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        검색결과 13,928

        3461.
        2013.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abdominal curl-up exercise may excessively increased superficial neck flexor such as sternocleidomastoid (SCM) muscle. Also, the muscle activity of the abdominal muscles haven’t investigated during abdominal curl-up with craniocervical flexion (CCF). Therefore, the purpose of our study was to determine the effect of CCF on the muscle activity of the abdominal and SCM muscles during abdominal curl-up. Twelve healthy subjects (six men and six women) with no history of abdominal or lower back pain within 6 weeks were recruited. Surface electromyographic signals were collected on SCM, rectus abdominis (RA), internal oblique (IO), and external oblique (EO) muscles bilaterally during performing the traditional abdominal curl-up and the abdominal curl-up with CCF. Paired t-tests were used to compare the differences in the muscle activity of the bilateral SCM, RA, EO, and IO muscles between the traditional abdominal curl-up and the abdominal curl-up with CCF (p<.05). There was significantly lower electromyogram (EMG) activity of the both SCMs during the abdominal curl-up with CCF (Right SCM, 39.50±15.29%MVIC; Left SCM, 38.24±17.31%MVIC) than with the traditional abdominal curl-up (Right SCM, 54.85±20.05%MVIC; Left SCM, 53.18±26.72%MVIC) (p<.05). The activity of abdominal muscles were not significantly different between the traditional abdominal curl-up and the abdominal curl-up with CCF. The abdominal curl-up with CCF requires significantly less muscle activity of SCM. Consequently, the abdominal curl-up with CCF is recommended to prevent excessive activation of superficial cervical flexors during abdominal curl-up exercise.
        4,000원
        3462.
        2013.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of the present study was to compare measurement precisions of the Oswestry Back Pain Disability Questionnaire (ODQ) and a computer adaptive testing (CAT) method. The ODQ has been regarded as one of the most reliable condition-specific measure for back pain for decades. Cross-sectional study was carried out with two independent convenient samples from two out-patient rehabilitation clinics for back pain (n1=42) and non-back pain group (n2=42). Participants were asked to fill out the ODQ and CAT of International Classification of Functioning, Disability and Health-Activity Measure (ICF-AM). A series of Rasch analyses were performed to calculate person ability measures. The CAT measures had greater relative precision in discriminating the groups than did the ODQ measure in comparisons of the relative precision. The CAT measure appears to be more effective than did the ODQ measure in terms of measurement precision. By administering test items calibrated in a way, CAT measures using item response theory may promise a means with measurement precision as well as efficiency.
        4,000원
        3463.
        2013.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to determine the effect of contralateral hip adduction (CHA) on the muscle activity of lumbar stabilizers and the angle of pelvic lateral tilting during hip abduction in side lying. Twenty healthy male subjects with no medical history of lower extremity or lumbar spine disorders were recruited for the study. Subjects randomly performed preferred hip abduction (PHA) and hip abduction with contralateral hip adduction in side lying. The muscle activities of the dominant side rectus abdominis, external oblique, internal oblique, quadratus lumborum, gluteus medius, and non-dominant side hip adductor longus were measured during PHA and CHA by using a surface electromyography (EMG) system. Pelvic lateral tilting motion was measured by using a three-dimensional motion analysis system. Data on EMG and pelvic motion were collected at the same time during PHA and CHA. A paired t-test was used to compare EMG activity and the angle of pelvic lateral tilting in the two exercises. The study found that the EMG activities of all muscles were more increased significantly in CHA than PHA condition. The angle of pelvic lateral tilting was more decreased significantly in CHA than PHA condition. These findings suggest that CHA could be recommended as a hip abduction exercise for activating lumbar stabilizers and decreasing compensatory pelvic lateral tilting motion.
        4,000원
        3464.
        2013.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to evaluate the differences in electromyographic (EMG) activities of upper limb muscles between cross- and parallel-aligned taping and to compare the effects of these 2 taping methods in healthy adults. Thirty subjects, who volunteered for this study, were tested under 3 taping conditions in random order: (1) no taping, (2) cross-aligned taping, and (3) parallel-aligned taping. EMG activities of the biceps brachii, triceps brachii, flexor carpi ulnaris, and extensor carpi radialis muscles were measured. All muscles showed significant differences in EMG activity among the 3 conditions (p<.05). In the post hoc test, biceps brachii and triceps brachii muscles showed significant differences in EMG activity between the no taping and the cross-aligned taping conditions and between the no taping and the parallel-aligned taping conditions. Additionally, the EMG activities of the flexor carpi radialis and extensor carpi radialis muscles appeared to be significantly different between the no taping and parallel-aligned taping conditions. These findings demonstrate that taping may be helpful for decreasing muscle activity, regardless of the direction of tape application. This study provides useful information to future researchers regarding the effects of taping on muscle activity.
