• Journal of Ecology and Environment
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• v.48 no.3
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• pp.285-295
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• 2024

Although invasive alien species (IAS) have a negative impact on native ecosystems and reduce ecosystem services and productivity, the understanding of IAS at the population level is still lacking. Coreopsis lanceolata, a perennial plant native to North America, is expanding its invasive range, but there is limited research on the invasion risk of this species, and measures to control its spread are inadequate. Therefore, we collected findings from selected studies on C. lanceolata, examining its morphological and growth characteristics, reproductive traits, and invasion strategies, sourced from scientific databases using its scientific name as the keyword. Researchers have conducted extensive research on C. lanceolata, primarily focusing on the extraction of chemical compounds for anticancer and antioxidant effects and numerous studies on seed germination conditions in the field of ecology. Coreopsis lanceolata has a negative impact on plant ecosystems in Australia and Japan, and its high invasiveness is associated with high seed production, high seed viability and longevity, rapid reproduction through rhizomes, high surface coverage, and long flowering periods. Few studies have examined the invasive potential of C. lanceolate and management techniques to stop its spread, despite worries about the detrimental effects of invasion on plant ecosystems. Therefore, additional research on the invasion risk and management of C. lanceolata is necessary. This review offers a thorough analysis of C. lanceolata, serving as a scientific foundation for devising future ecosystem management strategies.

• Journal of Korea Foundry Society
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• v.3 no.4
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• pp.248-255
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• 1983

The effect of chromium, aluminium and copper contents on the structures and mechanical properties of cast iron was investigated. 1) Mechanical properties were improved with the formation of ledeburite by chromium addition. The primary carbides dispersed in martensitic matrix contributed to high strength and wear resistance. 2) Small addition of aluminium decreased hardness of the cast iron. 3) The impact values were decreased by the formation of the double carbides but improved by the heat treatment. 4) Small addition of copper up to a certain level increased the hardness. Also impact values were considerably increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.604-613
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• 2018

In recent years, numerous train derailment accidents caused by deterioration and high speed technology of railways have increased. Guardrails or barriers of railway bridges are installed to restrain and prevent the derailment of the train body level. On the other hand, it can result in a high casualties and secondary damage. Therefore, a Derailment Containment Provision (DCP) within the track at the wheel/bogie level was developed. DCP is designed for rapid installation because it reduces the impact load on the barrier and inertia force on the steep curve to minimize turnover, fall, and trespass on the other side track of the bridge. In this paper, DCP was analyzed using LS-Dyna with a parameter study as the impact loading location and interface contact condition. The contact conditions were analyzed using the Tiebreak contact simulating breakage of material properties and Perfect bond contact assuming fully attached. As a result, the Tiebreak contact behaved similarly with the actual behavior. In addition, the maximum displacement and flexural failure was generated on the interface and DCP center, respectively. The impact analysis was carried out in advance to confirm the DCP design due to the difficulties of performing the actual impact test, and it could change the DCP anchor design as the analysis results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.3013-3022
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• 2013

Satisfying the large car impact condition of the high level SB5-B for "SMART Highway" longitudinal barriers, the possibility of increase of the small car impact velocity from 120km/h to 130km/h was investigated. Through computer simulation using input parameters calibrated to full-scale crash test results, various longitudinal semi-rigid barrier models were improved such that for the small car impact speed of 120km/h the change of longitudinal and transverse velocities of the impact vehicle can satisfy the THIV limit. The barrier model determined through this process satisfied the performance assessment criteria for SB5-B impact conditions. Varying the wing angle of slip block-outs of the passed barrier model, the possibility of increase of the small car impact velocity was investigated by FEA and a full-scale crash test was conducted. It has been shown that the possibility to increase the small car impact speed to 130km/h is high if the test facility condition for 130km/h impact velocity is better equipped.

• Steel and Composite Structures
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• v.16 no.6
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• pp.595-609
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• 2014

The paper is reporting some comparisons between experimental and numerical results in terms of failure mode, failure time and ballistic properties of mild steel sheet. Several projectile shapes have been considered to take into account the stress triaxiality effect on the failure mode during impact, penetration and perforation. The initial and residual velocities as well as the failure time have been measured during the tests to estimate more physical quantities. It has to be noticed that the failure time was defined using a High Speed Camera (HSC). Thanks to it, the impact forces (average and maximum level), were analyzed using numerical simulations together with an analytical description coupled to experimental observations. The key point of the model is the consideration of a shape function to define the pulse loading during perforation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.10 s.115
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• pp.1036-1043
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• 2006

Damping materials for reducing heavy-weight floor impact noise in reinforced concrete structures were tested in apartment buildings. The effect of damping materials and an impact isolator were compared with an on-site experiment conducted in a high-rise apartment building. The loss factor of damping material analyzed more than 2 times than rubber to $1.5{\sim}2.3$, could know that Damping layer has excellent attenuation performance in side of vibration reduction. The results showed that the resonance frequency increased but vibration acceleration level decreased when the damping materials were used. The heavy-weight impact sound levels of the structure decreased substantially at 63 Hz, whereas the sound levels of the structure with the impact isolator increased.

