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        검색결과 952

        481.
        2011.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This paper examines the effectiveness of English Teacher Employment Examination (TEE) listening section items by analyzing potential examinees’ mock test scores on the 2009 and 2010 TEEs and their answers to survey questions related to each item. In addition, the relationship between the mock test results and the type or content of the test items is examined. To analyze and interpret the data, descriptive statistics (including means and standard deviations, ANOVA, and PTMEA [point-measure] correlation) are calculated. The findings of this study not only show the common features and differences between the 2009 and 2010 TEEs but also suggest implications to improve the items in terms of five points: item-exposure, point distribution, item discrimination, excessive number of choices, and factors influencing level of difficulty.
        5,800원
        482.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The scope of this work investigates the relationship between the amount of oxygen-functional groups and hydrogen adsorption capacity with different concentrations of phosphoric acid. The amount of oxygen-functional groups of activated carbons (ACs) is characterized by X-ray photoelectron spectroscopy. The effects of chemical treatments on the pore structures of ACs are investigated by N2/77 K adsorption isotherms. The hydrogen adsorption capacity is measured by H2 isothermal adsorption at 298 K and 100 bar. In the results, the specific surface area and pore volume slightly decreased with the chemical treatments due to the pore collapsing behaviors, but the hydrogen storage capacity was increased by the oxygen-functional group characteristics of AC surfaces, resulting from enhanced electron acceptor-donor interaction at interfaces.
        3,000원
        483.
        2011.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study aims to validate the English learning anxiety scale for Korean primary school students. At the initial stage, 16 items of the Foreign Language Classroom Anxiety Scale (Horwitz, Horwitz, & Cope, 1986) were drawn from the literature reviews for the preliminary test. Then, 177 primary school students were sampled for the preliminary test. After the exploratory factor analysis was undertaken, the English Learning Anxiety Scale (ELAS) was reduced to 14 items, which consisted of two dimensions (oral English classroom anxiety, and low self-confidence in English). The main test was given to 573 primary school students from fourth grades to sixth grades in eight different schools in order to confirm validity and reliability of the ELAS. The results of the confirmatory factor analysis using structural equation modeling demonstrated that the ELAS is a valid (TLI, AGFI, CFI>.94, RMSEA=.049) and reliable (Cronbach’s α = 0.891) instrument.
        5,700원
        484.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to confirm the presence of putative glucoamylase gene in Tricholoma matsutake genome, the genomic DNA was prepared from T. matsutake NBRC30773 strain and was used as template to clone the glucoamylases gene (TmGlu1). We obtained the nucleotide sequence of TmGlu1 and its franking region. The coding region (from ATG to stop codon) is 2,186 bp. The locations of exons and introns were determined from the nucleotide sequences of 3’- and 5’-RACE PCR and RT- PCR products. On the other hand, to investigate the relationship between composition of medium and glucoamylase expression, we checked the expression level of glucoamylase gene by realtime reverse transcription PCR and measurement of glucoamylase enzyme activity. It was found that enzyme activity of glucoamylase was very low in different medium. Expression of glucoamylases gene appeared to not be affected by different carbon source.
        4,000원
        486.
        2011.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Climate change is an emerging environmental issue. To prevent possible trade sanctions from the industrialized trading partners, Taiwan proposed several policies to mitigate greenhouse gas emissions. This includes their preparation of the Greenhouse Gas Reduction Act is under legislature review and the Statute for Renewable Energy Management. Because Taiwan is not a member of the United Nations, it is excluded from participation in the United Nation Convention on Climate Change and lacks access to the flexible mechanisms defined under the Kyoto Protocol. The Taiwan Environment Protection Administration plans to encourage the local emitters to acquire foreign reduction credits to offset domestic emissions. This article approaches Taiwan’s mitigation policies and measures from an international legal perspective. It also introduces adaptation policies and recommends that the government establish a special national adaptation team to prepare data and criteria for risk prioritization. Finally, this paper recommends that the Parties of the UNFCCC adopt the ‘universal apply’principle for climate change and allow any governmental agency whose governing matters are covered by the convention, to participate and share emission-reduction responsibilities.
        5,100원
        487.
