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        검색결과 37,645

        501.
        2024.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Korean historical literatures offer numerous records on astronomical phenomena such as eclipses, comets, and close approaches, etc. Records of close approaches often use specific terms to describe the angular distance, which lack translation into modern numerical values. We study the usage of the five commonly used terms, namely, Entry (入, En), Invasion (犯, In), Occultation (掩, Oc), Eclipse (食, Ec), as well as the unit Chi (尺). Our analysis is based on more than 2,300 records from Goryeo (918–1392 CE) and Joseon (1392–1910 CE) Dynasties. Through statistical analysis, we determine their quantitative definitions. We convert the lunisolar calendar to the Julian and Gregorian date and utilize the modern ephemeris DE431 to calculate the angular distance between celestial bodies. We find that the angular distances of the terms En, In, Oc, and Ec correspond to respectively 1.78◦+2.36 −1.11, 0.89◦+3.54 −0.51, 0.44◦+1.15 −0.31, and 0.29◦+2.61 −0.16 for the Goryeo Dynasty and 1.36◦+1.15 −0.64, 0.51◦+1.11 −0.32, 0.25◦+0.27 −0.17, and 0.21◦+0.25 −0.11 for the Joseon Dynasty. Additionally, we determine the angular size of the unit Chi by using the records from Korean chronicles along with the drawings of comets’ tails in the Daily Log (天變謄錄). We estimate the unit Chi to be 1.11◦+0.46 −0.40 and find that the numerical definition was consistent throughout the two dynasties in Korea. Furthermore, we find that the terms were used to describe the closest approach and that there is no observational bias in the angular distances against the apparent magnitudes of the objects. We show that the terms En, In, Oc, and Ec represent decreasing angular distance in that order and this ordering was consistent in both dynasties.
        4,000원
        502.
        2024.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This research investigated the preparation of activated carbon derived from Krabok (Irvingia malayana) seed shells to improve the quality of crude glycerol obtained during biodiesel production. The activated carbon was prepared using a dry chemical activation method with NaOH, utilizing an innovative biomass incinerator. The results revealed that the resulting KC/AC-two-step exhibited favorable physicochemical adsorption properties, with a high surface area of 758.72 m2/g and an iodine number of 611.10 mg/g. These values meet the criteria of the industrial product standard for activated carbon No. TIS 900-2004, as specified by the Ministry of Industry in Thailand. Additionally, the adsorption efficiency for methylene blue reached an impressive 99.35 %. This developed activated carbon was then used to improve the quality of crude glycerol obtained from biodiesel production. The experimental results showed that the KC/AC-two-step increased the purity of crude glycerol to 73.61 %. In comparison, commercially available activated carbon (C/AC) resulted in a higher crude glycerol purity of 81.19 %, as analyzed by the GC technique. Additionally, the metal content (Zn, Cu, Fe, Pb, Cd, and Na) in purified glycerol using KC/AC-two-step was below the standards for heavy metals permitted in food and cosmeceuticals by the Food and Drug Administration of Thailand and the European Committee for Food Contact Materials and Articles. As a result, it can be inferred that Krabok seed shells have favorable properties for producing activated carbon suitable as an adsorbent to enhance crude glycerol purity. Furthermore, the improved crude glycerol from this research has potential for various industrial applications.
        4,200원
        503.
        2024.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Understanding the behavior of soil under cyclic loading conditions is essential for assessing its response to seismic events and potential liquefaction. This study investigates the effect of non-plastic fines content (FC) on excess pore pressure generation in medium-density sand-silt mixtures subjected to strain-controlled cyclic direct simple shear (CDSS) tests. The investigation is conducted by analyzing excess pore pressure (EPP) ratios and the number of cycles to liquefaction (Ncyc-liq) under varying shear strain levels and FC values. The study uses Jumunjin sand and silica silt with FC values ranging from 0% to 40% and shear strain levels of 0.1%, 0.2%, 0.5%, and 1.0%. The findings indicate that the EPP ratio increases rapidly during loading cycles, with higher shear strain levels generating more EPP and requiring fewer cycles to reach liquefaction. At 1.0% and 0.5% shear strain levels, FC has a limited effect on Ncyc-liq. However, at a lower shear strain level of 0.2%, increasing FC from 0 to 10% reduces Ncyc-liq from 42 to 27, and as FC increases further, Ncyc-liq also increases. In summary, this study provides valuable insights into the behavior of soil under cyclic loading conditions. It highlights the significance of shear strain levels and FC values in excess pore pressure generation and liquefaction susceptibility.
