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Derivation of the Extended Elastic Stiffness Formula of the Holddown Spring Assembly Comprised of Several Leaves

  • Song, Kee-Nam;Kang, H.S.;Yoon, K.H.
    • Nuclear Engineering and Technology
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    • v.31 no.3
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    • pp.328-334
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    • 1999
  • Based on the Euler beam theory and the elastic strain energy method, the elastic stiffness formula of the holddown spring assembly consisting of several leaves was previously derived. Even though the previous formula was known to be useful to estimate the elastic stiffness of the holddown spring assembly, recently it was reported that the elastic stiffness from the previous formula deviated greatly from the test results as the number of leaves was increased. The objective of this study is to extend the previous formula in order to resolve such an increasing deviation when increasing the number of leaves. Additionally, considering the friction forces acting on the interfaces between the leaves, we obtained an extended elastic stiffness formula. The characteristic test and the elastic stiffness analysis on the various kinds of specimens of the holddown spring assembly have been carried out; the validity of the extended formula has been verified by the comparison of their results. As a result of comparisons, it is found that the extended formula is able to evaluate the elastic stiffness of the holddown spring assembly within the maximum error range of + 12%, irrespective of the number of the leaves.

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The Economic Benefits of Breastfeeding (모유수유의 경제적 효과)

  • 현태선;김기남;강남미;임은영
    • Korean Journal of Community Nutrition
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    • v.7 no.6
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    • pp.863-871
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    • 2002
  • To compare the costs incurred by infant feeding between mothers who breastfed their infants and those who fed them infant formula, a questionnaire survey was carried out to 136 mothers living in Seoul, Cheongju and Chungju who breastfed and 199 mothers who formula-fed their infants. The cost of formula-feeding was estimated based on the expenditures for formula and feeding apparatus, and the time needed to wash bottles and prepare formula. The cost of breastfeeding was estimated based on the expenditures for food for the additional nutritional intake of these mothers. The mean cost of formula-feeding was ₩ 1,870,125 during the first year of the baby's life. The food cost for the additional nutritional intake of the breastfeeding mothers was ₩ 203.004 per year. The extra medical cost for respiratory illnesses in the formula-fed group compared to the breastfed group was W 62,920 because the formula-fed infants required medical attention for respiratory illnesses more often than the breast-fed infants. Therefore, breastfeeding could save ₩ 1,730,041 during the first year of an infant's life. We may have underestimated the cost savings from breastfeeding because we did not take into account the potentially decreased costs of fertility control and the health benefits for mothers. as well as the decreased usage of water and gas. Analyses showed that breastfeeding is not only nutritionally advantageous, but also economically advantageous for families and society.

AN INTEGRAL FORMULA AND ITS APPLICATIONS

  • Chai, Y.-D;Kim, Moonjeong
    • Bulletin of the Korean Mathematical Society
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    • v.39 no.1
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    • pp.89-95
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    • 2002
  • In this paper, we obtain an integral formula relating the measure of great spheres $S^{n-2}$ and arc length of a curve on the unit sphere $S^{n-1$ As an application of the formula, we develop a geometric inequality for a spherical curve and prone generalized version of Fenchel's theorem in $S^n$.

EXPLICIT MINIMUM POLYNOMIAL, EIGENVECTOR AND INVERSE FORMULA OF DOUBLY LESLIE MATRIX

  • WANICHARPICHAT, WIWAT
    • Journal of applied mathematics & informatics
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    • v.33 no.3_4
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    • pp.247-260
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    • 2015
  • The special form of Schur complement is extended to have a Schur's formula to obtains the explicit formula of determinant, inverse, and eigenvector formula of the doubly Leslie matrix which is the generalized forms of the Leslie matrix. It is also a generalized form of the doubly companion matrix, and the companion matrix, respectively. The doubly Leslie matrix is a nonderogatory matrix.

A FEW CLASSES OF INFINITE SERIES IDENTITIES FROM A MODULAR TRANSFORMATION FORMULA

  • Lim, Sung Geun
    • Journal of the Chungcheong Mathematical Society
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    • v.35 no.4
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    • pp.277-295
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    • 2022
  • The author proved a modular transformation formula for a function related to generalized non-holomorphic Eisenstein series and, using this formula, established a lot of infinite series identities. In this paper, we find more generalized series relations which contain the author's previous work.

A Longitudinal Study of Calcium and Phosphorus Intakes of Korean Infants from 1 to 3 Months in Breast-Fed vs Formula-Fed Infants (모유영양아와 인공영양아의 칼슘과 인의 섭취상태에 관한 종단적 연구)

  • 구재옥;최경숙
    • Korean Journal of Community Nutrition
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    • v.5 no.2
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    • pp.273-279
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    • 2000
  • This study was carried out to evaluate the calcium and phosphorus intakes and correlation with growth performance of 25male breast and formula-fed infants from 1 to 3 months postpartum. There were four groups breast-fed(BF) and three formula-fed groups(FFM, FFN and FFP). There was no significant difference in the height and weight of infants according to feeding methods and formula brands. Milk intake and the concentration of calcium and phosphorus from human milk and the formulas were measured. The average calcium content of human milk was 26.6$\pm$4.1mg/dl and 13.5$\pm$2.0mg/dl, respectively. The average calcium intakes of the brest-fed and formula-fed infants were 205.5$\pm$29.3mg/day and the 460.5$\pm$70.6mg/day, respectively the average calcium intake of breast-fed infants was significantly lower than that of formula fed infant. The percent of RDA(41%) of breast-fed infants was lower than that(75.4%) of formula fed infant. The average phosphorus intake of the brest-fed and formula-fed infants were 105.1$\pm$20.1mg/day and 288.3$\pm$37.3mg/day, respectively. The precent of RDA(27%) for brest fed was significantly lower than that(75.4%) of formula fed. The Ca/P ratios were 2.1 in brest fed and 1.6 in formula fed infant. The average calcium and phosphorus intakes of the formula fed infants was higher than that of the brest-fed infants. This data suggests the calcium and phosphorus intakes form human milk sufficiently support the growth of infants. Therefore, the level of calcium and phosphorus recommended dietary allowances for infants should be reduced.

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Studies on Semisolid Infant Foods (I) - Formulation and Their Nutritive Values - (반고체 이유(離乳) 보충식(補充食)에 관한 연구(硏究) (I)- Formulation과 그 영양가(營養價) 분석(分析) -)

  • Yoon, Suk-Kyong;Lee, Young-Chun
    • Journal of Nutrition and Health
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    • v.18 no.1
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    • pp.46-54
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    • 1985
  • Three types of infant food were experimentally prepared based on the average caloric requirement for, Koreans : Formula A, with 1/3 RDA for 4-6 month, formula B, with 1/2 RDA for 7-9 month, and formula C, with 2/3 RDA for 10-12 month old infants. Into each formula was added approximately 50% of rice. Analysis of the nutritive values on these formula showed no deviance Com the expected values in case of general nutrients while the percent of essential amino acids in protein was muck higher except methionine. Since iron content was found to be below the half of except values, a sufficient amount of iron as required in RDA should be additionally supplied, for example, in iron drops. The infant preference test on each formula showed much favorable acceptability : 50% of them responded as moderate, 33.3% as favorable, 12.5% as disliking, and 4.2% as disgusting. The test also showed no noticeable change in both feces and appetite.

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