• Journal of the Korean Chemical Society
• /
• v.49 no.6
• /
• pp.623-627
• /
• 2005

• Membrane and Water Treatment
• /
• v.3 no.4
• /
• pp.231-242
• /
• 2012

The performance of a nanofiltration membrane for treatment of a low-level radioactive liquid waste was investigated through static and dynamic tests. The liquid waste ("carbonated water") was obtained during conversion of $UF_6$ to $UO_2$. In the static tests membrane samples were immersed in the waste for 24, 48 or 72 h. The transport properties of the samples (hydraulic permeability, permeate flow, selectivity) were evaluated before and after immersion in the waste. In the dynamic tests the waste was permeated in a permeation flow front system under 0.5 MPa, to determine the selectivity of NF membranes to uranium. The surface layer of the membrane was characterized by zeta potential, field emission microscopy, atomic force spectroscopy and infrared spectroscopy. The static test showed that the pore size distribution of the selective layer was altered, but the membrane surface charge was not significantly changed. 99% of uranium was rejected after the dynamic tests.

• Journal of the Semiconductor & Display Technology
• /
• v.19 no.2
• /
• pp.55-59
• /
• 2020

Copper Oxide (CuO) films were deposited on the n-type silicon wafer by rf magnetron sputtering for heterojunction solar cells. And then the samples were treated as a function of the annealing temperature (300-600℃) in a vacuum. Their electrical, optical and structural properties of the fabricated heterojunction solar cells were then investigated and the power conversion efficiencies (PCE) of the fabricated p-type copper oxide/n-type Si heterojunction cells were measured using solar simulator. After being treated at temperature of 500℃, the solar cells with CuO film have PCE of 0.43%, Current density of 5.37mA/㎠, Fill Factor of 39.82%.

• Proceedings of the KIEE Conference
• /
• 2003.07c
• /
• pp.1556-1558
• /
• 2003

IGCT devices is a superior devices for power conversion purpose. The basic structure of the IGCT devices is same as that of GTO thyristor. This makes the blocking voltage higher and controllable on-state current higher. In this paper, we present static and dynamic characteristics of 4.5 kV PT-type IGCT devices as a function of minority carrier lifetime, n-base thickness and n-buffer thickness. We should choose proper structural parameters for good electrical characteristics of GCT devices.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.32 no.5
• /
• pp.8-13
• /
• 2000

X-ray diffraction technique was used to quantify change of cellulose crystallinity during refining. XRD data confirmed that fiber wall delamination was caused by the structural conversion of celluloses which occurred in a liquid medium during refining. The quantified crystallinity of celluloses in pulp fibers was closely associated with the change of fiber wall delamination, which was defined by measurement of fiber wall thickness. In particular, it was well recognized that low intensity beating showed a better response in the change of crystallinity than high intensity one. The decrease o cellulose crystallinity during refining considerably enhanced the improvement of interfiber bonding ability of a dried sheet.

• International Journal of Contents
• /
• v.12 no.2
• /
• pp.24-30
• /
• 2016

Ontology is known to be one of the most important technologies in achieving semantic web. It is critical as it represents the knowledge in a machine readable state. World Wide Web Consortium (W3C) has been contributing to the development of ontology for the last several years. However, the recommendation of W3C left out HTML despite the massive amount of information it contains. Also, it is difficult and time consuming to keep up with all the technologies especially in the case of constructing ontology. Thus, we propose a module and methods that reuse HTML documents, extract necessary information from HTML tags and mapping it to OWL 2. We will be combining two kinds of approaches which will be the structural refinement for making an ontology skeleton and linguistic approach for adding detailed information onto the skeleton.

• Bulletin of the Korean Chemical Society
• /
• v.20 no.7
• /
• pp.781-785
• /
• 1999

Ferrisilicates with MFI type structure were hydrothermally synthesized. The structural environments of iron in the ferrisilicates were characterized by XRD, SEM, IR, EPR, and ammonia-TPD. It has been shown that pH of the final gel mixture during the synthesis affects the crystal size, morphology, chemical composition and catalyticactivity. The results of the lattice parameters, IR, and EPR indicate the existence of a framework iron and the content of framework iron depends on pH of the synthesis gel. Finally, the catalytic activity of these zeolites was examined for the cyclohexane oxidation to cyclohexanol and cyclohexanone in the liquid phase. The conversion of this reaction was increased with increasing iron content of the framework lattice positions.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.2
• /
• pp.170-175
• /
• 2022

3-Hydroxypropionic acid (3HP) is a platform chemical and can be converted into other valuable C3-based chemicals. Because a large amount of glycerol is produced as a by-product in the biodiesel industry, glycerol is an attractive carbon source in the biological production of 3HP. Although eight 3HP-producing aldehyde dehydrogenases (ALDHs) have been reported so far, the low conversion rate from 3-hydroxypropionaldehyde (3HPA) to 3HP using these enzymes is still a bottleneck for the production of 3HP. In this study, we elucidated the substrate binding modes of the eight 3HP-producing ALDHs through bioinformatic and structural analysis of these enzymes and selected protein engineering targets for developing enzymes with enhanced enzymatic activity against 3HPA. Among ten AbKGSADH variants we tested, three variants with replacement at the Arg281 site of AbKGSADH showed enhanced enzymatic activities. In particular, the AbKGSADH^R281Y variant exhibited improved catalytic efficiency by 2.5-fold compared with the wild type.

• Journal of the Korea Convergence Society
• /
• v.13 no.4
• /
• pp.299-306
• /
• 2022

In this study, the applications of the architectural design elements in the cultural rehabilitation of idle industrial facilities are categorized to define typology of rehabilitation design method. The design strategies which embodies historicity, symbolism, and sustainability are analysed in terms of structural, material, and resource with preservation, restoration and conversion by precedents study of idle industrial facilities that have been implemented and operated by the government.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.11
• /
• pp.1373-1381
• /
• 2022

Fructan is a polysaccharide composed of fructose and can be classified into several types, such as inulin, levan, and fructo-oligosaccharides, based on their linkage patterns and degree of polymerization. Owing to its structural and functional diversity, fructan has been used in various fields including prebiotics, foods and beverages, cosmetics, and pharmaceutical applications. With increasing interest in fructans, efficient and straightforward production methods have been explored. Since the 1990s, yeast cells have been employed as producers of recombinant enzymes for enzymatic conversion of fructans including fructosyltransferases derived from various microbes and plants. More recently, yeast cell factories are highlighted as efficient workhorses for fructan production by direct fermentation. In this review, recent advances and strategies for fructan biosynthesis by yeast cell factories are discussed.