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        검색결과 1,884

        1361.
        2011.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Perovskite manganites such as RE1-xAxMnO3 (RE = rare earth, A = Ca, Sr, Ba) have been the subject of intense research in the last few years, ever since the discovery that these systems demonstrate colossal magnetoresistance (CMR). The CMR is usually explained with the double-exchange (DE) mechanism, and CMR materials have potential applications for magnetic switching, recording devices, and more. However, the intrinsic CMR effect is usually found under the conditions of a magnetic field of several Teslas and a narrow temperature range near the Curie temperature (Tc). This magnetic field and temperature range make practical applications impossible. Recently, another type of MR, called the low-field magnetoresistance(LFMR), has also been a research focus. This MR is typically found in polycrystalline half-metallic ferromagnets, and is associated with the spin-dependent charge transport across grain boundaries. Composites with compositions La0.7(Ca1-xSrx)0.3MnO3)]0.99/(BaTiO3)0.01 [(LCSMO)0.99/(BTO)0.01]were prepared with different Sr doping levels x by a standard ceramic technique, and their electrical transport and magnetoresistance (MR) properties were investigated. The structure and morphology of the composites were studied by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). BTO peaks could not be found in the XRD pattern because the amount of BTO in the composites was too small. As the content of x decreased, the crystal structure changed from orthorhombic to rhombohedral. This change can be explained by the fact that the crystal structure of pure LCMO is orthorhombic and the crystal structure of pure LSMO is rhombohedral. The SEM results indicate that LCSMO and BTO coexist in the composites and BTO mostly segregates at the grain boundaries of LCSMO, which are in accordance with the results of the magnetic measurements. The resistivity of all the composites was measured in the range of 90-400K at 0T, 0.5T magnetic field. The result indicates that the MR of the composites increases systematically as the Ca concentration increases, although the transition temperature Tc shifts to a lower range.
        3,000원
        1363.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate the effects of meditation music with lumbar stabilization exercise on balance, concentration and muscle activation. Participants are divided into Group A and Group B. Group A listened to meditation music while doing 4 sets of lumbar stabilization exercise. Group B did not listen to meditation music while doing 4 sets of lumbar stabilization exercise. Surface EMG data was obtained rectus abdominis, external oblique, erector spinae, multifidus muscle during lumbar stabilization exercise. To examine the effect of before-after experiment for concentration and balance, paired t-test was adopted. Changes in EMG data of each muscles were analyzed by independence t-test. There were statistically significant increasing at concentration level and balance level in Group A. But significant difference was not shown in muscle activation. The clinical effect of the meditation music with lumbar stabilization exercise was investigated in this study with more excellent results in concentration and balance. In conclusion, these results suggest that meditation music and lumbar stabilization exercise may be useful in elderly people.
        4,000원
        1364.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to investigate and reveal the effects that the complex exercise training consisting of aerobic exercise and strength training(sit up, push up) that everyone can easily practice regardless of a time and a place in order to manage practically the physical strength of the aged affects the difference on their body composition and the change of physical fitness level. Looking into the change of body composition of an experimental group, the weight of 2.5kg was reduced after applying complex training for 12 weeks and the body fat mass of 2.65kg was reduced. Also, the abdominal fat of 0.13% was decreased and the muscle mass of 1.56kg was increased. For the change factors of physical fitness, cardiovascular endurance, muscular strength, muscular endurance, balance and flexibility excluding agility showed significant improvement after applying complex exercise training. The improvement of health fitness of the aged under this study was significantly effective to improve specified body functions which had been lowered by aging and insufficient physical activities. So, it is regarded that their health fitness is the important factor to improve the activity competence required for daily life and to lead healthy living by the improved activity competence. Henceforth, it needs to study more the complex composition of several sports, exercise intensity and the frequency based on the previous researches and studies. In addition, it needs to develop the complex exercise training in accordance with various characteristics such as a sex of the aged, an age, a physical fitness level, environment, a disease and the program in consideration of the efficacy and safety during training.
