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        검색결과 13,900

        981.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Stroke patients have weak trunk muscle strength due to brain injury, so a single type of exercise is advised for restoring functionality. However, even after intervention, the problem still lies and it is suggested that another intervention method should be applied with exercise in order to deal with such problem. Objectives: To Investigate the effect of bridge exercise combined with functional electrical stimulation (FES) on trunk muscle activity and balance in stroke patients. Design: Randomized controlled trial. Methods: From July to August 2020, twenty stroke patients was sampled, ten patients who mediated bridge exercises combined with functional electrical stimulation were assigned to experiment group I, and ten patients who mediated general bridge exercises were assigned to experiment groupⅡ. For the pre-test, using surface EMG were measured paralyzed rectus abdominis, erector spinae, transverse abdominis/internal oblique muscle activity, and using trunk impairment scale were measured balance. In order to find out immediate effect after intervention, post-test was measured immediately same way pre-test. Results: Change in balance didn’t show significant difference within and between groups, but muscle activity of trunk was significant difference rectus abdominis and erector spinae within groups I (P<.01), also between groups was significant difference (P<.05). Conclusion: Bridge exercise combined with FES could improve trunk function more effectively than general bridge exercise due to physiological effect of functional electrical stimulation.
        4,000원
        982.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Back pain is associated with a high risk of recurrence. Various physical therapy techniques for back pain have been studied, including reprogramming the central nervous system by integrating sensation and motion with sensory exercise training. Objectives: To aimed verify the effectiveness of sensorimotor training in improving postural stability and pain levels. Design: A randomized controlled trial. Methods: The study population was randomized into a sensory exercise training group and trunk stabilization training group and treated three times a week for 4 weeks. Each group took part in sensorimotor training for 15 minutes or lumbar stabilization exercise for 15 minutes. Results: After the intervention both groups showed Improvements in the variables. There was a significant difference in the dynamic postural stability, limit of stability, and modified visual analog scale scores in the sensorimotor training group compared to the lumbar stabilization exercise group (P<.05). Conclusion: Sensorimotor training appears to be an effective physical therapy exercise program that can be applied in patients with low back pain to improve muscle control ability.
        4,000원
        983.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Although the scapular posterior tilt movement could facilitate the lower trapezius (LT) muscle activity, no study identified the effects of the scapular posterior tilt movement on the selective activation of the LT muscle during prone shoulder extension. Objectives: To examine the influences of additional scapular posterior tilt on electromyography (EMG) of the upper trapezius (UT) and the LT muscles during prone shoulder extension. Design: Cross-sectional study. Methods: There were 15 asymptomatic male participants in this study who performed prone shoulder extension with and without scapular posterior tilt movements. For the scapular posterior tilt movements, participants performed visual biofeedback training for scapular movement using motion sensor. During the exercises, the EMG activity of the UT and LT was recorded using surface EMG system. Results: The EMG activity of the LT significantly increased during prone shoulder extension with scapular posterior tilt compared to that of general prone shoulder extension, whereas that of the UT was not significantly different between the two exercises. Moreover, scapular posterior tilt application significantly decreased UT/LT muscle activity ratio. Conclusion: Scapular posterior tilt movement may be emphasized during exercise when facilitating LT muscle activation.
        4,000원
        984.
        2021.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This paper presents the characteristics of gentamicin-loaded into cetyl trimethyl ammonium intercalated montmorillonite (GtM/CTMA/Mt) as a hybrid composite for a slow-released antibacterial delivery systems. The work describes the successful immobilization of gentamicin into the interlayers of surfactant-modified montmorillonite. Physicochemical characterization of the material is carried out by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. The kinetics of the gentamicin release is investigated by in vitro study and analyzed based on UV–Vis spectrometry. In addition, antibacterial study is performed towards Klebsiella pneumoniae Staphylococcus aureus, Escherichia coli, and Streptococcus pyogenes. The results show that the gentamicin loading into CTMA/ Mt increases the effectiveness of the antibacterial activity, as shown by the higher inhibition zone for all tested bacteria, compared to gentamicin as a positive control. The kinetics study suggests that the gentamicin release obeys the modified Korsmeyer–Peppas model. The physicochemical study and activity test demonstrate the feasibility of the GtM/CTMA/Mt for practical applications.
