• Title/Summary/Keyword: X8

Search Result 8,976, Processing Time 0.044 seconds

Kinetics and Mechanism for the Reactions of N-Methyl-N-phenylcarbamoyl Chlorides with Benzylamines in Acetonitrile

  • 고한중;이호찬;이해황;이익준
    • Bulletin of the Korean Chemical Society
    • /
    • v.17 no.8
    • /
    • pp.712-715
    • /
    • 1996
  • Kinetic studies are carried out on the reactions of N-methyl-N-phenylcarbamoyl chlorides with benzylamines in acetonitrile. The selectivity parameters, ρX (=-0.6~-0.8), ρY (=1.0-1.1), and ρXY (=-0.14), suggest that the reaction proceeds by an SN2 mechanism. Kinetic isotope effects, kH/kD, involving deuterated nucleophiles (XC6H4CH2ND2) are all inverse type (<1.0), and the trends of changes in the magnitude are consistent with those expected for the observed negative sign of ρXY(=∂ρX/∂σY = ∂ρY/∂σX < 0). The relatively low activation enthalpies also support the proposed mechanism.

Complex Chalcogenides as Thermoelectric Materials: A Solid State Chemistry Approach

  • 정덕영;Lykourgos Iordanidis;최경신;Mercouri G. Kanatzidis
    • Bulletin of the Korean Chemical Society
    • /
    • v.19 no.12
    • /
    • pp.1283-1293
    • /
    • 1998
  • A solid state chemical approach to discover new mateials with enhanced thermoelectric properties is described. The aim is to construct three-dimensional bismuth chalcogenide framework structures which contain tonically interacting alkali or alkaline earth atoms. The alkali atoms tend to have soft "rattling" type phonon modes which result in very low thermal conductivity in these materials. Another desirable feature in this class of compounds is the low crystal symmetry and narrow band-gaps. Several promising materials such as BaBiTe3, KBi6.33S10, K2Bi8S13, β-K2Bi8Se13, K2.5Bi8.5Se14, Ba4Bi6Se13, Eu2Pb2Bi6Se13, Al1+xPb4-2xSb7+xSe15 (A=K, Rb), and CsBi4Te6 are described.

Cytogenetic Analysis of Seven Angelica Species (Angelica속 식물 7종의 세포유전학적 분석)

  • Choi, Hae-Woon;Koo, Dal-Hoe;Lee, Woo-Kyu;Kim, Soo-Young;Sung, Jung-Sook;Seong, Nak-Sul;Suh, Young-Bae;Bang, Jae-Wook
    • Korean Journal of Medicinal Crop Science
    • /
    • v.13 no.3
    • /
    • pp.118-121
    • /
    • 2005
  • Karyotypes were established in seven Angelica species cultivated in Korea. The somatic chromosome numbers were 2n = 2x = 22 with the basic number of x = 11 in all Angelica plants examined. Their metaphase chromosomes ranged from 3.56 ${\mu}M$. to 8.91 x. in length. Distinctive Karyotypes were found in two species, A. tenuissima with all metacentries, K(2n) = 2x = 22m, and A. genuflexa with all subtelocentrics, K(2n) = 2x = 22st. Karyotype formulas of A. gigas, A. acutiloha, A. sinensis, A. decursiva and A. dahurica were K(2n) = 2x = 20m + 2sm, K(2n) = 2x = 12m + 10sm, K(2n) = 2x = 16m + 6sm, K(2n) = 2x = 18m + 4sm and K(2n) = 2x = 10m + 10sm + 2st, respectively. Cytological data showed that chromosomal polymorphisms within species were observed in Angelica plants compare to other regions.

