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        검색결과 121

        1.
        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
        2.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mg81Ni19-8wt.% REO (oxides of Lanthanum and Cerium) alloys were successfully prepared using mechanical alloying method with Mg-Ni alloy and REO powder. Phase analysis, structural characterization, and microstructure imagine of the alloys were conducted using X-ray diffraction (XRD), metallurgical microscope, and transmission electron microscopy (TEM) methods. Multi-phase structures, including the primary phase of Mg2Ni and several secondary phases of Mg + Mg2Ni, MgNi-LaO, and MgNi-CeO, were found in in the as-cast Mg81Ni19- 8wt.% REO alloys. XRD and TEM results showed that Ce exhibits variable valence behavior at various stages, and the addition of REO promotes the nanocrystalline of the alloy. The hydrogen absorption capacity of ball-milled Mg81Ni19 and Mg81Ni19- 8wt.%REO alloy for 2 h at 343 K is 1.34 wt.% and 1.83 wt.%, which are much larger than 0.94 wt.% of as-cast Mg81Ni19 alloy. The addition of REO led to a decrease of the thermal decomposition temperature of the alloy hydride by approximately 20 K and a reduction of the activation energy of the hydrogen desorption reaction by 10% and 13%, respectively.
        4,300원
        5.
        2023.11 구독 인증기관·개인회원 무료
        Bis (2-ethylhexyl)phosphoric acid (HDEHP) is a renowned extractant, favored for its affinity to selectively remove uranium via its P=O groups. We previously synthesized HDEHP-functionalized mesoporous silica microspheres for solid-phase uranium adsorption. Herein, we investigated the kinetic and isothermal behavior of uranyl ion adsorption in mesoporous silica microspheres functionalized with phosphate groups. Adsorption experiments were conducted by equilibrating 20 mg of silica samples with 50 mL of uranium solutions, with concentrations ranging from 10 to 100 mgU L−1 for isotherms and 100 mgU L−1 for kinetics. Three distinct samples were prepared with varying HDEHP to TEOS molar ratios (x = 0.16 and 0.24) and underwent hydrothermal treatment at different temperatures, resulting in distinct textural properties. Contact times spanned from 1 to 120 hours. For x = 0.16 samples, it took around 50 and 11 hours to reach equilibrium for the hydrothermally treated samples at 343 K and 373 K, respectively. Adsorbed quantities were similar (99 and 101 mg g-1, respectively), indicating consistent functional group content. This suggests that the key factor influencing uranium adsorption kinetics is pore size of the silica. The sample treated at 373 K, with a larger pore size (22.7 nm) compared to 343 K (11.5 nm), experienced less steric hindrance, allowing uranium species to diffuse more easily through the mesopores. The data confirmed the excellent fit of pseudo-second-order kinetic model (R2 > 0.999) and closely matched the experimental value, suggesting that chemisorption governs the rate-controlling step. To gain further insights into uranium adsorption behavior, we conducted an adsorption isotherm analysis at various initial concentrations under a constant pH of 4. Both the Langmuir and Freundlich isotherm models were applied, with the Langmuir model providing a superior fit. The relatively high R2 value indicated its effectiveness in describing the adsorption process, suggesting homogenous sorbate adsorption on an energetically uniform adsorbent surface via a monolayer adsorption and constant adsorption site density, without any interaction between adsorbates on adjacent sites. Remarkably, differences in surface area did not significantly impact uranium removal efficiency. This observation strongly suggests that the adsorption capacity is primarily governed by the loading amount of HDEHP and the inner-sphere complexation with the phosphoryl group (O=P). Our silica composite exhibited an impressive adsorption capacity of 133 mg g-1, surpassing the results reported in the majority of other silica literature.
        6.