        4,000원
        3465.
        2013.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzes how different knee flexion angles affect the abdominal and pelvic muscle activity during supine bridging. Twenty healthy subjects participated in the study. We used surface electromyography (EMG) to measure how three different knee flexion angles (100°, 70°, and 40°) affected the activity of the transverse abdominis/internal oblique (TrA/IO), external oblique (EO), biceps femoris (BF), rectus femoris (RF), and gluteus maximus (GM) muscles on the dominant side during supine bridging. The one-way repeated analysis of variance (ANOVA) was used to determine the statistical significance of TrA/IO, EO, BF, RF and GM muscle activity and the GM/BF activity ratio. For the TrA/IO, EO, BF, and GM muscles, supine bridging with different knee flexion angles resulted in significant differences in abdominal and pelvic muscle activity. For the TrA/IO muscles, the post-hoc test demonstrated that muscle activity significantly increased at 40° compared to 70°; however, there were no significant differences between 100° and 70° or 100° and 40°. For the EO muscle, the post-hoc test demonstrated that muscle activity significantly increased at 40° compared to 100° and 70°; no significant difference was observed between angles 100° and 70°. For the BF muscle, the post-hoc test demonstrated that muscle activity significantly increased according to the knee flexion angle (40°>70°>100°). For the GM muscle, the post-hoc test demonstrated that muscle activity significantly increased according to the knee flexion angle (100°>70°>40°). However, for the RF muscle, there was no significant difference. Additionally, the GM/BF activity ratio significantly increased according to the knee flexion angle (100°>70°>40°). From these results, we can conclude that bridging with a knee flexion of 100° can strengthen the GM muscle, whereas bridging with a knee flexion of 40° is recommended to strengthen the IO, EO, and BF muscles. We can also conclude that knee flexion angles should be modified during supine bridging to increase the muscle activity of different target muscles.
        4,000원
        3466.
        2013.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        CSA, a cement mineral compound that is mainly composed of 3CaO·3Al2O3·CaSO4, generates ettringite as a hydration product after a reaction with glass (lime), gypsum and water to speed up the hardening process and enhance the strength and degree of expansion. When used as a cement admixture, there is increased production of ettringite, which can improve the initial strength in the first three days and ameliorate the reduction in the initial strength caused by the use of fly ash in particular. In this study, a hydrate analysis was performed using XRD and SEM after substitution with fly ash (30%) and CSA (8%) with the goal of observing the effect of CSA on the initial strength of a cement mixture containing fly ash. The results of the analysis showed that an addition of CSA promoted the production of ettringite and improved the initial strength, resulting in the generation of hydrates, which can effectively enhance the long-term strength of these materials.
        4,000원
        3467.
        2013.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Graphene oxide powders prepared by two different drying processes, freeze drying and spray drying, were studied to compare the effect of the drying method on the physical properties of graphene oxide powder. The graphene oxide dispersion was prepared from graphite by chemical delamination with the aid of sulfuric acid and permanganic acid, and the dispersion was further washed and re-dispersed in a mixed solvent of water and isopropyl alcohol. A freeze drying method can feasibly minimize damage to the sample, but it requires a long process time. In contrast, spray drying is able to remove a solvent in a relatively short time, though this process requires exposure to a high temperature for a rapid evaporation of the solvent. The powders prepared by freeze drying and spray drying were characterized and compared by Raman spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and by an elemental analysis. The graphene oxide powders showed similar chemical compositions; however, the morphologies of the powders differed in that the graphene oxide prepared by spray drying had a winkled morphology and a higher apparent density compared to the powder prepared by freeze drying. The graphene oxide powders were reduced at 900˚C in an atmosphere of N2. The effect of the drying process on the properties of the reduced graphene oxide was examined by SEM, TEM and Raman spectroscopy.
        4,000원
        3468.
