• Journal of fish pathology
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• v.6 no.2
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• pp.111-122
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• 1993

The mechanism by which $V_H$ region gene segments is selected in B lymphocyte is not known. Moreover, evidence for both random and nonrandom expression of $V_H$ genes in matured B cells has been presented previously. In this report, the technique of in situ hybridization allowed us to analyze expressed $V_H$ gene families in normal B lymphocyte at the single cell level. The analysis of normal B cells in this study eliminated any posssible bias resulting from transformation protocols used previously and minimized limitation associated with sampling size. Therefore, an accurate measure of the functional and expressed $V_H$ gene repertoire in B lymphocyte could be made. One of the most important controls for the optimization of in situ hybridization is to establish probe concentration and washing stringency due to the degree of nucleotide sequence similarlity between different families which in some cases can be as high as 70%. When the radioactive $C{\mu}$ and $V_{H}J558$ RNA probes are tested on LPS-stimulated adult spleen cells, $2{\sim}4{\times}106cpm$/slide shows low background and reasonable frequency of specific positive cells. For the washing condition. 40~50% formamide at $54^{\circ}C$ is found to be optimum for the $C{\mu}$. $V_{H}S107$ and $V_{H}J558$ probes. The analyzed results clearly demonstrate that the level of each different $V_H$ gene family expression is dependent upon the complexity or size of that family. These findings are also extended to the level of $V_H$ gene family expression in separated bone marrow B cells depend upon the various stage of differentiation and conclude no preferential utilization of specific $V_H$ gene family. Thus, the utilization of VH gene segments in B lymphocyte of adult BALB/c mice is random and is not regulated or changed during the differentiation of B cells.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.412-415
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• 1995

By adding 1wt.% $HfB_{2}$ into $Nd_{3-4}Fe_{77-78.5}B_{18.5}$ alloys, the grain growth of $Fe_{3}B/Nd_{2}Fe_{14}B$ composite phases during annealing was found to be hindered by 40~50%. It is proposed that the addition of $HfB_{2}$ leads to the formation of fine dispersoids of $HfB_{2}$ in the $Fe_{3}B/Nd_{2}Fe_{14}B$ composite magnet. The maximum energy product($(B.H)_{max}$) as well as intrinsic coercivity($_{i}H_{c}$) for the $Nd_{3}Fe_{78.5}B_{18.5}\;+\;1wt.%\;HfB_{2}$ alloy were enhanced by more than 25% $(B.H)_{max}=10\;MGOe,\;_{i}H_{c}=2.5\;kOe)$ due to the addition of $HfB_{2}$ while remanent magntization($B_{r}$) was reduced slightly. Itis deduced that the formation of fine dispersoids will also play a role of magnetic domain pinning.

• Kyungpook Mathematical Journal
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• v.54 no.4
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• pp.521-529
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• 2014

In this paper we derive some optimal convex combination bounds related to arithmetic mean. We find the greatest values ${\alpha}_1$ and ${\alpha}_2$ and the least values ${\beta}_1$ and ${\beta}_2$ such that the double inequalities $${\alpha}_1T(a,b)+(1-{\alpha}_1)H(a,b)<A(a,b)<{\beta}_1T(a,b)+(1-{\beta}_1)H(a,b)$$ and $${\alpha}_2T(a,b)+(1-{\alpha}_2)G(a,b)<A(a,b)<{\beta}_2T(a,b)+(1-{\beta}_2)G(a,b)$$ holds for all a,b > 0 with $a{\neq}b$. Here T(a,b), H(a,b), A(a,b) and G(a,b) denote the second Seiffert, harmonic, arithmetic and geometric means of two positive numbers a and b, respectively.

• The Pure and Applied Mathematics
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• v.6 no.2
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• pp.59-66
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• 1999

We introduce a new class of functions $H_{k}[A,{\;}B]$ described by subordination and we derive a few geometric properties for the class $H_{k}[A,{\;}B]$.

• Progress in Superconductivity and Cryogenics
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• v.19 no.2
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• pp.19-24
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• 2017

Cryogenic milling which is a combined process of low-temperature treatment and mechanical milling was applied to fabricate high critical current density $(J_c)MgB_2$ bulk superconductors. Liquid nitrogen was used as a coolant, and no solvent or lubricant was used. Spherical Mg ($6-12{\mu}m$, 99.9 % purity) and plate-like B powder (${\sim}1{\mu}m$, 97 % purity) were milled simultaneously for various time periods (0, 2, 4, 6 h) at a rotating speed of 500 rpm using $ZrO_2$ balls. The (Mg+2B) powders milled were pressed into pellets and heat-treated at $700^{\circ}C$ for 1 h in flowing argon. The use of cryomilled powders as raw materials promoted the formation reaction of superconducting $MgB_2$, reduced the grain size of $MgB_2$, and suppressed the formation of impurity MgO. The superconducting critical temperature ($T_c$) of $MgB_2$ was not influenced as the milling time (t) increased up to 6 h. Meanwhile, the critical current density ($J_c$) of $MgB_2$ increased significantly when t increased to 4 h. When t increased further to 6 h, however, $J_c$ decreased. The $J_c$ enhancement of $MgB_2$ by cryogenic milling is attributed to the formation of the fine grain $MgB_2$ and a suppression of the MgO formation.

