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        검색결과 392

        122.
        2018.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Soybean straw (SS)-based activated carbon was employed as a precursor to prepare carbon molecular sieves (CMSs) via chemical vapor deposition (CVD) technique using methane as carbon source. Prior to the CVD process, SS was activated by 0.5 wt% ZnCl2, followed by a carbonization at 500°C for 1 h in N2 atmosphere. N2 (77 K) adsorption-desorption and CO2 (273 K) adsorption tests were carried out to analyze the pore structure of the prepared CMSs. The results show that increasing the deposition temperature, time or methane flow rate leads the decrease in N2 adsorption capacity, micropore volume and average pore diameter of CMSs. The adsorption selectivity coefficient of CO2/CH4 achieves as high as 20.8 over CMSs obtained under the methane flow rate of 30 mL min–1 at 800°C for 70 min. The study demonstrates the prepared CMSs are a candidate adsorbent for CO2/CH4 separation.
        4,000원
        123.
        2018.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Large-size graphene samples are successfully prepared by combining ultrosonic assisted liquid phase exfoliation process with oxidation-deoxidation method. Different from previous works, we used an ultrasound-treated expanded graphite as the raw material and prepared the graphene via a facile oxidation-reduction reaction. Results of X-ray diffraction and Raman spectroscopy confirm the crystal structure of the as-prepared graphene. Scanning electron microscopy images show that this kind of graphene has a large size (with a diameter over 100 μm), larger than the graphene from graphite powder and flake graphite prepared through single oxidation-deoxidation method. Transmission electron microscopy results also reveal the thin layers of the prepared graphene (number of layers ≤3). Furthermore, the importance of preprocessing the raw materials is also proven. Therefore, this method is an attractive way for preparing graphene with large size.
        4,000원
        124.
        2017.12 구독 인증기관 무료, 개인회원 유료
        Education is undoubtedly the greatest instrument which man has devised for his own progress. All societies have one form of education or another but the use to which it is put varies. This study investigated study habits, academic locus of control and self-efficacy as correlates of academic achievement among undergraduate students of the University of Lagos, Nigeria. A descriptive research survey was utilised for the study. The sample consisted of 524 undergraduate students selected from five faculties through proportional stratified random sampling technique. Three research questions and corresponding hypotheses were tested at .05 significant level while data were generated using standardized psychological tests which are Internal Control Index (ICI), Self-Efficacy Scale (SES), Study Habit Inventory (SHI) and Cumulative Grade point Average (CGPA) of the participants. Pearson Product Moment Correlation Coefficient Statistics was used to analyse the data. Results obtained showed a significant relationship between study habits, locus of control, self-efficacy and academic achievement among undergraduate students of the University of Lagos, Nigeria. It was recommended that parents, lecturers and the stakeholders on the campus and in the society at large should empower the undergraduate students to match both external and internal locus of control by self-efficacy, competence and effective study habits to achieve their academic goals.
        4,000원
        125.
        2017.12 구독 인증기관 무료, 개인회원 유료
        With the rapid development of the global economy, transport safety and security have become the key issues in maritime transportation all over the world. In practical applications, the Automatic Identification System (AIS)-based measurement of similarities between different vessel trajectories plays an important role in improving maritime transportation, e.g., maritime navigation, maritime supervision and management. However, the received AIS datasets are usually composed of a large amount of redundant information which could significantly increase the computational complexity. To deal with this problem, a Douglas-Peucker (DP)-based calculation method is introduced in this paper to accurately compress the spatio-temporal AIS trajectories while preserving the main geometrical structures. Based on the compressed trajectories, it is able to accelerate the Dynamic Time Warping (DTW) algorithm for the measurement of similarities between different vessel trajectories. In particular, the combination of DP and DTW has the capacity of significantly reducing the computational cost and guaranteeing the accuracy of similarity measures. The experimental results have demonstrated the superior performance of the proposed method in terms of computational cost and accuracy of similarity measures.
