검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 13,918

        1841.
        2018.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The passivation of AZ91D Mg alloys by plasma anodization requires deliberate choice of process parameters due to the presence of large amounts of structural defects. We study the dependence of pore formation, surface roughness and corrosion resistance on voltage by comparing the direct current (DC) mode and the pulse wave (pulse) mode in which anodization is performed. In the DC plasma anodization mode, the thickness of the electrolytic oxide film of the AZ91D alloy is uneven. In the pulse mode, the thickness is relatively uniform and the formed thin film has a three-layer structure. The pulse mode creates less roughness, uniform thickness and improved corrosion resistance. Thus, the change of power mode from DC to pulse at 150 V decreases the surface roughness (Ra) from 0.9 μm to 0.1 μm and increases the corrosion resistance in rating number (RN) from 5 to 9.5. Our study shows that an optimal oxide film can be obtained with a pulse voltage of 150 V, which produces an excellent coating on the AZ91D casting alloy.
        4,000원
        1842.
        2018.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We report the structural, morphological and magnetic properties of the Ni70Mn30 alloy prepared by Planetary Ball Mill method. Keeping the milling time constant for 30 h, the effect of different ball milling speeds on the synthesis and magnetic properties of the samples was thoroughly investigated. A remarkable variation in the morphology and average particle size was observed with the increase in milling speed. For the samples ball milled at 200 and 300 rpm, the average particle size and hence magnetization were decreased due to the increased lattice strain, distortion and surface effects which became prominent due to the increase in the thickness of the outer magnetically dead layer. For the samples ball milled at 400, 500 and 600 rpm however, the average particle size and hence magnetization were increased. This increased magnetization was attributed to the reduced surface area to volume ratio that ultimately led to the enhanced ferromagnetic interactions. The maximum saturation magnetization (75 emu/g at 1 T applied field) observed for the sample ball milled at 600 rpm and the low value of coercivity makes this material useful as soft magnetic material.
        4,000원
        1843.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The International Headache Society (IHS) has validated cervicogenic headache (CGH) as a secondary headache type that is hypothesized to originate due to nociception in the cervical area. CGH is a common form of headache and accounts for 15% to 20% of all chronic and recurrent headaches. CGH is commonly treated with manual and exercise therapy. To date, no studies have isolated only one manual intervention in an attempt to determine its effectiveness. In this case study we present a 28-year-old patient with right upper cervical (UC) and occipital pain who responded well to a single manual intervention technique. This technique was applied in isolation for the first three visits and two therapeutic exercises prescribed on the fourth and fifth visit. In total, manual and exercise intervention occurred over 8 visits at which point in time the patient was discharged with no UC motion impairments, an NPRS rating of 0, a NDI and HDI demonstrating a 100% improvement and a 37% improvement in FOTO score. The traction based manual intervention and two therapeutic exercises prescribed for this patient were successful in relieving UC pain and CGH. At six months follow up, the patient was still symptom free.
        4,000원
        1844.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study, based on physical therapy interventions for menstruation disorders, observed the effect of Pilates stabilization exercises and Kinesio taping on dysmenorrhea and prostaglandin F2α levels. Female college students (n=37) who had >70 points on the mood disorder questionnaire (MDQ) and >4 points on the visual analogue scale (VAS) were divided into three different groups, the Pilates group (PG, n= 13), Pilates and Taping group (PTG, n=12), Taping group (TG, n=12). Pilates and taping were performed 3 times a week for 6 weeks. Pre- and post-menstruation difficulties were measured through the MDQ. Changes in blood prostaglandin F2α levels were also measured. Changes in pre- and post-menstrual pain and prostaglandin F2α levels were significantly reduced in the PG, PTG, and TG. Changes in pre- and postmenstrual pain and prostaglandin F2α levels resulted in significant differences in the PTG and TG. Dysmenorrhea and prostaglandin F2α levels were significantly decreased in the TG than in the PTG. These findings suggest that Pilates stabilization exercises and Kinesio taping are effective in decreasing menstrual difficulties and pain in female college students.