        4,000원
        504.
        2024.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Cat-scratch disease (CSD) is a bacterial infection which primarily transmitted to humans through scratches, bites, or licks from infected cats. Even though CSD is generally a mild condition, atypical symptoms may appear and must be distinguished from other diseases. We encountered a 57-year-old woman who presented with intermittent pain in the right upper quadrant and epigastric part of the abdomen, and had lost 11 kg within a few months. She never had a cat and did not recall being scratched by a cat. Radiologic examinations strongly suggest a malignant bile duct tumor, thus liver resection was done. However, the result of histopathology was a CSD. At follow-up, the patient was stable and also showed improvement in her general condition. Hence, proper preoperative examinations of the patients are crucial in order to avoid excessive or inadequate treatment.
        4,000원
        505.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Cerebral palsy presents significant challenges in motor function for affected children. While conventional bottom-up approaches are common in physical therapy, there is increasing interest in the efficacy of the top-down approach. Objectives: To investigated the impact of applying the top-down approach in physical therapy for a child diagnosed with cerebral palsy, focusing on functional improvement and quality of life. Design: A single-case study. Methods: The patient was a 15-year-old boy with spastic diplegic cerebral palsy who was entering middle school. Cerebral palsy treatment approach of the top-down method (jumping rope) was used to guide and direct physical therapy. Results: The child improved in muscle strength of lower extremity, gross motor function, participation and self-esteem, but the pattern of his gait seemed to be more severe on tiptoe. When the child participated in a jumping rope class, he was able to do more than 10 jumps. Conclusion: The effectiveness of the top-down approach in enhancing functional outcomes and quality of life in children with cerebral palsy. It highlights the potential of this approach in pediatric physical therapy, warranting further research validation.
        4,000원
        506.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Kinesio taping is being applied to improve ankle dorsiflexion in stroke patients. Currently, the elasticity of kinesio taping is applied in various ways. Objectives: To investigated the effect of tibialis anterior kinesio taping elasticity level on gait speed in stroke patients. Design: A randomized cross-over pilot study. Methods: A total of 12 study subjects were allowed to experience three conditions within a single group. The three conditions are strong elastic taping condition, weak elastic taping condition, and non-elastic taping condition. Study subjects were randomly assigned to each condition sequentially. For the evaluation, gait variables (cadence, gait speed, stride length) were measured 24 hours after applying the taping appropriate for each condition. Results: The strong elastic taping condition significantly increased gait variables compared to the weak elastic taping and non-elastic taping conditions (P<.05). Weak elastic taping significantly increased gait variables compared to non-elastic taping (P<.05). Conclusion: As tibialis anterior kinesio taping elasticity increased, gait variables significantly improved in stroke patients.