키토산을 이용한 김치의 숙성 지연과 보존기간 연장에 관한 연구

  • 서정숙;방병호;정은자
    • Proceedings of the Korean Journal of Food and Nutrition Conference
    • /
    • 2003.07a
    • /
    • pp.84-84
    • /
    • 2003
  • 고분자 키토산(분자량 약 800,000)을 농도별(0%, 0.1%, 0.2%, 0.3%)로 김치를 제조하여, pH, 적정산도, 총균수, 젖산균 수, 대장균군 수 및 관능검사를 조사한 결과는 다음과 같이 나타났다. 1. 키토산 무첨가 김치는 발효 후 6일경에 pH가 초기 5.4에서 4.1로 급격히 떨어졌으며 그 후부터는 천천히 떨어져 발효 후 약 15일 경과 후에는 3.9로 나타났다. 그러나 0.1%, 0.2% 및 0.3% 고분자 키토산을 첨가한 김치에서는 초기 pH 5.38, 5.30 및 5.28에서 6일경에는 pH가 0.1%, 0.2% 및 0.3% 고분자 키토산에서 4.23, 4.34 및 4.47로 각각 나타났다. 15일 경과 후에는 0.1% 고분자 키토산 김치는 키토산 무첨가 김치와 거의 같은 pH인 3.9로 나타났으나 0.2%와 0.3% 고분자 키토산 김치의 pH는 3.90보다 높은 4.10, 4.10으로 각각 나타났다. 2. 각 김치 종류별 적정산도를 측정한 결과는 발효초기에 모든 구가 0.72%로 나타났으며, 발효 후 6일 경에서는 키토산 무첨가, 0.1%, 0.2% 및 0.3% 고분자 키토산 김치의 적정산도는 각각 2.16%, 2.00%, 1.70% 및 1.30%로 나타났다. 그리고 15일 경과 후에는 키토산 무첨가 김치의 적정산도가 2.25%이였으나 0.1%, 0.2% 및 0.3% 고분자 키토산 김치는 각각 2.26%, 2.24 및 2.22%로 나타났다. 3. 발효가 진행 중에 총균수를 측정한 결과 시간과 더불어 총균수가 모든 구에 있어서 서서히 증가하였고 발효초기의 모든 김치구의 총균수는 2.5X105∼5.4X106 cfu/g 범위였으며, 김치 맛이 들기 시작한 6일경에서의 각 구별 총균수는 키토산 무첨가 김치가 2.4X109 cfu/g이였구 0.1%, 0.2% 및 0.3% 고분자 키토산 김치의 총균수는 각각 1.2X109 cfu/g, 4.0X108 cfu/g 및 1.1X107 cfu/g으로 나타났다. 그리고 김치가 완전히 익은 15일 후에는 무첨가 김치, 0.1%, 0.2% 및 0.3% 고분자 키토산 김치의 총균수는 5.4X107 cfu/g, 3.3X107 cfu/g, 1.8X108cfu/g 및 4.2X108 cfu/g로 나타났다. 4. 발효가 진행 중에 젖산균 수를 측정한 결과 시간과 더불어 젖산균 수가 모든 구에 있어서 서서히 증가하였으며, 발효초기의 모든 김치구의 젖산균 수는 2.0X104∼2.7X106 cfu/g 범위였으며 김치 맛이 들기 시작한 6일경에서의 각 구별 젖산균 수는 키토산 무첨가 김치가 3.2X108 cfu/g이었고, 0.1%, 0.2% 및 0.3% 고분자 키토산 김치의 젖산균 수는 각각 1.6X108 cfu/g, 13X108 cfu/g 및 9.6X107 cfu/g으로 나타났다. 그리고 김치가 완전히 익은 15일 후에는 무첨가 김치, 0.1%, 0.2% 및 0.3% 고분자 키토산 김치의 젖산균 수는 5.4X107 cfu/g, 3.3X107 cfu/g, 8.6X106 cfu/g 및 2.6X106 cfu/g로 나타났다. 5. 발효가 진행 중에 대장균 군 수가 시간과 더불어 대장균군 수가 모든 구에 있어서 6일까지는 서서히 증가하다가 그 후부터는 대장균 군 수가 감소하였다. 즉, 발효초기에는 모든 구가 2.0X104∼4.0X105 cfu/g이었고, 6일 경에는 8.9X104∼4.5X105 cfu/g로 약간 증가하였으며 15일후에는 키토산 무첨가 김치가 2.0X102 cfu/g이었으며, 0.1%, 0.2% 및 0.3% 고분자 키토산 김치의 대장균군 수는 각각 2.0X102 cfu/g, 1.1X102 cfu/g 및 4.0X101 cfu/g로 점점 감소하였다. 6. 관능검사 결과는 키토산 무첨가 김치와 0.1% 첨가 김치는 유사한 선호도를 나타내어 0.1% 첨가 김치가 기능성과 보존성을 높여줄 뿐만 아니라 선호도도 높은 것으로 나타났다.

  • PDF

A Study on the Rating of the Insureds' Anthropometric Data III. A study on the Modified Broca's Index to Estimate Standard Body Weight of Korean Adults (피보험체계측치(被保險體計測値)의 평가(評價)에 관한 연구(硏究) 제3보(第3報) 한국성인(韓國成人)의 표준체중(標準休重) 산출(算出)을 위한 변형(變形)Broca지수(指數)에 관한 연구(硏究))

