• Macromolecular Research
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• 제8권3호
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• pp.137-141
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• 2000

3,4-Di-(2'-hydroxyethoxy)-4-nitrostilbene (2) was prepared by the reaction of 2-iodoethanol with 3,4-dihydroxy-4-nitrostilbene (1). Diol 2 was condensed with 2,4-toluenediisocyanate ,3,3-dimethoxy-4,4'-biphenylenediisocyanate , and 1,6-hexamethylenediisocyanate to yield polyurethanes 3, 4, and 5 containing the NLO-chromophore. Polymers 3-5 were soluble in common organic solvents such as acetone and DMSO. The glass transition temperatures(T$\sub$g/) of the resulting polymers 3-5 were obseved around 100-114$^{\circ}C$. Electrooptic coefficients (r$\sub$33/) of the poled polymer films were in the range of 18-25 pm/V at 633 nm. Polymers 3-5 began to decompose around 250$^{\circ}C$ in TGA thermograms.

• Natural Product Sciences
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• 제28권2호
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• pp.53-57
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• 2022

As part of our continued study on the chemical constituents of Willughbeia edulis stems, a new dimeric lignan named edulignan (1) was isolated from its EtOAc-soluble extract. Based on NMR spectroscopic interpretation, the planar structure of 1 has been suggested to have two 2-substituted 4-chromanone subunits with different stereochemical configurations. In addition, the MS/MS analysis of the products obtained by acid-catalyzed hydrolysis of 1 was supportive of its structure. Unfornatually, the new compound 1 did not show 𝛼-glucosidase inhibitory activity with an IC₅₀ value > 250 𝜇M.

• Kyungpook Mathematical Journal
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• 제63권2호
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• pp.167-173
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• 2023

Let G be a finite group and let ν(G) be the probability that two randomly selected elements of G produce a nilpotent group. In this article we show that for every positive integer n > 0, there is a finite group G such that ${\nu}(G)={\frac{1}{n}}$. We also classify all groups G with ${\nu}(G)={\frac{1}{2}}$. Further, we prove that if G is a solvable nonnilpotent group of even order, then ${\nu}(G){\leq}{\frac{p+3}{4p}}$, where p is the smallest odd prime divisor of |G|, and that equality exists if and only if $\frac{G}{Z_{\infty}(G)}$ is isomorphic to the dihedral group of order 2p where Z_∞(G) is the hypercenter of G. Finally we find an upper bound for ν(G) in terms of |G| where G ranges over all groups of odd square-free order.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3665-3676
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• 2023

The use of ion exchange resins to remove ionic impurities from solution is prevalent in industrial process systems, including in the primary heat transport system (PHTS) purification circuit of nuclear power plants. Despite its extensive use in the nuclear industry, our general understanding of ion exchange cannot fully explain the complex chemistry in ion exchange beds, particularly when operated at or near their saturation limit. This work investigates the behaviour of mixed-bed ion exchange resin, saturated with species representative of corrosion products in a CANDU (Canadian Deuterium Uranium) reactor PHTS, particularly with respect to iron chemistry in the resin bed and the removal of lithium ions from solution. Experiments were performed under deaerated conditions, analogous to normal PHTS operation. The results show interesting iron chemistry, suggesting the hydrolysis of cation resin bound ferrous species and the subsequent formation of either a solid hydrolysis product or the soluble, anionic Fe(OH)₃^-.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3808-3814
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• 2023

The thermal stability of nitric acid solutions after contact with non-irradiated and irradiated tributyl phosphate (TBP) and its solution in Isopar-M has been studied. It has been established that exothermic processes occur during heating due to the interaction of soluble radiolysis products and the decomposition of the extractant with nitric acid. Such processes can occur at temperatures below 100 ℃, but unlike a thermal explosion that occurs in seconds, they are longer in time and are accompanied by weak heat evolution. Their intensity depends on the composition of the extractant, the concentration of HNO₃, and the volume ratio of the organic and aqueous phases. The presence of extractant degradation products in raffinates does not pose a risk of a rapid evolution of gaseous products during evaporation, however, the presence of reducing agents can significantly increase the intensity of the exothermic decomposition of raffinates.

