• 대한지역사회영양학회지
• /
• 제21권6호
• /
• pp.574-579
• /
• 2016

Objectives: Vitamin C has various functions such as antioxidative effect and supporting absorption of iron (Fe). Aim of this present study was to provide vitamin C nutrition information and to briefly evaluate absorption interaction of vitamin C and Fe content of vitamin C emphasized products. Methods: Vitamin C emphasized foods including beverages, cereal, snacks, chocolate products, other cocoa products, and sugary products were examined by HPLC. Fe contents in samples after dry-ashing were examined by ICP. Results: Vitamin C content ranges in various products tested were the following: beverages (n=11) $20.15{\pm}0.08{\sim}845.41{\pm}6.07mg$, cereal (n=11) $52.50{\pm}0.23{\sim}262.50{\pm}0.07mg$, snacks (n=1) $50.00{\pm}0.25mg$, chocolate products (n=1) $311.73{\pm}2.44mg$, other cocoa products (n=1) $311.73{\pm}2.44mg$, other sugary products (n=2) $52.50{\pm}0.23{\sim}262.50{\pm}0.07mg$. Vitamin C (n=27) analysis values ranged from 82 to 450% of the labeled value. Vitamin C content in vitamin C emphasized food (n=6) was estimated 7.7 times~56.6 times more than Fe content. Conclusions: Analyzed samples ranged more than 80% of the labeled value in vitamin C emphasized products, which complied with food labeling regulation. But, beverages (n=3), cereal (n=4), chocolate products (n=1) were 2 times more than the labeled value. To provide accurate nutrition information, food manufactures should supervise nutrition labeling and understand the interactions between nutrients. Also, consumer should decide about the adequate amount of nutrient intake by thoroughly checking nutrition labeling.

• 대한화학회지
• /
• 제55권6호
• /
• pp.905-911
• /
• 2011

[ $C_{60}(CH_2)_nOH$ ](n=0~2)와 $C_{60}(OH)_2$의 가능한 분자구조를 B3LYP/6-311G(d,f) 이론 수준에서 최적화 하였으며, 각 화합물의 가장 안정한 분자구조(global minimum)를 확인하고 결합에너지를 계산하여 구조적 특성에 따른 에너지와의 상호연관성을 고찰하였다. 보다 정확한 상대 에너지를 계산하기 위하여 진동주파수를 계산하여 영점 진동 에너지(zero-point vibrational energy, ZPVE)를 보정하였으며, IR 스펙트럼을 예측하였다. $C_{60}(CH_2)_nOH$ (n=0-2)에서 결합에너지의 경우, $-CH_2OH$기 보다 -OH기가 결합되었을 때 결합에너지가 약 10 kcal/mol 정도 더 안정한 것으로 나타났다.

• Journal of Microbiology and Biotechnology
• /
• 제26권7호
• /
• pp.1290-1302
• /
• 2016

Microalgae are being researched for their potential as attractive biofuel feedstock, particularly for their lipid production. For maximizing biofuel production, it is necessary to explore the effects of environmental factors on algal lipid-producing potential. In this study, the effects of nitrogen (N) sources (NO₂-N, NO₃-N, urea-N, NH₄-N, and N-deficiency) and carbon-to-nitrogen ratios (C/N= 0, 1.0, 3.0, and 5.0) on algal lipid-producing potential of Chlorella sp. HQ were investigated. The results showed that for Chlorella growth and lipid accumulation potential, NO₂-N was the best amongst the nitrogen sources, and NO₃-N and urea-N also contributed to algal growth and lipid accumulation potential, but NH₄-N and N-deficiency instead caused inhibitory effects. Moreover, the results indicated that algal lipid-producing potential was related to C/N ratios. With NO₂-N treatment and carbon addition (C/N = 1.0, 3.0, and 5.0), total lipid yield was enhanced by 12.96-20.37%, but triacylglycerol (TAG) yields decreased by 25.52-94.31%. As for NO₃-N treatment, carbon addition led to a 17.82-57.43%/25.86-82.67% reduction of total lipid/TAG yields. When NH₄-N was used as the nitrogen source, total lipid/TAG yields were increased by 46.67-113.33%/28.99-74.76% with carbon addition. The total lipid/TAG yields of urea-N treatment varied with C/N ratios. Overall, the highest TAG yield (TAG yield: 38.75 ± 5.21 mg/l; TAG content: 44.16 ± 4.35%) was achieved under NO₂-N treatment without carbon addition (C/N = 0), the condition that had merit for biofuel production.