        4,000원
        1365.
        2011.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This article aims to provide guiding principles for English language teacher evaluation through the review of recent accounts of research and practice. Teacher effectiveness needs to be contextually defined and measured. It is suggested that education providers need to work with all stakeholders in their systems both to define criteria for effective teaching and the means by which it may be assessed. As teacher evaluation is multifaceted, a range of data needs to be collected encompassing the views of all the stakeholders as well as the reflections of teachers themselves. Teacher evaluation should not be regarded as a summative product, the result of single evaluation measures conducted upon teachers, but should be thought of as a formative process in which teachers are actively engaged. Regarding evaluator training, it should not be assumed that those charged with evaluating teachers are, because of their positions, adequately trained to perform the evaluations. Evaluator training should be carried out before any evaluation is conducted under a new system. In order for the evaluation system to be meaningful and contribute to improvements in the education system as a whole, it should be seen primarily as a means of professional development for teachers as well as for anyone else involved in the process.
        5,700원
        1366.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Activated carbon fibers (ACFs) were prepared from cost effective commercial textiles through stabilization, carbonization, and subsequently activation by carbon dioxide. ACFs were characterized for surface area and pore size distribution by physical adsorption of nitrogen at 77 K. ACFs were also examined for various surface characteristics by scanning electron microscopy, Fourier transform infrared spectroscopy, and CHNO elemental analyzer. The prepared ACFs exhibited good surface textural properties with well developed micro porous structure. With improvement in physical strength, the commercial textile grade acrylic precursor based ACFs developed in this study may have great utility as cost effective adsorbents in environmental remediation applications.
        3,000원
        1367.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To understand the marine algal flora on Goheung coast, Korea, marine algae at 8 points were collected from November 2008 to February 2009 and from April to June 2009. Thirty-seven species (2 species of angiosperms, 5 chlorophytes, 12 phaeophytes, and 18 r
        4,800원
        1369.
        2010.12 구독 인증기관 무료, 개인회원 유료
        Gudul is a traditional heating system which was created by our ancestors. This study is focused to the developments of new flooring material through the physical and chemical analyses of the Gudul rocks. The study proceeded with selecting the theme and study areas, sampling, geological survey, several analyses of the rocks, development of new floor material (a kind of porcelain). Gudul rocks are sampled from a total of twenty one cities and counties are assigned to nine tuffs, five quartz porphyries, four gneisses and three schists in rock type. From the geological study, these rocks are very similar to ones in surrounding areas. Comparing Gudul rocks to others not used in Ondol, Gudul rocks show low densities, higher porosities and brittle features. Analyzed in thermal properties, the rocks are lower in conductivity but higher in conservation and resistance in the aspects of the properties. Considering mutual relations between thermal properties and chemistries of the rocks, conservative characteristics are proportional to MgO contents but not to SiO2. In particular, minute quartz grains in the rocks were gradually cracked and rejected under torch flames. Those features may indicate that quartz grains are closely related with the thermal resistances of the rocks. On the basis of above rock characteristics, new flooring material was made. The material includes the mixed states of amphibolite sludges with high MgO contents and white china soils (bearing kaolinte). Then, the material was tested in the above thermal properties under the variable mixed ratios. At the results, 4:6 (sludge : soil) ratio was the most excellent among above tested materials. So, the textiles used in architecture and the electric heating cushion and the mugcups were produced as test goods.