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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• pp.429-436
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• 2011

In this study, we have experimented with 9 players at the national delegate level. Although there were some differences in the average effects of 3 types of one-two straight movements after the application of wheel axle, there were no statistical differences in the case of surface reacting forces, electromyograms, and impact forces. When the right fist was impacted using the one-two straight movements and the wheel axle was applied with 3 segmentations, high impact forces were obtained for the pronation in the following order-72.01 $m/s^2$ (type 2), 70.93 $m/s^2$ (type 3), and 58.19 $m/s^2$ (type 1). Higher values of the surface reacting force were found for type 1 that did not exhibit pronation in the left foot, whereas in the case of the vertical direction of the right foot, type 2 with pronation exhibited higher values and impact forces. In the right electromyogram, high impact forces due to the activation of the muscular electric potential were obtained for lumbar erector (LE) spinae and triceps brachii (TB) with type 1; LE spina, latissimus dosi (LD), and upper trapezius (UT) with type 2; and brachioradialis (BR), UT, and rectus abdominal (RA) with type 3. Due to pronation and complex motions of the 3 pronation segmentations, the efficiency was higher for impacts due to one-two straight movements.

• The Journal of Economics, Marketing and Management
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• v.10 no.3
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• pp.1-8
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• 2022

Purpose: This study aims to examine the effect of SMEs' R&D competence on management performance. Research design, data, and methodology: The empirical data of this study are derived from 2,375 SMEs that participated in the material, parts, and equipment research and development support project conducted from 2014 to 2018. Among them, 2,230 data were analyzed by classifying them into high-tech and low-tech fields. SPSS 24.0 was used for statistical analysis and correlation analysis and T-TEST were applied. Results: It was analyzed that the level of R&D organization, research personnel, and the number of patent registrations all affected operating profit and sales. In particular, it has been proven that research personnel have a greater impact on management performance among the level of R&D organization, research personnel, and the number of patent registrations. In addition, there was a difference between high-tech and low-tech industries in the impact on operating profit and sales, which are indicators of management performance. Conclusions: This study suggests that R&D competence are strengthened to advance the material, parts, and equipment industries and to promote future growth, while differentiated support is needed according to each company's R&D competence and technology level.

• International Journal of Quality Innovation
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• v.9 no.3
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• pp.93-112
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• 2008

This study explores the influence of Taiwan's high-tech manufacturers' innovative strategy and innovation motivation concerning the implementation of innovative activities, as well as the influence of innovative activities implementation on business performance. The two intermediate variables, industry group and enterprise scale are also considered. Through a review of the relevant literature, a theoretical model of the influence relationship is developed, while an empirical analysis is simultaneously conducted on Taiwan's high-tech manufacturers. The research result shows that the internal driving force of innovative activities has a significant impact on the level of implementing technological innovative activities and cultural innovative activities. The external driving force of innovative activities has a significant impact on the level of implementing market innovative activities and management innovative activities. Companies adopting self-developed technology and purchased as well as self-developed technology strategies, perform better than those adopting purchased new technology or those with neither purchased nor self-developed technology strategies, at implementing technological innovative activities and cultural innovative activities. The level of implementing innovative activities has a significant influence on business performance (cost reduction and product/service differentiation). For the intermediate variables of "industry group" and "enterprise scale", it is proven in this study that they have no significant influence on the level of innovative activity implementation or business performance.

• Journal of Microbiology and Biotechnology
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• v.27 no.7
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• pp.1345-1358
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• 2017

The impact of overproduction of a heterologous protein on the metabolic system of host Lactococcus lactis was investigated. The protein expression profiles of L. lactis IL1403 containing two near-identical plasmids that expressed high- and low-level of the green fluorescent protein (GFP) were examined via shotgun proteomics. Analysis of the two strains via high-throughput LC-MS/MS proteomics identified the expression of 294 proteins. The relative amount of each protein in the proteome of both strains was determined by label-free quantification using the spectral counting method. Although expression level of most proteins were similar, several significant alterations in metabolic network were identified in the high GFP-producing strain. These changes include alterations in the pyruvate fermentation pathway, oxidative pentose phosphate pathway, and de novo synthesis pathway for pyrimidine RNA. Expression of enzymes for the synthesis of dTDP-rhamnose and N-acetylglucosamine from glucose was suppressed in the high GFP strain. In addition, enzymes involved in the amino acid synthesis or interconversion pathway were downregulated. The most noticeable changes in the high GFP-producing strain were a 3.4-fold increase in the expression of stress response and chaperone proteins and increase of caseinolytic peptidase family proteins. Characterization of these host expression changes witnessed during overexpression of GFP was might suggested the metabolic requirements and networks that may limit protein expression, and will aid in the future development of lactococcal hosts to produce more heterologous protein.