• Smart Structures and Systems
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• v.25 no.6
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• pp.707-717
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• 2020

In this paper, analysis of thermal post-buckling behaviors of sandwich nanobeams with two layers of multi-phase magneto-electro-thermo-elastic (METE) composites have been presented considering geometric imperfection effects. Multi-phase METE material is composed form piezoelectric and piezo-magnetic constituents for which the material properties can be controlled based on the percentages of the constituents. Nonlinear governing equations of sandwich nanobeam are derived based on nonlocal elasticity theory together with classic thin beam model and an analytical solution is provided. It will be shown that post-buckling behaviors of sandwich nanobeam in thermo-electro-magnetic field depend on the constituent's percentages. Buckling temperature of sandwich nanobeam is also affected by nonlocal scale factor, magnetic field intensity and electrical voltage.

• Medical Lasers
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• v.9 no.1
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• pp.84-87
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• 2020

Post-acne erythema (PAE) is one of the major problems during or after treatment of acne vulgaris with any modality. A variety of therapeutic options have been described with various clinical outcomes and side effects. We report here on treating a patient with PAE using 595-nm picosecond-domain neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. After four sessions of treatment, the patient displayed nearly complete improvement and no remarkable adverse effects. To the best of the authors' knowledge, this is the first case of the effective treatment of PAE using a 595-nm picosecond-domain Nd:YAG laser. We recommend that using a 595-nm picosecond-domain Nd:YAG laser can be both an effective and safe treatment option for treating PAE.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.185-194
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• 2020

The emergence of post-human beings in the 4th Industrial Revolution era led to an epistemological shift in the need for reflection on new relationships with non-human beings, away from human-centered modern humanism. For this reflection, post-human sensibility to empathize and understand the surrounding world is required. In order to cultivate this sensibility, we analyzed the case of art works that can think about and experience the post-human era based on the criteria of 'animal-becoming', 'earth-becoming', and 'machine-being' presented by post-humanist researcher Bridotti. Since the work of art reflects the spirit of the era, we confirmed the positive aspect of the text that can reflect and experience the post-human era. This study is meaningful as a basic study by presenting art works that can be used in art education to improve post-human sensitivity.

• Restorative Dentistry and Endodontics
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• v.45 no.2
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• pp.19.1-19.8
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• 2020

Objective: This study aimed to evaluate the effect of ultrasonic cleaning of the intracanal post space on the bond strength of fiber posts in oval canals filled with a premixed bioceramic (Bio-C Sealer [BIOC]) root canal sealer. Materials and Methods: Fifty premolars were endodontically prepared and divided into 5 groups (n = 10), based on the type of root canal filling material used and the post space cleaning protocol. A1: gutta-percha + AH Plus (AHP) and post space preparation with ultrasonic cleaning, A2: gutta-percha + BIOC and post space preparation with ultrasonic cleaning, B1: gutta-percha + AHP and post space preparation, B2: gutta-percha + BIOC and post space preparation, C: control group. Fiber posts were cemented with a self-adhesive luting material, and 1 mm thick slices were sectioned from the middle and cervical third to evaluate the remaining filling material microscopically. The samples were subjected to a push-out test to analyze the bond strength of the fiber post, and the results were analyzed with the Shapiro-Wilk, Bonferroni, Kruskal-Wallis, and Mann-Whitney tests (p < 0.05). Failure modes were evaluated using optical microscopy. Results: The results showed that the fiber posts cemented in canals sealed with BIOC had lower bond strength than those sealed with AHP. The ultrasonic cleaning of the post space improved the bond strength of fiber posts in canals sealed with AHP, but not with BIOC. Conclusions: BIOC decreased the bond strength of fiber posts in oval canals, regardless of ultrasonic cleaning.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.5
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• pp.445-454
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• 2020

Non-breakaway crashworthy sliding posts move rigidly with a vehicle in the early stage of vehicle impact. During this stage, a vehicle imparts its linear momentum to the post, experiencing first-stage speed loss followed by second-stage loss from the crush of the energy-absorbing pipe (EAP) installed under the guide rail. An EAP is the key element of a crashworthy sliding post and should be confined to the post foundation. This paper covers the development of an EAP for a sliding post of 507 kg, which is a sliding post type frequently used in Korea for cantilever signs. Detailed explanations of the designs for an EAP structure using LS-DYNA impact simulation are given, and the crashworthiness of the systems are confirmed through crash tests. The EAP presented in this paper can accommodate impacts from 0.9 ton-60 km/h to 1.3 ton-80 km/h, and is applicable to foundations up to 2.7 m in length.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.26 no.2
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• pp.61-69
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• 2020

