• Korean Journal of Materials Research
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• v.33 no.4
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• pp.135-141
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• 2023

The volatilization of alkali ions in (K,Na)NbO₃ (KNN) ceramics was inhibited by doping them with alkaline earth metal ions. In addition, the grain growth behavior changed significantly as the sintering duration (t_s) increased. At 1,100 ℃, the volatilization of alkali ions in KNN ceramics was more suppressed when doped with alkaline earth metal ions with smaller ionic size. A Ca²⁺-doped KNN specimen with the least alkali ion volatilization exhibited a microstructure in which grain growth was completely suppressed, even under long-term sintering for t_s = 30 h. The grain growth in Sr²⁺-doped and Ba²⁺-doped KNN specimens was suppressed until t_s = 10 h. However, at t_s = 30 h, a heterogeneous microstructure with abnormal grains and small-sized matrix grains was observed. The size and number of abnormal grains and size distribution of matrix grains were considerably different between the Sr²⁺-doped and Ba²⁺-doped specimens. This microstructural diversity in KNN ceramics could be explained in terms of the crystal growth driving force required for two-dimensional nucleation, which was directly related to the number of vacancies in the material.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.2
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• pp.59-69
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• 1989

The goby genus Tridentiger of Korea is reviewed and keys to following four species of the genus Tridentiger are provided for T. trigenocephalus, T. obscurus, T. nudicervicus and T. brevispinis. Among them, T. brevispinis is reported for the first time from Korea with the descriptions and illustrations of other three species of this genus in this paper. The external features of T. brevispinis are very similar with those of T. obscurus, however T. brevispinis is distinguished from T. obscurus by having the shorter 3rd dorsal spine, lesser number of gill rakers and longer intestine length. T. obscurus lives in the river mouth and esturaies around the coast of Korea, while T. brevispinis is collected from only the fresh water area.

• International journal of advanced smart convergence
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• v.7 no.1
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• pp.48-63
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• 2018

The combination of Simian Virus40 (SV40)'s large T antigen with its replication origin is commonly used in molecular studies to enhance the expression of heterogeneous genes through multiplying the plasmid copy number. There are no reports related to the impact of the SV40 T antigen on plant, multiple fissional, cell-type. This study explores the response of two multiple-fission microalgal cells, Scenedesmus quadricauda and Chlorella vulgaris, to the expression of the T-antigen, with aim of applying SV40 T-antigen to increase the expression efficiency of foreign genes in the two species. Different levels of low-expression have been constructed to control the expression of SV40 T antigen using three heterogenous promoters (NOS, CaMV35S, and CMV). Chlorella cultures showed slowdown in the growth rate for samples harboring the T antigen under the control of CaMV35S and CMV promoters, unlike Scenedesmus cultures which showed no significant difference between samples and could have silenced the expression.

• Bulletin of the Korean Mathematical Society
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• v.31 no.2
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• pp.237-242
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• 1994

One of the most well-known geometric lattices is a partition lattice. Every upper interval of a partition lattice is a partition lattice. The whitney numbers of a partition lattices are the Stirling numbers, and the characteristic polynomial is a falling factorial. The set of partitions with a single non-trivial block containing a fixed element is a Boolean sublattice of modular elements, so the partition lattice is supersolvable in the sense of Stanley [6]. In this paper, we rephrase four results due to Heller[1] and Murty [4] in terms of matroids and give several characterizations of partition lattices. Our notation and terminology follow those in [8,9]. To clarify our terminology, let G, be a finte geometric lattice. If S is the set of points (or rank-one flats) in G, the lattice structure of G induces the structure of a (combinatorial) geometry, also denoted by G, on S. The size vertical bar G vertical bar of the geometry G is the number of points in G. Let T be subset of S. The deletion of T from G is the geometry on the point set S/T obtained by restricting G to the subset S/T. The contraction G/T of G by T is the geometry induced by the geometric lattice [cl(T), over ^1] on the set S' of all flats in G covering cl(T). (Here, cl(T) is the closure of T, and over ^ 1 is the maximum of the lattice G.) Thus, by definition, the contraction of a geometry is always a geometry. A geometry which can be obtained from G by deletions and contractions is called a minor of G.

