• BMB Reports
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• v.42 no.3
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• pp.160-165
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• 2009

The temperate Staphylococcus aureus phage ${\Phi}11$ harbors cI and cro repressor genes similar to those of lambdoid phages. Using extremely pure ${\Phi}11$ Cro (the product of the ${\Phi}11$ cro gene) we demonstrated that this protein possesses a single domain structure, forms dimers in solution at micromolar concentrations and maintains a largely $\alpha$-helical structure even at $45^{\circ}C$. ${\Phi}11$ Cro was sensitive to thermolysin at temperatures ranging from $55-75^{\circ}C$ and began to aggregate at ${\sim}63^{\circ}C$, suggesting that the protein is moderately thermostable. Of the three homologous 15-bp operators (O1, O2, and O3) in the ${\Phi}11$ cI-cro intergenic region, ${\Phi}11$ Cro only binds efficiently to O3, which is located upstream of the cI gene. Our comparative analyses indicate that the DNA binding capacity, secondary structure and dimerization efficiency of thermostable ${\Phi}11$ Cro are distinct from those of P22 Cro and $\lambda$ Cro, the best characterized representatives of the two structurally different Cro families.

• BMB Reports
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• v.40 no.5
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• pp.740-748
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• 2007

To gain insight into the structure and function of repressor proteins of bacteriophages of gram-positive bacteria, repressor of temperate Staphylococcus aureus phage ${\phi}11$ was undertaken as a model system here and purified as an N-terminal histidine-tagged variant (His-CI) by affinity chromatography. A ~19 kDa protein copurified with intact His-CI (~ 30 kDa) at low level was resulted most possibly due to partial cleavage at its Ala-Gly site. At ~10 nM and higher concentrations, His-CI forms significant amount of dimers in solution. There are two repressor binding sites in ${\phi}11$ cI-cro intergenic region and binding to two sites occurs possibly by a cooperative manner. Two sites dissected by HincII digestion were designated operators $O_L$ and $O_R$, respectively. Equilibrium binding studies indicate that His-CI binds to $O_R$ with a little more strongly than $O_L$ and binding species is probably dimeric in nature. Interestingly His-CI binding affinity reduces drastically at elevated temperatures ($32-42^{\circ}C$). Both $O_L$ and $O_R$ harbor a nearly identical inverted repeat and studies show that ${\phi}11$ repressor binds to each repeat efficiently. Additional analyses indicate that ${\phi}11$ repressor, like $\lambda$ repressor, harbors an N-terminal domain and a C-terminal domain which are separated by a hinge region. Secondary structure of ${\phi}11$ CI even nearly resembles to that of $\lambda$ phage repressor though they differ at sequence level. The putative N-terminal HTH (helix-turn-helix) motif of ${\phi}11$ repressor belongs to the HTH -XRE-family of proteins and shows significant identity to the HTH motifs of some proteins of evolutionary distant organisms but not to HTH motifs of most S. aureus phage repressors.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.5
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• pp.62-66
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• 2006

We investigate various $\Phi(t)-stability$ of comparison differential equations and we abtain necessary and/or sufficient conditions for the uniform asymptotic and exponential asymptotic stability of the nonlinear differential equation x'=f(t, x).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.959-964
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• 2007

To investigate the influence of partial discharge(PD) distribution characteristics due to various defects on the power cable joints interface, we used the K-means clustering method. As the result of PD number(n) distribution analyzing on $\Phi-n$ graph, the phase angle($\Phi$) of cluster centroid shifted to $0^{\circ}\;and\;180^{\circ}$ increasing with applying voltage. It was confirmed that the PD quantify(q) and euclidean distance of centroid were increased with applying voltage from the centroid distribution analyzing of $\Phi-q$ plane. The dispersion degree was increased with calculated standard deviation of the $\Phi-q$ cluster centroid. The PD number and mean value on $\Phi-q$ graph were some different by electric field concentration with defect types.

• Bulletin of the Korean Mathematical Society
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• v.22 no.1
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• pp.11-15
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• 1985

Manddelberg [9] has shown that a Clifford algebra of a free quadratic space over an arbitrary semi-local ring R in Brawer-Wall group BW(R) is determined by its rank, determinant, and Hasse invariant. In this paper, we prove a corresponding result when R is a full ring.Throughout this paper, unless otherwise specified, we assume that R is a commutative ring having 2 a unit. A quadratic space (V, B, .phi.) over R is a finitely generated projective R-module V with a symmetric bilinear mapping B: V*V.rarw.R which is non-degenerate (i.e., the natural mapping V.rarw.Ho $m_{R}$(V,R) induced by B is an isomorphism), and with a quadratic mapping .phi.: V.rarw.R such that B(x,y)=1/2(.phi.(x+y)-.phi.(x)-.phi.(y)) and .phi.(rx) = $r^{2}$.phi.(x) for all x, y in V and r in R. We denote the group of multiplicative units of R by U9R). If (V, B, .phi.) is a free rank n quadratic space over R with an orthogonal basis { $x_{1}$,.., $x_{n}$}, we will write < $a_{1}$,.., $a_{n}$> for (V, B, .phi.) where the $a_{i}$=.phi.( $x_{i}$) are in U(R), and denote the space by the table [ $a_{ij}$ ] where $a_{ij}$ =B( $x_{i}$, $x_{j}$). In the case n=2 and B( $x_{1}$, $x_{2}$)=1/2 we reserve the notation [a $a_{11}$, $a_{22}$] for the space. A commutative ring R having 2 a unit is called full [10] if for every triple $a_{1}$, $a_{2}$, $a_{3}$ of elements in R with ( $a_{1}$, $a_{2}$, $a_{3}$)=R, there is an element w in R such that $a_{1}$+ $a_{2}$w+ $a_{3}$ $w^{2}$=unit.TEX>=unit.t.t.t.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.2
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• pp.117-129
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• 2009