• 한국토양비료학회지
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• 제1권1호
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• pp.1-5
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• 1968

수량(收量)이 낮은 답토양(畓土壤)에 역분해성(易分解性) 유기물(有機物)로서 Soluble Starch를 첨가(添加)하여 $30{\pm}2^{\circ}C$에서 21 일간(日間) 담수(湛水) Incubation 하면서 토양(土壤)의 pH, Eh 변화(變化), 수용성(水溶性) Fe, Mn 및 $SiO_2$의 용출량(溶出量)을 조사(調査) 연구(硏究)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 유기물(有機物)을 첨가(添加)할 경우(境遇)에는 유기물(有機物)을 처리(處理)하지 않았을때 보다 초기(初期) 1주일간(週日間) Eh는 200mv 더 낮아 환원(還元)이 심(甚)하였다. 2. pH는 무처리(無處理)에서는 담수초기(湛水初期) 약간 하강(下降)하는 경향(傾向)이다가 계속(繼續) 상승(上昇)하여 pH 6.0 정도(程度)를 유지하였으나 유기물처리시(有機物處理時)에는 초기(初期)에는 급격(急激)한 환원(還元)에 의(依)해 pH가 상승(上昇)하였다가 7 일후(日後)에는 떨어져서 계속(繼續) pH 4.5 정도(程度)를 유지(維持)하였다. 3. 유기물(有機物)을 처리(處理)하지 않았을때는 수용성(水溶性) Fe, Mn 및 $SiO_2$는 담수환원(湛水還元)에 의(依)하여 약간 증가(增加)를 보이고 있으나 유기물처리시(有機物處理時)에는 수용성(水溶性) Fe는 약(約) 20배(倍), Mn 약(約) 10배(倍) $SiO_2$는 3배정도(倍程度)로 증가(增加)하였다. 4. 유기물(有機物) 처리시(處理時)에 수용성(水溶性) Mn 및 $SiO_2$의 용출량(溶出量)은 pH와 유의적(有意的)인 상관관계(相關關係)([$H^+$] & Mn ${\gamma}=0.734^{**}$, [$H^+$] & $SiO_2$ ${\gamma}=0.750^{**}$)가 있었으며 pH5.0 이하(以下)에서 용출량(溶出量)이 급증(急增)하였다.

• Animal Bioscience
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• 제35권12호
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• pp.1892-1903
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• 2022

Objective: A series of experiment were conducted to evaluate the effects of replacing a part of soybean meal (SBM) at 6% of broiler diets with fermented soybean meal (FSBM) obtained by single or two-stage fermentation by measuring growth performance, antioxidant activity in the jejunum and distal intestinal microflora. Methods: Soybean meal samples were prepared by single-stage fermentation using Bacillus velezensis (Bv) (FSBM_B), or Lactobacillus spp. (as commercial control) (FSBM_L). Additional SBM sample was prepared by two-stage fermentation using Bv and subsequently using Lactobacillus brevis ATCC 367 (Lb) (FSBM_B+L). Enzyme activity, chemical composition, trichloroethanoic acid-nitrogen solubility index (TCA-NSI) and antioxidant activity were measured. Then, in an in vivo study, 320 Ross308 broilers were divided into four groups with ad libitum supply of feed and water. Four groups were fed either a corn-soybean meal diet (SBM), or one of fermented SBM diets (FSBM_B+L, FSBM_B, and FSBM_L). Growth, serum characteristics, microflora, and the mRNA expression of selected genes were measured. Results: Compared to SBM, FSBM_B+L contained lower galacto-oligosaccharide, allergic protein, and trypsin inhibitor, and higher TCA-NSI by about three times (p<0.05). Reducing power and 1,1-diphenyl-2-picrylhydrazyl free radical scavenging ability correlated positively with the TCA-NSI content in FSBM. Growth performances were not significantly different among four groups. In jejunum of 35-day-old broilers, partial replacement of SBM by FSBM_B+L increased the activity of superoxide dismutase and catalase (CAT), and the FSBM_B group had the highest catalase activity (p<0.05). Partial replacement of SBM by FSBM increased relative mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and peptide transporter 1 (PepT1) (p<0.05); however, FSBM_B+L increased CAT mRNA level to 5 times of the control (p<0.05). Conclusion: Using Bv- and Lb-processed SBM through two-stage fermentation to partially replace 6% of diets will improve the gut's antioxidant activity under commercial breeding in broilers.

