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        검색결과 618

        281.
        2006.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Theoretical framework of motor learning is used to enhance perceptual motor skill in physical therapy intervention, which can be subdivided into two main types-explicit and implicit. The purpose of this study was to examine whether stroke patients with unilateral brain damage learn implicitly a motor skill using the arm ipsilateral to the damaged hemisphere. Speculation then followed as to the formation of therapeutic plans and instructions provided to patients with stroke. 20 patients with stroke and 20 normal participants were recruited. All the subjects practiced serial reaction time tasks for 30 minutes a day and retention tests on the following day. The tasks and tests involved pressing the corresponding buttons to 4 colored circles presented on a computer screen as quickly and accurately as possible. Patients with stroke responded more slowly than controls. However, both groups showed decreased reaction time in the experimental and retention periods. Also, there was no significant difference between both groups regarding explicit knowledge of consecutive order. Therefore, patients with stoke had the ability to learn implicitly a perceptual motor skill. Prescriptive instruction using implicit and explicit feedback may be beneficial for motor skill learning in physical therapy intervention for patients with brain damage.
        4,000원
        282.
        2006.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to assess the influence of spine orthosis and sit-to-stand motor strategies on ground reaction force (GRF) and lower extremity muscle activity. Twenty healthy adult men participated, and subjects randomly performed sit-to-stand motions in three different conditions: Momentum-transfer strategy (MTS); MTS with spine orthosis; and zero-momentum strategy (ZMS) with spine orthosis. GRF data, onset time, and muscle activity were determined and compared using force plate and electromyography. Data were statistically analyzed by the SPSS version 13.0. One-way repeated analysis of variance (ANOVA) was used to determine the statistical significance, and least significant difference was used as a post hoc test. The level of significance was .05. The results of this study were as follows: 1. Peak GRF and relative time to peak GRF were not significantly different in the three different conditions (p>.05). 2. Onset time of four muscles, tibialis anterior, gastrocnemius, biceps femoris and rectus femoris, in the three different conditions were significantly different (p<.05). 3. The tibialis anterior and rectus femoris muscle activity before hip-off and tibialis anterior, gastrocnemius, and rectus fermoris muscle activity after hip-off were significantly different in the three different conditions (p<.05).
        4,000원
        283.
        2006.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Yttrium aluminum garnet (YAG) powders were synthesized via mechanochemical solid reaction using with three types of aluminum compounds. reacted mechanochemically with all A1 compounds and formed YAM (yttrium aluminum monoclinic), YAG and YAP (yttrium aluminum perovskite) phases depending on the starting materials. The ground samples containing showed the best reactivity, whereas the ground sample containing A100H, which had the largest surface area, exhibited pure YAG after calcination at . The sample containing Al had the least reactivity, producing YAP along with YAG at . The types and grinding characteristics of the starting materials and grinding time are believed to be important factors in the mechanochemical synthesis of YAG.
        4,000원
        285.
        2006.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Muscle weakness in the hemiplegia following stroke is an important factor which determines the quality of life in the future. Therefore, muscle strengthening exercise is essential for functional recovery in hemiplegic patients. Even though the popular conception is that muscle strengthening exercise causes spasticity and associated reaction that hemiplegia patients don't want, and that it disturbs functional recovery, recently there have been many new reports against that opinion. Therefore, the effects of strengthening exercise programs on functional recovery in hemiplegic patients are still controversial. The purpose of this study was to determine the effects of strengthening exercise programs for the knee joint using isokinetic exercise on the associated reaction of the upper extremities. Comparing the muscle activities of biceps brachii and triceps brachii during, before, and immediately after 2 and 5 minute intervals of isokinetic exercise, we examined the increase and decrease of associated reaction. Twenty stroke inpatients participated in this study. Surface electromyography was used to get muscle activity data from biceps brachii and triceps brachii. The major findings of this study were as follows: 1. The flexor and extensor peak torque were significantly higher on the sound side than the affected side (p<.05). 2. Before and after strengthening exercise, there was no significant difference in muscle activities (surface electromyographic root mean square values) between the sound and affected side. 3. Muscle activities were examined during, before, and immediately after 2 and 5 minute intervals of isokinetic exercise. There were significant differences in muscle activities between, before and during the exercises, during exercise and 5 minutes after exercise in the biceps brachii (p<.05), and during exercise and 5 minutes after exercise in the triceps brachii (p<.05). In conclusion, there was no relation between strengthening exercise and associated reaction in the upper extremities. Rather, muscle activities after exercise had a tendency to decrease relative to before the exercise. Thus, it is considered that intensive strengthening exercise contributes to improvement of functional recovery without increase in associated reaction in hemiparetic patients.
        4,000원
        286.
