• Journal of Microbiology and Biotechnology
• /
• v.21 no.8
• /
• pp.808-817
• /
• 2011

Because of its elevated cellulolytic activity, the filamentous fungus Trichoderma harzianum has a considerable potential in biomass hydrolysis applications. Trichoderma harzianum cellobiohydrolase I (ThCBHI), an exoglucanase, is an important enzyme in the process of cellulose degradation. Here, we report an easy single-step ion-exchange chromatographic method for purification of ThCBHI and its initial biophysical and biochemical characterization. The ThCBHI produced by induction with microcrystalline cellulose under submerged fermentation was purified on DEAE-Sephadex A-50 media and its identity was confirmed by mass spectrometry. The ThCBHI biochemical characterization showed that the protein has a molecular mass of 66 kDa and pI of 5.23. As confirmed by smallangle X-ray scattering (SAXS), both full-length ThCBHI and its catalytic core domain (CCD) obtained by digestion with papain are monomeric in solution. Secondary structure analysis of ThCBHI by circular dichroism revealed ${\alpha}$- helices and ${\beta}$-strands contents in the 28% and 38% range, respectively. The intrinsic fluorescence emission maximum of 337 nm was accounted for as different degrees of exposure of ThCBHI tryptophan residues to water. Moreover, ThCBHI displayed maximum activity at pH 5.0 and temperature of $50^{\circ}C$ with specific activities against Avicel and p-nitrophenyl-${\beta}$-D-cellobioside of 1.25 U/mg and 1.53 U/mg, respectively.

• The Korean Journal of Pesticide Science
• /
• v.21 no.1
• /
• pp.1-8
• /
• 2017

Although a global ban on the use of endosulfan, an organochloline insecticide, has taken effect in mid-2012, it has been still used in several countries, including India and China, and detected in diverse environments in the world due to its relative persistence and semi-volatility. In this study, the effect of endosulfan on soil bacterial community was investigated using 16S rRNA gene pyrosequencing method. When endosulfan was applied to an upland soil at a rate of 100 mg/kg soil (ES soil), the number of operational taxonomic units (OTU) and diversity indices for bacteria initially decreased and gradually recovered to the level of the non-treated soil (NT soil) during an eight-week incubation period. At bacterial phylum level, relative abundances of Proteobacteria and Verrucomicrobia were higher while those of Chloroflexi and Spirochaetes were lower in the ES soil than in the NT soil, suggesting that an endosulfan application affects the bacterial community structure in soil. In the ES soil, the relative abundances of the OTUs affiliated to the genera Sphingomonas and Burkholderia increased in the initial period of incubation while those affiliated to the genera Pseudonocardia and Opitutus increased in the late period of incubation. Because the first three genera contain bacterial strains reported to degrade endosulfan, they are expected to be involved in the degradation of endosulfan, probably one after another.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.12
• /
• pp.511-517
• /
• 2016

Current oil-type potential transformers for trains are filled with insulating oil, which could have problems like explosions due to rising inner pressure during train operation. Therefore, mold and dry-type potential transformers are being developed to prevent explosions. One problem in manufacturing mold-type transformers is preventing void formation around the coiled core inside the mold during epoxy filling, which could cause an electrical spark. Micro voids can remain in the resin after filling, and macro voids can occur due to the structure shape. A transformer that is being developed has a cavity at the junction of the core and the coil for better performance, and when highly viscous epoxy flows inside the cavity channel, macro voids can form inside it. Therefore, in this study, the free-surface flow of the mold filling procedure was analyzed numerically by applying the VOF method. The results were used to understand the phenomena of void formation inside the cavity and to modify the process conditions to reduce voids.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.1
• /
• pp.67-75
• /
• 2014

A full-scale static test for a composite structure small aircraft (KC-100) was conducted in the KARI. The test includes 15 full-scale test and 7 local test conditions. Test requirements with test schedule, test article with dummy structures, test load generation, test system, and equipment are introduced for the test. Test load data of the 1st test condition(U1) was analyzed to evaluate an accuracy of load control for the test. The analysis results show that load data obtained during test were within tolerance of Static Null Pacing Error(SNPE) and the error value of load control was 8.6N. The error of load controls for the full-scale static test using dozens of actuators was calculated by a method suggested by authors. Test data for all other test conditions is also shown in this paper. Finally, reactions measured from restraint system of the U1 test condition show that the reaction changes as load increment. The factors which may change the change of reactions for a full-scale static test are introduced in this study.

