• Journal of Microbiology
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• v.44 no.5
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• pp.530-536
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• 2006

Bacteriophage P4, a satellite phage of coliphage P2, is a very useful experimental tool for the study of viral capsid assembly and cos-cleavage. For an in vitro cos-cleavage reaction study of the P2-P4 system, new shortened and selectable markers containing P4 derivative plasm ids were designed as a substrate molecules. They were constructed by swapping the non-essential segment of P4 DNA for either the kanamycin resistance (kmr) gene or the ampicillin resistance (apr) gene. The size of the genomes of the resulting markers were 82% (P4 ash8 delRI:: kmr) and 79% (P4 ash8 delRI:: apr) of the wild type P4 genome. To determine the lower limit of genome size that could be packaged into the small P4-size bead, these shortened P4 plasmids were converted to phage particles with infection of the helper phage P2. The conversion of plasmid P4 derivatives to bacteriophage particles was verified by the heat stability test and the burst size determination experiment. CsCl buoyant equilibrium density gradient experiments confirmed not only the genome size of the viable phage form of shortened P4 derivatives, but also their packaging into the small P4-size head. P4 ash8 delRI:: apr turned out to be the smallest P4 genome that can be packaged into P4-sized head.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.2
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• pp.1-8
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• 2009

Purpose: The purpose of this study is to compare degrees of asthenopia in after wearing of dispensed reading glasses with different criterion of P.D. Methods: The person who has minus near correction power (distance correction value (-)) is compared to the degree of asthenopia by wearing of dispensed reading glasses with near P.D(-B) and distance P.D. The person who has plus near correction power is compared to degree of asthenopia by wearing of dispensed reading glasses with near P.D-B, distance P.D, near P.D-A. The "Near-P.D-A" means reduced optical centre distance of reading glasses of positive correction value at which the same effect of prism B.O through near visual point in distance glasses exist at near visual point in reading glasses. Results: When near correction value is (-), dispensed reading glasses with distance P.D have caused less asthenopia than dispensed glasses with near P.D-B. When the near correction value is (+), we cannot confirm that which P.D is more useful for reading glasses. As a result of this study, dispensed reading glasses with near P.D-A have caused less asthenopia than another criterion of P.D. Conclusion: The effect of prism B.I through a near visual point in distance glasses ((-) correction value) reduce convergence demand. Therefore (-) correction value-reading glasses support convergence in near vision, because the effect of prism B.I of reading glasses is smaller than that of distance glasses. When the near correction value is (+), centration points can be determined by one of near P.D-A, near P.D-B, distance P.D.

• Fisheries and Aquatic Sciences
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• v.5 no.1
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• pp.28-31
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• 2002

Effects of cimetidine, a cytochrome P450 inhibitor, on the benzo[a]pyrene (BaP)-mediated cytochrome P450 induction and lipid peroxidation of liver in olive flounder, Paralichthys olivaceus, were investigated. Fish were fed either a cimetidine-supplemented diet or a cimetidine-free control diet once daily to satiation for 3 days. After 6 hrs of last feeding, the fish received intraperitoneal (i.p.) injection of BaP (20 mg/kg of body weight) dissolved in sterile corn oil $(100 \mu L)$ or received only a corn oil i.p. injection. At 1, 2, 3, and 7 days after the injection, hepatic cytochrome P450 and thiobarbituric acid reactive substances (TBARS), an indicator of lipid peroxidation, were analyzed. BaP injection resulted in an increase of hepatic cytochrome P450, and the fish fed the cimetidine-supplemented diet before injection of BaP showed delayed increase of hepatic cytochrome P450 compared to the fish fed a cimetidine-free diet and BaP injected. Injection of BaP clearly induced hepatic lipid peroxidation, and consistently higher TBAR values were shown in the fish fed a cimetidine­supplemented diet before injection of BaP than the fish injected with BaP alone.

• Bulletin of the Korean Mathematical Society
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• v.39 no.1
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• pp.123-131
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• 2002

Let A(p, k) (p, k$\in$N) be the class of functions f(z) = $z^{p}$ + $a_{p+k}$ $z^{p+k}$+… analytic in the unit disk. We introduce a subclass H(p, k, λ, $\delta$, A, B) of A(p, k) by using the Ruscheweyh derivative. The object of the present paper is to show some properties of functions in the class H(p, k, λ, $\delta$, A, B). B).

