• Title/Summary/Keyword: the Kramer model

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A study on optimum design and high efficiency operation for commutatorless Kramer type slip power recovery system of induction motor (유도전동기의 무정류자 크레므형 슬립전력회수 시스템의 적정설계 및 고효율화 운전에 관한 연구)

  • 유춘식;홍순일;노창주;이형기
    • Journal of Advanced Marine Engineering and Technology
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    • v.11 no.4
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    • pp.59-74
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    • 1987
  • In this dissertation, a complete model of commutatorless static Kramer type slip power recovery system of 3.phi. induction motor has been designed and tested in the laboratory, and the experimental results are compared with the numerical values. The main results of this study are summerized as follows. (1) Maintenance and repair of the mechanical commutator is obviated by adopting a thyristor commutator in place of the mechanical commutator in the conventional Kramer system. (2) The experimental results of developed torque, and stator current are generally coincided with the numerical values obtained by the derived equation, proving their validity. (3) This system is simulated and the following operational characteristics are obtained with suitable design values : (a) The speed control range of 7:1 is obtained when the turn ratio of induction motor is lowered to about 3:1 to 4:1 and the generating constant of auxiliary synchronous motor is increased to 120-175 range. (b) Its efficiency can be increased to 75-85%, the range for static Scherbius system and its power factor takes values in the range of 65-85%, which is twice of the range for static Scherbius system.

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A Comparative Case Study on the CSR Strategies of Toyota and Hyundai Motors in China (중국에서의 도요타와 현대자동차의 CSR전약에 관한 비교 사례분석)

  • Seo, Min-Kyo
    • International Commerce and Information Review
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    • v.13 no.4
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    • pp.151-176
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    • 2011
  • Recently, the importance and requirement for Corporate Social Responsibility(CSR) is continuously growing in both korea and foreign countries. This paper tried to analyze on the theoretical trend of CSR and to draw out managemental implications for Korean firms' global CSR strategy by means of comparative case study for the CSR activities of Toyota and Hyundai Motor in China. The results and implications of this study are as follows. First, this study showed that these companies had carried out a systemic legal and ethical responsibility. Second, according to the model of Porter & Kramer and Ibuki Eiko, these companies had recognized the importance of CSR and had recently begun to implement their strategic CSR Third, Toyotas' CSR activities in China are more closely related to auto industry and more strategic in compare with Hyundai Motors' CSR activities in China. Fourth, therefore, the more strategic and long-term planned effective CSR activities of Korean firms in China will be needed in the future.

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Categorization of Creating Shared Value Activities Towards Rural Area (농촌을 대상으로 한 공유가치창출(CSV) 활동의 유형화)

  • Kang, Chung Han;Lee, Dong Min;Moon, Jung Hoon
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.9 no.6
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    • pp.171-181
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    • 2014
  • CSV(Creating Shared Value) model was proposed by Porter and Kramer (2011) to address relationship between businesses and society. Namely, it means that CSV deals with business value and social problem solving simultaneously. In this paper, the notion of CSV was applied to the food enterprise, and the cases of CSV with farming area were discovered. Especially, this paper proposed the framework for analyzing CSV activity based on the three-level of CSV suggested by Porter and Kramer (2011) and strategic options for vertical coordination proposed by Peterson et al. (2001). As a result of case analysis applying the proposed framework in this study, three types of CSV activity were discovered: Local food type, downstream support type, and joint corporate establish type. Local food type creates CSV based on momentary purchase or specification contract as strategic options for vertical coordination. Downstream support type creates CSV mainly based on relation-based alliance as a strategic option for vertical coordination. Lastly, joint corporate establish type creates CSV based on equity-based alliance as a strategic option for vertical coordination. This paper contributed to the CSV literatures for discovering cases of CSV with farming area and categorizing discovered cases applying proposed framework.

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Lead Isotope Study on Lead-Zinc Ore Deposits in the Eastern and Southern Parts of the Gyeongsang Basin (경상분지 동남부 연 · 아연광상에 대한 납 동위원소 연구)