        4,000원
        507.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Children with cerebral palsy face challenges in maintaining body stability because of structural and functional defects. Their ability for responsive balance control is diminished. While there exist various trunk stabilization exercises such as Kinetic Link training (KLT) and the Bird-dog posture, there is a notable dearth of research that applies KLT specifically to children with cerebral palsy. Objectives: To investigate the effects of KLT and Bird-dog exercise on gross motor function and balance in children with cerebral palsy. Design: Quaxi-experimental study. Methods: The study participants were randomly divided into two groups: 15 individuals in the KLT group and 15 in the Bird-dog group. General characteristics were examined, and initial measurements of Gross motor function measure (GMFM) and Pediatric balance scale (PBS) were taken prior to the intervention. Each group engaged in KLT exercises and Bird-dog exercises for 20 minutes, three times a week over an 8 week period. Following the completion of the 8 week intervention, secondary measurements of GMFM and PBS were conducted. Results: In the KLT group, both PBS and GMFM showed a significant increase after the intervention compared to before (P<.05). Similarly, in the Bird-dog group, both PBS and GMFM significantly increased after the intervention compared to before (P<.05). There was a significant difference observed in PBS when comparing the pre- and post-intervention changes between the two groups (P<.05), whereas no significant difference was found in GMFM between the groups when comparing the pre- and post-intervention changes (P>.05). Conclusion: The interventions involving KLT and Bird-dog exercises were observed to effectively enhance PBS and GMFM in children with cerebral palsy. Specifically, it was evident that KLT was more beneficial in improving balance abilities compared to Bird-dog exercise.
        4,000원
        508.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Most non-pharmacological interventions for tension-type headache (TTH) focus on direct intervention in areas associated with headaches, with limited research exploring the indirect effects of interventions utilizing the fascia. Objectives: To investigate the effects of superficial back line (SBL) stretching and head-neck massage interventions on the range of motion (ROM) and neck disability index (NDI) of TTH. Design: Randomized controlled trial. Methods: The study participants were randomly allocated into three groups: SBL stretching group (n=9), head-neck massage group (n=9), and combined group (n=9). Prior to the intervention, measurements were taken for neck flexion ROM, straight leg raising test (SLRT) ROM, and NDI. The intervention consisted of 30-minute sessions conducted twice a week for 8 weeks. The second measurement took place 4 weeks after the intervention, followed by a third measurement conducted after an additional 4 weeks of intervention. Results: Comparing neck flexion ROM within each group, a significant increase was observed in the SBL stretching group after 8 weeks compared to before the intervention (P<.05). Regarding the comparison of SLRT ROM within each group, a significant increase was noted after 8 weeks compared to before the intervention in the SBL stretching, head-neck massage, and combined groups (P<.05). In terms of the comparison of NDI within each group, a significant decrease was observed in all three group after the intervention compared to before the intervention (P<.05). Conclusion: 8-week intervention involving SBL stretching, head-neck massage, and their combined application demonstrated effectiveness in improving neck flexion ROM, SLRT ROM, and the NDI for individuals with TTH.
        4,000원
        509.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Problem-based learning (PBL) is presented as a superior teaching method compared to existing lecture-based learning. Objectives: To analyzed the effectiveness of creative problem-solving competency, class participation, and self-efficacy in physical therapy students after PBL. Design: Questionnaire design. Methods: This study involved 29 physical therapy students and analyzed changes in their creative problem-solving competency, class participation, and self-efficacy and the correlations between these measurement variables before and after PBL on the “Therapeutic Exercise & Practice” subject. Results: PBL in the musculoskeletal exercise therapy-related subject significantly improved class participation and self-efficacy (P<.05) compared to conventional lecture-based learning, but there was no significant difference in creative problem-solving competency. There was also a positive correlation between a higher level of class participation and higher self-efficacy (P<.05). Conclusions: PBL in the “Therapeutic Exercise & Practice” subject in the Department of Physical Therapy can be an effective educational strategy to increase students’ class participation and self-efficacy. Accordingly, instructors in this department should systematically construct the design of PBL curricula to improve the quality of educational content.
        4,000원
        510.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: This study investigated quadriceps femoris muscle activity by comparing concentric and eccentric contractions with self-selective squat speed. Objectives: Study participants agreed in advance and included 30 male college students in their 20s without musculoskeletal system disease. Design: A randomized controlled trial. Methods: Participants who participated in this study agreed in advance and recruited 30 male college students in their 20s who had no disease with musculoskeletal system to conduct this study. When squatting at a self-selected speed, the subjects were evaluated using one-way ANOVA to compare concentric and eccentric contraction muscle activity. Results: There were significant differences between the rectus femoris, vastus medialis, and vastus lateralis regarding concentric contractions.contractions. There was a significant difference in vastus medialis but no significant difference between rectus femoris and vastus lateralis for eccentric contractions. Conclusion: During concentric contraction, all muscles and eccentric contractions indicated significant improvement in the vastus medialis. Therefore, to minimize knee joint injury and maximize efficient muscle activity, self-selected slow and moderate speeds based on self-selection speed when performing the sit-down motion during a squat and moderate speed with fast motions when performing the standing motion should be considered as high muscle activities.