• Korean Journal of Materials Research
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• v.32 no.9
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• pp.361-368
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• 2022

The overall process, from the pre-treatment of aluminum substrates to the eco-friendly neutral electroless Ni-P plating process, was observed, compared, and analysed. To remove the surface oxide layer on the aluminum substrate and aid Ni-P plating, a zincation process was carried out. After the second zincation treatment, it was confirmed that a mostly uniform Zn layer was formed and the surface oxide of aluminum was also removed. The Ni-P electroless plating films were formed on the secondary zincated aluminum substrate using electroless plating solutions of pH 4.5 and neutral pH 7.0, respectively, while changing the plating bath temperature. When a neutral pH7.0 electroless solution was used, the Ni-P plating layer was uniformly formed even at the plating bath temperature of 50 ℃, and the plating speed was remarkably increased as the bath temperature was increased. On the other hand, when a pH 4.5 Ni-P electroless solution was used, a Ni-P plating film was not formed at a plating bath temperature of 50 ℃, and the plating speed was very slow compared to pH 7.0, although plating speed increased with increasing bath temperature. In the P contents, the P concentration of the neutral pH 7.0 Ni-P electroless plating layer was reduced by ~ 42.3 % compared to pH 4.5. Structurally, all of the Ni-P electroless plating layers formed in the pH 4.5 solution and the neutral (pH 7.0) solution had an amorphous crystal structure, as a Ni-P compound, regardless of the plating bath temperature.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4B
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• pp.333-343
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• 2006

MANET and P2P applications have a common nature that they don't have any fixed infrastructures that might maintain network topologies. With such common characteristics, a P2P application can be a killer application over MANET. Due to absence of reliable node which serves indexing services in MANET, fully distributed P2P applications are more suitable for MANET. By using DHT like Chord, we can save network bandwidth and avoid a point of failure of a directory server. However, since MANET allows nodes to depart from network freely, P2P file sharing applications using Chord lookup protocol should address how to recover the keys stored at the departed node. In this paper, we propose BU-Chord in order to detect and recover the departure of nodes by creating and storing backup file information in distributed manner. Our BU-Chord shows off better performance than existing Chord especially in case of high departure rate of nodes.

• Journal of Industrial Convergence
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• v.6 no.1
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• pp.57-72
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• 2008

In this study, general outline of P2P(peer to peer) application was analyzed dealing with security attacks and threats on the P2P environment. Information security service was studied to provide secure P2P service under the information threats. This study proposes two methods to provide secure information security service. One is a method to use personal firewall software on the peer. The other is a method to use key distribution protocol for confidentiality and integrity.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.5
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• pp.139-145
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• 2009

Recently P2P (Peer-to-Peer) networks and applications have been expanded to various field. However, because the construction of P2P network did not influence a underlying network topology or property, it may be inefficient. Especially, this inefficiency is more serious in MANET because MANET has narrow bandwidth and energy constraint. When we use a proactive routing protocol in MANET, we can know hop counts between two nodes. And, we can construct a P2P overlay network using this hop count information. However, In case of using hop count only, we can avoid a interference path selection problem and a zig-zag problem. We propose a method of improving P2P contents distribution using virtual positions. We calculate virtual positions from hop counts using the trigonometry. This method solves a interference path selection problem and a zig-zag problem. This method also allows a P2P network to influence underlying network topology. We adopt this method to a network which uses a virtual geographic routing, a proactive routing protocol, or a reactive routing protocol. We show that our proposed methods improve P2P contents distribution performance over MANET through a simulation.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.181-187
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• 1988

Using a Tn5-Mob system, pEA9 was characterized as a self-transmissible plasmid carrying a kanamycin resistance marker. The self-transfer frequencies of pEA9 varied greatly depending on pH values. The transfer frequency was about $4\times 10^{-5}$ at pH 5, that was 10 times higher than one at pH 6.5. With a helper plasmid, transfer frequencies were increased about $10^{4}$ times than the frequencies obtained without it.

• Journal of the Korean Ceramic Society
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• v.30 no.3
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• pp.206-214
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• 1993

Coherent precipitation of Zn3P2 during Zn diffusion in a GaInAsP/InP heterostructure was studied using high-resolution transmission electron microscopy. Zn-diffusion-induced intermixing of Ga and In across the GaInAsP/InP heterointerface provided a Ga-mixed InP region which was nearly lattice-matched with Zn3P2 crystal and thus allowed thecoherent precipitation of Zn3P2. The Zn3P2 precipitates were preferentially nucleated at stacking faults which were formed to relax interfacial strain built up by the intermixing. The precipitates were grown to planar epitaxial layer along (100) plane in the lattice-matched region. The TEM images and diffraction pettern revealed that the tetragonal Zn3P2 crystals were coherently matched to the fcc structured GaInP matrix by the {{{{ SQRT {2} $\times$ SQRT {2} $\times$2 }} arrangement. The precipitation reaction of Zn3P2 was explained by an atomic migration model based on the kick-out mechanism.