• Bulletin of the Korean Mathematical Society
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• v.40 no.1
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• pp.29-51
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• 2003

In this paper we construct a natural filtration associated to the plethysm $S_{r}(\wedge^2 \varphi)$ over arbitrary commutative ring R. Let $\phi$ : G longrightarrow F be a morphism of finite free R-modules. We construct the natural filtration of $S_{r}(\wedge^2 \varphi)$ as a $GL(F){\times}GL(G)$- complex such that its associated graded complex is ${\Sigma}_{{\lambda}{\in}{\Omega}_{\gamma}}=L_{2{\lambda}{\varphi}$, where ${{\Omega}_{\gamma}}^{-}$ is a set of partitions such that $│\wedge│\;=;{\gamma}\;and\;2{\wedge}$ is a partition of which i-th term is $2{\wedge}_{i}$. Specializing our result, we obtain the filtrations of $S_{r}(\wedge^2 F)\;and\;D_{r}(D_2G).

• Nuclear Engineering and Technology
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• v.5 no.2
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• pp.150-158
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• 1973

General physical properties and radiation durabilities of some domestic woods and imported lauans were measured and discussed as a preliminary study on the preparation of W. P. C. The data obtained indicate that 1) the hardness of wood is generally proportional to the specific gravity and to the bending strength, 2) the hardness of wood measured in tangential direction to the annual ring increases along with the distance from the center of the annual ring to the peel, 3) the changes of specific gravity under 100 Mrad gamma irradiation are not remarkable, 4) the hardnesses of the soft woods are decreased more -readily than those of the hard woods, but the decreases of hardnesses are not extreme upto 10 Mrad sugges ting that the woods are sufficiently durable to gamma irradiation of below 10 Mard in the preparation of W. P. C.

• Korean Journal of Optics and Photonics
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• v.5 no.2
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• pp.245-251
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• 1994

The charateristics of switching between two modes in a ring dye laser has been analyzed by the Monte-Carlo computer simulation. The effect of including pump fluctuations in the first-passage-time (FPT) distributions was compared with the distribution with the quantum fluctuation. The results show the same tendency in both cases, such as steep increases from 0 to peak an exponential decrease in long time range. However the introduction of pumping fluctuation is turned out to shorten the mean FPT. The variation of the mean FPT is examined for the various fluctuationrelated parameters. The mean FPT is lengthened when pump parameter a is increased while it is shorted when Q. $\GAMMA$ are decreased. eased.

• Restorative Dentistry and Endodontics
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• v.9 no.1
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• pp.101-106
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• 1983

It was the purpose of this study to investigate the fracture mode of dental amalgam by observing the crack propagation, and to relate this to the microstructure of the amalgam. Caulk 20th Century Regular, Caulk Spherical, Dispersalloy, and Tytin amalgam alloys were used for this study. After each amalgam alloy and Hg measured exactly by the balance was triturated by the mechanical amalgamator (Capmaster, S.S. White), the triturated mass was inserted into the cylindrical metal mold which was 4 mm in diameter and 12 mm in height and was pressed by the Instron Universal Testing Machine at the speed of 1mm/min with 120Kg. The specimen removed from the mold was stored in the room temperature for a week. This specimen was polished with the emery papers from #100 to #200 and finally on the polishing cloth with 0.06${\mu}Al_2O_3$ powder suspended in water. The specimen was placed on the Instron testing machine in the method similar to the diametral tensile test and loaded at the crosshead speed of 0.05mm/min. The load was stopped short of fracture. The cracks on the polished surface of specimen was examined with scanning electron microscope (JSM-35) and analyzed by EPMA (Electron probe microanalyzer). The following results were obtained. 1. In low copper lathe-cut amalgam, the crack went through the voids and ${\gamma}_2$ phase, through the ${\gamma}_1$ phase around the ${\gamma}$ particles. 2. In low copper spherical amalgam, it was observed that the crack passed through the ${\gamma}_2$ and ${\gamma}_1$ phase, and through the boundary between the ${\gamma}_1$ and ${\gamma}$ phase. 3. In high copper dispersant (Dispersalloy) amalgam, the crack was found to propagate at the interface between the ${\gamma}_1$ matrix and reaction ring around the dispersant (Ag-Cu) particles, and to pass through the Ag-Sn particles. 4. In high copper single composition (Tytin) amalgam, the crack went through the ${\gamma}_1$ matrix between ${\eta}$ crystals, and through the unreacted alloy particle (core).

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.6
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• pp.601-607
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• 2015

A set of novel silicon controlled rectifier (SCR) devices' characteristics have been analyzed and verified under the electrostatic discharge (ESD) stress. A ring-shaped diffusion was added to their anode or cathode in order to improve the holding voltage (Vh) of SCR structure by creating new current discharging path and decreasing the emitter injection efficiency (${\gamma}$) of parasitic Bipolar Junction Transistor (BJT). ESD current density distribution imitated by 2-dimensional (2D) TCAD simulation demonstrated that an additional current path exists in the proposed SCR. All the related devices were investigated and characterized based on transmission line pulse (TLP) test system in a standard $0.5-{\mu}m$ 24 V CDMOS process. The proposed SCR devices with ring-shaped anode (RASCR) and ring-shaped cathode (RCSCR) own higher Vh than that of Simple SCR (S_SCR). Especially, the Vh of RCSCR has been raised above 33 V. What's more, their holding current is kept over 800 mA, which makes it possible to design power clamp with SCR structure for on chip ESD protection and keep the protected chip away from latch-up risk.