• 대한수학회지
• /
• 제38권3호
• /
• pp.623-631
• /
• 2001

Let $\kappa$ be a real abelian field of conductor f and $\kappa$(sub)$\infty$ = ∪(sub)n$\geq$0$\kappa$(sub)n be its Z(sub)p-extension for an odd prime p such that płf$\phi$(f). he aim of this paper is ot compute the cohomology groups of circular units. For m>n$\geq$0, let G(sub)m,n be the Galois group Gal($\kappa$(sub)m/$\kappa$(sub)n) and C(sub)m be the group of circular units of $\kappa$(sub)m. Let l be the number of prime ideals of $\kappa$ above p. Then, for mm>n$\geq$0, we have (1) C(sub)m(sup)G(sub)m,n = C(sub)n, (2) H(sup)i(G(sub)m,n, C(sub)m) = (Z/p(sup)m-n Z)(sup)l-1 if i is even, (3) H(sup)i(G(sub)m,n, C(sub)m) = (Z/P(sup)m-n Z)(sup l) if i is odd (※Equations, See Full-text).

• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제10권4호
• /
• pp.199-206
• /
• 2003

Let N be a right near-ring. N is said to be strongly reduced if, for $a\inN$, $a^2 \in N_{c}$ implies $a\;\in\;N_{c}$, or equivalently, for $a\inN$ and any positive integer n, $a^{n} \in N_{c}$ implies $a\;\in\;N_{c}$, where $N_{c}$ denotes the constant part of N. We will show that strong reducedness is equivalent to condition (ⅱ) of Reddy and Murty's property $(^{\ast})$ (cf. [Reddy & Murty: On strongly regular near-rings. Proc. Edinburgh Math. Soc. (2) 27 (1984), no. 1, 61-64]), and that condition (ⅰ) of Reddy and Murty's property $(^{\ast})$ follows from strong reducedness. Also, we will investigate some characterizations of strongly reduced near-rings and their properties. Using strong reducedness, we characterize left strongly regular near-rings and ($P_{0}$)-near-rings.

• KSBB Journal
• /
• 제20권4호
• /
• pp.266-270
• /
• 2005

탄소원과 질소원의 무게비가 Thraustochytrium aureum ATCC 34304의 성장 및 지방산 조성에 미치는 영향을 규명하였다. 초기 당농도에 관계없이 배양 5일 후의 균체농도는 C/N 값이 증가하면 증가하였다가 감소하였다. 각 초기 당 농도에 따라서, 균체농도가 최대가 되는 C/N의 비는 각기 고유한 값을 나타내었다. 초기 당농도 5 g/L 내지 25 g/L 범위내에서 균체농도가 최대가 되는 C/N 값은 1 내지 4 사이에 분포하였다. C/N 비에 따른 균체수율 $Y_{x/s}$의 값은 C/N의 값이 증가하면 감소하였으나 10 내지 20 사이의 범위에서는 0.35 의 일정한 값을 유지하였다. T. aureum ATCC 34304가 생합성하는 포화지방산인 미리스트산의 조성은 C/N 비의 변화에 영향을 받지 않았으나 팔미트산의 조성은 C/N 값 4 이하에서는 $20\%$ 내외의 값을 나타내었고 C/N 값이 증가하면 $15\%$까지 감소하였다. 탄소수사 18개인 $C_{18:}$의 지방산 중 올레인산 $(C_{18:1})$과 리놀레인산 $(C_{18:2})$의 조성은 C/N 값이 증가하면 $0\%$에서 각각 $20\%$ 및 $7\%$까지 지속적으로 증가하였다. 반면 $\gamma$-리놀레인산 $(C_{18:3})$의 조성은 C/N 값의 증가에 따라 $5\%$에서 $2\%$까지 감소하였다. 탄소수가 20개 이상인 $\omega-3$ 다중불포화 지방산 중 EPA $(C_{20:5})$와 DPA $(C_{22:5})$의 조성은 C/N 값의 증가에 따라 감소하는 경향을 나타내었으며, DHA $(C_{22:6})$ 조성은 C/N 값이 증가하더라도 $40\%$ 내외의 간을 유지하였다.