Several researches have been done to estimate the earth pressure on a vertical circular shaft considering three dimensional arching effect and verified them by conducting model tests. However, any equation suggested so far is not applicable in case of multi-layered soils and/or C-${\phi}$ soils. In this study, new equation for estimating the earth pressure acting on the vertical shaft in c-${\phi}$ soils is proposed. A parametric study is performed to investigate the significance of the cohesion when estimating the coefficient of earth pressure in C-${\phi}$ soils and estimating earth pressures in vertical shafts. A method which can estimate the earth pressure on vertical shafts in layered soils is also proposed by assuming a failure surface in layered soils and using the modified equation. This paper is Part I of companion papers focusing on the theoretical aspect of model developments; the experimental verification will be made in Part II.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.11
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• pp.1588-1593
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• 2014

The scott transformer changes three-phase power to two single-phase power. However, this method causes unbalance and fluctuation of voltage by the change of electric railload. Recently, the AC railway system based on $3{\Phi}/1{\Phi}$ back-to-back (BTB) voltage source converter (VSC) has been proposed to solve these problems. Meanwhile, battery energy storage system (BESS) is used to compensate voltage instantaneously in power system. In this paper, BESS application to the AC railway system based on $3{\Phi}/1{\Phi}$ BTB VSC is suggested to compensate voltage instantaneously. The application effect is shown through simulation using MATLAB/SIMULINK.

• Journal of Bio-Environment Control
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• v.26 no.1
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• pp.27-34
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• 2017

This study was carried out to estimate structural stabilities in respect of ground footings of plastic greenhouses on reclaimed lands. A 6m-wide multi-span plastic greenhouse with steel spiral piles as well as two 8.2m-wide single-span greenhouses with steel spiral piles and continuous pipe foundation respectively were built up on a reclaimed land with a SPT N-Value of 2 and measured how much the greenhouses were lifted up and subsided. In addition, the uplift capacity of three kinds of spiral piles(${\phi}50$, ${\phi}75$ and ${\phi}100$) was determined on a nearby reclaimed land. The results showed that the greenhouses with spiral piles had a slight vertical displacement like moving up and down but the scales of the rising up and sinking were negligible when compared to that of the greenhouses. The vertical displacement of the multi-span greenhouse ranged from +9.0mm(uplift) to -11.5mm(subsidence). As for the single-span greenhouses with spiral piles and continuous pipe foundation, the measurements showed that it varied from +1.3mm to -7.7mm and from +0.9mm to -11.2mm, respectively. The allowable uplift capacity of spiral piles could all be determined under criteria of ultimate load and accordingly had a value of 0.40kN, 1.0kN and 2.5kN, respectively. It was not entirely certain enough to make a final judgement on structural stabilities in respect of ground footings, it appeared likely however that the greenhouses with steel spiral piles was tentatively observed without any problems on reclaimed lands within the period.

• Korean Journal of Microbiology
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• v.23 no.2
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• pp.115-121
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• 1985

Five representative virulent phages (J1, TK93, K1, PD5, and CP1) and one temperate phage (.phi.1043) of Lactobacillus casei were compared to each other by analyzing the agarose gel electrophoretic patterns of restriction enzyme-digested phage DNAs. Nucleic acids of all the tested phages were double stranded DNA. DNAs of J1, TK93, K1, and ${\phi}$ 1043 phages had a size of about 42kb, but the size of PD5 and CP1 DNAs was avout 140kb. J1, TK93, K1, PD5, CP1, and ${\phi}$ 1043 DNAs were digested to 13, 13, 11, 14, 14, and 12 fragments by EcoR1, respectively, and showed its characteristec restriction patterns. Cohesive ends were present in J1, TK93, and ${\phi}$ 1043, but were absent in K1, PD5, and CP1. Restriction maps of J1 and TK93 DNAs showed nearly complete homology and their evolutionary relationship based upon the restriction analysis was discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.11
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• pp.1531-1541
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• 2002

The NOx emission characteristics of C$H_4$-Air coflow jet flames were numerically and experimentally investigated. NOx was measured using a chemiluminescent detection and calculated by the parabolic -type equation solver with a detatiled NOx chemistry. The fuel flow rate( $Q_{F}$), the diameter of mixture nozzle and the equivalence rate(Ф) were varied to discuss the EINOx of each flames at the various combustion conditions. The NOx emission index(EINOx) was introduced to quantify the NOx emission from the parametrically varied flames. The results show that Prompt EINOx increases on a logarithmic profile with increasing ${\Phi}$ and keeps nearly constant for the variation of $Q_{F}$. Thermal EINOx reaches the maximum value at around ${\Phi}$ =1.5 and then slowly decrease for ${\Phi}$ >1.5. In addition, Thermal EINOx increases with increasing $Q_{F}$, but nearly indifferent to the variation of the mixture nozzle diameter. Total EINOx also shows a peak at around ${\Phi}$ =1.5, followed by a relatively sharp decrease for 1.5< ${\Phi}$ <2.5 and increase slowly for 2.5 < ${\Phi}$ < $\infty$ The present Total EINOx trend is well explained by a combination of above Thermal and Prompt EINOx trend with the variation of ${\Phi}$ n of ${\Phi}$.