  • Chang, Byung Uck;Chang, Ho Wan;Cheong, Chang Sik
    • Economic and Environmental Geology
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    • v.28 no.1
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    • pp.19-24
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    • 1995
  • Based upon the lead isotopic compositions of the galenas collected from Pb-Zn ore deposits distributed in the eastern and southern parts of the Gyeongsang basin, we investigated what kinds of source materials were involved in the formation of these ore deposits and compared the lead isotopic characteristics of these ore deposits with those of the ore deposits in the Taebaegsan area. The isotopic compositions of the common leads from Pb-Zn ore deposits in the Gyeongsang basin show the variation with the relatively limited range ($^{206}Pb/^{204}Pb=18.156{\sim}18.377$, $^{207}Pb/^{204}Pb=15.482{\sim}15.638$, and $^{208}Pb/^{204}Pb=37.953{\sim}38.605$). They are plotted on or below ore lead growth curve(Cumming & Richards, 1975) and average crustal lead evolution curve (Stacey & Kramer, 1975). In the plumbotectonic model IV(Zartman & Haines, 1988), they are plotted between the evolution curves of mantle and orogene. But the lead isotopic compositions of the common leads in the Taebaegsan area are plotted on and above upper crust curve. Considering the above-mentioned lead isotopic characteristics, the linear trend shown in the isotopic compositions of the common leads in the Gyeongsang basin can be considered as the mixing isochron between high radiogenic crustal materials such as the Ryongnam massif and low radiogenic materials derived from depleted mantle or materials with relatively low U/Pb and Th/U ratios.

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Analytical solution and experimental study of membrane penetration in triaxial test

  • Ji, Enyue;Zhu, Jungao;Chen, Shengshui;Jin, Wei
    • Geomechanics and Engineering
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    • v.13 no.6
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    • pp.1027-1044
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    • 2017
  • Membrane penetration is the most important factor influencing the measurement of volume change for triaxial consolidated-drained shear test for coarse-grained soil. The effective pressure p, average particle size $d_{50}$, thickness $t_m$ and elastic modulus $E_m$ of membrane, contact area between membrane and soil $A_m$ as well as the initial void ratio e are the major factors influencing membrane penetration. According to the membrane deformation model given by Kramer and Sivaneswaran, an analytical solution of the membrane penetration considering the initial void ratio is deduced using the energy conservation law. The basic equations from theory of plates and shells and the elastic mechanics are employed during the derivation. To verify the presented solution, isotropic consolidation tests of a coarse-grained soil are performed by using the method of embedding different diameter of iron rods in the triaxial samples, and volume changes due to membrane penetration are obtained. The predictions from presented solution and previous analytical solutions are compared with the test results. It is found that the prediction from presented analytical solution agrees well with the test results.

Field and Strain Dependence of the Critical Current and the n-value for an Internal-tin Processed $Nb_3Sn$ Strand (내부확산법으로 제조된 $Nb_3Sn$ 초전도 선재의 임계전류 및 n-값의 자장, 변이 의존성)

  • Oh, Sang-Jun;Choi, Hee-Kyung;Lee, Chul-Hee;Kim, Kee-Man
    • Progress in Superconductivity
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    • v.9 no.2
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    • pp.152-156
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    • 2008
  • Detailed field and strain dependence of the critical current and the n-value for an internal-tin processed $Nb_3Sn$ strand have been measured. Both the compressive and tensile strain is applied reversibly using Walter spiral probe made of BeCu up to 0.73 %. There is a correlation between the critical current and the n-value for the $Nb_3Sn$ strand studied in this work and the field dependence of the n-value is in agreement with a recent empirical formula. It was further shown that the critical current can be reasonably well fitted by the scaling law based on strong-coupling theory of superconductivity using the relation between the critical current and the n-value.

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Rheological Properties of Exopolysaccharide p-KG03 Produced by Marine Microalgae Gyrodinium impudicum strain KG03

  • Im, Jeong-Han;Kim, Seong-Jin;Park, Gyu-Jin;An, Se-Hun;Lee, Hyeon-Sang;Lee, Hong-Geum
    • 한국생물공학회:학술대회논문집
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    • 2003.04a
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    • pp.611-614
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    • 2003
  • The rheological properties of exopolysaccharide, p-KG03, produced by marine microalgae Gyrodinium impudicum strain KG03 had been studied. The intrinsic viscosity of this p-KG03 was calculated to 65.22 and 50.75 $d{\ell}/g$ using Huggins and Kramer equations (xanthan gum 24.41 and 24.03). Aqueous dispersions at p-KG03 concentrations ranging from 0.1 to 1.0 % (w/w) showed marked shear-thinning properties as Power-Law behavior. In aqueous dispersions of p-KG03 1.0 %, consistency index (K) and flow behavior index (n) were 2,172 and 0.52. The apparent viscosity and the influence of shear rate on different conditions as p-KG03 concentrations, pH, NaCl, $CaCl_2$ and temperature in aqueous solutions were measured. And p-KG03 had mixed with aqueous solutions of xanthan gum and gellan gum, and invested the change of mixed aqueous solution behavior.

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