        2013.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The printing of nanomaterials onto certain substrates is one of the key technologies behind high-speed interconnection and high-performance electronic devices. For the printing of next-generation electronic devices, a printing process which can be applied to a flexible substrate is needed. A printing process on a flexible substrate requires a lowtemperature, non-vacuum process due to the physical properties of the substrate. In this study, we obtained well-ordered Ag nanowires using modified gravure printing techniques. Ag nanowires are synthesized by a silver nitrate (AgNO3) reduction process in an ethylene glycol solution. Ag nanowires were well aligned by hydrodynamic force on a micro-engraved Si substrate. With the three-dimensional structure of polydimethylsiloxane (PDMS), which has an inverse morphology relative to the micro-engraved Si substrate, the sub-micron alignment of Ag nanowires is possible. This technique can solve the performance problems associated with conventional organic materials. Also, given that this technique enables large-area printing, it has great applicability not only as a next-generation printing technology but also in a range of other fields.
        4,000원
        3469.
        2013.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        To observe the formation of defects at the interface between an oxide semiconductor and SiO2, ZnO was preparedon SiO2 with various oxygen gas flow rates by RF magnetron sputtering deposition. The crystallinity of ZnO depends on thecharacteristic of the surface of the substrate. The crystallinity of ZnO on a Si wafer increased due to the activation of ionicinteractions after an annealing process, whereas that of ZnO on SiO2 changed due to the various types of defects which hadformed as a result of the deposition conditions and the annealing process. To observe the chemical shift to understand of defectdeformations at the interface between the ZnO and SiO2, the O 1s electron spectra were convoluted into three sub-peaks bya Gaussian fitting. The O 1s electron spectra consisted of three peaks as metal oxygen (at 530.5eV), O2− ions in an oxygen-deficient region (at 531.66eV) and OH bonding (at 532.5eV). In view of the crystallinity from the peak (103) in the XRDpattern, the metal oxygen increased with a decrease in the crystallinity. However, the low FWHM (full width at half maximum)at the (103) plane caused by the high crystallinity depended on the increment of the oxygen vacancies at 531.66eV due tothe generation of O2− ions in the oxygen-deficient region formed by thermal activation energy.
        4,000원
        3470.
        2013.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The milling and particulate characteristics of Al alloy-Al2O3 powder mixtures for a reaction-bonded Al2O3 (RBAO) process were studied. A commercially available prealloyed Al powder with Zn, Mg, Cu and Cr alloying elements (7475 series) was mixed with a calcined sinter-active Al2O3 powder and then milled in centrifugal milling equipment for ~48 hrs. The Al alloy-Al2O3 powder mixtures after milling were characterized and evaluated in various ways to reveal their particulate characteristics during milling. The milling efficiency of the Al alloy increased with a longer milling time. Comminution of the Al alloy particles started with its elongation, showing a high aspect ratio. With a longer milling time, the elongated Al alloy particle changed in terms of its shape and size, becoming equiaxially fine particles. Regardless of the milling efficiency of the Al alloy particles, all of the Al alloy particles repeatedly experienced strong plastic deformation during milling, giving rise to higher density of surface defects, such as microcracks, and leading to higher residual microstress within the Al alloy particles. The chemical reactions, oxidation behavior and hydration behavior of the Al alloy particles and the hydrolysis characteristics of their reaction with the environment were also observed during the milling process and during the subsequent powder handling steps.
        4,000원
        3471.
        2013.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The deformation properties of a TiC-Mo eutectic composite were investigated in a compression test at temperaturesranging from room temperature to 2053K and at strain rates ranging from 3.9×10−5s−1 to 4.9×10−3s−1. It was found that thismaterial shows excellent high-temperature strength as well as appreciable room-temperature toughness, suggesting that thematerial is a good candidate for high-temperature application as a structure material. At a low-temperature, high strength isobserved. The deformation behavior is different among the three temperature ranges tested here, i.e., low, intermediate and high.At an intermediate temperature, no yield drop occurs, and from the beginning the work hardening level is high. At a hightemperature, a yield drop occurs again, after which deformation proceeds with nearly constant stress. The temperature- andyield-stress-dependence of the strain is the strongest in this case among the three temperature ranges. The observed high-temperature deformation behavior suggests that the excellent high-temperature strength is due to the constraining of thedeformation in the Mo phase by the thin TiC components, which is considerably stronger than bulk TiC. It is also concludedthat the appreciable room-temperature toughness is ascribed to the frequent branching of crack paths as well as to the plasticdeformation of the Mo phase.
        4,000원
        3472.