        2011.05 구독 인증기관·개인회원 무료
        xylanolytic gut bacterium isolated from Eisenia fetida, Cellulosimicrobium sp. strain HY-13, produced an extracellular glycoside hydrolase capable of efficiently degrading mannose-based substrates such as locust bean gum (LBG), guar gum, mannotetraose, and mannopentaose. The purified mannan-degrading enzyme (ManS, 34,926 Da) from strain HY-13 was found to have an N-terminal amino acid sequence of DEATTDGLHVVDD, which has not yet been identified. Under the optimized reaction conditions of 50℃ and pH 7.0, ManK exhibited extraordinary high specific activities of 7,109 IU/mg and 5,158 IU/mg toward LBG and guar gum, respectively, while the enzyme showed no effect on sugars substituted with p-nitrophenol and various non-mannose carbohydrates. ManK strongly attached to Avicel, lignin, β-cyclodextrin, and poly(3-hydroxybutyrate) granules, but not bound to chitin, chitosan, curdlan, or insoluble oat spelt xylan. The aforementioned characteristics of ManS suggest that it is a unique endo-β -1,4-mannanase with out additional carbohydrolase activities, which differentiates it from other well-known carbohydrolases.
        488.
        2011.05 구독 인증기관·개인회원 무료
        The α-proteobacterium Wolbachia pipientis infects a wide range of arthropods and filarial nematodes. Wolbachia is maternally inherited and is known to induce reproductive anomalies such as cytoplasmic incompatibility, feminization, male killing and parthenogenesis induction (PI). Trichogramma kaykai is a tiny wasp that parasitizes on lepidopteran eggs. When a female of the wasp is infected with PI-Wolbachia, the female produces female offspring via gamete duplication without the aid of sperm. As she ages, however, the fraction of male offspring increases. In this study, we investigated the effect of host genetic background on the expression of sex ratio between isofemale lines. Virgin females of six isofemale lines were allowed to lay eggs individually for 10 days. There was the positive relationship between female age and the offspring sex ratio. Furthermore, the sex ratio was significantly different among isofemale lines, implying that the host genetic background had an effect on the sex ratio. Based on the results, evolution of symbiosis in terms of sex ratio and future experimental design are discussed.
        491.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The conducting polymer-coated multi-walled carbon nanotubes (MWCNTs) were prepared by template polymerization of aniline and pyrrole on the surface of MWCNTs in order to develop the novel electromagnetic interference (EMI) shielding materials. The conducting polymer phases formed on the surface of MWCNTs were confirmed by field emission-scanning electron microscopy and field emission-transmission electron microscopy. Both permittivity and permeability were significantly improved for the conducting polymer-coated MWCNTs due to the intrinsic electrical properties of MWCNTs and the conducting properties of coated polymers. The electromagnetic waves were effectively absorbed based on the permittivity nature of conducting polymer and MWCNTs preventing the secondary interference from reflecting the electromagnetic waves. The highly improved EMI shielding efficiency was also obtained for the conducting polymer-coated MWCNTs showing the synergistic effects by combining MWCNTs and the conducting polymers.
        4,000원
        492.
        2011.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Ag2O를 첨가한 압축 벤토나이트에 대하여 관통 확산법으로 요오드 이온의 이동 특성을 관찰하였다. Ag2O를 첨가하지 않은 압축 벤토나이트와 마찬가지로 Ag2O를 첨가한 압축 벤토나이트에서도 요오드 이온은 확산에 의하여 이동하는데, Ag2O를 첨가한 압축 벤토나이트는 Ag2O를 첨가하지 않은 압축 벤토나이트에 비하여 요오드 이온의 초기 누출 시간이 지연되는 것으로 나타났다. Ag2O를 첨가한 압축 벤토나이트에서 요오드 이온의 초기 누출 시간 지연은 확산 용액으로 순수 요오드 이온 수용액을 사용하였을 때 뿐만 아니라 0.1 M NaCl-요오드 이온 수용액을 사용하였을 때에도 관찰되었다. 또한 Ag2O를 첨가한 압축 벤토나이트의 겉보기 확산 계수는 Ag2O를 첨가하지 않은 압축 벤토나이트의 겉보기 확산 계수보다 낮은 값을 나타내었다. Ag2O를 첨가하지 않은 압축 벤토나이트의 유효 확산 계수는 기존 문헌에 보고된 값 과 거의 일치하는 결과를 얻었으며, Ag2O를 첨가한 압축 벤토나이트에서 요오드 이온의 유효 확산 계수는 Ag2O 첨가에 따라 대체적으로 감소하는 경향을 나타내었다.