        2023.11 구독 인증기관·개인회원 무료
        When decommissioning of nuclear facilities happens, large amounts of radioactive wastes are released. Because costs of nuclear decommissioning are enormous, effective and economical decontamination technologies are needed to remove radioactive wastes. During NPP operation, corrosion product called Chalk River Unidentified Deposits (CRUD) is generated. CRUD is an accumulation of substances and corrosion products consisting of dissolved ions or solid particles such as Ni, Fe, and Co on the surface of the NPP fuel rod coating. CRUD is slowly eroded by the circulation of hot pressurized water and later deposits on the fuel rod cladding or external housing, thereby reducing heat production by the nuclear fuel. Decontamination of radiologically contaminated metals must be performed before disposal, and several methods for decontaminating CRUD are being studied in many countries. Decontamination technology is an alternative to reducing human body covering and reducing radioactive waste disposal costs, and much research and development has been conducted to date. Currently, the importance of decontamination is emerging as the amount of waste stored in radioactive waste storage is close to saturation, and the amount of radioactive waste generated must be minimized through active decontamination. In this study, a preliminary study was conducted on the removal of CRUD by multiple membrane in an electro-kinetic process using an electrochemicalbased decontamination method. Preliminary research to develop a technology to electrochemically remove CRUD by using a self-produced electrochemical cell to check the pH change over time of the CRUD cell according to voltage, electrolyte, membrane and pH change.
        7.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study presents the synthesis, characterization, and utilization of marine macroalgae-derived bio-carbon catalysts (BC and KOH-AC) for the efficient conversion of waste cooking oil (WCO) into biodiesel. The biochar (BC) was produced through slow pyrolysis of macroalgal biomass, which was subsequently activated with potassium hydroxide (KOH) to produce a KOH-modified activated carbon (KOH-AC) catalyst. Advanced characterization techniques, including SEM, EDX, XRD, FTIR, and TGA, were used to examine the physicochemical characteristics of the catalysts. The synthesized catalysts were utilized to produce biodiesel from WCO, and the results revealed that the highest biodiesel yields, 98.96%, and 47.54%, were obtained using KOH-AC and BC catalysts, respectively, under optimal reaction conditions of 66 °C temperature, 12.3 M/O molar ratio, 130 min time, and 3.08 wt.% catalyst loading via RSM optimization. The kinetic and thermodynamic parameters, such as k, Ea, ΔH, ΔS, and ΔG, were determined to be 0.0346 min− 1, 43.31 kJ mol− 1, 38.98 kJ mol− 1, − 158.38 J K− 1 mol− 1, and 92.58 kJ mol− 1, respectively. The KOH-AC catalyst was recycled up to five times, with a significant biodiesel yield of 80.37%. The fuel properties of the biodiesel met ASTM (D6751) specifications, ensuring that it has excellent fuel characteristics and can be used as an alternative fuel.
        5,500원
        9.
        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
        10.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Osteoarthritis is a common condition with an increasing prevalence and is a common cause of disability. Osteoarthritic pain decreases the quality of life, and simple gait training is used to alleviate it. Knee osteoarthritis limits joint motion in the sagittal and lateral directions. Although many recent studies have activated orthotic research to increase knee joint stabilization, no study has used patellar tendon straps to treat knee osteoarthritis. Objects: This study aimed to determine the effects of patellar tendon straps on kinematic, mechanical, and electromyographic activation in patients with knee osteoarthritis. Methods: Patients with knee osteoarthritis were selected. After creating the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), leg length difference, Q-angle, and thumb side flexion angle of the foot were measured. Kinematic, kinetic, and muscle activation data during walking before and after wearing the orthosis were viewed. Results: After wearing the patellar tendon straps, hip adduction from the terminal stance phase, knee flexion from the terminal swing phase, and ankle plantar flexion angle increased during the pre-swing and initial swing phases. The cadence of spatiotemporal parameters and velocity increased, and step time, stride time, and foot force duration decreased. Conclusion: Based on the results of this study, the increase in plantar flexion after strap wearing is inferred by an increase due to neurological mechanisms, and adduction at the hip joint is inferred by an increase in adduction due to increased velocity. The increase in cadence and velocity and the decrease in gait speed and foot pressure duration may be due to joint stabilization. It can be inferred that joint stabilization is increased by wearing knee straps. Thus, wearing a patellar tendon strap during gait in patients with knee osteoarthritis influences kinematic changes in the sagittal plane of the joint.