As post-harvest processes of onions are carried by a 20 kg-net package which results in high-cost and low-efficiency, especially, the insufficient drying and physical damage of onions after harvesting leads to a huge second loss in storage, we had developed a low-cost, high-efficiency post-harvest bulk handling machinery system by collecting onions on a farm using ton-bags, drying with forced air circulation, and sorting/packaging. The post-harvest bulk handling machinery system consisted of 6 devices, and this study designed an automatic feed hopper with a feeding rate control device, an inclined belt conveyor with a two-step chute, and an automatic pallet unloading device for feeding onions into the sorting/packing line. This study also analyzed the performance and control of the total system. The device had 1-ton handling capacity, but the operational condition was set to increase the capacity. The three-step filling method of pallet by the velocity control of the inclined belt conveyor was applied in the post-harvest bulk handling machinery system for the prevention of physical damage. If one worker was set to operate the total system, the time required to complete one palletized load was approximately 5 minutes and 5 seconds. The calculated daily handling capacity was approximately 94 tons, when the daily actual working time was 8 hours. When the developed system was applied to the managerial size of 2,000 ton, the processing cost per ton of the system was decreased by 19.5%, compared with the existing 20 kg-net package-based handling. The developed post-harvest bulk handling machinery system would be a good substitute for the rapid decline and aging of rural labor.

• Journal of Information Technology Services
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• v.19 no.5
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• pp.107-124
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• 2020

Due to spread of covid-19, which began in December 2019, the usage of online distance learning has expanded within colleges. However, because of the lack of readiness for running online distance learning, professors and students had to experience a lot of inconvenience. In the near future, the usage of online distance learnig is expected to more expand, thus, it seems that there should be a strategies for sustainable online learning operations. This study aims to investigate which factors have impact on the continuance intention to usage of online distance learning of airline department students, focused on Post-Acceptance Model. For the empirical analysis, this study utilized a structural equation model after collecting 136 survey data. The results is as follow; First, user interface has positive impact on confirmation and confirmation has positive impact on satisfaction of online distance learning. Seconds, confirmation has positive impact on perceived usefulness, flow and social presence. Third, social presence has positive impact on satisfaction of online distance learning, but perceived usefulness and flow didn't have statistically meaningful impact on satisfaction. Finally, statisfaction of online distance learning has huge positive impact on continuance intention to usage. It is expected that the implications of this study enable colleges effectively to run online distance learning in preparation for the post-covid 19 era.

• Journal of Korean Academy of Rural Health Nursing
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• v.15 no.1
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• pp.16-29
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• 2020

Purpose: The purpose of this study was to determine the effect on depression and self-esteem in elders taking part in the Magma healing program. Methods: This study was a single group pre-post quasi-experimental design. The participants were elders over 60 who had complained of depression more than once within the last 3 months, and who were living in the jurisdiction of a health clinic in the 3-area of Chungnam. Data from 14 elders who participated in the Magma healing program were analyzed using nonparametric paired t-test with SPSS 25.0. Results: The study results showed that the Magma healing program had statistically significant results in reducing depression (z=-2.91, p=.004) and improving self-esteem (z=-2.91, p=.004) in elders. Conclusion: The Magma healing program has been proven to be a very useful program to reduce depression in elders and promote self-esteem, thereby integrating their lives and leading to successful aging.

• The Journal of Korean Physical Therapy
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• v.32 no.2
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• pp.80-87
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• 2020

Purpose: Some patients who have undergone surgery due to lumbar disc herniation still complain of leg pain and other abnormal sensations. Therefore, the study examined the effects of the neurodynamics on pain and other abnormal nerve sensations in post-operated patients with lumbar disc herniation. Methods: The participants of this study comprised 20 adults (10 males and 10 females) who were diagnosed with lumbar disc herniation. The subjects were classified into two groups of 10 patients each in the lower extremity neurodynamics (LEN) and lumbar stabilization exercise (LSE) groups. Each intervention was applied twice a day for one week and was composed of two different exercise patterns; one was applied by a therapist, and the other was performed by the patients themselves. The data were analyzed using assessment methods of Digital Infrared Thermal Imaging (DITI), Toronto clinical neuropathy scoring system (TCNSS), Sympathetic Skin Response (SSR) test, and Oswestry Disability Index (ODI) scale. Results: Significant differences in TCNSS, DITI, ODI scale were observed between the LEN and LSE group (p<0.01). On the other hand, there was no significant difference in the SSR test between pre and post-treatment (p>0.05). Conclusion: The results indicated that neurodynamics treatment is effective in pain reduction and abnormal sensations, such as leg muscle cramps, in post-operated patients with lumbar disc herniation.

• Journal of the Korean Dietetic Association
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• v.26 no.3
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• pp.208-220
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• 2020

In modern society, the online to offline (O2O) market has become an emerging market. Based on social and cultural phenomena, the importance of "FOODTECH" linked with mobile applications is growing in the food and restaurant industry. This study examined subjective food application service quality, perceived value, and post-purchase behavior intentions. According to this study, of foodtech service quality attributes, only information, mobility, and reliability had positive (+) relationships with perceived value. However, foodtech service quality attributes did not have a direct impact on behavior intentions. Perceived values had a positive (+) relationship with behavior intentions and showed full mediation effects between foodtech service quality attributes and behavior intentions. Based on these results, future research on the relationship among food application service quality, perceived value, and post-purchase behavior intentions is needed.