        2013.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A 90 wt% Mg-10 wt% NbF5 sample was prepared by mechanical milling under H2 (reactive mechanical grinding). Its hydriding and dehydriding properties were then examined. Activation of the 90 wt% Mg-10 wt% NbF5 sample was not required. At n=1, the sample absorbed 3.11 wt% H for 2.5 min, 3.55 wt% H for 5 min, 3.86 wt% H for 10 min, and 4.23 wt% H for 30 min at 593K under 12 bar H2. At n=1, the sample desorbed 0.17 wt% H for 5 min, 0.74 wt% H for 10 min, 2.03 wt% H for 30 min, and 2.81 wt% H for 60 min at 593K under 1.0 bar H2. The XRD pattern of the 90 wt% Mg-10 wt% NbF5 after reactive mechanical grinding showed Mg, β-MgH2 and small amounts of γ-MgH2, NbH2, MgF2 and NbF3. The XRD pattern of the 90 wt% Mg-10 wt% NbF5 dehydrided at n=3 revealed Mg, β-MgH2, a small amount of MgO and very small amounts of MgH2 and NbH2. The 90 wt% Mg-10 wt% NbF5 had a higher initial hydriding rate and a larger quantity of hydrogen absorbed for 60 min than the 90 wt% Mg-10 wt% MnO and the 90 wt% Mg-10 wt% Fe2O3, which were reported to have quite high hydriding rates and/or dehydriding rates. The 90 wt% Mg-10 wt% NbF5 had a higher initial dehydriding rate (after an incubation period) and a larger quantity of hydrogen desorbed for 60 min than the 90 wt% Mg-10 wt% MnO and the 90 wt% Mg-10 wt% Fe2O3.
        4,000원
        3473.
        2013.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The hardenability of low-carbon boron steels with different molybdenum and chromium contents was investigated using dilatometry, microstructural observations and secondary ion mass spectroscopy (SIMS), and then discussed in terms of the segregation and precipitation behaviors of boron. The hardenability was quantitatively evaluated by a critical cooling rate obtained from the hardness distribution plotted as a function of cooling rate. It was found that the molybdenum addition was more effective than the chromium addition to increase the hardenability of boron steels, in contrast to boron-free steels. The addition of 0.2 wt.% molybdenum completely suppressed the formation of eutectoid ferrite, even at the slow cooling rate of 0.2˚C/s, while the addition of 0.5 wt.% chromium did this at cooling rates above 3˚C/s. The SIMS analysis results to observe the boron distribution at the austenite grain boundaries confirmed that the addition of 0.2 wt.% molybdenum effectively increased the hardenability of boron steels, as the boron atoms were significantly segregated to the austenite grain boundaries without the precipitation of borocarbide, thus retarding the austenite-to-ferrite transformation compared to the addition of 0.5 wt.% chromium. On the other hand, the synergistic effect of molybdenum and boron on the hardenability of boron steels could be explained from thermodynamic and kinetic perspectives.
        4,000원
        3474.
        2013.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        As continued scaling becomes increasingly difficult, 3D integration has emerged as a viable solution to achieve higher bandwidths and good power efficiency. 3D integration can be defined as a technology involving the stacking of multiple processed wafers containing integrated circuits on top of each other with vertical interconnects between the wafers. This type of 3D structure can improve performance levels, enable the integration of devices with incompatible process flows, and reduce form factors. Through silicon vias (TSVs), which directly connect stacked structures die-to-die, are an enabling technology for future 3D integrated systems. TSVs filled with copper using an electro-plating method are investigated in this study. DC and pulses are used as a current source for the electro-plating process as a means of via filling. A TiN barrier and Ru seed layers are deposited by plasma-enhanced atomic layer deposition (PEALD) with thicknesses of 10 and 30 nm, respectively. All samples electroplated by the DC current showed defects, even with additives. However, the samples electroplated by the pulse current showed defect-free super-filled via structures. The optimized condition for defect-free bottom-up super-filling was established by adjusting the additive concentrations in the basic plating solution of copper sulfate. The optimized concentrations of JGB and SPS were found to be 10 and 20 ppm, respectively.
        4,000원
        3475.