        4,000원
        493.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the catalytic combustion of propionaldehyde, which is an Offensive Odorant Substance assigned by the Korean Ministry of Environment (KMOE), over alumina-supported manganese oxide (Mn/Al2 O3) catalysts was investigated. The combustion reaction was carried out in a fixed-bed reactor at the temperature range of 200 ∼340 ℃. Mn/Al2O3 catalysts with Mn loadings ranging from 3.9 to 18.3 wt.% were prepared by impregnation method. The physicochemical characteristics of the catalysts were analyzed by X-Ray Diffraction (XRD), Scanning Electronic Microscopy (SEM) and Brunauer-Emmett-Teller (BET). The Mn crystalline phases of the Mn/Al2O3 catalysts were identified as α-Mn2O3 and β-MnO2. Mn oxides were covered on γ-Al2O3 supports with an average diameter of around 1 μm. With the increase of Mn loadings, the BET surface areas, pore volumes and average pore diameters of the Mn/Al2O3 catalysts decreased. The catalytic activities of Mn/Al2O3 catalysts increased as the Mn loading was increased from 3.9 wt.% to 18.3 wt.%. The catalyst with 18.3 wt.% Mn loading was able to achieve 100% propionaldehyde conversion at 260 ℃. For the same temperature, a lower Gas Hourly Space Velocity (GHSV) and a lower propionaldehyde concentration promote the complete combustion of propionaldehyde.
        4,000원
        494.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the bipolar basidiomycete Pholiota nameko, a pair of homeodomain protein genes located at the A mating-type locus regulates mating compatibility. In the present study, we used a DNA-mediated transformation system in P. nameko to investigate the homeodomain proteins that control the clamp formation. When a single homeodomain protein gene (A3- hox1 or A3-hox2) from the A3 monokaryon strain was introduced into the A4 monokaryon strain, the transformants produced many pseudo-clamps but very few clamps. When two homeodomain protein genes (A3-hox1 and A3-hox2) were transformed either separately or together into the A4 monokaryon, the ratio of clamps to the clamp-like cells in the transformants was significantly increased to approximately 50%. We, therefore, concluded that the gene dosage of homeodomain protein genes is important for clamp formation. When the sip promoter was connected to the coding region of A3-hox1 and A3-hox2 and the fused fragments were introduced into NGW19-6 (A4), the transformants achieved more than 85% clamp formation and exhibited two nuclei per cell, similar to the dikaryon (NGW12 -163 × NGW19-6). The results of real-time RT-PCR confirmed that sip promoter activity is greater than that of the native promoter of homeodomain protein genes in P. nameko. So, we concluded that nearly 100% clamp formation requires high expression levels of homeodomain protein genes and that altered expression of the A mating-type genes alone is sufficient to drive true clamp formation.
        4,600원
        496.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A Truncatipennes species, Pentagonica subcordicollis Bates is newly recorded in Korea. Here we provide a diagnosis and systematic accounts of P. subcordicollis. Consequently, a total of three species of Pentagonia have been recorded in the Korea, including the present species.
        3,000원
        497.