        4,300원
        1370.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study was to investigate the source of contamination during semen processing for in vitro uses. In the present study, frozen semen was prepared from liquid semen in our laboratory for in vitro fertilization (IVF) experiments due to lack of fresh semen. Antibiotics were added in the frozen semen extender (kanamycin and gentamicin) and in vitro culture (IVC) medium (gentamicin) for further inhibiting growth of microorganisms. Nevertheless, proliferations of microorganisms were observed in IVC culture drop during culturing of IVF embryos using frozen semen. Randomly 3 samples were taken from the liquid semen, frozen semen and egg yolk. Contaminated IVC medium, frozen-thawed semen, liquid semen and egg yolk were cultured in de Man, Rogosa and Sharpe (MRS) agar medium. Whitish colonies were detected in contaminated IVC drop, frozen-thawed semen samples and egg yolk but no colonies were formed in liquid semen samples. Gram-negative and rod-shaped identical bacteria were found in both frozen-thawed semen sample and contaminated IVC drop and egg yolk samples. Enterobacter cloacae were confirmed by API 20E kit according to manufacturer's instruction with identification value (% ID) 94.3% and T index 0.88. Antibiotic susceptibility tests were done according to Clinical and Laboratory Standards Institute (CLSI) by using ampicillin, amikacin, cephalothin, gentamicin, kanamycin, tetracycline, oxytetracycline, sulfamethoxazole trimethoprim, norfloxacin and ciprofloxacin test. Among them Enterobacter cloacae were resistant to ampicillin, amikacin, cephalothin, gentamicin, kanamycin but susceptible to tetracycline, oxytetracycline, sulfamethoxazole trimethoprim, norfloxacin and ciprofloxacin. From these findings it could be suggested that this contamination sources might be from egg yolk.
        4,000원
        1371.
        2010.12 KCI 등재 구독 인증기관·개인회원 무료
        The Trichoderma disease, commonly referred to as green mold, has been previously considered as a problem in mushroom production, because it typically occurred in association with low-quality compost or poor hygiene. We studied growth of Trichoderma spp. (Trichoderma aggressivum, Trichoderma atroviride, Trichoderma harzianum, Trichoderma koningii, Trichoderma viride) is under the control of environment factors ; 15℃ - 35 ℃ of incubation temperature, pH 3 - pH 11 of medium and 55% - 75% moisture content of rice straw medium. At the temperature of incubation, Trichoderma spp. had the highest growth rate at 25 ℃ and had no growth at 35 ℃. At the pH of medium, Trichoderma spp. had the highest growth rate at pH 5 and had the lowest growth rate at pH 11. In the Moisture content of rice straw medium, Trichoderma spp. had the highest growth at 75% moisture content and had the lowest growth rate at 55% moisture content.
        1372.
        2010.12 KCI 등재 구독 인증기관·개인회원 무료
        Essential oil from Chamaecyparis obtusa leaves and water extract from Pseudotsuga menziesii sawdust were examined for antifungal activity against Trichoderma spp. (Trichoderma aggressivum, Trichoderma atroviride, Trichoderm harzianum. Trichoderma koningii, Trichoder-ma viride). Generally, essential oil and water extract inhibited the growth of Trichoderma spp. by about 25% and 33%, respectively, at 1000 ppm. Antifungal activity of water extract was slightly higher than essential oil at 1000 ppm. Antifungal activity was increased with increasing concentration of essential oil and water extract. This study was carried out the investigation of the chemical composition of essential oil from Chamaecyparis obtusa leaves and water extract from Pseudotsuga menziesii sawdust. The essential oil was analyzed by GC-MS and water extract analyzed by GC-MS/HS. Thirty-eight components were identified, of which terpinyl acetate (13.41%), elemol (11.86%) and isobornyl acetate (7.89%) were the main compounds in essential oil. Twenty-four components were identified, of which 2-Isopropoxy-ethylamine (46.45%), Epifluorohydrin (8.62%) and Trans-2,3-Dimethyloxirane (7.78%) were the main compounds in water extract. Based on all results described above, we conclude that the essential oil and water extact may have a potent in vitro antifungal activity against Trichoderma spp.
        1373.
