• Journal of the Korean Society of Safety
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• v.13 no.3
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• pp.45-50
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• 1998

The low grade domestic kaoline, such as pink-C and white-D, was converted to metakaoline, which has pozzolanic reactivity by heat treatment in the temperature range of $600^{\circ}C$ to 100$0^{\circ}C$ for preparing the spacer. The spacer was used for supporting the reinforced steel rod during construction to improve the safety of architecture. Pink-C and white-D were completely dehydroxylated when burnt at 80$0^{\circ}C$ for 1 hour and converted to metakaoline. The compressive strengths of specimens added calcined pink-C were lower than those of press molding mortar products inspite of calcining conditions. When white-D with calcined 80$0^{\circ}C$ and 100$0^{\circ}C$ for 1 hour was mixed 30% in the weight ratio of cement, the specimens cured 28 days had 338 $kg/cm^2$ and 347 $kg/cm^2$ of compressive strengths, respectively.

• Land and Housing Review
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• v.3 no.2
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• pp.169-175
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• 2012

In recent, there are many studies associated with energy piles to save initial construction cost for ground source heat pump system. In this study, to evaluate geothermal exchange rates two types (a connection type and a slinky type) of cast-in-place energy piles (PRD, 4.5m in depth, 1,200 mm in diameter) were constructed for the tests and their efficiencies were compared with numerical analysis results. As a result, starting with operation, geothermal exchange rate gradually decreases due to exchange of lower ground temperature. In the case of connection type, temperature difference is $0.37^{\circ}C$ in heating mode and $0.34^{\circ}C$, in cooling mode, respectively. In addition, in case of a connection type, geothermal exchange rate in heating mode is 2,314W/m and in cooling mode, 252.2W/m whose value is 9% higher than in heating mode. In the case of slinky type, the average geothermal exchange rate in heating mode is 168.0W/m, which is about 27% lower than that of connection type.

• Communications of the Korean Mathematical Society
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• v.10 no.2
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• pp.483-490
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• 1995

A parametric cubic spline interpolating at fixed number of nodes is constructed by formulating a parametric cubic $g^2$ B-splines $S_3(t)$ with not equally spaced parametric knots. Since the fact that each component is in $C^2$ class is not enough to provide the geometric smoothness of parametric curves, the existence of $S_3(t)$ oriented toward the modified second-order geometric continuity is focalized in our work.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.9-14
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• 2009

In this paper, using the binary (N,M,L,1) low correlation zone(LCZ) sequence set with specific property, we propose the construction method of a quaternary LCZ sequence set with parameters (2N,2M,L,2). The binary LCZ sequence using this method must have period $N{\equiv}3$ mod 4, balance property, and specific correlation property. The proposed method is modified from the construction method of binary LCZ sequence set by using binary LCZ sequence with specific condition proposed by Kim, Jang, No, and Chung[4].

• KSBB Journal
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• v.31 no.1
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• pp.27-32
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• 2016

Several CoA transferases from Clostridium beijerinckii, C. perfringens and Klebsiella pneumoniae were examined for biosynthesis of lactate-containing polyhydroxyalkanoates (PHAs) in recombinant Escherichia coli XL1-Blue strain. The CB3819 gene and the CB4543 gene from C. beijerinckii, the pct gene from C. perfringens and the pct gene from K. pneumoniae, which encodes putative CoA transferase gene, respectively, was co-expressed with the Pseudomonas sp. MBEL 6-19 phaC1437 gene encoding engineered Pseudomonas sp. MBEL 6-19 PHA synthase 1 ($PhaC1_{Ps6-19}$) to examine its activity for the construction of key metabolic pathway to produce poly(3-hydroxybutyrate-co-lactate) [P(3HB-co-LA)]. The recombinant E. coli XL1-Blue expressing the phaC1437 gene and CB3819 gene synthesized poly(3-hydroxybutyrate) [P(3HB)] homopolymer to the P(3HB) content of 60.5 wt% when it was cultured in a chemically defined medium containing 20 g/L of glucose and 2 g/L of sodium 3-hydroxybutyrate. Expression of the phaC1437 gene and CB4543 gene in recombinant E. coli XL1-Blue also produced P(3HB) homopolymer to the P(3HB) content of 51.2 wt% in the same culture condition. Expression of the phaC1437 gene and the K. pneumoniae pct gene in recombinant E. coli XL1-Blue could not result in the production of PHAs in the same culture condition. However, the recombinant E. coli XL1-Blue expressing the phaC1437 gene and the C. perfringens gene could produce poly(3-hydroxybutyrate-co-lactate [P(86.4mol%3HB-co-13.7 mol%LA) up to the PHA content of 10.6 wt% in the same culture condition. Newly examined CoA transfereases in this study may be useful for the construction of engineered E. coli strains to produce PHA containing novel monomer such lactate.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.4
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• pp.276-282
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• 2013