        4,000원
        13.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Previous studies have reported that improving the spinal stability could be more effective in the prevention and treatment of recurrence. Lumbar stabilization exercise is known to strengthen the lumbar extension muscles and enhance physical, psychological and social functions. Objectives: To investigated the effect of lumbar spiral stenosis on the kinetic link training and lumbar stabilization exercise. Design: A randomized controlled trial. Methods: Study was preformed by randomly allocated 28 LSS participants into a kinetic link training group (KLT, n=14) and a lumbar stabilization exercise group (LSE, n=14). Kinetic link training and lumbar stabilization exercise were performed to subjects in both groups 5 times a week for 6 weeks. To verify the effect of LSS, changes in VAS, ODI, and proprioception before and after intervention were observed. Results: In KLT, statistically significant changes were found in VAS, ODI, and Proprioception before and after intervention. In LSE, there were significant changes in VAS and ODI before and after intervention. KLT and LSE before and after intervention indicated significant differences in proprioception. Conclusion: KLT and LSE are applied to LSS, there are effects of pain decrease, lumbar recovery and proprioception improvement.
        4,000원
        14.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There are a number of methods to evaluate the quality of squid. However, when purchasing the fish, consumers and retails rely only on the sensory test and flavor in the field. Therefore, this study was aimed to prove relationship between scientific indicator and sensory test. Total viable cell count (TVC), viable cell count of Pseudomonas spp., pH and volatile basic nitrogen (VBN) were selected as scientific indicators and mesured during the storage of squid at different temperature. The squid was storaged at 3 different temperature (5oC, 15oC, 20oC). Off flavor determination time was measured by R-index, and kinetic modeling was conducted. Activation energies of offflavor determination time, TVC, Pseudomonas spp, VBN, and pH were 51.210 kJ/mol, 42.88 kJ/mol, 50.283 kJ/mol, 72.594 kJ/mol and 41.99 kJ/mol respectively. Activation energy of off-flavor determination time was approximated to viable cell count of Pseudomonas spp., TVC, pH and VBN as an order. Especially, viable cell count of Pseudomonas spp. had best match of the activation energy. Therefore, it was judged that indicator of off-flavor determine time was viable cell count of Pseudomonas spp..
        4,000원
        16.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Since chronic ankle instability (CAI) can adversely affect postural control, core stability exercises have been investigated to improve postural control. However, only a few studies have focused on kinetic chain exercises. Objectives: To investigate the effects of open kinetic chain (OKC) and closed kinetic chain (CKC) core stability exercises on static and dynamic balance abilities and vertical jump height in CAI patients. Design: Randomized controlled trial. Methods: The 18 participants enrolled in this study were randomly divided into the OKC group (n=9) and CKC group (n=9). Static and dynamic balance abilities and vertical jump height were measured before and after the intervention. The intervention program comprising OKC or CKC core stability exercises depending on the groups was conducted for 30 min twice a week for 6 weeks in 12 sessions. Results: In the OKC group, static measured with the eyes open or closed and dynamic balance abilities were significantly improved after the intervention (P<.05). In the CKC group, dynamic balance ability was significantly increased (P<.05). A significant difference was observed in static balance ability measured with the eyes open between the two groups (P<.05). Vertical jump height was significantly increased after the intervention in both groups (P<.05). Conclusion: OKC and CKC core stability exercises improve static and dynamic balance abilities and vertical jump height in CAI patients. Specifically, the OKC core stability exercise was more effective in enhancing static balance ability than the CKC core stability exercise.