        4,000원
        511.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Chronic back pain not only causes physical discomfort and decreased functionality but also affects emotional well-being, resulting in feelings of anxiety, depression, and other psychological issues. Studies have indicated that cognitive functional therapy and motor control exercises can alleviate chronic low back pain and associated psychological issues. Objectives: To investigated the effect of chronic low back pain on the cognitive functional therapy (CFT) and motor control exercises (MCE). Design: Quaxi-experimental study. Methods: Forty patients with chronic low back pain were randomly assigned and divided into 20 cognitive functional therapy group with motor control exercises group (CFTMG) and 20 patients in motor control exercises group (MCEG). After applying CFT with motor control exercises and motor control exercises for 8 weeks, changes in numeric pain rating scale (NPRS), Oswestry disability index (ODI) and Fear-avoidance beliefs questionnaire (FABQ) were observed. Results: In the CFTMG, statistically significant changes were observed in NPRS, ODI, and FABQ before and after the intervention. In the MCEG, statistically significant changes were observed in VAS and ODI before and after the intervention. Conclusion: The application of CFTM and MCE in patients suffering from chronic low back pain has demonstrated effectiveness in alleviating pain, enhancing back function, and reducing kinesiophobia associated with the condition.
        4,000원
        512.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: The Nordic hamstring exercise is a closed-chain exercise that effectively activates all lower extremity muscles, but there is a lack of consideration of ankle joint which affects exercise effectiveness. One of the major advantages of the Nordic exercise have been known as strengthening lower extremity extensors. This manifests the exercise increases activities of the ankle plantar flexors as well as hip extensors. Objectives: To investigated the impacts of changes in ankle position on the lower extremity musculature and subjective difficulties during the Nordic hip extension exercise. Design: Cross-sectional study. Methods: Twenty the healthy male participants participated in this study. Participants perform three variations of the Nordic exercises including three ankle positions. Each Nordic exercise was defined as ankle position (neutral, dorsiflexion and plantar flexion). During the Nordic exercise, erector spine (ES), gluteus maximus (GM), biceps femoris (BF), gastrocnemius (GCM) activities and subjective difficulties (Borg RPE score) were measured. Results: Muscular activities of the biceps femoris and gastrocnemius were significantly different among the three ankle conditions, which showed controversial results (P<.05). The biceps femoris activity was significantly higher with the dorsiflexion condition, compared to the others (P<.05). On the other hand, activity of the gastrocnemius was significantly higher with the plantarflexion position compared to the others (P<.05). Conclusion: Present study suggests the ankle positional changes could affect lower muscular activities during the Nordic exercise. Although it is difficult to affirm the causes due to limited data, selective activation of the biceps femoris might accomplish with ankle dorsi flexion and that of the gastrocnemius might accomplish with the ankle plantarflexion during the Nordic exercises.
        4,000원
        513.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present research focuses on the tribological behavior of the AA5083 alloy-based hybrid surface composite using aluminosilicate and multi-walled-carbon nanotube through friction stir processing for automotive applications. The friction stir processing parameters (tool rotation and traverse speed) are varied based on full factorial design to understand their influence on the tribological characteristics of the developed hybrid composite. The surface morphology and composition of the worn hybrid composite are examined using a field-emission scanning electron microscope and an energy-dispersive x-ray spectroscope. No synergistic interaction is observed between the wear rate and friction coefficient of the hybrid composite plate. Also, adhesive wear is the major wear mechanism in both base material and hybrid composite. The influence of friction stir process parameters on wear rate and the friction coefficient is analyzed using the hybrid polynomial and multi-quadratic radial basis function. The models are utilized to optimize the friction stir processing parameters for reducing the rate of wear and friction coefficient using multi-quadratic RBF algorithm optimization.