  • Im, Young-Hoon
    • The Journal of the Korean life insurance medical association
    • /
    • v.4 no.1
    • /
    • pp.44-76
    • /
    • 1987
  • Present study was undertaken to establish the modified Broca's indices to estimate standard body weight by using a total of 5,496 insured persons who were medically examined at the Honam Medical Room of Dong Bang Life Insurance Company Ltd. from January, 1983 to January, 1986. The results were as follows: 1. The linear regression equations of body weight to $height^3$ to estimate standard body weight were as follows: In male, for $18{\sim}19$ age group $y=7.272{\times}10^{-6}{\times}x^3+23.560$ for $20{\sim}29$ age group $y=8.187{\times}10^{-6}{\times}x^3+22.031$ for $30{\sim}39$ age group $y=8.627{\times}10^{-6}{\times}x^3+23.169$ for $40{\sim}49$ age group $y=9.561{\times}10^{-6}{\times}x^3+20.994$ for $50{\sim}59$ age group $y=8.604{\times}10^{-6}{\times}x^3+23.081$ and for all ages group $y=7.778{\times}10^{-6}{\times}x^3+25.929$ In female, for $18{\sim}19$ age group $y=8.252{\times}10^{-6}{\times}x^3+18.920$ for $20{\sim}29$ age group $y=7.715{\times}10^{-6}{\times}x^3+22.409$ for $30{\sim}39$ age group $y=8.808{\times}10^{-6}{\times}x^3+21.440$ for $40{\sim}49$ age group $y=9.691{\times}10^{-6}{\times}x^3+21.940$ for $50{\sim}59$ age group $y=12.550{\times}10^{-6}{\times}x^3+11.031$ and for all ages group $y=7.300{\times}10^{-6}{\times}x^3+26.601$ In both sexes, for all ages group $y=8.342{\times}10^{-6}{\times}x^3+22.998$ 2. The modified Broca's index is expressed by formula $\{height(cm)-100\}{\times}K(kg)$. K is obtained from the following formula standard weight to average height estimated $\frac{by\;means\;of\;linear\;regression\;equation(kg)}{\{Average\;height(cm)-100\}{\times}K(kg)}$=1 Author's modified Broca's indices are as follows: In male, for $18{\sim}19$ age group $\{height(cm)-100\}{\times}0.85(kg)$ for $20{\sim}29$ age group $\{height(cm)-100\}{\times}0.90(kg)$ for $30{\sim}39$ age group $\{height(cm)-100\}{\times}0.95(kg)$ for $40{\sim}49$ age group $\{height(cm)-100\}{\times}1.00(kg)$ for $50{\sim}59$ age group $\{height(cm)-100\}{\times}0.95(kg)$ and for all ages group $\{height(cm)-100\}{\times}0.95(kg)$ In female, for $18{\sim}19$ age group $\{height(cm)-100\}{\times}0.90(kg)$ for $20{\sim}29$ age group $\{height(cm)-100\}{\times}0.90(kg)$ for $30{\sim}39$ age group $\{height(cm)-100\}{\times}1.00(kg)$ for $40{\sim}49$ age group $\{height(cm)-100\}{\times}1.05(kg)$ for $50{\sim}59$ age group $\{height(cm)-100\}{\times}1.05(kg)$ and for all ages group $\{height(cm)-100\}{\times}1.00(kg)$ In both sexes, for all age group $\{height(cm)-100\}{\times}0.95(kg)$ 3. Several types of modified Broca's index recommended by author are as follows: I. In male, for $18{\sim}29$ age group $\{height(cm)-100\}{\times}0.90(kg)$ and for $30{\sim}59$ age group $\{height(cm)-100\}{\times}0.95(kg)$ In female, for $18{\sim}29$ age group $\{height(cm)-100\}{\times}0.90(kg)$ and for $30{\sim}39$ age group $\{height(cm)-100\}{\times}1.00(kg)$ II. In male, for all ages group $\{height(cm)-100\}{\times}0.95(kg)$ In female, for all ages group $\{height(cm)-100\}{\times}1.00(kg)$ III. In both sexes, for all ages group $\{height(cm)-100\}{\times}0.95(kg)$ Note: The first type of modified Broca's index is the most precise one in estimating standard body weight among several types established by author. 4. Error of estimated standard body weight appearing by applying modified Broca's indices is generally greater in short build persons than in tall build persons and is more dominant especially in female group.

  • PDF

Studies on the Quality of Silage from Domeestic Herbage I. Effects of water , corn starch and glucose as additives on Kudzu ( Puerarie thunbergii Bentham ) silage (야초 사일리지의 품질향상에 관한 연구 I. 칡 사일리지 제조에 있어서 물, 전분, 포도당 첨가효과)

  • Kim, Dae-Jin;Leem, Wan
    • Journal of The Korean Society of Grassland and Forage Science
    • /
    • v.7 no.3
    • /
    • pp.162-167
    • /
    • 1987
  • This experiment was conducted to determine the effect of the feeding value for the wild legumes silage-making with additives. The chopped Kudzu (Puerarie thunbergii Bentham) of wild legumes was ensiled by the conventional method in the small experimental silo of 2 liters. The additives used in the present experiments were water (8%),water (8%) plus corn starch (3%) and water (8%) plus glucose (3%). These additives as well as that of control without additive were set up and these silage were compared with the conventional corn silage. The fermentative qualities and the characteristic of fiber (neutral detergent fiber, NDF; acid detergent fiber, ADF; acid detergent lignin, ADL) of silage produced was determined by chemical analysis, and dry matter digestibility (DMD) was evaluated by pepsin-cellulase technique. The results obtained are summarized as follows: 1 The weight of Kudzu silage was lost under the 10% for all the treatments. 2 In degree of pH for the Kudzu silages with glucose, starch, control and water treatments were high 3.80,4.04,4.57 and 5.34, respectively.