        4,000원
        17.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 훈제오리 슬라이스에서 Escherichia coli 유통 중 생장 예측을 위한 dynamic model을 개발하였다. E. coli는 2개의 훈제 오리 시료(16.7%) 에서 1.23 log CFU/ g검출되었다. 10-30oC 보관에 따라 E. coli의 μmax는 0.05- 0.36 log CFU/g/h, LPD는 4.39-1.07h, h0 값은 0.24-0.51을 나타내었다. 개발된 모델의 검증은 15oC, 23oC에서 수행 하였다. 모델 검증 결과 RMSE값이 0.130으로 개발된 모델이 다른 온도에 적용하기에 적합하다고 판단하였다. 이 러한 결과는 E. coli로 개발된 모델은 훈제오리 슬라이스에서 E. coli의 변화하는 온도에 따른 생장을 예측하는 데 유용하다.
        4,000원
        18.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Water disinfection using UV-LED(Light emitting diode) has many advantages, such as smaller footprint and power consumption as well as relatively longer lifespan than those of conventional mercury-UV lamps. Moreover, UV-LED disinfection is considered an environmentally benign process due to its mercury-free nature. In this study, disinfection using an LED module emitting 275nm UV was carried out. 384 UV-LEDs were put into a cylinder tube with a capacity of 1.7 liters. The UV intensity of the UV-LED module was controlled from 1.7 to 8.4 mW/cm2. The disinfection efficiency for the model microorganism solutions(E. coli ) was monitored. As the UV intensity(I) and contact time(t) varied, inactivation of the microorganisms from 2 to 4-log-removals(i.e., 99 to 99.99% of disinfection efficiency) was achieved. Disinfection using UV-LED was followed to 1st order reaction and the reaction rate constant, k was determined. In addition, the relationship between UV intensity(I) and contact time(t) in order to obtain 99.99% of disinfection efficiency was modeled: I1.2∙𝑡= 460, which indicates that the product of UV intensity and contact time requiring 4-log-removals is always constant.
        4,000원
        19.
        2021.10 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        본 논문은 키넥트 센서에서 랜덤 무향 칼만 필터에 기반한 잡음 제거를 통하여 신체 골격을 추정하는 방법을 제안한다. 일반적인 RGB 값과 깊이 정보를 제공하는 키넥트 카메라는 시간 영역에서 변동하는 센서 응답으로 인해 잡음이 포함된다. 기존의 방법은 다양한 필터링 기법을 사용하여 잡음 제거를 시도하였으나 잡음의 비선형성 때문에 한계가 있었다. 따라서 본 논문에서는 비선형 잡음 특성을 예측하고 업데이트하기 위하여 랜덤 무향 칼만 필터를 적용하고 이를 바탕으로 자세 인식을 위한 3 차원 공간에서 신체 관절 포인트를 예측하였다. 실험 결과 제안한 방법은 기존의 방법보다 잡음 감소 및 뼈대 추정에서 우수한 성능을 가지는 것을 확인하였다.
        4,000원
        20.
        2021.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Deuterium is a crucial clean energy source required for nuclear fusion and is a future resource needed in various industries and scientific fields. However, it is not easy to enrich deuterium because the proportion of deuterium in the hydrogen mixture is scarce, at approximately 0.016%. Furthermore, the physical and chemical properties of the hydrogen mixture and deuterium are very similar. Therefore, the efficient separation of deuterium from hydrogen mixtures is often a significant challenge when using modern separation technologies. Recently, to effectively separate deuterium, studies utilizing the ‘Kinetic Quantum Sieving Effect (KQS)’ of porous materials are increasing. Therefore, in this review, two different strategies have been discussed for improving KQS efficiency for hydrogen isotope separation performance using nanoporous materials. One is the gating effect, which precisely controls the aperture locally by adjusting the temperature and pressure. The second is the breathing phenomenon, utilizing the volume change of the structure from closed system to open system. It has been reported that efficient hydrogen isotope separation is possible using these two methods, and each of these effects is described in detail in this review. In addition, a specific-isotope responsive system (e.g., 2nd breathing effect in MIL-53) has recently been discovered and is described here as well.
        4,000원
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