        4,000원
        126.
        2017.11 구독 인증기관·개인회원 무료
        β-glucosidase is an enzyme that hydrolyzes glycosidic bonds to generate terminal non-reducing residues in β-D-glucosides and oligosaccharides. These enzymes are used to degrade the plant cell walls of plant biomass. The 170 lactic acid bacteria isolated from beachu kimchi were examined for their β-glucosidase activity(E.C. 3.2.1.21.). Among the tested lactic acid bacteria, 48 strains utilized cellobiose as a carbon source. The highest β-glucosidase activity was 0.0537±0.0021(U/mg protein) in MSE129. MSE129 was identified to be Weissella koreenisis using 16S rRNA gene sequence analysis.
        127.
        2017.11 구독 인증기관·개인회원 무료
        With special condition in the geography, maritime industry is improvement rapidly in the planet, which is covered by approximately 360,000,000 km2 of Saline water. Together with the development of this field, freight transportation industry becomes one of the most important service in the world as well as in Hai Phong. Meanwhile the number of company and quality of service increased due to the demanding of citizen, the price for this activities also raised.
        131.
        2017.10 구독 인증기관·개인회원 무료
        The comstock mealybugs had been occurred at a Muscat of Alexandria’ organic vineyard in Okcheon. They had beenfound in the vines’s trunk since mid-June and moved to cane and leaves since early July, and also had been found ingrape clusters since late-July. The number of comstock mealybug and the grape’s fruit damage in Eco-friendly vineyardswere higher than in conventional culture vineyard. And the marketability of green variety grape was more damaged fromcomstock mealybug than the black variety grape. Toxicities of 8 organic agricultural materials(OAM) were evaluated tocomstock mealybug at the recommended concentration. As a results, Lightyellow sophora and Derris extracts exhibitedstrong insecticidal activity with 100% mortality. When the Lightyellow sophora extract was uniformly distributed on thevine from early-July to mid-July, commercial grapes could be harvested. Therefore, I thought that we can control comstockmealybug by spraying OAM in a timely period.
        132.
        2017.10 구독 인증기관·개인회원 무료
        Hypsizygus marmoreus (Peck) H.E. Bigelow is a typical white-rot fungus and is widely cultivated in China and Japan. In this study, the genome of a monokaryon strain HM26-F1 was sequenced using Illumina and Pacbio platforms. The genome sequences of 32,238,363 bp with 49.40% G+C content were obtained and 14,443 gene models coding for proteins were determined. The divergence time was 144 million years ago (MYA) and diverged from other fungi belonging to Agaricales around the late of Jurassic Period. 363 carbohydrate-active enzymes (CAZymes) genes were detected in this genome. And there were higher number of class II peroxidases (11) and multicopper oxidases (22) for degrading lignin. In addition, 418 genes were enriched involving in purine metabolism for IMP and GMP synthesis. And, there were 7 secondary metabolite clusters in the genome, including 3 terpene, 2 polyketide biosynthase, 1 nonribosomal peptide synthetase and 1 siderophore. Combining Hiseq 2500 and Pacbio platforms resulted in a more complete and less fragmented genome. H. marmoreus had high abilities to degrade lignocellulose. IMP and GMP may be the basis of the crab flavor. Information obtained from this study enhances our knowledge about degradation mechanisms of lignocellulose and secondary metabolism.
        133.