        4,000원
        985.
        2021.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, photocatalytic degradation of ammonia in petrochemical wastewater is investigated by solar light photocatalysis. Two-dimensional ultra-thin atomic layer structured MoS2 are synthesized via a simple hydrothermal method. We examine all prepared samples by means of physical techniques, such as SEM-EDX, HRTEM, FT-IR, BET, XRD, XPS, DRS and PL. And, we use fullerene modified MoS2 nanosheets to enhance the activity of photochemically generated oxygen (PGO) species. Surface area and pore volumes of the MoS2-fullerene samples significantly increase due to the existence of MoS2. And, PGO oxidation of MB, TBA and TMST, causing its concentration in aqueous solution to decrease, is confirmed by the results of PL. The generation of reactive oxygen species is detected through the oxidation reaction from 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). It is found that the photocurrent density and the PGO effect increase in the case with modified fullerene. The experimental results show that this heterogeneous catalyst has a degradation of 88.43% achieved through visible light irradiation. The product for the degradation of NH3 is identified as N2, but not NO2−or NO3−.
        4,600원
        986.
        2021.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, Ni nanoparticle supported by graphene oxide (GO) (Ni-GO) is successfully synthesized through hydrothermal synthesis and calcination, and Cr(VI) is extracted from aqueous solution. The morphology and structure of Ni- GO composites are characterized by scanning electron microscopy (SEM), trans mission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). High-resolution transmission electron microscopy (HRTEM) and XRD confirms the high dispersion of Ni nanoparticle after support by GO. Loading Ni on GO can obviously enhance the stability of Ni-GO composites. It can be calculated from TGA that the mass percentage of Ni is about 60.67%. The effects of initial pH and reaction time on Cr(VI) removal ability of Ni-GO are investigated. The results indicate that the removal efficiency of Cr(VI) is greater than that of bared GO. Ni-GO shows fast removal capacity for Cr(VI) (<25 min) with high removal efficiency. Dynamic experiments show that the removal process conforms to the quasi-second order model of adsorption, which indicates that the rate control step of the removal process is chemical adsorption. The removal capacity increases with the increase of temperature, indicating that the reaction of Cr(VI) on Ni-GO composites is endothermic and spontaneous. Combined with tests and characterization, the mechanism of Cr(VI) removal by rapidly adsorption on the surface of Ni-GO and reduction by Ni nanoparticle is investigated. The above results show that Ni-GO can be used as a potential remediation agent for Cr(VI)-contaminated groundwater.
        4,000원
        987.
        2021.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Composite materials offer distinct and unique properties that are not naturally inherited in the individual materials that make them. One of the most attractive composites to manufacture is the aluminum alloy matrix composite, because it usually combines easiness of availability, light weight, strength, and other favorable properties. In the current work, Powder Metallurgy Method (PMM) is used to prepare Al2024 matrix composites reinforced with different mixing ratios of yttrium oxide (Y2O3) particles. The tests performed on the composites include physical, mechanical, and tribological, as well as microstructure analysis via optical microscope. The results show that the experimental density slightly decreases while the porosity increases when the reinforcement ratio increases within the selected range of 0 ~ 20 wt%. Besides this, the yield strength, tensile strength, and Vickers hardness increase up to a 10 wt% Y2O3 ratio, after which they decline. Moreover, the wear results show that the composite follows the same paradigm for strength and hardness. It is concluded that this composite is ideal for application when higher strength is required from aluminum composites, as well as lighter weight up to certain values of Y2O3 ratio.
        4,000원
        988.