• Honam Mathematical Journal
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• v.31 no.4
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• pp.463-478
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• 2009

Let k be an imaginary quadratic field, ℌ the complex upper half plane, and let ${\tau}{\in}k{\cap}$ℌ, q = exp(${\pi}i{\tau}$). And let n, t be positive integers with $1{\leq}t{\leq}n-1$. Then $q^{{\frac{n}{12}}-{\frac{t}{2}}+{\frac{t^2}{2n}}}{\prod}^{\infty}_{m=1}(1-q^{nm-t})(1-q^{nm-(n-t)})$ is an algebraic number [10]. As a generalization of this result, we find several infinite series and products giving algebraic numbers using Ramanujan's $_{1{\psi}1}$ summation. These are also related to Rogers-Ramanujan continued fractions.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.1
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• pp.25-35
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• 2013

Automatically deriving only individual don't-care minterms that can effectively reduce a Boolean logic expressions are being investigated. Don't-care conditions play an important role in optimizing logic design. The type of unknown don't-care minterms that can always reduce the number of product terms in Boolean expression are referred as single hypothetical don't-care (S-HDC) minterms. This paper describes the Quasi Quine-McCluskey method that systematically derives S-HDC minterms. For the most part, this method is similar to the original Quine-McCluskey method in deriving the prime implicants. However, the Quasi Quine-McCluskey method further derives S-HDC minterms by applying so-called a combinatorial comparison operation. Upon completion of the procedure, the designer can review generated S-HDC minterms to test its appropriateness for a particular application.

• Journal of Magnetics
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• v.18 no.3
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• pp.321-325
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• 2013

The problem of mixed convection in a differentially heated lid-driven square cavity filled with Cu-water nanofluid under effect of a magnetic field is investigated numerically. The left and right walls of the cavity are kept at temperatures of $T_h$ and $T_c$ respectively while the horizontal walls are adiabatic. The top wall of the cavity moves in own plane from left to right. The effects of some pertinent parameters such as Richardson number (ranging from 0.1 to 10), the volume fraction of the nanoparticles (ranging 0 to 0.1) and the Hartmann number (ranging from 0 to 60) on the fluid flow and temperature fields and the rate of heat transfer in the cavity are investigated. It must be noted that in all calculations the Prandtl number of water as the pure fluid is kept at 6.8, while the Grashof number is considered fixed at 104. The obtained results show that the rate of heat transfer increases with an increase of the Reynolds number, while but it decreases with increase in the Hartmann number. Moreover it is found that based the Richardson and Hartmann numbers by increase in volume fraction of the nanoparticles the rate of heat transfer can be enhanced or deteriorated compared to the based fluid.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.239-246
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• 2003

We have examined the 16S-23S rRNA intergenic spacer region (ISR) of Vibrio vulnificus KCTC 2959. ISRs were amplified by primers complementary to conserved regions of 16S and 23S rRNA genes. ISR amplicons were cloned and sequenced. Analysis of the ISR sequences showed that V. vulnificus KCTC 2959 contains five types of polymorphic ISRs. Size of ISRs ranged from 424 to 741 bp in length and the number of tRNA genes ranged from one to four. The ISRs were designated as ISR-E $(tRNA^{Glu}),\;ISR-IA\;(tRNA^{Ile}-tRNA^{Ala})$, ISR-EKV $(tRNA^{Glu}-tRNA^{Lys}-tRNA^{Val})$, ISR-IAV $(tRNA^{Ile}-tRNA^{Ala}-tRNA^{val})$ and ISR-EKAV $(tRNA^{Glu}-tRNA^{Lys}-tRNA^{Ala}-tRNA^{Val})$ based on their tRNA genes. Multiple alignment of representative sequences from different Vibrio species revealed several domains of high sequence variability. We used the sequences of variable domains to design species-specific primer for detection PCR. Specificity of the primers was examined using genomic DNA prepared from 18 different Vibrio species. The results showed that the PCR using primers designed in this study can be used to detect V. vulnificus from other Vibrio species.

• International journal of advanced smart convergence
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• v.12 no.1
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• pp.64-69
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• 2023

We devise a collaboration construction method based on the SPRT (Sequential Probability Ratio Test) for malware detection in IoT. In our method, high-end IoT nodes having capable of detecting malware and generating malware signatures harness the SPRT to give a reward of malware signatures to low-end IoT nodes providing useful data for malware detection in IoT. We evaluate our proposed method through simulation. Our simulation results indicate that the number of malware signatures provided for collaboration is varied in accordance with the threshold for fraction of useful data.

• Journal of Korea Technology Innovation Society
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• v.19 no.3
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• pp.658-685
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• 2016

In technology economic theory, technology innovation through R&D is regarded as a core element of economic growth. This research analyzes how R&D input factor (R&D as a percentage of GDP, total number of researchers, the proportion of science and engineering degree) affects GDP, economic outcome variable, through mediating variable (S&T papers, patent registration). The most effective variable among R&D activity variables is following order: the number of S&T papers (0.967), the total number of researchers (0.373), the proportion of R&D expenditure (0.191), the number of patent registration (0.049), the proportion of science and engineering degree (0.007). It is that the proportion R&D expenditure and the total number of researchers shows greater indirect impact through S&T papers and patent than the direct impact on GDP. This implies the importance of high-quality human resources training and the necessity of maintaining the scale of R&D fund or the importance on GDP. Moreover, S&T papers turns out to have the greatest effect on GDP and implies new outcome and value by sharing and expanding new knowledge and technology created by R&D