• Journal of the Korean Institute of Intelligent Systems
• /
• v.19 no.4
• /
• pp.592-594
• /
• 2009

In this paper we consider voting analysis in the political science in connection with $B_n$(or $M_n${0, 1}), the semigroup of the binary relations on X with n elements. We also consider it in connection with $M_n$(F) (or $B_n$(F)), the semigroup of all fuzzy binary relations on X. Also we establish a possibility theorem and an impossibility theorem in voting analysis based on preferences in $B_n$ and $M_n$(F).

• Communications of the Korean Mathematical Society
• /
• v.28 no.4
• /
• pp.669-677
• /
• 2013

In this paper we introduce the notion of NI near-rings similar to the notion introduced in rings. We give topological properties of collection of strongly prime ideals in NI near-rings. We have shown that if N is a NI and weakly pm near-ring, then $Max(N)$ is a compact Hausdorff space. We have also shown that if N is a NI near-ring, then for every $a{\in}N$, $cl(D(a))=V(N^*(N)_a)=Supp(a)=SSpec(N){\setminus}int\;V(a)$.

• The Korean Journal of Food And Nutrition
• /
• v.13 no.6
• /
• pp.553-557
• /
• 2000

Fatty acid composition of frond, spororphyll and stipe of Miyeok (Undaria pinnatifida) were extensively analyzed to evaluate a nutrient significance of n-3 polyenes, n-6 polyenes, ${\gamma}$-linolenic acid (18:3, n-6) and $\alpha$-linolenic acid (18:3, n-3). Polyenes of $\alpha$-linolenic acid (22:6, n-3), stearidonic acid (18:4, n-3), eicosapentaenoic acid (20:5, n-3) and docosahexaenoic acid (22:6, n-3) were as high as 29.69%, but ${\gamma}$-linolenic acid (18:3, n-6) was as low as 0.90% when compared to total polyenes of 44.18% in frond. The n-3 polyenes of neutural lipids, glycolipids and phospholipids were 22.40%, 35.82% and 3.53% in frond, 5.26%, 9.51% and 2.37% in stipe and 8.01%, 4.49% and 2.14% in sporophyll, respectively. These results suggest that total polyenes and n-3 polyenes in frond of Miyeok may be used as resource of functional food.

• Journal of the Korean Mathematical Society
• /
• v.45 no.4
• /
• pp.993-1005
• /
• 2008

Let {$X,\;X_n;n{\geq}1$} be a sequence of i.i.d. random variables. Set $S_n=X_1+X_2+{\cdots}+X_n,\;M_n=\max_{k{\leq}n}|S_k|,\;n{\geq}1$. Then we obtain that for any -1$\lim\limits_{{\varepsilon}{\searrow}0}\;{\varepsilon}^{2b+2}\sum\limits_{n=1}^\infty\;{\frac {(log\;n)^b}{n^{3/2}}\;E\{M_n-{\varepsilon}{\sigma}\sqrt{n\;log\;n\}+=\frac{2\sigma}{(b+1)(2b+3)}\;E|N|^{2b+3}\sum\limits_{k=0}^\infty\;{\frac{(-1)^k}{(2k+1)^{2b+3}$ if and only if EX=0 and $EX^2={\sigma}^2<{\infty}$.

• Bulletin of the Korean Mathematical Society
• /
• v.53 no.4
• /
• pp.959-970
• /
• 2016

In this paper, we generalize the stability for an n-dimensional cubic functional equation in Banach space to set-valued dynamics. Let $n{\geq}2$ be an integer. We define the n-dimensional cubic set-valued functional equation given by $$f(2{{\sum}_{i=1}^{n-1}}x_i+x_n){\oplus}f(2{{\sum}_{i=1}^{n-1}}x_i-x_n){\oplus}4{{\sum}_{i=1}^{n-1}}f(x_i)\\=16f({{\sum}_{i=1}^{n-1}}x_i){\oplus}2{{\sum}_{i=1}^{n-1}}(f(x_i+x_n){\oplus}f(x_i-x_n)).$$ We first prove that the solution of the n-dimensional cubic set-valued functional equation is actually the cubic set-valued mapping in [6]. We prove the Hyers-Ulam stability for the set-valued functional equation.

• Journal of the Korean Chemical Society
• /
• v.16 no.6
• /
• pp.369-372
• /
• 1972

The dissociation constants of dibasic carboxylic acids $(HOOC(CH_2)_nCOOH$, n = 0~4] in methanol, N, N-dimethylformamide and acetonitrile have been determined by the potentiometric method with a glass electrode. The difference between over-all dissociation constants in each other solvent is found to be of the same order of magnitude, and the $K_1/K_2$ ratios in aprotic dimethylformamide and acetonitrile are much greater than those in protic methanol and water.