The reclaimed water has been highlighted as a representative alternative to solve the lacking water resources. This study examined the reduction of residual free chlorine by temperature (5, 15, $25^{\circ}C$) and initial injection concentration (1, 2, 4, 6 mg/L) in the reclaimed water and carried out propose on the calculating method of the optimal chlorine dosage. As the reclaimed water showed a very fast reaction with chlorine at the intial time comparing to that of drinking water, the existing general first-order decay model ($C_t=C_o(e^{-k_bt})$) was not suitable for use. Accordingly, the reduction of residual free chlorine could be estimated in a more accurate way as a result of applying the exponential first-order decay model ($C_t=a+b(e^{-k_bt})$). ($r^2$=0.872~0.988). As a result of calculating the bulk decay constant, it showed the highest result at 653 $day^{-1}$ under the condition of 1 mg/L, $25^{\circ}C$ for the initial injection whereas it showed the lowest result at 3.42 $day^{-1}$ under the condition of 6 mg/L, $5^{\circ}C$ for the initial injection. The bulk decay constant tends to increase as temperature increases, whereas the bulk decay constant tends to decrease as the initial injection concentration increases. More accurate calculation for optimal chlorine dosage could be done by using the experimental results for 30~5,040 min, after the entire response time is classified into 0~30 min and 30~5,040 min to calculate the optimal chlorine dosage. In addition, as a result of calculating the optimal chlorine dosage by temperature, the relationships of initial chlorine demand (y) by temperature (x) could be obtained such as y=1.409+0.450x to maintain 0.2 mg/L of residual free chlorine at the time after 4 hours from the chlorine injection.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.6
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• pp.226-233
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• 2023

In this study, the basic physical properties and microstructure of concrete interlocking blocks with amount of different CO₂ gas injection were analyzed according to determine the applicability of In-situ carbonation technology to construction secondary products. The amount of carbon dioxide gas injection was selected as 0, 0.1, 0.3, 0.5, 0.7 wt.% compared to cement amount. A lab-scale press equipment was designed to apply developed carbonation technology to real construction site. And mixer for stable CO₂ gas injection was designed. Using the designed devices, CO₂ gas injected samples were created and physical property of samples were performed. As a result of the physical property test, as the CO₂ injection amount increased to 0.3 %, it showed higher strength behavior compared to the original mix. And more than 0.5 % samples showed lower strength behavior than original sample, but they satisfied the standard of concrete interlocking block. This results were determined that CO₂ injection contributed to the creation of hydrates such as C-S-H. Therefore, the possibility of applying carbonation technology, which injects CO₂ during mixing, to various secondary construction products was confirmed.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.393-399
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• 2004

Useful genes can be Screened from various environments by construction of metagenomic DNA libraries. In this study, water samples were collected from several lakes in mid Korea, and analyzed by T-RFLP to examine diversities of the microbial communities. The crude DNAs r were extracted by the SDS-based freezing-thawing method, and then further purified using an $UltraClean^{TM}$ kit (MoBio, USA). The metagenomic libraries were constructed with the DNAs partially digested with EcoR I, BamH I, and Sac II in Escherichia coli DH 10B using the pBACe3.6 vector. About 44.0 Mb of metagenomic libraries were obtained with average inserts 13-15 kb in size. The bphC genes responsible for degradation of aromatic hydrocarbons via mets-cleavage were identified from the metagenomic libraries by colony hybridization using the bphC specific sequence as a probe. The 2,3-dihydroxybiphenyl (2, 3-DHBP) dioxygenase gene (bphC ), capable of degradation of 2,3-DHBP, was cloned and its nucleotide Sequences analyzed. The genes consisted of 966 and 897 base pairs with an ATG initiation codon and a TGA termination codon. The activity of the 2,3-DHBP dioxygenase was highly expressed to 2,3-DHBP and Showed a broad substrate range to 2,3-DHBP, catechol, 3-methylcatechol and 4-methylcatechol. These results in-dicated that the bphC gene identified from the metagenomes derived from lake water might be useful in the development of a potent strain for degradation of aromatic pollutants.

• Journal of the Korea Society of Computer and Information
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• v.25 no.8
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• pp.9-21
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• 2020

With the proliferation of RDF knowledge graphs(KGs), there arose a need of a standardized schema representation of the graph model for effective data interchangeability and interoperability. The need resulted in the development of SHACL specification to describe and validate RDF graph's structure by W3C. Relational databases(RDBs) are one of major sources for acquiring structured knowledge. The standard for automatic generation of RDF KGs from RDBs is R2RML, which is also developed by W3C. Since R2RML is designed to generate only RDF data graphs from RDBs, additional manual tasks are required to create the schemas for the graphs. In this paper we propose an approach to automatically generate SHACL schemas for RDF KGs populated by R2RML mappings. The key of our approach is that the SHACL shemas are built only from R2RML documents. We describe an implementation of our appraoch. Then, we show the validity of our approach with R2RML test cases designed by W3C.

• Journal of Korean Society of Steel Construction
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• v.15 no.2
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• pp.109-116
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• 2003

An investigation on the structural behavior of cold-formed steel lipped C-section stud for interior walls or partitions was carried out. This experimental research was carried out to study the ultimate and service load capacity of stud assemblies that are subjected to lateral loads. Each test specimen consisted of three or four lipped C-section studs and two C-section tracks that restrained both ends. The major factors considered in this experiment were the perforation on the web, the connection of the bridge channel and the special clip. The effect of the plaster board and the ply wood, which were attached to the tension flange on the flexural strength, was also investigated. Thereafter, the test strength capacities were compared with the nominal strength, based on the AISI Specifications (1996).