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        검색결과 9,512

        601.
        2023.07 구독 인증기관 무료, 개인회원 유료
        This research presents a conceptual framework for a comprehensive understanding of the causes of user migration from social media networking sites. The results of our survey show that users’ intentions to switch social media platforms are influenced by user satisfaction, alternative attractiveness, peer influence, and perceived switching costs.
        4,000원
        602.
        2023.07 구독 인증기관·개인회원 무료
        Local consumption is considered to have a positive environmental and social impact. A new supply chain strategy has been devised to provide small and medium-sized local farms with enhanced efficiency and accessibility: a bidirectional distribution. Bidirectional distribution is a practice of backhauling local produce on emptied wholesale trucks for redistribution through wholesale markets while employing the existing network of rural stores and wholesale suppliers. Building on the cue utilization theory, this study investigated the effect of product information about bidirectional distribution on consumers’ perceived environmental value, personal well-being value, quality beliefs, and community social and economic value.
        603.
        2023.07 구독 인증기관·개인회원 무료
        As digital technology becomes more prevalent in today’s business environment and interest in digital trust rises, restaurants need to identify whether and how their mobile apps enhance the customer experience, and what features of the apps can strengthen customers’ attachment to them. However, few studies have examined the role of restaurant mobile apps as a catalyst for building customer loyalty. Considering restaurant mobile apps as a means to build a trustworthy relationship between customers and restaurants, this study develops and validates a research framework to measure digital trust between restaurants and customers through restaurant mobile apps. Specifically, due to the lack of measurement constructs for digital trust, a reliable and valid set of measurements that can explain digital trust in relation to restaurant mobile apps is developed and the effects of mobile apps’ digital trust on customers’ trust in a restaurant brand, overall experience, and their continued use intention are assessed.
        604.
        2023.07 구독 인증기관·개인회원 무료
        Despite both travel and work being vital for human functioning, inconsistent views on whether they’re opposing domains, a so-called work-leisure conflict, are documented in tourism and management literature. For example, some researchers argued that leisure activities may damage people’s job performance based on the compensatory reasoning in the short run (e.g., consume time and vigor), while others, in contrast, proposed that leisure and travel may contribute to one’s work efficiency due to recovering from stress, self-development, and so forth. To add more understanding to this dilemma, this research proposes a novel role that tourism memory plays in enhancing people’s creativity at the individual level, a key factor in individual and organizational success. Thus, the proposed effect illustrates that travel might be conducive to job performance in the long run.
        605.
        2023.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This work presents four high-amplitude variable YSOs (≃3 mag at near- or mid-IR wavelengths) arising from the SPICY catalog. Three outbursts show a duration that is longer than 1 year, and are still ongoing. And additional YSO brightened over the last two epochs of NEOWISE observations and the duration of the outburst is thus unclear. Analysis of the spectra of the four sources confirms them as new members of the eruptive variable class. We find two YSOs that can be firmly classified as bona fide FUors and one object that falls in the V1647 Ori-like class. Given the uncertainty in the duration of its outburst, an additional YSO can only be classified as a candidate FUor. Continued monitoring and follow-up of these particular sources is important to better understand the accretion process of YSOs.
        4,000원
        606.
        2023.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This paper is written as a follow-up observations to reinterpret the radial velocity (RV) of HD 36384, where the existence of planetary systems is known to be ambiguous. In giants, it is, in general, difficult to distinguish the signals of planetary companions from those of stellar activities. Thus, known exoplanetary giant hosts are relatively rare. We, for many years, have obtained RV data in evolved stars using the high-resolution, fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at the Bohyunsan Optical Astronomy Observatory (BOAO). Here, we report the results of RV variations in the M giant HD 36384. We have found two significant periods of 586 d and 490 d. Considering the orbital stability, it is impossible to have two planets at so close orbits. To determine the nature of the RV variability variations, we analyze the HIPPARCOS photometric data, some indicators of stellar activities, and line profiles. A significant period of 580 d was revealed in the HIPPARCOS photometry. H𝛼 EW variations also show a meaningful period of 582 d. Thus, the period of 586 d may be closely related to the rotational modulations and/or stellar pulsations. On the other hand, the other significant period of 490 d is interpreted as the result of the orbiting companion. Our orbital fit suggests that the companion was a planetary mass of 6.6 𝑀J and is located at 1.3 AU from the host.
        4,000원
        607.