        4,000원
        1845.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the effects of group exercise program on health conditions and quality of life in cerebral palsy. Adults with cerebral palsy in their 20’s who participated in the evaluation of measurement tools prior to and following the experiment. The control group was engaged in manual exercise for the range of joint movement and extension exercise for arms, legs and trunk, and experimental group performed group exercise program including boccia exercise. The health condition and quality of life of the experimental group were significantly increased after intervention (.05<). There was a slight increase in the control group, however it was not statistically significant. As a result of comparing the health condition and quality of life of the two groups, the value of the experimental group was significantly higher than that of the control group. The results of this study suggest that exercise programs for patients with cerebral palsy in the twenties are considered as beneficial interventions to improve health conditions and quality of life.
        4,000원
        1846.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to analyze the effects of manual therapy on lower extremity alignment in pelvic malalignment. The subjects were 20 adults with pelvic malalignment. They were divided into two groups: manual therapy group (n=10) and stretching exercise group (n=10). Each group performed the intervention two times per week for 4 weeks. The lower extremity alignment was measured by pelvic deviation, functional leg length inequality, and plantar pressure distribution, which were measured between pre- and post-test. In the result of pelvic deviation, there was a significant difference between the pre- and post-test of the manual therapy group and stretching exercise group. In the result of the functional leg length inequality, there was a significant difference between the pre- and post- test of the manual therapy group. In the result of plantar pressure distribution, there was a significant difference between the pre- and post- test of the manual therapy group. These findings suggest manual therapy improves the pelvic deviation, functional leg length inequality, and plantar pressure distribution in the pelvic malalignment.
        4,000원
        1847.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to identify the effects of kinesio taping (KT) applied in a proprioceptive neuromuscular facilitation (PNF) pattern on the pain, weight-bearing distribution (WBD), and walking ability of knee osteoarthritis (KOA) patients. Thirty women with KOA were randomly allocated to a control group (n=15) with KT at the quadriceps only, and a PNF pattern group (n=15) with KT at the quadriceps and gastrocnemius muscle. Pain intensity was measured using a visual analogue scale during walking. In addition, WBD, and walking ability were measured before and 30 minutes after KT application. The VAS significantly reduced in both groups after the intervention (p<.05). WBD (p<.05, ES=.32) and walking ability (p<.05, ES=.38) showed a significant change in the PNF pattern group, and in the inter-group comparison, the PNF pattern group showed a significant difference compared to the control groups. These results demonstrate that KT application with PNF pattern effectively attenuate the pain and improves WBD and walking ability in KOA patients.
        4,000원
        1848.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of present study was to investigate the effect of kinesio taping on pulmonary function in stroke patients using manual wheelchairs. Twenty stroke patients were divided into a wood chair group (WCG, n=10), a wheelchairs group (WG, n=10), and a kinesio taping with wheelchairs group (KWG, n=10). Taping with wheelchairs group was applied kinesio taping on back muscles (vertical paraspinal strips and oblique strips). All three groups were trained in upright seated posture for 30 minutes. Pulmonary function tests were performed with forced expiratory volume in one second, forced vital capacity and peak expiratory flow as spirometer. There was a significant increase in forced expiratory volume in one second and forced vital capacity only in KWG. The results of this study demonstrate that kinesio taping has an immediate effect on the improvement of pulmonary function in stroke patients using manual wheelchairs.
        3,000원
        1849.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to analyze the six personality factors of rehabilitation therapists and to identify the effects of these factors on their job stress and turnover intention. This study involved physical therapists and occupational therapists as rehabilitation therapists. A structured questionnaire was distributed to rehabilitation therapists, and 186 answered copies were used for data analysis. The results of the survey were as follows: Among the six personality factors, the rehabilitation therapists showed the highest level of honesty–humility and the lowest level of openness to experience. In terms of job stress, the subjects experienced the highest level of stress from job autonomy and the lowest level of stress from relationship conflict. In terms of turnover intention and work motivation reduction, the subjects scored above the median points, showing their high levels of turnover intention. In addition, higher levels of extraversion and agreeableness in the rehabilitation therapists led to a statistically significant reduction in their turnover intention and a statistically significant decrease in most of their job stress factors. Based on these results, organizational management aimed at increasing the personality factors of extraversion and agreeableness is necessary as a measure to effectively manage rehabilitation therapists’ job stress and turnover intention.