        2017.10 구독 인증기관·개인회원 무료
        Mushrooms have been valued as a traditional source of natural bioactive compounds for centuries and have recently been exploited for potential components in cosmetics industry. Numerous mushrooms and their ingredients have been known to be beneficial to the skin and hair. The representative ingredients are as follows: phenolics, polyphenolics, terpenoids, selenium, polysaccharides, vitamins and volatile organic compounds. These compounds show excellent antioxidant, anti-aging, anti-wrinkle, skin whitening, and moisturizing effects which make them ideal candidates for cosmetics products. This review provides some perspectives of mushrooms (and/or extracts) and their ingredients presently used, or patented to be used, in both cosmeceuticals for topical administration and nutricosmetics for oral administration. With the small percentage of mushrooms presently identified and utilized, more mushroom species will be discovered, verified, and cultivated in the future, boosting the development of relevant industry. Combining with progress in genomics, proteomics, metabolomics, and systems pharmacology, mushrooms can find their way into cosmetics with multiple approaches.
        134.
        2017.07 구독 인증기관 무료, 개인회원 유료
        This study develops a framework that links commitment, relationship investment, relationship learning, functional conflict and innovation orientation to innovation. This framework has three main features. First, it examines the direct effects of commitment and relationship investment on relationship learning. Second, it examines the direct effect of relationship learning on innovation. Third, it investigates the moderating effects of functional conflict and innovation orientation on the relationship between relationship learning and innovation.
        3,000원
        135.
        2017.05 구독 인증기관·개인회원 무료
        Somatic cell nuclear transfer (SCNT) is the technique which generates embryos by transferring diploid nucleus into an enucleated oocyte, it has produced specific animals successfully in a variety of species. However, the developmental capacity of SCNT embryos is still relatively lower than that of embryos produced in vivo. Oocyte is a kind of lipid rich cells, its quality limits the efficiency of embryo production. L-carnitine is a co-enzyme facilitating the transportation of long chain fatty acids across the inner mitochondria membrane where fatty acids are used for generating adenosine triphosphate (ATP) via beta-oxidation. It also has antioxidant actions which may protect mitochondrial membranes and DNA against damage induced by reactive oxygen species (ROS). Whether L-carnitine is functional in bovine SCNT embryos are unknown. Therefore, the objective of this study was to examine the effects of L-carnitine on oocyte maturation and developmental competence of subsequent SCNT embryos. L-carnitine was supplemented during IVM, then intracellular ROS and GSH levels, mitochondrial activity, gene expression of COCs were analyzed at the end of IVM. SCNT embryos were produced subsequently, apoptosis detection and gene expression evaluation were performed in blastocysts. In the results, treatments with 1.5 mM and 3 mM L-carnitine significantly improved maturation rates (P<0.05). Treatments with 3 mM L-carnitine effectively induced improvement in nuclear maturation, intracellular GSH levels and mitochondrial activity, as well as a reduction in intracellular ROS levels (P<0.05). mRNA levels of CPT1A, ACAA1, ACAA2, AREG, EREG, SOD1, GPX4, GLUT1 and CDC2 transcripts were effectively up-regulated by 3 mM L-carnitine treatments (P < 0.05). Similarly, 3mM L-carnitine induced an increase in blastocyst developmental rates and an improvement in blastocyst quality (P<0.05). Our study indicates that L-carnitine treatment during IVM improves oocyte nuclear maturation and subsequent SCNT embryo development.
        136.
        2017.04 구독 인증기관 무료, 개인회원 유료
        A robust adaptive control approach is proposed for underactuated surface ship linear path-tracking control system based on the backstepping control method and Lyapunov stability theory. By employing T-S fuzzy system to approximate nonlinear uncertainties of the control system, the proposed scheme is developed by combining “dynamic surface control” (DSC) and “minimal learning parameter” (MLP) techniques. The substantial problems of “explosion of complexity” and “dimension curse” existed in the traditional backstepping technique are circumvented, and it is convenient to implement in applications. In addition, an auxiliary system is developed to deal with the effect of input saturation constraints. The control algorithm avoids the singularity problem of controller and guarantees the stability of the closed-loop system. The tracking error converges to an arbitrarily small neighborhood. Finally, MATLAB simulation results are given from an application case of Dalian Maritime University training ship to demonstrate the effectiveness of the proposed scheme.