        4,800원
        514.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The complexation of silicon with carbon materials is considered an effective method for using silicon as an anode material for lithium-ion batteries. In the present study, carbon frameworks with a 3D porous structure were fabricated using metal–organic frameworks (MOFs), which have been drawing significant attention as a promising material in a wide range of applications. Subsequently, the fabricated carbon frameworks were subjected to CVD to obtain silicon-carbon complexes. These siliconcarbon complexes with a 3D porous structure exhibited excellent rate capability because they provided sufficient paths for Li-ion diffusion while facilitating contact with the electrolyte. In addition, unoccupied space within the silicon complex, combined with the stable structure of the carbon framework, allowed the volume expansion of silicon and the resultant stress to be more effectively accommodated, thereby reducing electrode expansion. The major findings of the present study demonstrate the applicability of MOF-based carbon frameworks as a material for silicon complex anodes.
        4,500원
        515.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This work involves the development of a novel waste-derived carbon dots (CDs) conjugated with silver (Ag) nanohybrid system-based Fluorescence Resonance Energy Transfer (FRET) sensor for the detection of melamine. CDs and Ag nanoparticles served as energy donors and energy acceptors, respectively. CDs were synthesized from orange peel waste through a combined hydrothermal and ultra-sonication route. The synthesized CDs had hydroxyl, amino, and carboxyl groups on their surface, explaining that waste-derived CDs can act as reducing and stabilizing agents and showed strong absorption and fluorescence emission at 305 and 460 nm, respectively. The bandgap, linear refractive index, conduction band, and valance band potential of CDs were observed to be 2.86, 1.849, 1.14, and 4.002 eV, respectively. No significant difference was observed in the fluorescence properties at different pH (acid and alkaline) and ionic concentrations. Given their fluorescent nature, the synthesized CDs were used for the detection of melamine. The fluorescence of CDs was found to be quenched by Ag+ due to the FRET energy transfer between CDs to Ag. Notably, the zeta potential of Ag@CDs was changed from − 28.7 mV to − 30.6 mV after the incorporation of Ag+. Ag@CDs showed excellent selectivity and sensitivity toward the sensing of melamine in the aqueous solutions with the limit of detection ~ 0.85 μM. Increasing the melamine level also raises the FL intensity of Ag@CDs. The substrate was effectively used in the detection of melamine in milk as a real application and the recovery percentage was found to be 98.03%. Moreover, other adulterants such as urea and formaldehyde can be detected selectively by Ag@CDs. Overall, the synthesized Ag@CDs can be used as an efficient material for sensing applications involving such food adulterants.
        4,600원
        516.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fluorine (F) recovery from wet process phosphoric acid (WPA) is essential for sustainable resource utilization and environmental protection. This work systematically investigates the F recovery mechanism by air stripping from three simulated systems: H3PO4- H2SiF6-H2O, H3PO4- HF-H2O, H3PO4- H2SiF6-HF-Al3+-H2O, and from two industrial systems: WPA and WPA-Al3+ under different stripping temperatures (60–110 ℃) and stripping times (0–120 min). The influence on the existence form of F, the content of Al3+ cations and the addition of active silica on the F removal rate in the phosphoric acid solution is studied by analyzing the changes in the contents of F, P and Si. The results indicate that the F in the form of H2SiF6 is more easily released from the phosphoric acid solution than that in the form of HF. While, the release of F is inhibited in the presence of the Al3+ in the solution due to the formation of Al-F complexes that are characterized by 19F NMR, 31Si NMR and FTIR techniques. Interestingly, the addition of active silica can promote the conversion of HF to H2SiF6 in the solution and significantly improve the release rate of F. The researching results can provide an important guidance for industrial practice of WPA.