• Journal of the Korean Magnetics Society
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• v.21 no.1
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• pp.15-22
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• 2011

It is necessary to describe the hysteresis characteristics of magnetic material precisely for the analysis or design of system with ferromagnetic materials. Although Preisach model is regarded as the most accurate method to describe the hysteresis characteristics, it is not widely applied to the real systems because of some difficulties. The conventional Preisach model shows the numerical instabilities during the iterative computations because the density distribution obtained from the sets of M-H curves are strongly localized. To remove such numerical instabilities, M-B instead of M-H is adopted as an implementation variable in normal Preisach modeling. The two dimensional computations with hysteresis characteristics by using normal Preisach modeling are tested and the result showed that the modeling by using M-B variables showed better stabilities than M-H variables.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.885-888
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• 1999

This study was carried out to determine the reaction kinetic constant of the dehydration - thermal decomposition of $Na_2B_4O_7{\cdot}10H_2O/Na_2B_4O_7{\cdot}5H_2O$ and to investigate the durability during the repeated use of a chemical heat-storage material and the reproducibility of reaction system. The order of the dehydration reaction was 1st-order. The reaction rate was directly proportional to a partial pressure difference of water steam. The kinetic constant was 0.27 and the reproducibility of dehydration reaction for a kinetic constant and a reaction order was excellent. The activity variation in the durability test of a chemical heat-storage material was within range of ${\pm}5%$ during the repeatedly use in several times.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.1029-1033
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• 1997

Fundamental research of non-isothermic analysis of reaction rate has been carried out for the heat storage system using the thermal decomposition of $Na_2B_4O_7{\cdot}10H_2O$. It was found that the equilibrium temperature of the thermal decomposition reaction was lowered less than 373K in $Na_2B_4O_7{\cdot}10H_2O/Na_2B_4O_7{\cdot}5H_2O$ system, but the heat efficiency was unchanged. The initiation temperature of the reaction was varied from low to high temperature region with heating rate. The reaction order of the dehydration reaction by the thermal decomposition was appeared to be 0.67 by non-isothermic analysis, thereby $Na_2B_4O_7{\cdot}10H_2O$ may be used as a hemical heatstorage material.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.95-103
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• 1992

Laminar natural convection heat transfer from an isothermal rectangular beam attached to horizontal and vertical adiabatic plates has been studied for various aspect ratios of the beam and Grashof numbers. The local Nusselt number was increased with decreasing H/B for the constant beam width, B, and with increasing H/B for the constant beam height, H. The total mean Nusselt number of the vertical type was higher than that of horizontal type in the range of H/B.leq.0.52, but reversed in the H/B>0.52 at constant beam width. The total mean Nusselt number of the horizontal type was generally higher than that of vertical type at constant beam height. The total mean Nusselt number of the vertical type was higher than that of horizontal type in the range of H/B.leq.0.43 at constant wetted perimeter, but reversed in the H/B$\leq$0.43.

• Journal of Life Science
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• v.18 no.4
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• pp.461-466
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• 2008

Transforming growth $factor-{\beta}$ ($TGF-{\beta}$)-dependent apoptosis is important in the elimination of damaged or abnormal cells from normal tissues in vivo. Gadd45b has been known to participate in $TGF-{\beta}-induced$ apoptosis by the activation of p38 kinase. In this report, we show that Gadd45b is an immediate-early response gene for $TGF-{\beta}$ during apoptosis in EpH4 cells. To elucidate the molecular mechanism of $TGF-{\beta}-induced$ Gadd45b gene expression, we cloned the 5'-flanking region of the mouse Gadd45b gene. When transfected into EpH4 cells, this 5'-flanking region conferred promoter activity and inducibility by $TGF-{\beta}$. Deletion analyses demonstrated that the minimal promoter activity was detected in the proximal region 220 bp upstream of the transcription initiation site. We also found that the proximal Gadd45b promoter is activated by $TGF-{\beta}$ through the action of Smad2, Smad3, and Smad4. Finally, we show that the expression of Gadd45b gene by $TGF-{\beta}$ is suppressed in EpRas cells in which $TGF-{\beta}$ could not induce apoptosis, suggesting that Gadd45b may be a crucial target for $TGF-{\beta}-induced$ apoptosis in EpH4 cells.