        4,000원
        137.
        2017.04 구독 인증기관·개인회원 무료
        Nowadays, container transport services play a substantial role in global cargo transportation by serving as an intermodal between the exporter and importer. Container shipping has become increasingly important over the past few decades due to its obvious advantages. However, Vietnam's container market has shown severely ongoing competition among numerous domestic and foreign shipping lines resulting in serious consequences occurring such as the freight rates substantially decreasing within the last ten years. In fact, Vietnam's sea lanes have become more defensive to cover the losses of shipping companies. Selection of criteria for competitive evaluation of container transport companies is necessary to help recognize the problems within the enterprise especially relating to its position in the market and from here, business management are able to put strategic plans in place and reasonable policy in order to be able to survive and grow.
        138.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The extragalactic background suggests half the energy generated by stars was reprocessed into the infrared (IR) by dust. At z1.3, 90% of star formation is obscured by dust. To fully understand the cosmic star formation history, it is critical to investigate infrared emission. AKARI has made deep mid-IR observation using its continuous 9-band filters in the NEP field (5.4 deg2), using 10% of the entire pointed observations available throughout its lifetime. However, there remain 11,000 AKARI infrared sources undetected with the previous CFHT/Megacam imaging (r ~25.9ABmag). Redshift and IR luminosity of these sources are unknown. These sources may contribute signi cantly to the cosmic star-formation rate density (CSFRD). For example, if they all lie at 1< z <2, the CSFRD will be twice as high at the epoch. We are carrying out deep imaging of the NEP eld in 5 broad bands (g; r; i; z; and y) using Hyper Suprime-Camera (HSC), which has 1.5 deg field of view in diameter on Subaru 8m telescope. This will provide photometric redshift information, and thereby IR luminosity for the previously-undetected 11,000 faint AKARI IR sources. Combined with AKARI's mid-IR AGN/SF diagnosis, and accurate mid- IR luminosity measurement, this will allow a complete census of cosmic star-formation/AGN accretion history obscured by dust.
        4,000원
        139.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since the launch of the Herschel Space Observatory, our understanding about the photo-dissociation regions (PDR) has taken a step forward. In the bandwidth of the Fourier Transform Spectrometer (FTS) of the Spectral and Photometric Imaging REceiver (SPIRE) on board Herschel, ten CO rotational transitions, including J = 4-3 to J = 13-12, and three fine structure lines, including [Ci] 609, [Ci] 370, and [Nii] 205 μm, are covered. I present our findings from the FTS observations at the nuclear region of M83, based on the spatially resolved physical parameters derived from the CO spectral line energy distribution (SLED) map and the comparisons with the dust properties and star-formation tracers. This article discusses (1) the potential of using [Nii] 205 and [Ci] 370 μm as star-formation tracers; (2) the excitation mechanisms of warm CO in the nuclear region of M83.
        3,000원
        140.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this research is to explore the interaction patterns in an English (L2)-mediated Mandarin Chinese (L3) class (native-taught) for young monolingual Korean (L1) learners. Twenty-nine class videos were collected and transcribed into 152 pages of Chinese, English, and Korean for this analysis. The interaction patterns in the English-mediated Chinese classes were analyzed using the IRF framework of Sinclair and Coulthard (1975) and Tsui (1994). The results and discussions were integrated into four main patterns to interpret the English-mediated Chinese classes: 1) the native Chinese teacher’s needs for class assistance, 2) the students’ enthusiastic but inadequate use of English, 3) the students’ voluntary Korean scaffolding, and 4) the students’ class participation needs. On the one hand, this research has provided the students’ response to the teacher’s use of Chinese and English (in a foreign language-only environment), which is intended for a better understanding of a classroom with a trilingual teacher and monolingual students. On the other hand, the research has implications for understanding use of an L2 to facilitate an L3 classroom, particularly in the situation of using two foreign languages in one classroom.
        6,700원