        2023.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The GMT-Consortium Large Earth Finder (G-CLEF) is the first instrument for the Giant Magellan Telescope (GMT). G-CLEF is a fiber feed, optical band echelle spectrograph that is capable of extremely precise radial velocity measurement. G-CLEF Flexure Control Camera (FCC) is included as a part in G-CLEF Front End Assembly (GCFEA), which monitors the field images focused on a fiber mirror to control the flexure and the focus errors within GCFEA. FCC consists of an optical bench on which five optical components are installed. The order of the optical train is: a collimator, neutral density filters, a focus analyzer, a reimager and a detector (Andor iKon-L 936 CCD camera). The collimator consists of a triplet lens and receives the beam reflected by a fiber mirror. The neutral density filters make it possible a broad range star brightness as a target or a guide. The focus analyzer is used to measure a focus offset. The reimager focuses the beam from the collimator onto the CCD detector focal plane. The detector module includes a linear translator and a field de-rotator. We performed thermoelastic stress analysis for lenses and their mounts to confirm the physical safety of the lens materials. We also conducted the global structure analysis for various gravitational orientations to verify the image stability requirement during the operation of the telescope and the instrument. In this article, we present the opto-mechanical detailed design of G-CLEF FCC and describe the consequence of the numerical finite element analyses for the design.
        5,100원
        608.
        2023.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The main goal of the Korean VLBI Network Calibrator Survey (KVNCS) is to expand the VLBI calibrators catalog for KVN, KaVA(KVN and VERA Array), EAVN(East-Asian VLBINetwork), and other extended regions. The secondKVNCS (KVNCS2) aimed to detect VLBI fringes of new candidates for calibrators in the K band. Out of the 1533 sources whose single-dish flux density in the K band was measured with KVN telescopes (Lee et al. 2017), 556 sources were observed with KVN in the K band. KVNCS2 confirmed the detection of VLBI fringes of 424 calibrator candidates over a single baseline. All detected sources had a high Signal-to-Noise Ratio (SNR) of >25. Finally, KVNCS2 confirmed 347 new candidates as VLBI calibrators in the K band, resulting in a 5% increase in the sky coverage compared to previous studies. The spatial distribution was quasi-uniform across the observable region (Dec. > −32.5◦). In addition, the possibility as calibrator candidates for the detected sources was checked, using an analysis of the flux-flux relationship. Ultimately, the KVNCS catalog will not only become the VLBI calibrator list but is also useful as a database of compact radio sources for astronomical studies.
        4,000원
        609.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Mobilization movements was applied with different forces and frequencies for different clinicians. Force transmission varies with frequency. Objectives: The purpose of this study was to examine the effects of frequency- specific application of grade III PA movement on muscle tone and muscle activity around the lumbar vertebrae. Design: A one group pretest-posttest design. Methods: Twenty study subjects applied grades III of PA movement exercise of 0.5 Hz and 1 Hz with a force of 13 N around the 1st and 3rd lumbar vertebrae, and muscle tone and muscle activity were measured and compared before and after. Results: This study showed that 0.5 Hz grade III PA activity exerted an effect on the decrease in muscle tone of the 1st and 3rd right and left lumbar muscles. It was found that 0.5 Hz affected the right side of L1 and 1.0 Hz affected the left side of L1 in near-activity when applying the grade III PA movement by frequency. Conclusion: In the future, it will be necessary to investigate the effect of applying frequency according to various grades of PA movement.
        4,000원
        610.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Proprioceptive neuromuscular facilitation (PNF) has been proven effective in a myriad of clinical fields as a treatment to restore function in patients with musculoskeletal disorders, damage to the central nervous system, or sports injuries. Objectives: The purpose of this study was to investigate the effect of a 2-week PNF exercise intervention on the degree of calcification, pain perception, and shoulder joint function in persons with calcific tendinitis (CT) of the supraspinatus. Design: Matched pairs design. Methods: This study was classified into a PNF group (n=8) and a control group (n=7) through a matched pairs design. Filmed x-rays, Visual Analogue Scale (VAS), Simple Shoulder Test (SST), and Constant-Murley Scale (CMS) were used to assess the long and short axis of calcified deposits, self-awareness of pain, and shoulder joint function of the subjects. 8 participants in the PNF group received a scapular and upper extremity PNF exercise intervention for 30 minutes per session, 10 times/week for 2 weeks while no intervention in the control group. Results: Two-way repeated analysis of variance (ANOVA) showed a significant improvement after the 2-week PNF exercise intervention on calcified deposits, pain, and shoulder joint function (P<.05), whereas no changes in the control. Conclusion: These findings suggest that the intensive 2-week PNF exercise may maximize intervention effects to reduce calcified deposits and pain in a relatively short period time and is effective for restoring shoulder function without combining other treatments or exercises in patients with supraspinatus CT.
