• Korean Journal of Mathematics
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• v.18 no.4
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• pp.395-407
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• 2010

In this paper, we prove the generalized Hyers-Ulam stability of the following quadratic functional equations $$cf\(\sum_{i=1}^{n}x_i\)+\sum_{j=2}^{n}f\(\sum_{i=1}^{n}x_i-(n+c-1)x_j\)\\=(n+c-1)\(f(x_1)+c\sum_{i=2}^{n}f(x_i)+\sum_{i<j,j=3}^{n}\(\sum_{i=2}^{n-1}f(x_i-x_j\)\),\\Q\(\sum_{i=1}^{n}d_ix_i\)+\sum_{1{\leq}i<j{\leq}n}d_id_jQ(x_i-x_j)=\(\sum_{i=1}^{n}d_i\)\(\sum_{i=1}^{n}d_iQ(x_i)\)$$ in random normed spaces.

• Communications of the Korean Mathematical Society
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• v.10 no.4
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• pp.875-880
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• 1995

Let $S_p(\alpha)$ denote the class of the Spirallike functions of order $\alpha, 0 < $\mid$\alpha$\mid$ < \frac{\pi}{2}$ Let $\Pi_N$ denote the subset of $S_p(\alpha)$ consisting of all products $z\Pi^N_{j=1}(1-u_j z)^{-mt_j}$ where $m = 1 + e^{-2i\alpha},$\mid$u_j$\mid$ = 1, t_j > 0$ for $j = 1, \cdots, N$ and $\sum^{N}_{j=1}{t_j = 1}$. In this paper we prove that extreme points of $S_p(\alpha)$ may be found which lie in $\Pi_N$ for some $N \geq 2$. We are let to conjecture that all exreme points of $S_p(\alpha)$ lie in $\Pi_N$ for somer $N \geq 1$ and that every such function is an extreme point.

• Progress in Superconductivity and Cryogenics
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• v.15 no.1
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• pp.45-50
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• 2013

Closed-loop J-T (Joule-Thomson) refrigeration cycle is advantageous compared to common open loop $N_2$ decompression system in terms of nitrogen consumption. In this study, two closed-loop pure $N_2$ J-T refrigeration systems with sub-atmospheric device for cooling High Temperature Superconductor (HTS) power cable are investigated. J-T cooling systems include 2-stage compressor, 2-stage precooling cycle, J-T valve and a cold compressor or an auxiliary vacuum pump at the room temperature. The cold compressor and the vacuum pump are installed after the J-T valve to create sub-atmospheric condition. The temperature of 67 K is possible by lowering the pressure up to 24 kPa at the cold part. The optimized hydrocarbon mixed refrigerant (MR) J-T system is applied for precooling stage. The cold head of precooling MR J-T have the temperature from 120 K to 150 K. The various characteristics of cold compressor are invstigated and applied to design parameter of the cold compressor. The Carnot efficiency of cold compressor system is calculated as 16.7% and that of vacuum pump system as 16.4%. The efficiency difference between the cold compressor system and the vacuum pump system is due to difference of enthalpy change at cryogenic temperature, enthalpy change at room temperature and different work load at the pre-cooling cycle. The efficiency of neon-nitrogen MR J-T system is also presented for comparison with the sub-atmospheric devices. These systems have several pros and cons in comparison to typical MR J-T systems such as vacuum line maintainability, system's COP and etc. In this paper, the detailed design of the subcooled $N_2$ J-T systems are examined and some practical issues of the sub-atmospheric devices are discussed.

• The Bulletin of The Korean Astronomical Society
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• v.32 no.2
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• pp.64.2-64.2
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• 2007

• Archives of Pharmacal Research
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• v.17 no.3
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• pp.194-198
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• 1994

The antitumor effects of the 2E4 and anti--Tac, monoclonal antibodies directed to Il-2 receptor (IL-2R) conjugated with .alpha.-particle emitting radionuclide bismuth-212., were compared. The $^{212}Bi-2E4$ demonstratedspecific cytotocicity to EL4J3, 4, a I$L-2R^+$ cell line, than to EL4J, a $IL-2R^-$ cell line in thymidine incorporation assy. TEX>$^{212}Bi-2E4$ exerted the maximal antitumor effect in that % T/C in C57BL/6 mice implanted with EL4J3.4 ascitic tumor was 331% at the concentration of $50{\;}{\mu}Ci$, while that of $^{212}Bi-anti-Tac$ was 258% at $100{\;}{\mu}Ci$.

