UAM traffic and capacity, sharing and managing milestone information among stakeholders is expected to improve UAM aircraft departure flow and enhance operational efficiency.

• Journal of the Korean Society of Physical Medicine
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• v.19 no.3
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• pp.73-80
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• 2024

PURPOSE: This study examined the immediate effects of thoracic mobility exercises on the thoracic range of motion and chest expansion to provide data on thoracic mobility exercises in adults. METHODS: Adults were assigned randomly to two groups: the group that performed thoracic mobility exercises (TME group; n=10) or the group that performed thoracic mobility exercises using balance tools (TMEB group; n=10). The exercises were performed for 10 min in three different positions. The range of motion and chest expansion were measured before and after the exercise. RESULTS: The within-group comparisons before and after the intervention showed significant differences in the range of motion measurements for lateral flexion and rotation in the TME and TMEB groups (p < .05); difference in measurements of chest expansion was observed only in the TMEB group (p < .05). No significant differences in the range of motion for flexion and extension were observed in either group or during chest expansion in the TME group (p > .05). The between-group comparisons showed a significant difference in left lateral flexion (p < .05), whereas no other measures differed significantly (p > .05). CONCLUSION: The TME and TMEB groups showed significant increases in the thoracic range of motion; the TMEB group showed a significant increase in chest expansion.

• Journal of the International Relations & Interdisciplinary Education
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• v.4 no.2
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• pp.63-76
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• 2024

Digital technology is progressively transforming rural education and offering unprecedented opportunities for advancement. This study aims to analyze the impact of digital technology on rural education, focusing on the usage of digital resources in Wencheng County, Zhejiang Province, as a case study. The primary objective of this research is to explore how the application of digital technology contributes to balanced educational development in rural areas and to identify the key challenges and issues that accompany such technological advancements. The study revealed several significant issues in Wencheng County's rural education system, including inefficient use of digital resources, inadequate digital skills among educators, and insufficient exploration of digital innovation. In particular, the redundant purchasing of digital educational resources and the inefficient utilization of these resources, coupled with the low adaptability of teachers to digital technologies, emerged as major concerns. The study proposes strategies to address these issues. Ultimately, it presents an optimized pathway for successfully implementing digitalization in rural education and offers policy insights that could be applied in other regions to achieve similar improvements.

• Advances in concrete construction
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• v.17 no.2
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• pp.75-92
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• 2024

High Strength steel reinforced Reactive Powder Concrete (RPC) Beam is a new type of beams which has evident advantages than the conventional concrete beams. However, there is limited research on the shear bearing capacity of high-strength steel reinforced RPC structures, and there is a lack of theoretical support for structural design. In order to promote the application of high-strength steel reinforced RPC structures in engineering, it is necessary to select a shear model and derive applicable calculation methods. By considering the shear span ratio, steel fiber volume ratio, longitudinal reinforcement ratio, stirrup ratio, section shape, horizontal web reinforcement ratio, stirrup configuration angle and other variables in the shear test of 32 high-strength steel reinforced RPC beams, the applicability of three theoretical methods to the shear bearing capacity of high-strength steel reinforced RPC beams was explored. The plasticity theory adopts the RPC200 biaxial failure criterion, establishes an equilibrium equation based on the principle of virtual work, and derives the calculation formula for the shear bearing capacity of high-strength steel reinforced RPC beams; Based on the Strut and Tie Theory, considering the softening phenomenon of RPC, a failure criterion is established, and the balance equation and deformation coordination condition of the combined force are combined to derive the calculation formula for the shear bearing capacity of high-strength reinforced RPC beams; Based on the Rankine theory and Rankine failure criterion, taking into account the influence of size effects, a calculation formula for the shear bearing capacity of high-strength reinforced RPC beams is derived. Experimental data is used for verification, and the results are in good agreement with a small coefficient of variation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.4
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• pp.483-493
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• 2024

This study analyzed changes in groundwater recharge due to urbanization and future climate change using the SWAT hydrological model in the Anseong river basin (1,647 km²) adjacent to the west sea of Korea. The urbanization scenario was constructed based on increasing urban density and expansion, resulting in a decrease in groundwater recharge and recharge rate by 19.9 mm and 1.77 %, respectively. Future climate change scenarios were simulated using two models representing extreme rainfall and drought, with the drought model indicating that maintaining an average recharge rate of 21.6 % would be challenging. Results from the combined scenario of urbanization and extreme drought suggest that groundwater recharge during the spring season in urban areas would be most significantly affected.

• Restorative Dentistry and Endodontics
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• v.49 no.3
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• pp.25.1-25.9
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• 2024

Objectives: This study aimed to evaluate the color stability and solubility of Biodentine and NeoPutty in contact with different irrigation solutions. Materials and Methods: Biodentine and NeoPutty were set in cylindrical molds with 7 mm diameter and 1.5 mm high and immersed in distilled water, 17% ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine (CHX), 9% 1-hydroxyethylidene 1,1-diphosphonate (HEDP), and 5% sodium hypochlorite (NaOCl) solutions for 24 hours. The color change was measured with a spectrophotometer. The solubility values were calculated as the mass loss was expressed as a percentage of the original mass using an analytical balance with 10^-4 g accuracy. Data were analyzed with Kruskal-Wallis followed by Mann-Whitney U tests, and 2-way analysis of variance test followed by Bonferroni corrections for pairwise comparisons for solubility and color stability with a 5% significance threshold, respectively. Results: Biodentine exhibited higher color changes compared to the NeoPutty contact with all solutions except distilled water (p < 0.05). Both hydraulic cements (HCs) showed higher discoloration values immersion in CHX followed by NaOCl. No statistically significant difference was found between Biodentine and NeoPutty regardless of irrigation solution in terms of solubility (p > 0.05). Solubility values were lower in the distilled water group compared to EDTA and CHX (p < 0.05). Conclusions: Tested HCs showed solubility and color changes at various rates. NeoPutty could be an appropriate material in aesthetic areas. The usage of HEDP as an irrigant solution can be considered suitable for various endodontic treatments due to its relatively lower solubility and discoloration values.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.657-666
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• 2014

Coal gasification technology is considered as next generation clean coal technology even though it uses coal as fuel which releases huge amount of greenhouse gas because it has many advantages for carbon capture. Coal or pet-coke slurry gasification is very attractive technology at present and in the future because of its low construction cost and flexibility of slurry feeding system in spite of lower efficiency compared to dry feeding technology. In this study, we carried out gasification experiment using bituminous coal slurry sample by integrating coal slurry feeding facility and slurry burner into existing dry feeding compact gasifier. Especially, our experiment was conducted under fairly lower operation temperature than that of existing entrained-bed gasifier, resulting in partial slagging operation mode in which only part of ash was converted to slag and the rest of ash was released as fly ash. Carbon conversion rate was calculated from data analysis of collected slag and ash, and then cold gas efficiency, which is the most important indicator of gasifier performance, was estimated by carbon mass balance method. Fairly high performance considering pilot-scale experiment, 98.5% of carbon conversion and 60.4% of cold gas efficiency, was achieved. In addition, soundness of experimental result was verified from the comparison with chemical equilibrium composition and energy balance calculations.