        2021.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Ti-Al-Si target and Cr-Si target are sputtered alternately to develop a multi-layered nitride coating on a steel mold to improve die-casting lifetime. Prior to the multi-layer deposition, a CrN layer is developed as a buffer layer on the mold to suppress the diffusion of reactive elements and enhance the cohesive strength of the multi-layer deposition. Approximately 50 nm CrSiN and TiAlSiN layers are deposited layer by layer, and form about three μm-thickness of multi-layered coating. From the observation of the uncoated and coated steel molds after the acceleration experiment of liquid metal injection casting, the uncoated mold is severely eroded by the adhesion of molten metallic glass. On the other hand, the multi-layer coating on the mold prevents element diffusion from the metallic glass and mold erosion during the experiment. The multi-layer structure of the coating transforms the nano-composite structured coating during the acceleration test. Since the nano-composite structure disrupts element diffusion to molten metallic glass, despite microstructure changes, the coating is not eroded by the 1,050 oC molten metallic glass.
        4,000원
        989.
        2021.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Bi2MoO6 (BMO) via the structure-directing role of CO(NH2)2 is successfully prepared via a facile solvothermal route. The structure, morphology, and photocatalytic performance of the nanoflake BMO are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), fluorescence spectrum analysis (PL), UV-vis spectroscopy (UVvis) and electrochemical test. SEM images show that the size of nanoflake BMO is about 50 ~ 200 nm. PL and electrochemical analysis show that the nanoflake BMO has a lower recombination rate of photogenerated carriers than particle BMO. The photocatalytic degradation of tetracycline hydrochloride (TC) by nanoflake BMO under visible light is investigated. The results show that the nanoflake BMO-3 has the highest degradation efficiency under visible light, and the degradation efficiency reached 75 % within 120 min, attributed to the unique hierarchical structure, efficient carrier separation and sufficient free radicals to generate active center synergies. The photocatalytic reaction mechanism of TC degradation on the nanoflake BMO is proposed.
        4,000원
        990.
        2021.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Effects of growth variables and post-growth annealing on the optical, structural and electrical properties of magnetron-sputtered Ga0.04Mg0.10Zn0.86O films are characterized in detail. It is observed that films grown from pure oxygen plasma showed high resistivity, ~102 Ω·cm, whereas films grown in Ar plasma showed much lower resistivity, 2.0 × 10− 2 ~ 1.0 × 10−1 Ω·cm. Post-growth annealing significantly improved the electrical resistivity, to 4.3 ~ 9.0 × 10−3 Ω·cm for the vacuum annealed samples and to 1.3 ~ 3.0 × 10−3 Ω·cm for the films annealed in Zn vapor. It is proposed that these phenomena may be attributed to the improved crystalline quality and to changes in the defect chemistry. It is suggested that growth within oxygen environments leads to suppression of oxygen vacancy (Vo) donors and formation of Zn vacancy (VZn) acceptors, resulting in highly resistive films. After annealing treatment, the activation of Ga donors is enhanced, Vo donors are annihilated, and crystalline quality is improved, increasing the electron mobility and the concentration. After annealing in Zn vapor, Zn interstitial donors are introduced, further increasing the electron concentration.
        4,000원
        991.
        2021.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Understanding of effects of changes in the particle size of the matrix material on the mullite whisker growth during the production of porous mullite is crucial for better design of new porous ceramics materials in different applications. Commercially, raw materials such as Al2O3/SiO2 and Al(OH)3/SiO2 are used as starting materials, while AlF3 is added to fabricate porous mullite through reaction sintering process. When Al2O3 is used as a starting material, a porous microstructure can be identified, but a more developed needle shaped microstructure is identified in the specimen using Al(OH)3, which has excellent reactivity. The specimen using Al2O3/SiO2 composite powder does not undergo mulliteization even at 1,400 oC, but the specimen using the Al(OH)3/SiO2 composite powder had already formed complete mullite whiskers from the particle size specimen milled for 3 h at 1,100 oC. As a result, the change in sintering temperature does not significantly affect formation of microstructures. As the particle size of the matrix materials, Al2O3 and Al(OH)3, decreases, the porosity tends to decrease. In the case of the Al(OH)3/SiO2 composite powder, the highest porosity obtained is 75% when the particle size passes through a milling time of 3 h. The smaller the particle size of Al(OH)3 is and the more the long/short ratio of the mullite whisker phase decreases, the higher the density becomes.