• Membrane Journal
• /
• v.30 no.4
• /
• pp.252-259
• /
• 2020

Olefins are industrially important materials used for the synthesis of various petrochemicals. During the polymerization process, unreacted olefin monomers are discharged together with a large amount of nitrogen. For economic benefits, these olefin gases should be efficiently separated from nitrogen. In this study, a poly(glycidyl methacrylate-co-methyl methacrylate) (PGM) comb-like copolymer was synthesized and 4,4'-diaminoazobenzene (DAAB) was introduced to the copolymer to prepare a cross-linked membrane for C₃H₆/N₂ separation. PGM and DAAB were readily reacted at room temperature through an epoxide-amine reaction without additional thermal treatment. PGM-based membrane, which is a glassy polymer, showed a faster permeation of N₂ compared to C₃H₆. The pristine PGM membrane exhibited the N₂ permeability of 0.12 barrer and the high N₂/C₃H₆ selectivity of 32.4. As DAAB was introduced as a cross-linker, the thermal stability of the membrane was significantly improved, which was confirmed by TGA result. The N₂/C₃H₆ selectivity was decreased at 1 wt% of DAAB content, but the N₂ permeability increased by approximately 4.7 times. We analyzed N₂/C₃H₆ gas separation properties through a glassy polymer-based membrane, which has not been widely studied. Also, we proposed that thermal stability of the membrane can be greatly improved by the cross-linking method.

• Journal of the Korean Chemical Society
• /
• v.55 no.3
• /
• pp.463-471
• /
• 2011

A novel $N_2O_2$ Schiff base ligand, N,N'-bis(4-methoxysalicylidene)phenylendiamine(4-$CH_3O$-Salphen), has been synthesized. It has been revealed that the compound is very useful for the spectrophotometric quantification of Fe(II) and Fe(III) ions in aqueous solutions, such as mineral water, hot spring water, sea water, and waste water. The optimum conditions for the quantitative analysis are the followings; [4-$CH_3O$-Salphen]=$4.0{\times}10^{-4}\;M$, DMF/$H_2O$=70/30(v/v), pH=3.4~3.8, T= at $55^{\circ}C$, and prereaction time=1.0 hr. The sample of single valence state was prepared by the preliminary oxidation or reduction using $H_2O_2$ ($5.0{\times}10^{-4}\;M$) and $NH_2OH{\cdot}HCl$ ($5.0{\times}10^{-4}\;M$). The quantitative analyses of Fe(II) and Fe(III) ion were performed by measuring the absorbance at 434 nm and 456 nm, respectively. The estimated mean values agreed well with the standard values within the range of 2.00~6.90%. The limit of detection was 27.9 ng/mL for Fe(II) and 55.8 ng/mL for Fe(III).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.11a
• /
• pp.371-374
• /
• 2000

The electrochemical properties of LiM $n_2$ $O_4$as a cathode and an anode for the lithium secondary battery were evaluated. When LiM $n_2$ $O_4$ material was used as the cathode with the current collector of aluminum, the 1st specific capacity and the 1st Ah efficiency in LiM $n_2$ $O_4$/lithium cell were 123 mAh/g and 91.7%, respectively The anodic properties of LiM $n_2$ $O_4$ material was also evaluated in the LiM $n_2$ $O_4$/1ithium cell with the current collector of copper. It showed that the LiM $n_2$ $O_4$ was useful as the anode for the lithium secondary battery. During the 1st discharge, a potential plateau was observed at the potential of 0.3 $V_{Li}$ Li+/. The 1st specific charge capacity and the 1st specific discharge capacity were 790 mAh/s and 362 mAh/g, respectively. Therefore, the 1st Ah efficiency was 46%. The discharge capacity was gradually faded with the charge-discharge cycling to about 50th cycles. Thereafter, the discharge capacity was stabilized to about 110 mAh/g.

• Journal of the Korean Ceramic Society
• /
• v.44 no.4 s.299
• /
• pp.189-193
• /
• 2007

Effect of additive composition on fracture toughness of in situ-toughened $SiC-Si_3N_4$ composites was investigated for five different additive compositions. The highest toughness $(6.4MPa{\cdot}m^{1/2})\;in\;SiC-Si_3N_4$ composites investigated herein was obtained when an Y-Mg-Si-Al-O-N oxynitride glass was used as a sintering additive. The improvement in fracture toughness was produced by enhanced bridging and deflection by $Si_3N_4$ grains.