• 생약학회지
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• 제46권3호
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• pp.234-242
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• 2015

Allium hookeri (Liliaceae), native to India is widely cultivated in Korea lately as a medicinal plant. This study was performed to evaluate the antioxidant and lifespan extending effects of the root of A. hookeri. Methanol extract from the root of A. hookeri was successively partitioned as methylene chloride, ethyl acetate, n-butanol and H₂O soluble fractions. Antioxidant effects of the fractions were measured by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH), and superoxide quenching activities. Lifespan extending effects of the fractions were investigated using Caenorhabditis elegans model system. In addition, stress resistant, superoxide dismutase (SOD) and catalase activities, and intracellular reactive oxygen species (ROS) levels were also studied. Furthermore, we had investigated aging-related factors such as reproduction, food intake, growth and movement of C. elegans to find any sample-induced significant change. Our results revealed that ethyl acetate soluble fraction from the root of A. hookeri showed the most potent antioxidant and lifespan extending effects, and this fraction elevated the most potent SOD and catalase activities of worms, and reduce intracellular ROS accumulation.

• 한국환경과학회지
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• 제7권5호
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• pp.707-716
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• 1998

The chemical characteristics of precipitation was investigated in Pusan area. Samples were collected from January to November in 1996 at 4 sites, and analyzed pH, major soluble ionic components(C $l^{[-10]}$ , N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$, N $a^{+}$, $K^{+}$, N $H_4$$^{+}$, $Mg^{2+}$, $Ca^{2+}$). The order of anion and cation concentrations for the initial precipitation were C $l^{[-10]}$ ＞ S $O_4$$^{2-}$ ＞ N $O_3$$^{[-10]}$ , and $Ca^{2+}$ ＞ N $a^{+}$ ＞ N $H_4$$^{+}$ ＞ $Mg^{2+}$ ＞ $K^{+}$, respectively. At coastal sites(P1 and P2) C $l^{[-10]}$ and N $a^{+}$ of maritime sources (seasalt) were high, but at inland sites(P3 and P4) nss-C $a^{2+}$ and nss-S $O_4$$^{2-}$ were high. Calcium ion for the initial precipitation showed high value of enrichement factor(EF) relative to seawater composition. The contribution of seasalt to the composition of precipitation was higher at bite P1 (53.5%) than those of the other sites. Throughout the year the concentrations of major ions for the initial precipitation were low in the heavy rain season. The mean pH for the initial precipitation was 5.4 and showed the negative relationship with the precipitaion amount. The S $O_4$$^{2-}$ and N $O_3$$^{[-10]}$ do not play an important role in rain acidification due to the high(97%) neutralizing effect of amonia and calcium species.and calcium species.

• 한국식품영양학회지
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• 제33권5호
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• pp.576-583
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• 2020

The purpose of this study was to compare the quality characteristics of silken tofu products from the commercial market in Korea. Seven types of commercial silken tofu were sampled and their physicochemical properties, including soluble solid contents, salinity, pH, total acidity, moisture contents (total solid contents), crude protein and fat contents were evaluated. The TPA results suggest that the texture of silken tofu was very different from one another according to the type of and the amount of coagulant. The commercial silken tofu showed a range of pH 5.53~6.48, total acidity of 0.12~0.32%, soluble solid contents of 2.62~5.07 °Brix, salinity of 2.28~4.30%, and moisture contents of 87.10~92.24%, respectively. In terms of the coagulant of tofu, besides the GDL (glucono-δ- lactone), other coagulants such as MgCl₂ for making 'silken tofu' in the Korean tofu market. The quality characteristics differed depending on the constituents of sample and the coagulants of tofu used. These results are expected to be useful in identifying new trends in the domestic silken tofu industry.