        4,000원
        1850.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The original focus of this study was to investigate the immediate effects of lumbar rotational mobilization on the one-legged standing ability. Fifteen subjects (6 men and 9 women, mean age = 22.77 (SD = 1.21), mean height = 165.46cm (SD = 11.65), mean weight = 61.46kg (SD = 8.29) volunteers from healthy individuals were recruited and randomized to a lumbar rotational mobilization (LRM) group and a trunk rotational exercise (TRE) group. Mobilization (grade 3 or 4) was applied to the LRM group on the lumbar spine (L1 to L5) in a side-lying, and trunk twist exercise (left and right side) was applied the to the TRE group with lunge position. Center of pressure (COP) and the velocity of the center of pressure (VCOP) of each participant were measured as a balance ability through one leg standing position. Results are as follows. In within-group difference, the COP of the LRM group reduced during standing with the right foot, but the VCOP change of the LRM was not statistically significant. In between-groups difference, COP of TRE group was decreased compared with LRM group only during left leg standing in the eyes (p <.05). The results of this study suggest that LRM is more effective than TRE in improving balance ability.
        4,000원
        1851.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It has been reported that gastrocnemius tightness and posterior talar glide are crucial factors influencing ankle dorsiflexion. However, the relationship of ankle dorsiflexion and these factors is not identified in previous studies. The purpose of this study was to identify the relationship of ankle dorsiflexion passive range of motion and gastrocnemius tightness and posterior talar glide. Twenty-five male subjects participated in this study. Bilateral weight-bearing ankle dorsiflexion passive range of motion and amount posterior talar glide of participants were measured using an inclinometer. Change in myotendinous junction of medial gastrocnemius was measured using ultrasonography to identify gastrocnemius tightness. Pearson product moment correlations were performed to examine correlations between ankle dorsiflexion passive range of motion and gastrocnemius tightness and posterior talar glide. Present findings revealed significant correlation between ankle dorsiflexion passive range of motion and gastrocnemius tightness (p=0.017, r=0.336). Also, ankle dorsiflexion passive range of motion was correlated with posterior talar glide (p=0.001, r=0.470). The present findings provide experimental evidence for factors influencing weight-bearing ankle dorsiflexion.
        3,000원
        1852.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The annealing characteristics of a cold rolled Al-6.5Mg-1.5Zn alloy newly designed as an automobile material is investigated in detail. The aluminum alloy in the ingot state is cut to a thickness of 4 mm, a total width of 30 mm and a length of 100 mm and then reduced to a thickness of 1 mm (reduction of 75%) by multi-pass rolling at room temperature. Annealing after rolling is performed at temperatures ranging from 200 to 400 ℃ for 1 hour. The tensile strength of the annealed material tends to decrease with the annealing temperature and shows a maximum tensile strength of 482MPa in the material annealed at 200 ℃. The tensile elongation of the annealed material increases with the annealing temperature, while the tensile strength does not, and reaches a maximum value of 26 % at the 350 ℃ annealed material. For the microstructure, recovery and recrystallization actively occur as the annealing temperature increases. The recrystallization begins to occur at 300 ℃ and is completed at 350 ℃, which results in the formation of a fine grained structure. After the rolling, the rolling texture of {112}<111>(Cu-Orientation) develops, but after the annealing a specific texture does not develop.
        4,000원
        1853.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In recent years, solar cells based on crystalline silicon(c-Si) have accounted for much of the photovoltaic industry. The recent studies have focused on fabricating c-Si solar modules with low cost and improved efficiency. Among many suggested methods, a photovoltaic module with a shingled structure that is connected to a small cut cell in series is a recent strong candidate for low-cost, high efficiency energy harvesting systems. The shingled structure increases the efficiency compared to the module with 6 inch full cells by minimizing optical and electrical losses. In this study, we propoese a new Conductive Paste (CP) to interconnect cells in a shingled module and compare it with the Electrical Conductive Adhesives (ECA) in the conventional module. Since the CP consists of a compound of tin and bismuth, the module is more economical than the module with ECA, which contains silver. Moreover, the melting point of CP is below 150 ℃, so the cells can be integrated with decreased thermal-mechanical stress. The output of the shingled PV module connected by CP is the same as that of the module with ECA. In addition, electroluminescence (EL) analysis indicates that the introduction of CP does not provoke additional cracks. Furthermore, the CP soldering connects cells without increasing ohmic losses. Thus, this study confirms that interconnection with CP can integrate cells with reduced cost in shingled c-Si PV modules.