        4,000원
        611.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Swallowing disorder is a common disease that can cause various complications such as malnutrition, dehydration, aspiration pneumonia, and poor quality of life, and can affect people of all ages, from infants to the elderly. Swallowing disorder rehabilitation is a complex process involving various skills such as exercise, diet modification, and posture adjustment. This study implements a rehab program for swallowing disorders using the Kinesio Tapping technique. Design: Prospective pilot case study. Objectives: To improve laryngeal detachment by providing external support to the muscles involved in swallowing using kinesio taping for conventional complex swallowing disorder rehabilitation. Methods: The study included 16 participants who were diagnosed with swallowing difficulties after a stroke and admitted to a rehabilitation ward in Ulsan. The average age of the participants, consisting of 9 males and 7 females, was 69.0 years (SD=1.23) and 64.0 years (SD=1.45), respectively. The stroke types were hemorrhagic and infarction, with onset periods ranging from 6 to 12 months (SD=1.11) in all participants. Each participant received a video fluoroscopy study (VFSS) for six months using the taping method developed by the research team. Kinesio taping techniques were developed by two professional physical therapists and one occupational therapist based on anatomical movements. Results: Significant differences were observed in self-training on the bed after the rehabilitation program compared to the initial period Kinesio taping can help improve laryngeal dislocation and reduce the risk of aspiration by providing external support to the muscles involved in swallowing. However, the effectiveness and optimal application techniques of kinesio taping in the rehabilitation of swallowing disorders are not yet clear. Conclusion: The results of this study could lead to the development of a new treatment protocol that incorporates kinesio taping as a standard therapy for the rehabilitation of swallowing disorders in bedridden patients.
        4,000원
        612.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Selective doping of pyridinic nitrogen in carbon materials has attracted attention due to its significant properties for various applications such as catalysts and electrodes. However, selective doping of pyridinic nitrogen together with controlling skeletal structure is challenging in the absence of catalysts. In this work, four precursors including four fused aromatic rings and pyridinic nitrogen were simply carbonized in the absence of catalysts in order to attain mass synthesis at low cost and a high percentage of pyridinic nitrogen in carbon materials with controlled edges. Among four precursors, dibenzo[f,h] quinoline (DQ) showed an extremely high percentage of pyridinic nitrogen (96 and 86%) after heat treatment at 923 and 973 K, respectively. Experimental spectroscopic analyses combined with calculated spectroscopic analyses using density functional theory calculations unveiled that the C-H next to the pyridinic nitrogen in DQ generated gulf edge structures with controlled pyridinic nitrogen after carbonization. By comparing the reactivities among the four precursors, three main factors required for maintaining the pyridinic nitrogen in carbon materials with controlled edges, such as (1) high thermal stability of the pyridinic nitrogen, (2) the presence of one pyridinic nitrogen in one ring, and (3) the formation of gulf edges including pyridinic nitrogen to protect the pyridinic nitrogen by the C-H groups on the gulf edges, were revealed.
        6,000원
        613.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, gold nanoparticles (AuNPs) were synthesised using green chemistry to decorate multi-walled carbon nanotubes (MWCNTs) made from walnut shells transmission electron microscopy, field-emission scanning electron microscopy (FESEM), atomic force microscopy and fourier transforms infrared spectroscopy were used to diagnose MWCNTs and AuNPs. MWCNT-COOAu, MWCNT-COO and MWCNT-Au were diagnosed by Raman, energy dispersive X-ray analysis and FESEM. The effect of AuNPs, MWCNT-COO, MWCNT-COOAu and MWCNT-Au on pure and serum alkaline phosphatase (ALP) enzyme activity was studied in vitro using the enzyme-substrate 4-nitrophenyl disodium orthophosphate. For pure enzymes, Vmax slightly increased as the concentration of MWCNT-Au, MWCNT-COOAu and MWCNTCOO increased, whereas the Vmax values decreased as the concentration of AuNPs increased. The inhibition type for all NPs varied. For serum ALP enzyme, the Vmax values for Au-based NPs decreased as the concentration of NPs increased. The Vmax values exceeded the standard value at the concentrations of 25, 50 and 75 ppm for MWCNT-Au and MWCNT-COOAu, whereas the Vmax values increased over the standard value for all concentrations of AuNPs.