  • PDF

Variations in the Properties of LSGM System Electrolyte with Sr and Mg Addition and Sintering Conditions (Sr과 Mg 첨가량 및 소결조건에 따른 LSGM계 전해질의 특성 변화)

  • Lee, Mi-Jai;Park, Sang-Sun;Choi, Byung-Hyun
    • Journal of the Korean Ceramic Society
    • /
    • v.39 no.4
    • /
    • pp.352-358
    • /
    • 2002
  • The variations of the properties of Sr and Mg added $LaGaO_3$ system electrolyte with the amount of the additive and the sintering condition were studied. Main phase was (La$_{1-x}Sr_x)(Ga_{1-y}Mg_y)O_{3-\delta}$ phase for each compositions and the single phases $(La_{0.85}Sr_{0.15})(Ga_{0.85}Mg_{0.15})O_{3-\delta},(La_{0.85}Sr_{0.15})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$ and $(La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O{3-\delta}$ were obtained with the decrease in the sintering temperature and Mg addition. Thermal expansion coefficient of the $(La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$ decreased with the increase in the sintering temperature. Electric conductivity of electrolyte sintered at $1500^{circ}C$ for 1h was 0.14 S/cm at $800^{circ}C$ with 1 mA.

SPECTRAL DUALITIES OF MV-ALGEBRAS

  • Choe, Tae-Ho;Kim, Eun-Sup;Park, Young-Soo
    • Journal of the Korean Mathematical Society
    • /
    • v.42 no.6
    • /
    • pp.1111-1120
    • /
    • 2005
  • Hong and Nel in [8] obtained a number of spectral dualities between a cartesian closed topological category X and a category of algebras of suitable type in X in accordance with the original formalism of Porst and Wischnewsky[12]. In this paper, there arises a dual adjointness S $\vdash$ C between the category X = Lim of limit spaces and that A of MV-algebras in X. We firstly show that the spectral duality: $S(A)^{op}{\simeq}C(X^{op})$ holds for the dualizing object K = I = [0,1] or K = 2 = {0, 1}. Secondly, we study a duality between the category of Tychonoff spaces and the category of semi-simple MV-algebras. Furthermore, it is shown that for any $X\;\in\;Lim\;(X\;{\neq}\;{\emptyset})\;C(X,\;I)$ is densely embedded into a cube $I^/H/$, where H is a set.

X-ray PIV Measurements of Velocity Field of Blood Flows

  • Lee, Sang-Joon;Kim, Guk-Bae
    • International Journal of Vascular Biomedical Engineering
    • /
    • v.4 no.1
    • /
    • pp.1-8
    • /
    • 2006
  • The x-ray PIV method was improved for measuring quantitative velocity fields of real blood flows using a coherent synchrotron x-ray source. Without using any contrast media or seeding particles, this method can visualize flow pattern of blood by enhancing the phase-contrast and interference characteristics of blood cells based on a synchrotron x-ray imaging mechanism. The enhanced x-ray images were achieved by optimizing the sample-to-scintillator distance, the sample thickness, and hematocrit. The quantitative velocity fields of blood flows inside opaque tubes were obtained by applying a 2-frame PIV algorithm to the x-ray images of the blood flows. The measured velocity field data show typical features of blood flows such as the yield stress effect. The non-Newtonian flow characteristics of blood flows were analyzed using the x-ray PIV method and the experimental results were compared with hemodynamic models.

  • PDF

STRONG τ-MONOLITHICITY AND FRECHET-URYSOHN PROPERTIES ON Cp(X)

  • Kim, Jun-Hui;Cho, Myung-Hyun
    • Honam Mathematical Journal
    • /
    • v.31 no.2
    • /
    • pp.233-237
    • /
    • 2009
  • In this paper, we show that: (1) every strongly ${\omega}$-monolithic space X with countable fan-tightness is Fr$\'{e}$chet-Urysohn; (2) a direct proof of that X is Lindel$\"{o}$f when $C_p$(X) is Fr$\'{e}$chet-Urysohn; and (3) X is Lindel$\"{o}$f when X is paraLindel$\"{o}$f and $C_p$(X) is AP. (3) is a generalization of the result of [8]. And we give two questions related to Fr$\'{e}$chet-Urysohn and AP properties on $C_p$(X).