        4,000원
        992.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        National concerns about air pollution are growing. The importance of indoor air quality is emerging because people live in an indoor environment more than 90% of the day. In particular, the indoor air quality of schools needs to be managed as teenagers are vulnerable to environmental pollution. The government has designated the School Health Act in order to manage indoor air quality in schools. Air purifiers have been operated to improve indoor air quality in the classroom since 2018. In this study, we performed on-site evaluations in some classrooms, and then we proposed a plan for improving the air quality in the classroom. In this study, PM10, PM2.5, and CO2 in classrooms in Chungnam were measured to analyze the effect of air cleaner supply. A portable aerosol spectrometer (PAS, model 1.109, Grimm) and CO2 meter (TES 1370, TES) were used as measuring instruments. Schools A and B exceeded the recommended standards, while school C met the standards. The ratio of PM10, PM2.5 in classrooms A and B was 0.58 and 0.5, respectively. Correlation analysis was performed between indoor and outdoor pollutants to analyze the effects of particulate pollutants present in each classroom. First, the measured concentration of fine particles was classified according to/on the basis of factors that affect/influence the internal environment of the classroom. Then, fine dust concentrations measured at the same time as AQMS were classified with regard to the external factors. The gradients for each classroom were 1.57, 1.63, and 1.54, although there were differences in concentration, but they were relatively similar. It is necessary to develop and disseminate customized air purifiers considering the activity of the occupants of classrooms. It is important to consider the areas in which s tudents breathe when installing air purifiers in the classroom. In addition, follow-up management of air purifiers is an essential element. For efficient operation and management of indoor air quality, it is necessary to develop and disseminate standard manuals for air purifiers. It is proposed that an environmental manager should be deployed in schools to manage environmental issues. Standardization of air purifiers, management guidelines for standard manuals, and field support for environmental sheriffs should be established on a legal basis.
        4,300원
        993.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was undertaken to investigate whether HEPA filter-equipped air purifiers can remove aerosolized virus, whether the removed virus can re-scatter through the filter, and how long the removed virus keeps its infectivity in the filter. For this investigation, six HEPA filter-equipped air purifiers produced by different companies were tested against PhiX174 and MS2 phages aerosolized by nebulizers. For viral detection from the air, LB agar plates covered with Escherichia coli hosts and an Andersen air sampler were used, and from the surface, the swab method was used. Both the aerosolized PhiX174 and MS2 viruses absorbed by the HEPA filters in the air purifiers were not detected from the air through filters or the surface of the outlet of the air purifiers. During the operation of the air purifiers at medium mode, the infectious viral concentration of these viruses in the HEPA filters decreased to 0%~12.3% as the time period passed. These results regarding infectious viral concentration differences were assumed to be due to the different wind speed and air volume among the six air purifiers. Based on observations over 5 days, the infectious viral concentration of the PhiX174 phage was 8,600 times lower when the air purifier was operated than when it was not operated. Overall, our results demonstrate that HEPA filter-equipped air purifiers can efficiently remove the two aerosolized viruses and the removed viruses in the HEPA filter could not re-spread and maintain their infectivity.