• Bulletin of the Korean Mathematical Society
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• v.50 no.3
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• pp.983-991
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• 2013

For each real number $n$ > 6, we prove that there is a sequence $\{pk(n,z)\}^{\infty}_{k=1}$ of fourth degree self-reciprocal polynomials such that the zeros of $p_k(n,z)$ are all simple and real, and every $p_{k+1}(n,z)$ has the largest (in modulus) zero ${\alpha}{\beta}$ where ${\alpha}$ and ${\beta}$ are the first and the second largest (in modulus) zeros of $p_k(n,z)$, respectively. One such sequence is given by $p_k(n,z)$ so that $$p_k(n,z)=z^4-q_{k-1}(n)z^3+(q_k(n)+2)z^2-q_{k-1}(n)z+1$$, where $q_0(n)=1$ and other $q_k(n)^{\prime}s$ are polynomials in n defined by the severely nonlinear recurrence $$4q_{2m-1}(n)=q^2_{2m-2}(n)-(4n+1)\prod_{j=0}^{m-2}\;q^2_{2j}(n),\\4q_{2m}(n)=q^2_{2m-1}(n)-(n-2)(n-6)\prod_{j=0}^{m-2}\;q^2_{2j+1}(n)$$ for $m{\geq}1$, with the usual empty product conventions, i.e., ${\prod}_{j=0}^{-1}\;b_j=1$.

• Communications of the Korean Mathematical Society
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• v.19 no.2
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• pp.211-217
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• 2004

In a ring $R_n(K,\;J)$ where K is a commutative ring with identity and J is an ideal of K, all prime ideals of $R_n(K,\;J)$ are of the form either $M_n(P)\;o;R_n(P,\;P\;{\cap}\;J)$. Therefore there is a one to one correspondence between prime ideals of K not containing J and prime ideals of $R_n(K,\;J)$.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.275-280
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• 2001

Bacteriocin J105 is a proteinaceous inhibitory substance produced by Latococcus latis subsp. lactis j105 isolated from Kimchi. Bacteriocin J105 was purified to homogeneity by the pH-dependent adsorption-desorption method and reverse-phase HPLC from the culture broth of Lactococcus lactis subsp. lactis J105. Purification of bacteriocin J105 resulted in a 1.47-fold increase in the specific activity and the recovery was 1.5%. Its molecular mass measured by the electrophoretic pattern in the sodium, dodecyl sulfate polyacrylamide gel was about 3.4 kDa. It was stable at $121^{\circ}C$ for 15 min at pH between 2 and 4. However, at pH above 5, bacteriocin was rapidly inactivated. Twenty-one residues from the N-terminal portion of bacteriocin J105 were sequenced using sequence analysis of lantibiotics. Bacteriocin J105 showed significant homology with known nisin A from lactic acid bacteria.

• Korean Journal of Poultry Science
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• v.19 no.1
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• pp.35-45
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• 1992

This study was carried out to investigate the effect of different dose of 312nm UV irradiation on ash and phosphorus contents in metatarsus of broiler chicks, whose dorsal skins were exposed to the UV light. Day old Hubbard line broiler chicks were fed with vitamin D deficient diet for 3 weeks and the defeathered dorsal skins were exposed to different dise (0.32, 0.65, or 0.98 J/$\textrm{cm}^2$) of 312nm UV light. The metatarsus bones were collected on 0, 1, 2, 3, 4 or 5 days after irradiation and defatted, dried, ashed and dissolved in 6N-HCI. The P concentrations were determined by spectrophotometry. When the 0.32 J/$\textrm{cm}^2$ dose was applied, the ash contents in metatarsus bones o( chicks were 42, 46 and 40% on 0, 1 and 3 days after irradiation, respectively. The maximum level, 46% was appeared at 2 days after exposure as 0.65 J/$\textrm{cm}^2$ was treated. When 0.98 J/$\textrm{cm}^2$ irradiation was applied, the high concentrations, 47 and 47% were shown on 1 and 2 days after irradiation, respectively. The 0.98 J/$\textrm{cm}^2$ among three levels of dose increased the most amount of ash in metatarsus bone. In respect to the P content in the chick bone the increased level, 19.4% was shown on 3 days after UV treatment with 0.32 J/$\textrm{cm}^2$. The maximum levels, 18.1 and 20.0% were present on 3 and 2 days after exposure to the 0.65 and 0.98 J/$\textrm{cm}^2$ of UV dose, respectively. It was shown that the higher dose of UV irradiation increased the more P concentration in matatarsus of chicks and the production rate was faster than those from 0.32 and 0.65 J/$\textrm{cm}^2$ treatments.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.1
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• pp.79-88
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• 2002

13%Cr martensitic stainless steel has been used mainly with a material for fish pre-processing machinery. However, it has not very nice cutting section because of little of the carbon content. Therefore, SUS420J2 steel that contents 0.3%C with high-strength in spite of the rust is used with a material for fish pre-processing machinery. However, studies on the corrosion characteristics of SUS420J2 steel are relatively rare. Especially, the corrosion phenomenon may cause serious degradation because the fish pre-processing machinery is exposed always to seawater environment. In this paper, the immersion corrosion test was carried out at seawater environment (pH=7.52) on SUS420J2 steel specimens that have various post-treatment conditions and its corrosion characteristics were evaluated. From test results, the specimens such as base metal, vacuum heat treatment, electrolytic polishing and tempering after quenching tend somewhat sensitive from the corrosion. In the case of vacuum heat treatment specimen of continuous immersion during 360 days, the weight loss ratio was high about seven times when compared with the different specimens. On the contrary, SUS420J2 steel specimen that has the heat treatment of tempering after quenching and the electrolytic polishing was less sensitive from the corrosion, and the weight loss ratio was very low.