        2006.04 구독 인증기관·개인회원 무료
        In the present study, the focus is on the synthesis of nanosized WC powder by the chemical vapor condensation proces. The synthesized W-C system powder by the CVC process shows W2C, W, WO3 phases and can not shows WC phase. After recarburization heat treatment under mixture gas atmosphere of argon and hydrogen gases, the synthesized W-C system powder fully transformed to the pure WC. The synthesized WC powder after recarburization heat treatment has an average particle size of 20 nm. The nano-sized WC powder can be prepared by the combination of the CVC process and heat treatment methods.
        287.
        2006.04 구독 인증기관·개인회원 무료
        Monodispersed and nano-sized Ni powders were synthesized from aqueous nickel sulfate hexahydrate inside nonionic polymer network by using wet chemical reduction process. The sucrose was used as a nonionic polymer network source. The effect of reaction conditions such as the amount of sucrose and a various reaction temperature, nickel sulfate hexahydrate molarity. The influence of a nonionic polymer network on the particle size of the prepared Ni powders was characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and particle size analysis (PSA). The results showed that the obtained Ni powders were strong by dependent of the reaction conditions. In particular, the Ni powders prepared inside a nonionic polymer network had smooth spherical shape and narrow particle size distribution.
        288.
        2006.04 구독 인증기관·개인회원 무료
        We have demonstrated that textured nanocomposites can be fabricated by slip casting followed by partial oxidation. reaction sintering of mixed suspensions of and SiC powders in a high magnetic field. The sintered density was changed by the degree of oxidation at 1200C and 1300C. The degree of orientation of alumina in the nanocomposite was examined on the basis of the X-ray diffraction patterns and scanning electron micrographs. It is confirmed that aluminaoriented nanocomposites were fabricated. The three-point bending strength at room temperature was observed for the nanocomposites.
        290.
        2006.04 구독 인증기관·개인회원 무료
        We have demonstrated that textured nanocomposites can be fabricated by slip casting followed by partial oxidation - reaction sintering of mixed suspensions of and SiC powders in a high magnetic field. The sintered density was changed by the degree of oxidation at 1200C and 1300C. The degree of orientation of alumina in the nanocomposite was examined on the basis of the X-ray diffraction patterns and scanning electron micrographs. It is confirmed that alumina-oriented nanocomposites were fabricated. The three-point bending strength at room temperature was observed for the nanocomposites.
        291.
        2006.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        4,000원
        292.
        2005.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        5,400원
        294.
        2005.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the previous study, three kinds of monomers and the functional monomer, acetoacetoxyethyl methacrylate (AAEM), which could improve the film property and cross-linkage, were polymerzied into acrylic resin copolymers (HSA-98-20, HSA-98-0, HSA-98+20) containing 80% solid content. In this study, the high-solid coatings(HSA-98-20C, HSA-98-0C, HSA-98+20C) were prepared by the curing reaction between acrylic resins containing 80% solid content and isocyanate at room temperature. Various properties were examined for the film coated with the prepared high-solid coatings. The introduction of AAEM in the coatings enhanced the abrasion resistance and solvent resistance of coatings, which indicated the possible use of high-solid coatings for top-coating materials of automobile. The curing times measured by viscoelastic measurement were 350, 264, and 212 min for HSA-98-20C, HSA-98-0C, and HSA-98+20C, respectively. This shows that the curing times become shorter with increasing Tg values.
        4,000원
        295.
        2005.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is interesting to discover the reaction kinetics of the newly developed molybdenum containing catalysts. The dissociation/adsorption of nitrogen on molybdenum surface is known to be structure sensitive, which is similar to that of nitrogen on iron surface. The rates over molybdenum nitride catalysts are increased with the increase of total pressure. This tendency is the same as that for iron catalyst, but is quite different from that for ruthenium catalyst. The activation energies of the molybdenum nitride catalysts are almost on the same level, although the activity is changed by the addition of the second component. The reaction rate is expressed as a function of the concentration of reactants and products. The surface nature of CO3Mo3N is drastically changed by the addition of alkali, changing the main adsorbed species from NH2 to NH on the surface. The strength of NHx adsorption is found to be changed by alkali dopping.
        4,000원
        300.
        2005.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanostructured and composite powders have been prepared by mechanochemical reaction from mixtures of Ti, BN, and powders. The raw materials have reacted to form a uniform mixture of TiN, and or depending on the amount of used in the starting mixtures, and the reaction proceeded through so-called mechanically activated self-sustaining reaction (MSR). Fine TiN and crystallites less than a few tens of nanometer were homogeneously dispersed in the amorphous or matrix after milling for 12 hours. These amorphous matrices became crystalline phases after annealing at high temperatures as expected, but the original microstructure did not change significantly
        4,000원