• 대한수학회논문집
• /
• 제30권2호
• /
• pp.65-72
• /
• 2015

The minimum rank mr(G) of a simple graph G is defined to be the smallest possible rank over all symmetric real matrices whose (i, j)-th entry (for $i{\neq}j$) is nonzero whenever {i, j} is an edge in G and is zero otherwise. The corona $C_n{\circ}K_t$ is obtained by joining all the vertices of the complete graph $K_t$ to each n vertex of the cycle $C_n$. For any t, we obtain an upper bound of zero forcing number of $L(C_n{\circ}K_t)$, the line graph of $C_n{\circ}K_t$, and get some bounds of $mr(L(C_n{\circ}K_t))$. Specially for t = 1, 2, we have calculated $mr(L(C_n{\circ}K_t))$ by the cut-vertex reduction method.

• 한국재료학회지
• /
• 제1권1호
• /
• pp.9-17
• /
• 1991

화학증착법에 의해 $Si_3N_4-TiC$ 복합재료 위에 코팅된 TiC 박막은 TiN 박막에 비하여 우수한 미세구조와 열충격저항, 계면결합을 가지고 있는 것으로 나타났다. 화학증착법에 의한 TiN 박막은 TiC 박막에 비해 강철과의 마찰계수가 작고 화학적으로 안정하였다. 실험결과는 코팅된 절삭공구가 우수한 내 마모성을 갖고 있는 것으로 나타났다. 또한, 다중 코팅된 절삭공구는 단일 코팅된 공구보다 우수한 내 마모성을 보였다

• Journal of Applied Biological Chemistry
• /
• 제51권6호
• /
• pp.262-271
• /
• 2008

Natural abundances of stable isotopes of nitrogen and carbon (${\delta}^{15}N$ and ${\delta}^{13}C$) are being widely used to study N and C cycle processes in plant and soil systems. Variations in ${\delta}^{15}N$ of the soil and the plant reflect the potentially variable isotope signature of the external N sources and the isotope fractionation during the N cycle process. $N_2$ fixation and N fertilizer supply the nitrogen, whose ${\delta}^{15}N$ is close to 0%o, whereas the compost as. an organic input generally provides the nitrogen enriched in $^{15}N$ compared to the atmospheric $N_2$. The isotope fractionation during the N cycle process decreases the ${\delta}^{15}N$ of the substrate and increases the ${\delta}^{15}N$ of the product. N transformations such as N mineralization, nitrification, denitrification, assimilation, and the $NH_3$ volatilization have a specific isotope fractionation factor (${\alpha}$) for each N process. Variation in the ${\delta}^{13}C$ of plants reflects the photosynthetic type of plant, which affects the isotope fractionation during photosynthesis. The ${\delta}^{13}C$ of C3 plant is significantly lower than, whereas the ${\delta}^{13}C$ of C4 plant is similar to that of the atmospheric $CO_2$. Variation in the isotope fractionation of carbon and nitrogen can be observed under different environmental conditions. The effect of environmental factors on the stomatal conductance and the carboxylation rate affects the carbon isotope fractionation during photosynthesis. Changes in the environmental factors such as temperature and salt concentration affect the nitrogen isotope fractionation during the N cycle processes; however, the mechanism of variation in the nitrogen isotope fractionation has not been studied as much as that in the carbon isotope fractionation. Isotope fractionation factors of carbon and nitrogen could be the integrated factors for interpreting the effects of the environmental factors on plants and soils.

• Bulletin of the Korean Chemical Society
• /
• 제33권7호
• /
• pp.2287-2294
• /
• 2012

Deep blue fluorescent host materials based on a novel spiro[benzo[c]fluorene-7,9'-fluorene] core structure with side aromatic wings in the 5- and 9-positions, namely, 5,9-di(naphthalen-2-yl)spiro[benzo[c]fluorene-7,9'-fluorene] (DN-SBFF), 5,9-bis(4-t-butylphenyl)spiro[benzo[c]fluorene-7,9'-fluorene] (BP-SBFF), and 5,9-bis(4-fluorophenyl)spiro[benzo[c]fluorene-7,9'-fluorene] (FP-SBFF), were designed and successfully prepared using the Suzuki reaction. The physical properties of these materials and their EL characteristics as blue host materials doped with N,N,N',N'-tetraphenylspiro[benzo[c]fluorene-7,9'-fluorene]-5,9-diamine (TPA-SBFF) were investigated. The device used comprised ITO/N,N'-diphenyl-N,N'-bis[4-(phenyl-m-tolyl-amino)phenyl]-biphenyl-4,4'-diamine (DNTPD)/N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine (NPB)/(FP-SBFF):dopant x%/tris(8-hydroxyquinoline)aluminum ($Alq_3$)/LiF. The device obtained using FP-SBFF doped with TPA-SBFF showed high color purity (0.13, 0.18) and an efficiency of 6.61 cd/A at 7 V.