        2010.12 KCI 등재 구독 인증기관·개인회원 무료
        In the past studies of Lyophlium shimeji, it was reported that the quantity of sufficient starch used as a carbon source was able to supply the factor that allows successful fruit-body formation without raising osmotic pressure in the medium. Glucoamylase are exo Glucosyl hydrolase, which catalyze the release glucose from the nonreducing ends of amylose, amylopectin, and other polysaccharides. Glucoamylase genes are found in many prokaryotic and eukaryotic microbes that use starch as a carbon source. It was believed to be important in the utilization of starch by the basidiomycetous fungus. Glucoamylase activity in the medium increased markedly during fruit-body formation. So study of the characteristic of glucoamylase in Pholiota nameko will provide the basis for P .nameko fruit body formation. In this research, in order to confirm the presence of glucoamylase gene in P. nameko genome, the genomic DNA was prepared from P. nameko NGW19-6 strain and was used as template to amplify the glucoamylases gene (PnGlu1). To prepare genomic DNA from the P. nameko NGW19-6 strain, the mycelium was grown on 10 ml of PD liquid medium (potato 200 g/l ,Glucose 20 g/l) prepared with tap water in a 100 ml Erlenmeyer flask and at 25°C for 7 days. Genomic DNA fragment encoding the glucoamylase protein (PnGlu1) were amplified by PCR with degenerate primer F15-GP2-AF/F15-GP2-BR. The primer pair was designed based on the amino acid sequences GLGEPKF and FDLWEEI, respectively, which are conserved in the glucoamylase protein of Laccaria bicolor. This produce fragments of approximately 400 bp. Next, to amplify the whole genomic clone of PnGlu1, oligonucleotide primer PnGP2F/ PnGP2R were designed based on the nucleotide sequence of DNA fragments amplified by cassette PCR method. The produced fragment has significant homology with glucoamylase of L. bicolor. To investigate the relationship between different composition of medium and glucoamylase expression, we checked the expression level of glucoamylase gene by realtime RT-PCR and measurement of glucoamylase enzyme activity.
        498.
        2010.12 KCI 등재 구독 인증기관·개인회원 무료
        Rhizopogon roseolus (Corda) Th. M. Fr. (=R. rubescens Tul. & Tul.), known as “shoro” in Japan, is a hypogeous basidiomycete that is an important ectomycorrhizal symbiont of Pinaceae. In order to cultivate this edible ectomycorrhizal mushroom, several researches have tried to promote mycorrhization of this mushroom on host Pinus thunbergii roots: Pine seedlings were inoculated with mycelium in vitro, or with crushed fruiting bodies in nature. However, successful cultivation of this mushroom has not been fully refined. We have developed the useful mycelial inoculum that enable to produced abundant ectomycorrhizas and then to form fruiting body under greenhouse nursery conditions. We selected the superior strain that rapidly colonized and produced a lot of ectomycorrhizas in root of P. thunbergii. The mycelial inoculum was composed of mineral solution and homogenate of mycelium that had been cultured in liquid medium. Addition of surfactant in the mycelial inoculum resulted in stimulation of mycorrhzal formations in host roots. When the mycelial inoculum containng surfactant were introduced to the mother plant system in which the colonized seedling had been planted into in the nursery, stimulatally effects were observed on not only mycorrhzation of the seedlings but also fruiting body formation. Genotype analysis using microsatellite markers for R. roseolus showed that fruiting bodies produced in the nursery were originated from the inoculated strain. These results suggest that the mycelial inoculum containg surfactant could be the model of mycelial spawn for “shoro”.
        499.
        2010.12 KCI 등재 구독 인증기관·개인회원 무료
        Basidiomycetes can degrade lignocellulosic biomass, and some basidiomycetes produce alcohol dehydrogenase, so it is feasible to produce alcohol from basidiomycetes. Agaricus blazei, Flammulina velutipes and Tricholoma matsutake have been used for mushroom fermentation to produce alcohol. To investigate whether Pholilta nameko can be used for mushroom fermentation, and find out the relationship between mannitol-1-phosphate dehydrogenase and alcohol dehydrogenase, we cloned mannitol-1-phosphate dehydrogenase gene from P. nameko, which is a zinc-containing long- chain alcohol dehydrogenase. Mpd, the gene encoding mannitol-1-phosphate dehydrogenase (MPD), has been sequenced and characterized from basiodiomycete P. nameko. The length of the coding region is 1360bp. The gene encodes a putative protein of 359 amino acids; predicted protein molecular weight is 38.6 kDa and an isoelectric point is PI = 7.34. The locations of exons and introns in the gene were deduced on the basis of interruptions in the amino acid sequence that were homologous to those in the MPD of Laccaria bicolor, the coding region was split into 6 exons and 5 introns. The protein deduced from the gene MPD showed more than 46% sequence identity to 20 fungal MPDs or alcohol dehydrogenases documented in the Gene bank protein database, based on BLASTP analysis, and was phylogenetically close to the MPDs of L. bicolor and Coprinopsis cinerea. This protein shared the same conserved domain with the alcohol dehydrogenase.