        4,000원
        1854.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study investigates the effects of isothermal holding temperature and time on the microstructure, hardness and Charpy impact properties of medium-carbon bainitic steel specimens. Medium-carbon steel specimens with different bainitic microstructures are fabricated by varying the isothermal conditions and their microstructures are characterized using OM, SEM and EBSD analysis. Hardness and Charpy impact tests are also performed to examine the correlation of microstructure and mechanical properties. The microstructural analysis results reveal that granular bainite, bainitic ferrite, lath martensite and retained austenite form differently in the specimens. The volume fraction of granular bainite and bainitic ferrite increases as the isothermal holding temperature increases, which decreases the hardness of specimens isothermally heat-treated at 300 ℃ or higher. The specimens isothermally heat-treated at 250 ℃ exhibit the highest hardness due to the formation of lath martensite, irrespective of isothermal holding time. The Charpy impact test results indicate that increasing isothermal holding time improves the impact toughness because of the increase in volume fraction of granular bainite and bainitic ferrite, which have a relatively soft microstructure compared to lath martensite for specimens isothermally heat-treated at 250 ℃ and 300 ℃.
        4,000원
        1855.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Copper oxide thin films are deposited using an ultrasonic-assisted spray pyrolysis deposition (SPD) system. To investigate the effect of substrate temperature and incorporation of a chelating agent on the growth of copper oxide thin films, the structural and optical properites of the copper oxide thin films are analyzed by X-ray diffraction (XRD), field-emssion scanning electron microscopy (FE-SEM), and UV-Vis spectrophotometry. At a temperature of less than 350 ℃, threedimensional structures consisting of cube-shaped Cu2O are formed, while spherical small particles of the CuO phase are formed at a temperature higher than 400 ℃ due to a Volmer-Weber growth mode on the silicon substrate. As a chelating agent was added to the source solutions, two-dimensional Cu2O thin films are preferentially deposited at a temperature less than 300 ℃, and the CuO thin film is formed even at a temperature less than 350 ℃. Therefore the structure and crystalline phase of the copper oxide is shown to be controllable.
        4,000원
        1856.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        W-10 wt% Ti alloys that have a homogeneous microstructure are prepared by thermal decomposition of WO3-TiH2 powder mixtures and spark plasma sintering. The reduction and dehydrogenation behavior of WO3 and TiH2 are analyzed by temperature programmed reduction and a thermogravimetric method, respectively. The X-ray diffraction analysis of the powder mixture, heat-treated in an argon atmosphere, shows W- oxides and TiO2 peaks. Conversely, the powder mixtures heated in a hydrogen atmosphere are composed of W, WO2 and TiO2 phases at 600 ℃ and W and W-rich β phases at 800 ℃. The densified specimen by spark plasma sintering at 1500 ℃ in a vacuum using hydrogen-reduced WO3-TiH2 powder mixtures shows a Vickers hardness value of 4.6 GPa and a homogeneous microstructure with pure W, β and Ti phases. The phase evolution dependent on the atmosphere and temperature is explained by the thermal decomposition and reaction behavior of WO3 and TiH2.
        4,000원
        1857.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nitrogen is a serious contaminant in natural gas because it decreases the energy density. The natural gas specification in South Korea requires a N2 content of less than 1 mol%. Thus, cost-effective N2 removal technology from natural gas is necessary, but until now the only option has been energy-intensive processes, e.g., cryogenic distillation. Using porous materials for the removal process would be beneficial for an efficient separation of CH4/N2 mixtures, but this still remains one of the challenges in modern separation technology due to the very similar size of the components. Among various porous materials, metal-organic frameworks (MOFs) present a promising candidate for the potential CH4/N2 separation material due to their unique structural flexibility. A MIL-53(Al), the most well-known flexible metal-organic framework, creates dynamic changes with closed pore (cp) transitions to open pores (ops), also called the ‘breathing’ phenomenon. We demonstrate the separation performance of CH4/N2 mixtures of MIL-53(Al) and its derivative MIL-53-NH2. The CH4/N2 selectivity of MIL- 53-NH2 is higher than pristine MIL-53(Al), suggesting a stronger CH4 interaction with NH2.