        2010.12 KCI 등재 구독 인증기관·개인회원 무료
        Phenotypic traits (physiological characteristics and somatic incompatibility) and genotypic traits (target region amplification polymorphism TRAP) were used to survey the diversity in Chinese Auricularia auricula systematically, which consisted of 32 main cultivated strains. The 27 important and stable physiological indexes were evaluated; somatic incompatibility test (SIT) reaction was described from three aspects: type, pigment, and intensity while intensity clustering alone revealed the phenotypic diversity among the 32 strains;16 pairs of TRAP primer combinations produced 535 unambiguous and reproducible DNA fragments, of these 524 (97.9%) were polymorphic. The phylogenetic trees were constructed by Unweighted Pair-group Method with Arithmetic Averages (UPGMA), which distributed the test strains into four to six major groups respectively. The principal coordinate analysis (PCO) of the three methods (physiological characteristics, SIT intensity and TRAP) exhibited highly similar clustering patterns, revealing that all the test strains can be divided into three groups considered significantly correlated with geographical regions. Results revealed the occurrence of relatively low diversity of A. auricula in the study. The cultivated strains in the same region are more similar physiologically and some strains are suspected to be synonymous. This study suggests that the value for estimating diversity are represented by TRAP>SIT reaction intensity>physiological characteristics in A. auricula, and PCO analysis can provided more effective and visible information than the UPGMA clustering dendrogram. Our finding will facilitate future germplasm resources management and breeding program of A. auricula in China.
        1374.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        5,200원
        1375.
        2010.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Jews and Palestinians are entitled to self-determination in the historical area of Palestine. An Arab state, the Kingdom of Jordan, has been established in Eastern Palestine and a Jewish state, Israel, in part of Western Palestine. The status of the intermediate area, known as the West Bank is as yet undetermined. It was part of Palestine which the League of Nations destined for a Jewish national home, since, however, the majority of the population of the West Bank are Palestinian Arabs, who are entitled to a right of self-determination, Israel will have to relinquish its claims to this area. The Palestinians for their part will have to accept the Jewish right of selfdetermination in the state of Israel. Among the issues that will need to be negotiated between the parties are borders, the status of Jerusalem, security arrangements, refugees, settlements and water issues.
        4,900원
        1376.
        2010.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The methods for determining the diffusion parameters for the diffusion of d-limonene, a major volatile compound of orange juice, through a multi-layered food packaging material and predicting its absorption into the packaging material have been investigated. The packaging material used was the 1.5-mm thick multi-layered packaging material composed of high impact polystyrene (HIPS), polyvinylidene chloride (PVDC), and low density polyethylene (LDPE). Orange juice was placed in a cell where volatiles were absorbed in the sample package and kept at 23±2oC for 72 hr. The d-limonene absorbed in a 1.5-mm thick multi-layered food packaging material was analyzed by a solid phase micro-extraction (SPME). The absorption parameters for the absorption of d-limonene in the packaging material were determined and absorption of d-limonene into the packaging material was predicted using absorption storage data. The SPME desorption at 60oC for 1 hr resulted in the most sensitive and reproducible results. The diffusion coefficients of d-limonene in the packaging material and the partition coefficient at 23±2oC were approximately 1-2×10-12m2/s and 0.03, respectively. The absorption profile no earlier than 30 hr was fit well by a model derived from the Fick’s law.
        4,000원
        1380.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Purpose: The purpose of this study was to estimate the effects of subliminal music with balance imagery training on balance and concentration. Methods: The participants were 45 seniors in an undergraduate school in Korea. The subliminal music with balance imagery training intervention was carried out for 20 minutes. Other interventions were also carried out for 20 minutes. 12 seniors(Group A) listened to subliminal music with balance imagery training, 12 seniors(Group B) listened to subliminal music, 11 seniors(Group C) received balance imagery training, and 10 seniors(Group D) had no intervention(Control group). The grid test is related to measured levels of concentration intensity. Romberg one legged standing test was carried out for 30 seconds. The collected data was analyzed by one-paired t test and one way ANOVA using the SPSS Windows 12 ver. program. Results: The major findings of this study were as follows: Concentration levels of Group A and C improved, and balance levels of Group C and D improved. There was a statistically significant decrease in concentration between Group A and B, Group A and C after intervention. Conclusion: These findings suggest that listening to subliminal music with balance imagery training may be useful in managing concentration in seniors. So it provides basic information for further concentration on improving education on music with balance imagery training.
        4,000원