        4,000원
        994.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The degree and intensity of unpleasant and disgusting odors perceived through a person's sense of smell can vary depending on personal or social and cultural characteristics. In addition, it is not effective to manage odors solely on the basis of concentration levels because odors can be combined according to temperature, humidity, and frequency, so that they can be recognized differently even if the same person smells the same substance. The mobile odor application was developed to enable real time monitoring of odor characteristics reflecting the actual condition of the field. Accordingly, the Green Future Foundation, a civic group, conducted an environmental campaign to record and share the information of odors in school zone using the first version of the application. The real time monitoring of field odor was able to improve the problems of the current standard methods for the examination and assessment of odors. However, with regard to the first version of the application, the process and results of odor recording through odor measurement applied the direct olfactory method and were less relevant. Therefore, it was difficult to organize data due to duplicate selection. For that reason, this study was conducted to overcome the problems of the first version of the mobile application and to effectively and accurately reflect odors and personal characteristics. This odor application that has been developed is able to monitor and assess odors based on 5 features: classification, character, strength level, hedonic tone, and acceptability.
        4,000원
        995.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two lab-scale trickle-bed type biofilters with a single fungal species (Aspergillus fumigatus, Acidomyces acidophilus, respectively) have been studied to investigate the simultaneous removal of inorganic (hydrogen sulfide) and organic (butyl acetate) compounds. The biofilter with Aspergillus fumigatus treated simultaneously two different compounds with removal capacity of 1,511 mgS/m3/hr and 6,324 mgC/m3/hr; and the biofilter inoculated with Acidomyces acidophilus had the removal capacity of 1,254 mgS/m3/hr and 6,045 mgC/m3/hr. Stable operational performance was observed in both biofilters under an acidic condition of pH 2 to 4. Based on pseudo-first-order removal rates as a function of depth in the biofilter, Aspergillus fumigatus showed a twice faster rate of hydrogen sulfide removal than Acidomyces acidophilus, 15.9% (Aspergillus fumigatus) and 17.9% (Acidomyces acidophilus) of total sulfur removed were oxidized to produce sulfates, and 77.8% (Aspergillus fumigatus) and 79.4% (Acidomyces acidophilus) were accumulated in the form of S0 through the bed in both biofilters, respectively.
        4,000원
        996.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The sampling bag is used as a storage container for odor gas samples. It is known that the substances recovery rate of odor bags decreases during storage time, and the degree of recovery varies depending on the characteristics of the gas sample and the material of the bag. This study investigated the recovery rate of VFA (ACA, PPA, BTA, VLA) in PEA bags during storage time. In addition, a model was developed to estimate the recovery rate of each substance as a function of time. Standard gas (ACA, PPA, BTA, VLA mixed) recovery rate was used for the model development. The concentration of the compound in the bag was measured by SIFT-MS at intervals of 1 to 2 hours. The recovery rate according to the storage time was calculated as the ratio to the initial concentration. The recovery rate of each substance according to the storage period (12h, 24h, 36h, 48h) was ACA (66.2%, 62.8%, 55.6%, 52.0%), PPA (77.6%, 72.1%, 63.0%, 58.1%, 86.6%), BTA (86.6%, 81.3%, 71.6%, 66.9%), VLA (94.8%, 89.0%, 76.6%, 71.7%). The recovery rate continued to decrease over the course of 48 hours of storage time. ACA, PPA, and BTA showed the greatest decrease within the initial 12 hours, which is form of exponential decrease. Therefore, we considered a 1~3 degree polynomial regression model and a 1~2 degree exponential decay model. Each developed model was evaluated by r², RMSE, MAPE, AIC, and then a model for each substance was selected. Selected models were tested with recovery rate data from swine farm odor samples. Only the ACA model exhibited a good performance (r² = 0.76).