        4,500원
        517.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hybrid nanocomposites of aluminium (NHAMMCs) made from AA5052 are fabricated via stir casting route by reinforcing 12 wt% Si3N4 and 0.5 wt% of graphene for usage in aeronautical and automotive applications due to the lower density and higher strength to weight proportion. The wear characteristics of the NHAMMCs are evaluated for different axial load, rotational speed, sliding distance and sliding time based on Box-Behnken design (BBD) of response surface methodology (RSM). Orowan strengthening mechanism is identified from optical image which improves the strength of the composite. Outcomes show that with higher axial load and rotational speed, there is substantial increase in wear loss whereas with increased sliding distance and sliding time there is no considerable increase in wear loss due to the lubricating nature of the reinforced graphene particles since it has higher surface area to volume ratio. Besides, artificial intelligence approach of neuro-fuzzy (ANFIS) model is developed to predict the output responses and the results are compared with the regression model predictions. Prediction from ANFIS outplays the regression model prediction.
        6,400원
        518.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pharmaceutical products occurring in freshwater bodies create numerous problems for the water bodies owing to their bio-toxic nature. In order to remove such pharmaceutical pollutants, a novel Er-doped Bi4O5Br2/ g-C3N5 nanocomposite was prepared by one-pot synthesis and applied for the photocatalytic removal process. The Er ions doped on the surface of Bi4O5Br2/ g-C3N5 nanocomposite exhibited 97% degradation of tetracycline in 60 min under visible light irradiation, which is higher than pure g-C3N5 and Bi4O5Br2 photocatalysts. The improved photocatalytic properties are attributed to the outstanding visible light harvesting capacity and quick charge carrier separation efficiency which greatly reduced the recombination rate in the heterojunctions. Based on radical trapping experiments, the •O2 −, h+ and •OH radicals played a prominent role in the photodegradation reactions under visible light. Finally, the ternary Er-doped Bi4O5Br2/ g-C3N5 nanocomposite is effectively recyclable with quite a stable photocatalytic removal rate. This work enables a new perspective on the rational design of rare-earth-based nanocomposites for various pharmaceutical pollutants treatment processes.
        4,000원
        519.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we investigate the impact of Isophorone diisocyanate functionalized graphene oxide (IPDI-GO) on the flame retardancy of rigid polyurethane foam (RPUF). IPDI-GO was synthesized and introduced into the RPUF matrix. The flame retardancy of RPUF was significantly enhanced by the incorporation of IPDI-GO, as evidenced by a reduction in peak heat release rate (PHRR) by 25% and total smoke production (TSP) by 15% in comparison to pure RPUF when IPDI-GO was incorporated at 3 wt%. Scanning electron microscopy (SEM) revealed that IPDI-GO contributed to the formation of a compact, continuous char layer on the RPUF surface. This study underscores the potential of IPDI-GO as a promising flame retardant additive for RPUF.
        4,000원
        520.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cellulose has experienced a renaissance as a precursor for carbon fibers (CFs). However, cellulose possesses intrinsic challenges as precursor substrate such as typically low carbon yield. This study examines the interplay of strategies to increase the carbonization yield of (ligno-) cellulosic fibers manufactured via a coagulation process. Using Design of Experiments, this article assesses the individual and combined effects of diammonium hydrogen phosphate (DAP), lignin, and CO2 activation on the carbonization yield and properties of cellulose-based carbon fibers. Synergistic effects are identified using the response surface methodology. This paper evidences that DAP and lignin could affect cellulose pyrolysis positively in terms of carbonization yield. Nevertheless, DAP and lignin do not have an additive effect on increasing the yield. In fact, combined DAP and lignin can affect negatively the carbonization yield within a certain composition range. Further, the thermogravimetric CO2 adsorption of the respective CFs was measured, showing relatively high values (ca. 2 mmol/g) at unsaturated pressure conditions. The CFs were microporous materials with potential applications in gas separation membranes and CO2 storage systems.
        4,500원