• The Journal of Society for e-Business Studies
• /
• v.18 no.4
• /
• pp.215-240
• /
• 2013

This research has reviewed the major composition concepts and the positive research results in the selected studies which were theoretically based on IDT (Innovation Diffusion Theory), IRM (Model of Innovation Resistance), TAM(Technology Acceptance Model), and IAPA(Information Asset Protection Activity) in order to improve the theoretical explanation of major characterized factors influencing on the introduction of MST (Mobile Security Technology). The characterized factors for the adaptation of MST and 17 hypotheses on the MST study models in order to test the effects on the intention to use are empirically verified by utilizing the analysis method of structure equation model. As a result of a study, First, the most influential characterized factors of IRM are shown as compatibility, complexity, relative advantage, information asset protection in order. Second, the characterized factors affecting intention to use are shown as relative advantage, compatibility, innovation resistance, performance expectancy. The results of this study are relevantly significant to establish the theoretical foundation of the study on the adaptation of MST and The verification of the characterized factors provide strategic implication for the introduction of MST and policy direction which alleviates informational gap between new MST and previous Security Technology to diffusion agency.

• Journal of Digital Convergence
• /
• v.12 no.6
• /
• pp.375-384
• /
• 2014

This research was done to determine and analyze a qualitative on the essential structure of the experiences of stroke patients with combined treatment of oriental and western medicine. Methods: Participants in this study were targeting 25 stroke patients who live mostly in D city and received the combined treatment of oriental and western medicine, but received oriental medicine treatments based on their own wills. Data were collected and recorded through in-depth interviews. Data analysis was conducted by Colaizzi's phenomenological method. Results: As a result, their acculturation were classified into 21 clusters of theme and 6 categories. Selected 6 categories as follows. 'being severely shocked from sudden attack', 'being depressed with rehabilitation', 'western therapy was more effective in emergency situations', 'having limitations in western therapy', 'selecting oriental therapy for themselves', 'discovering the meaning of rehabilitation in oriental therapy'. Conclusion: Based on these necessary data for systematic oriental rehabilitation development.

• Journal of the Korean Geographical Society
• /
• v.39 no.4
• /
• pp.620-632
• /
• 2004

This paper tries to examine differences between geography classes taught by majored and non-majored teacher and to find problems in the latter case, tv observing four middle school geography classes in Seoul, from April to May 2003. The observation was fecund on (1) organization of a class (2) dialogue between teacher and students (3) strategy of explanation. In addition, the author conducted personal interviews with social studies teachers in the schools where the observations were made. The analyses of the observed classes were made by micro-ethnographic research method. Major findings of the observation and analysis are as follows. First, the transition from one topic to another topic was not smooth in the case of non-majored teacher class. Second, the questions that the non-majored teacher posed in the classroom played less significant role in keeping up the class in an organized fashion than those that the majored teacher posed. Third, the non-majored teacher focused on the concepts, terms and contents appeared in the textbook and simply tried to explain them, whereas the majored teacher demonstrated teaching methods such as comparing and contrasting cases to provide students with a more dynamic and comprehensive understanding on the topic they teamed. Fourth, the non-majored teacher used maps less frequently and less actively than the majored teacher. In addition, although the non-majored teachers are well aware of their problems in the class as a non-majored teacher, they think that the problems are inevitable in a given curriculum structure of social studies in Korea.