        4,000원
        1858.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This investigates the microstructure and mechanical properties of Al hybrid material prepared by electromagnetic duo-casting to determine the effect of heat treatment. The hybrid material is composed of an Al-Mg-Si alloy, pure Al and the interface between the Al-Mg-Si alloy and pure Al. It is heat-treated at 373, 573 and 773K for 1h and T6 treated (solution treatment at 773K for 1h and aging at 433K for 5h). As the temperature increases, the grain size of the Al-Mg-Si alloy in the hybrid material increases. The grain size of the T6 treated Al-Mg-Si alloy is similar to that of one heat-treated at 773K for 1h. The interface region where the micro-hardness becomes large from the pure Al to the Al-Mg-Si alloy widens with an increasing heat temperature. The hybrid material with a macro-interface parallel to the tensile direction experiences increased tensile strength, 0.2% proof stress and the decreased elongation after T6 heat treatment. On the other hand, in the vertical direction to the tensile direction, there is no great difference with heat treatment. The bending strength of the hybrid material with a long macro-interface to the bending direction is higher than that with a short macro-interface, which is improved by heat treatment. The hybrid material with a long macro-interface to the bending direction is fractured by cracking through the eutectic structure in the Al-Mg-Si alloy. However, in the hybrid material with a short macro-interface, the bending deformation is observed only in the limited pure Al.
        4,000원
        1859.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Intermetallic compound matrix composites have been expected to be established as high temperature structural components. Ni3Al is a representative intermetallic alloy, which has excellent ductility even at room temperature by adding certain alloying elements. Ni3Al matrix composites with aluminum oxide particles, which are formed by the in-situ reaction between the alloy and aluminum borate whiskers, are fabricated by a powder metallurgical method. The addition of aluminum borate whiskers disperses the synthetic aluminum oxide particles during sintering and dramatically increases the strength of the composite. The uniform dispersion of reaction synthesized aluminum oxide particles and the uniform solution of boron in the matrix seem to play an important role in the improvement in strength. There is a dramatic increase in strength with the addition of the whisker, and the maximum value is obtained at a 10 vol% addition of whisker. The Ni3Al composite with 10 vol% aluminum oxide particles 0.3 μm in size and with 0.1 wt% boron powder fabricated by the conventional powder metallurgical process does not have such high strength because of inhomogeneous distribution of aluminum oxide particles and of boron. The tensile strength of the Ni3Al with a 10 vol% aluminum borate whisker reaches more than twice the value, 930 MPa, of the parent alloy. No third phase is observed between the aluminum oxide and the matrix.
        3,000원
        1860.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Lead free (1-x)(0.675BiFeO3-0.325BaTiO3)- xLiTaO3 (BFBTLT, x = 0, 0.01, 0.02, and 0.03, with 0.6 mol% MnO2 and 0.4 mol% CuO) were prepared by a solid state reaction method, followed by air quenching and their crystalline phase, morphology, dielectric, ferroelectric and piezoelectric properties were explored. An X-ray diffraction study indicates that lithium (Li) and tantalum (Ta) were fully incorporated in the BFBT materials with the absence of any secondary phases. Dense ceramic samples (> 92 %) with a wide range of grain sizes from 3.70 μm to 1.82 μm were obtained in the selected compositions (0 ≤ x ≤ 0.03) of BFBTLT system. The maximum temperatures (Tmax) were mostly higher than 420 oC in the studied composition range. The maximum values of maximum polarization (Pmax ≈ 31.01 μC/cm2), remnant polarization (Prem ≈ 22.82 μC/cm2) and static piezoelectric constant (d33 ≈ 145 pC/N) were obtained at BFBT-0.01LT composition with 0.6 mol% MnO2 and 0.4 mol% CuO. This study demonstrates that the high Tmax and d33 for BFBTLT ceramics are favorable for industrial applications.
        4,000원