        2013.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The purpose of this paper was to investigate the effect of a high-energy milling (HEM) process on the particle morphology and the correlation between a thermal treatment and tetragonal/monoclinic nanostructured zirconia powders obtained by a precipitation process. To eliminate chloride residue ions from hydrous zirconia, a modified washing method was used. It was found that the used washing method was effective in removing the chloride from the precipitated gel. In order to investigate the effect of a pre-milling process on the particle morphology of the precipitate, dried Zr(OH)4 was milled using a HEM machine with distilled water. The particle size of the Zr(OH)4 powder exposed to HEM reduced to 100~150 nm, whereas that of fresh Zr(OH)4 powder without a pre-milling process had a large and irregular size of 100 nm~1.5 μm. Additionally, modified heat treatment process was proposed to achieve nano-sized zirconia having a pure monoclinic phase. It was evident that two-step calcining process was effective in perfectly eliminating the tetragonal phase, having a small average particle of ~100 nm with good uniformity compared to the sample calcined by a single-step process, showing a large average particle size of ~300 nm with an irregular particle shape and a broad particle size distribution. The modified method is considered to be a promising process for nano-sized zirconia having a fully monoclinic phase.
        4,000원
        3476.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to reveal the impact of continuous antagonist strengthening( CAS) and Evjenth-Hamberg stretching(EHS) on the cervical mobility in the university students with abnormal transformation of forward head posture( FHP). Our experiment was conducted 3 times a week for 6 weeks in a total of 20 individuals : continuous antagonist strengthening(CAS) group(n=10) & Evjenth-Hamberg stretching(EHS) group(n=10). In a pre and post comparison, both CAS group and EHS group appeared significantly in mSBI and SBA(p<.05) and the two-group comparison showed a significant difference(p<.05) : CAS group showed better effects. Thus, it is considered that the combined use with continuous antagonist strengthening(CAS) had better effects for cervical mobility than Evjenth-Hamberg stretching(EHS) alone.
        4,000원
        3477.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was to investigate the needs of the functional abnormality of the Temporomandibular joint. The purpose of this study was to find out basic concept for the Chiropractic-care necessity of the neuromuscular skeletal patients with functional abnormality of the temporomandibular joint. I evaluated the change of the range of motion, neck pain, headache by post xray, orthopedic test and patient's charts. The range of motion at temporomandibular joint was improved and the necessity of chiropractic care was recognized in the neuromuscular skeletal patients with having temporomandibular joint problems.
        4,000원
        3478.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to test the effect of Gastrocnemius and Low Back-muscle isotonic exercise on static•dynamic standing balance during the period of 4 weeks. This study was two groups pretest-posttest design. Nineteen subjects who were over 22 years old were randomly assigned to either the experimental group that received the Gastrocnemius muscle exercise(n=9) or the low back muscle exercise(n=10) : The former group performed isotonic exercise(plantar flexion), the latter group performed isotonic exercise(trunk extension) a total of 18 times for three times per week for four weeks. Two groups also performed static and dynamic balance before the exercise and 4weeks after the exercise. The data were analyzed by using the paired t-test and independent t-test. The results were as follows: As compared with change of dynamic balance performance capacity at two groups, a significant difference was shown in the test(p<.05), but not in static balance(p>.05). Also, a significant difference of balance between groups was not shown in the test. In this study indicated that gastrocnemius and low back muscle isotonic exercise will have positive impact on standing balance.
        4,000원
        3479.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to identify the effective lumbar area exercise program to prevent falls of the elderly by dividing 14 female elders over 65 living in Daegu into two groups such as resistance exercise group and resistance & stabilization exercise group, and applying a 60 minute exercise program three times a week for 12 weeks. The followings are the results. First, both of resistance exercise and resistance & stabilization exercise brought improvement of lumbar strength and there was no significant difference between two groups. Second, there was no significant difference in lower limb strength in resistance exercise group but resistance & stabilization exercise group showed significant increase in lower limb flexor strength. To make a summary of the above results, it can be said that 12 weeks’ resistance & stabilization exercise is effective to the lumbar strength and lower limb strength of the elderly. Accordingly, if combining resistance exercise and stabilization exercise appropriately, we can build a successful preventive program which even the elderly who cannot perform resistance exercise easily can follow.
        4,000원
        3480.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to examine the changes on lumbar muscle strength in relation to 12-week pilates mat exercise of elderly women. The participants are chosen for 17 people who is an experimental group and 14 people who is an comparison group who except wastage and pilates mat exercise program was gradually intensify applied three times a week, during 12 weeks. The peak torque of flexion was increased(p<.01) and the difference of ratio of agonist to antagonist was decreased(p<.001). The total work of flexion and extension had significant increased(p<.001) at 120°/sec. As a result of all these, it was judged as positive effect for body composition, basal physical fitness and lumbar muscle strength after pilates mat exercise in 12 weeks. These positive effects showed that pilates mat exercise could got conclusions that mitigated the musculoskelctal disorders, slow down the progress of disorders, helped as a functions of physical.
        4,000원