• The Journal of Advanced Prosthodontics
• /
• v.5 no.4
• /
• pp.471-478
• /
• 2013

PURPOSE. The aim of the study was to evaluate the effect of annealing on the nanostructure and hardness of Co-Cr metal ceramic samples that were fabricated with a direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS. Five groups of Co-Cr dental alloy samples were manufactured in a rectangular form measuring $4{\times}2{\times}2$ mm. Samples fabricated by a conventional casting technique (Group I) and prefabricated milling blanks (Group II) were examined as conventional technique groups. The DMLS samples were randomly divided into three groups as not annealed (Group III), annealed in argon atmosphere (Group IV), or annealed in oxygen atmosphere (Group V). The nanostructure was examined with the small-angle X-ray scattering method. The Rockwell hardness test was used to measure the hardness changes in each group, and the means and standard deviations were statistically analyzed by one-way ANOVA for comparison of continuous variables and Tukey's HSD test was used for post hoc analysis. P values of <.05 were accepted as statistically significant. RESULTS. The general nanostructures of the samples were composed of small spherical entities stacked atop one another in dendritic form. All groups also displayed different hardness values depending on the manufacturing technique. The annealing procedure and environment directly affected both the nanostructure and hardness of the Co-Cr alloy. Group III exhibited a non-homogeneous structure and increased hardness ($48.16{\pm}3.02$ HRC) because the annealing process was incomplete and the inner stress was not relieved. Annealing in argon atmosphere of Group IV not only relieved the inner stresses but also decreased the hardness ($27.40{\pm}3.98$ HRC). The results of fitting function presented that Group IV was the most homogeneous product as the minimum bilayer thickness was measured (7.11 ${\AA}$). CONCLUSION. After the manufacturing with DMLS technique, annealing in argon atmosphere is an essential process for Co-Cr metal ceramic substructures. The dentists should be familiar with the materials that are used in clinic for prosthodontics treatments.

• Journal of the Korean Electrochemical Society
• /
• v.9 no.1
• /
• pp.1-5
• /
• 2006

Lithium titanium oxide $(Li_4Ti_5O_{12})$ with spinel-framework structures as anode material for lithium-ion battery was prepared by sol-gel and high energy ball milling (HEBH) method. According to the X-ray diffraction (XRD), Particle Size Analyses(PSA) and scanning electron microscopy (SEM) analysis, uniformly distributed $Li_4Ti_5O_{12}$ particles with grain sizes of 100 nm were observed. Half cells, consisting of $Li_4Ti_5O_{12}$ as working electrode and lithium foil as both counter and reference electrodes showed the high performance of high rate discharge capacity and 173 mAh/g at 0.2C in the range of $1.0\sim2.5 V$. Furthermore, the crystalline structure of $Li_4Ti_5O_{12}$ didn't transform during the lithium intercalation and deintercalation process.

• Journal of Korean Society of Forest Science
• /
• v.79 no.1
• /
• pp.33-41
• /
• 1990

The purpose of this study is to investigate the developmental process of plant community during the secondary succession through the analysis of floristic composition, life form etcectra in burned site, and the structure of forest stand before forest fire occurrence was estimated by the method of anatomical wood identification for dead trees in burned site, Cheisuk-bong in Mt. Chiri of Korea. Plant community before forest fire occurrence was estimated the high mountain conifer stand of the last successional stage to consist of Pinus koraiensis(75%), Abies koreana(15%) and Picea jezoensis(10%), and Betula costata was survived only one species after forest fire occurrence. The total number of plant species in the investigated area was 19 families and 23 species that was identified. The dominate species in burned site were Festuca ovina and Arrhenatherum elatius, Carex humilis, Ligularia fischeri etcectra in the investigated area flora. The life form of plant in burned site was the erect from 47.8%, the tufted from 30.4%, the branched and the prostrate from was both 8.7%, It was assumed that dominant species in the burned sites were Gramineae (Festuca ovina, Arrhenatherum elatius), Carex humilis ${\rightarrow}$Sorbus commixta, Rhododendron schrippenbachii, Sambucus williamsii var. coreana, Tripterygium regelii ${\rightarrow}$Acer pseudo-sieboldianum var. koreanum, Betula costata, Quercus mongolica${\rightarrow}$Pinaceae forest(Pinus koraiensis, Abies koreana, Picea jezoznsis).