• Korean Journal of Poultry Science
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• v.24 no.3
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• pp.107-116
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• 1997

In order to achieve optimal reproductive performance, reliable morphological and physiological basic data on the reproductive organs are desirable. Adult male Korean ring-necked pheasant in inactive(mid of January) and active state (end of April) were used in this study. In addition, five active state pheasants were received a single dose of 60Co-ray 500 rads each to damage the testes. The objective of this study was to investigate the distribution pattern of protein gene product (PGP) 9.5 and ${\alpha}$-tubulin in the pheasant testes of the active, inactive and ${\gamma}$-ray irradiated active states. The results obtained were summarized as follows 1. The seminiferous tubules collected in inactive states( mid of Jan) showed narrow lumen, and the spermatogonia and the Sertoli cell were well preserved. The PGP 9.5 immunoreactivity of these tubules showed a positive reaction in paranucleus area of the spermatogonia, and a positive reaction in a small number of the Leydig cells in the interstitium of the seminiferous tubules. 2. The seminiferous tubules were dilated in active state(end of April) as compared with the inactive state. The PGP 9.5 reactivity in these tubules showed a positive reaction in many Leydig cells in the interstitium of the seminiferous tubules, and the testes of ${\gamma}$-ray irradiated group showed partially weak reaction in the interstitium of the seminiferous tubules. 3. The ${\alpha}$-tubulin reactivity in the seminiferous tubules of the inactive testes was strongly positive in the cytoplasmic process of the Sertoli cell from the basal stem region to the apical ex-tension. From the broad part of the stem region to the luminal space, the active testes showed a strong positive reaction. The ${\gamma}$-ray irradiated groups showed diminished reaction in the basal region.

• BMB Reports
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• v.36 no.6
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• pp.552-557
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• 2003

Oligomers with $\alpha$-aminooxy acids are reported to form very stable turn and helix structures, and they are supposed to be useful peptidomimetics for drug design. A recent report suggested that homochiral oxa-peptides form a strong eight-member-ring structure by a hydrogen bond between adjacent aminooxy-acid residues in a $CDCl_3$ solution. In order to design an $\alpha$-MSH analog with a stable turn conformation, we synthesized four tetramers and one pentamer, based on $\alpha$-MSH sequence, and determined the solution structures of the molecules by two-dimensional NMR spectroscopy and simulated annealing calculations. The solution conformations of the three peptidomimetic molecules (TLV, TDV, and TLL) in DMSO-$d_6$ contain a stable 7-membered-ring structure that is similar to a $\gamma$-turn in normal peptides. Newly-designed tetramer TDF and pentamer PDF have a ball-type rigid structure that is induced by strong hydrogen bonds between adjacent amide protons and carbonyl oxygens. In conclusion, the aminooxy acids, easily prepared from natural or unnatural amino acids, can be employed to prepare peptidomimetic analogues with well-defined turn structures for pharmaceutical interest.

• Communications of the Korean Mathematical Society
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• v.32 no.1
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• pp.7-17
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• 2017

Let R be a commutative ring with zero-divisors Z(R). The extended zero-divisor graph of R, denoted by $\bar{\Gamma}(R)$, is the (simple) graph with vertices $Z(R)^*=Z(R){\backslash}\{0\}$, the set of nonzero zero-divisors of R, where two distinct nonzero zero-divisors x and y are adjacent whenever there exist two non-negative integers n and m such that $x^ny^m=0$ with $x^n{\neq}0$ and $y^m{\neq}0$. In this paper, we consider the extended zero-divisor graphs of idealizations $R{\ltimes}M$ (where M is an R-module). At first, we distinguish when $\bar{\Gamma}(R{\ltimes}M)$ and the classical zero-divisor graph ${\Gamma}(R{\ltimes}M)$ coincide. Various examples in this context are given. Among other things, the diameter and the girth of $\bar{\Gamma}(R{\ltimes}M)$ are also studied.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.612-615
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• 2003

In this paper, a design of radiation detector for gamma column scanner is introduced. Distillation column is important unit in Petro-chemical industries, and its on-line diagnose is very important. To get density profile measured by the radiation transmitted through column is well method for on-line diagnose as gamma scanning. For this purpose radiation detection circuit, radiation source and mechanical system for moving source and detector are required. Conventional radiation detection circuit for this application is sensitive to electric noise because of interface between the radiation circuit and the controller for mechanical system. The radiation detection system introduced here is using loop coil instead of slip ring to remove contact noise. Radiation detection system designed here for gamma scanning consist of BGO detector, high voltage circuit, PHA circuit and FSK modem. The BGO detector is used as radiation sensor, high voltage circuit and peak height analysis circuit is essential to process the signal generated from BGO detector. Micro controller convert measured data into ASCII data. FSK modem transmit ASCII data. Transmitted ASCH data is picked up in antenna coil and processed for combined function with mechanical system. This method gives good result by isolating the controlling circuit of mechanical system from radiation detecting circuit which is sensitive to noise.

• Journal of the Korean Mathematical Society
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• v.48 no.2
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• pp.301-309
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• 2011

Let R = $Mat_2(F)$ be the ring of all 2 by 2 matrices over a finite field F, X the set of all nonzero, nonunits of R and G the group of all units of R. After investigating some properties of orbits under the left (and right) regular action on X by G, we show that the graph automorphisms group of $\Gamma(R)$ (the zero-divisor graph of R) is isomorphic to the symmetric group $S_{|F|+1}$ of degree |F|+1.