        4,000원
        997.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to assess the pollution level in 13 crowded subway stations in an effort to understand the spatial and seasonal factors of Indoor Air Quality. The main measured items were particulate pollutants such as PM10 and PM2.5 and gaseous pollutants such as CO2, HCHO, Rn, TVOC, BTEX, and Styrene at concourses and platforms in the summer and winter periods. The influence of the draught created by the movement of the train was classified into lateral and island platforms, and the concentrations of PM by location (entrance, middle, and end) were statistically compared and analyzed. As a result, the concentrations of PM were confirmed high in the order of Platform > Concourse > Ambient air. In particular, in the case of platform PM10, the frequency exceeding the standard value (100 μg/m3) was 38.5% and the maximum concentration was 196.2 μg/m3. All gaseous pollutants were at lower levels than the standard, and the factors affecting CO2 and Rn were identified as the number of users and geological characteristics, respectively. The principal component analysis (PCA) demonstrated that PM was found to be a major indicator of the air quality management of subway stations. In particular, the concentrations at entrance and end areas in the lateral platform were about 1.4 times higher with regard to PM10 than in the middle area, and about 1.9 times higher with regard to PM2.5 due to the effect created by the draught produced by the movement of the train. Therefore, in order to manage PM in the platform area, a specialized management plan for places with particularly high PM concentration within the platform area is required. In addition, it is necessary to evaluate the effect created by the draught produced by train movement when selecting locations for measuring indoor air quality.
        4,000원
        998.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the odor dilution rate at 15 locations around three schools in Seoul using an onsite olfactometer. In addition, odor intensity, odor quality, and hedonic tone by direct sensory method were measured along with measurement of the field odor dilution rate, and instrument analysis using odor sensor array and TD-GC was also measured. Onsite olfactometer measurements show that only one of the three schools measured odors exceeding the strict emission acceptance standard of 10 at three points. The average odor intensity at each point measured by the direct sensory method of five persons was in the range of 2.7 to 0.3. The difference in the number of odor dilution rates around schools in Seoul could be related to the level of income by region. The odor environment around each school was judged to be well managed in areas with higher income levels, indicating a lower odor dilution rate. The correlation coeffcient between the odor intensity measured by the direct sensory method and the onsite olfactometer was 0.79, indicating high correlation. The correlation coefficient of sensor array and TD-GC toward the odor intensity was -0.28 and 0.02, respectively. This suggests that a method based on a person's sense of smell should be introduced when measuring low-level odor dilution rates in non-industrial areas, such as school zones.
        4,000원
        999.
        2021.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        An 8-year-old, spayed female Maltese dog was presented with a one-month history of erythema, swelling and alopecia of periocular region with pruritus. The skin lesions were first detected at the age of three years, but this was the first time that symptoms had appeared in the eyes. Physical examination revealed markedly swollen and erythematous eyelids and conjunctiva including Meibomian glands. In addition, periocular alopecia and tears were identified. Slit lamp microscopy revealed erythema of conjunctiva and swelling of Meibomian glands. The Schirmer’s tear test was normal. Impression smear cytology of eyes revealed sterile neutrophils and corneal epithelial cells. There were no virus or bacterial infections in the eyes. On skin examination, generalized erythema was detected but there were no other skin lesions. A case of allergic blepharoconjunctivitis associated with canine atopic dermatitis was diagnosed based on history taking and skin examination. Treatment included cetirizine, cyclosporine, prednisolone and Forus eye drops®. The owner was instructed to wear an Elizabethan collar around his dog's neck at all times and restrict walking. And the diet was changed to hypoallergenic dog food. Medications and environmental restrictions significantly reduced erythema, edema and swelling of meibomian glands. Pruritus was also decreased. Six weeks later, the edema lesions of eyes disappeared.
        4,000원
        1000.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The adsorption method that is widely used in the field of odor control generally utilizes activated carbon. However, the development of an economical and efficient adsorbent is required due to the increased use of activated carbon and the high cost of raw materials. Accordingly, the use of waste as a raw material for new adsorbents is attracting attention both in Korea and abroad. In this study, the current status of domestic and overseas waste generation, characteristics of adsorbents, and research trends were investigated, and through this, it was found that a waste-derived adsorbent was an adequate substitute in terms of adsorption capacity and price compared to activated carbon.
        4,900원