        4,500원
        614.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon-based materials have emerged as an excellent class of biomedical materials due to their exceptional mechanical properties, lower surface friction, and resistance to wear, tear, and corrosion. Experimental studies have shown the promising results of carbon-based coatings in the field of biomedical implants. The reasons for their successful applications are their ability to suppress thrombo-inflammatory reactions which are evoked as an immune response due to foreign body object implantation. Different types of carbon coatings such as diamond-like carbon, pyrolytic carbon, silicon carbide, and graphene have been extensively studied and utilized in various fields of life including the biomedical industry. Their atomic arrangement and structural properties give rise to unique features which make them suitable for multiple applications. Due to the specificity and hardness of carbon-based precursors, only a specific type of coating technique may be utilized for nanostructure development and fabrication. In this paper, different coating techniques are discussed which were selected based on the substrate material, the type of implant, and the thickness of coating layer. Chemical vapor deposition-based techniques, thermal spray coating, pulsed laser deposition, and biomimetic coatings are some of the most common techniques that are used in the field of biomaterials to deposit a coating layer on the implant. Literature gathered in this review has significance in the field of biomedical implant industry to reduce its failure rate by making surfaces inert, decreasing corrosion related issues and enhancing biocompatibility.
        5,200원
        615.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated durian (Durio zibethinus) peels to produce powdered activated carbon (DPAC). The influence of process variables such as carbonization temperature, activation time, contact time, CO2 flow rate, and adsorption dosage was optimized using response surface methodology (RSM). A six-factor and two levels Box–Behnken design (BBD) was used to optimize the parameters. The independent variables were activation temperature (°C), duration (min), CO2 flow rate during the activation process (L/min), irradiation of adsorbent (kGy), irradiation duration (min), and adsorbent dosage (g) while phenol removal (mg/L) was the dependent variable (response). Following the observed correlation coefficient values, the design was fitted to a quadratic model (R2 = 0.9896). The optimal removal efficiency (97.25%) was observed at an activation temperature of 900 °C, activation time of 30 min, CO2 flow rate of 0.05 L/min, irradiation dose of 100 kGy, contact time of 35 min and adsorption dosage of 0.75 g. The optimal DPAC showed a BET surface of 281.33 m2/ g. The removal efficiency was later compared with a commercially available activated carbon which shows a 98.56% phenol removal. The results show that the durian peel could be an effective precursor for making activated carbon for phenol removal, and irradiation can significantly enhance surface activation.
        4,000원
        616.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this experimental work, a p-type c-Si (100) substrate with 8 × 8 × 2 mm dimension was taken for TiCN thin-film coating deposition. The whole deposition process was carried out by chemical vapor deposition (CVD) process. The Si substrate was placed within the CVD chamber at base pressure and process pressure of 0.75 and 500 mTorr, respectively, in the presence of TiO2 (99.99% pure) and C (99.99% pure) powder mixture. Later on, quantity of C powder was varied for different set experiments. The deposition of TiCN coating was carried out in the presence of N2– H2–TiCl4–CH3CN gas mixture and 600 ℃ of fixed temperature. The time for deposition was fixed for 90 min with 10 and 5 ℃ min− 1 heating and cooling rate, respectively. Later on, heat treatment process was carried out over these deposited TiCN samples to investigate the changing characteristics. The heat treatment was carried out at 800 ℃ within the CVD chamber in the absence of any gas flow rate. The morphological properties of heat-treated samples have been improved significantly, evidence is observed from SEM and AFM analyses. The structural analysis by XRD has been suggested, upgradation in crystallinity of the heat-treated film as it possessed with sharp and higher intensity peaks. Evidence has been found that the electrochemical properties are enhanced for heat-treated sample. Raman spectroscopy shows that the intensity of acoustic phonon modes predominates the optic phonon modes for untreated samples, whereas for heat-treated samples, opposite trends have been observed. However, significant degradation in mechanical properties for heat-treated sample has been observed compared to untreated sample.
        5,800원
        617.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To compete with the growth of fashion shopping platforms in the online fashion market, general shopping platforms have begun to expand their product categories to include fashion items. This research examines the characteristics that influence consumers’ trust in each of these platforms and their intention to reuse them. Applying the concept of platforms, this study also distinguishes between general shopping platforms and fashion shopping platforms and compares their characteristics. This study surveyed 788 consumers in their 20s and 30s with experience in using general shopping platforms or fashion shopping platforms (389 and 399 respondents, respectively). SPSS was used to conduct frequency analysis, factor analysis, and cross-tabulations, and AMOS was used to conduct confirmatory factor analyses and structural equation analyses. The results were as follows: platform reputation, shopping convenience, and interactivity all influenced consumer trust. For fashion shopping platforms, the product quality factor significantly improved consumer trust. However, for general shopping platforms, the product quality factor only influenced reuse intentions to reuse and did not contribute to improving trust. Platform reputation and information offering have influenced reuse intentions for both shopping platforms. Regardless of the type of shopping platform, platform reputation has influenced reuse intentions and consumer trust, and platform esthetics didn’t have affect consumer trust and consumers’ reuse intentions. Consumer trust influenced the intention to reuse on both platforms.
        5,500원
        618.
        2023.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Compared to operational wastes, nuclear power plant (NPP) decommissioning wastes are generated in larger quantities within a short time and include diverse types with a wider range of radiation characteristics. Currently used 200 L drums and IP-2 type transport containers are inefficient and restrictive in packaging and transporting decommissioning wastes. Therefore, new packaging and transport containers with greater size, loading weight, and shielding performance have been developed. When transporting radioactive materials, radiological safety should be assessed by reflecting parameters such as the type and quantity of the package, transport route, and transport environment. Thus far, safety evaluations of radioactive waste transport have mainly targeted operational wastes, that have less radioactivity and a smaller amount per transport than decommissioning wastes. Therefore, in this study, the possible radiation effects during the transport from NPP to disposal facilities were evaluated to reflect the characteristics of the newly developed containers and decommissioning wastes. According to the evaluation results, the exposure dose to transport workers, handling workers, and the public was lower than the domestic regulatory limit. In addition, all exposure dose results were confirmed, through sensitivity analysis, to satisfy the evaluation criteria even under circumstances when radioactive materials were released 100% from the container.
        4,800원
        619.
        2023.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The emission of off-gas streams from used fuel recycling is a concern in nuclear energy usage as they contain radioactive compounds, such as, 3H, 14C, 85Kr, 131I, and 129I that can be harmful to human health and environment. Radioactive iodine, 129I, is particularly troublesome as it has a half-life of more than 15 million years and is prone to accumulate in human thyroid glands. Organic iodides are hazardous even at very low concentrations, and hence the capture of 129I is extremely important. Dynamic adsorption experiments were conducted to determine the efficiency of sodium mordenite, partially exchanged silver mordenite, and fully exchanged silver mordenite for the removal of methyl iodide present at parts per billion concentrations in a simulated off-gas stream. Kinetic analysis of the system was conducted incorporating the effects of diffusion and mass transfer. The possible reaction mechanism is postulated and the order of the reaction and the values of the rate constants were determined from the experimental data. Adsorbent characterization is performed to investigate the nature of the adsorbent before and after iodine loading. This paper will offer a comprehensive understanding of the methyl iodide behavior when in contact with the mordenites.
        5,500원
        620.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The prolonged and heavy East Asian summer precipitation in 2020 may have been caused by an enhanced Madden-Julian Oscillation (MJO), which requires evaluation using forecast models. We examined the performance of GloSea6, an operational forecast model, in predicting the East Asian summer precipitation during July 2020, and investigated the role of MJO in the extreme rainfall event. Two experiments, CON and EXP, were conducted using different convection schemes, 6A and 5A, respectively to simulate various aspects of MJO. The EXP runs yielded stronger forecasts of East Asian precipitation for July 2020 than the CON runs, probably due to the prominent MJO realization in the former experiment. The stronger MJO created stronger moist southerly winds associated with the western North Pacific subtropical high, which led to increased precipitation. The strengthening of the MJO was found to improve the prediction accuracy of East Asian summer precipitation. However, it is important to note that this study does not discuss the impact of changes in the convection scheme on the modulation of MJO. Further research is needed to understand other factors that could strengthen the MJO and improve the forecast.
        4,200원