• Journal of computational fluids engineering
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• v.19 no.3
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• pp.24-28
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• 2014

With ever rising concerns about saving of fossil fuel resource, there have been an increasing demand for use of energy more efficiently. The electric motor driven inverters can be a great help to improve energy efficiency. They are also used to control the motor speed to the actual need. Therefore the use of them can lead to reduce energy consumption. In particular, the medium voltage(MV) drive systems used for pumps, fans, steel rolling mills and tractions have widespread applications in the industry. They cover power ratings from 0.4MW to 40MW at the MV level of 2.3kV to 13.8kV. The majority of the installed MV drive systems however, are in the 1MW to 4MW range with voltage rating from 3.3kV to 6.6kV. But they are required to reduce size and weight like other power electronic equipments. In this paper, we studied on the 3.3kV(105A) compact rack type inverter system for improving the cooling efficiency. At first, we confirmed the tendency of temperature with computational simulation using ANSYS ICEPAK and actual experimental tests. And then we researched thermal performance improvement designs in order to reduce temperature of the transformer for the safe operation. It can reduce temperature of transformer that using pipe type flow guide in the system. As a result, we found out more efficient solution by thermal-fluid analysis.

• IE interfaces
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• v.16 no.3
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• pp.291-299
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• 2003

The managerial environment of automobile industry has been rapidly changing, mainly with the tighter standard of legal and environmental regulations, the pressure of cost reduction from the end-user, the various functional improvements of vehicles, and the globalization management. In order to survive in this complicate circumstances, the automakers have strongly pursued the mutual collaboration with the suppliers, especially tier-1, for the optimal selection of parts/materials and the assembly manufacturing processes of the new model development. They prepare the early involvement program for the suppliers during the conceptual design stage, and implement the win-win strategy of technology development activity, in order to improve the value creation. This study considers the strategic technology management of automotive steel sheets makers on the aspects of strategy, processes, human & physical resources, and organization structure. It also suggests the corporate strategies of steel mills, in order to obtain the technology competence.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.227-229
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• 2003

We present a process for printing active matrix displays. In this process, transistors are fabricated using soluble semi-conducting and conducting materials. Accurate definition of the transistor channel and other circuit components is achieved by direct inkjet printing combined with surface energy patterning. We present results on our 4,800 pixel, 50 dpi, active matrix displays.

• Women's Health Nursing
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• v.12 no.3
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• pp.204-209
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• 2006

Purpose: The Edinbergh Postnatal Depression Scale (EPDS) has seen widespread use in epidemiological and clinical studies. The objective of this research was to translate and to test the reliability and validity of the 10-item EDPS in Korea. Methods: Subjects were 145 women who were 6 to 10 weeks post delivery. To test reliability, the internal consistency was assessed by Cronbach's alpha coefficient. Validity testing was performed using convergent validity by Pearson's correlation. Data was gathered at 3 hospitals during Oct. 2005 after obtaining an informed consent. Result: The mean age of the subjects was 29.9 years. and the mean parity was 1.46 times. The mean EPDS score was 18.4. Reliability analysis showed a satisfactory result (Cronbach's alpha coefficient=.84). There were significant positive correlations between EPDS and Mills postnatal depression and anxiety check list scores as expected(r=.69, p<.001) and thus supported convergent validity. Conclusion: The study findings showed that the Korean version of the EPDS-10 is a reliable and valid instrument that can be used for measuring postnatal depression in Korea.

• Nuclear Engineering and Technology
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• v.52 no.9
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• pp.2130-2137
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• 2020

The standard method for calculating anti-neutrino emissions from a reactor involves knowing the fractional fission rates for the most important fissioning nuclides in the reactor. To calculate these rates requires detailed reactor physics calculations based upon the reactor design, fuel design, burnup dependent fuel composition, location of specific fuel assemblies in the core and detailed operational data from the reactor. This has only been published for a few reactors during specific time periods, whereas to be of practical use for anti-neutrino reactor monitoring it is necessary to be able to predict these on the publicly available information from any reactor, especially if using these data to subtract the anti-neutrino signal from other reactors to identify an undeclared reactor and monitor its operation. This paper proposes a method to estimate the fission fractions for a specific reactor based upon publicly available information and provides a database based upon a series of spent fuel inventory calculations using the FISPIN10 code and its associated data libraries.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2007.05a
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• pp.19-32
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• 2007

A new generation of fiber-based papermaking chemicals were presented for the first time at the PTS Pulp Technology Symposium 2005, and then several articles were published in various magazine in Asia ("Paper Asia"), the US ("Pulp & Paper"), and Europe ("Wochenblatt fuel Papierfabrikation"). The information generated quite an interest in the paper industry. Extensive studies of these papermaking additives have been made recently, new information obtained, and the compounds have gained more recognition in the industry. The company J. Rettenmaier und Soehne developed of a group of fiber-based papermaking additives. They includ combination of fibers with sizing agents, starch, fluorochemicals, minerals, biocides and some others. This article presents in-depth study of the AKD modified micronized cellulose as an example of the fiber-based papermaking chemicals cocept. The material of the present paper is based mostly on the results of the pilot paper machine study at the Paper Research Institute PTS (Heidenau, Germany), and includes case studies from the mills, which used $ARBOCELPLUS^{(R)}-AKD$ compounds. It should be noted that the $ARBOCELPLUS^{(R)}$ compounds were not designed to replace traditional additives in paper industry. They should rather be used in those areas, where application of "normal" chemicals is especially problematic.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.1
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• pp.77-83
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• 2011

In this thesis, 50W Doherty amplifier was designed and implemented for Beyond 3G's repeater and base-station. Auxiliary amplifier of doherty amplifier was implemented by Gate bias control circuit. Though gate bias control circuit solved auxiliary's bias problem, output characteristics of doherty amplifier was limited. To enhance the output characteristic relativize Drain control circuit And To improve power efficiency make 3-way Doherty power amplifier. therefore, 3-way GDCD (Gate and Drain bias Control Doherty) power amplifier is embodied to drain bias circuit for General Doherty power amplifier. The 3-way GDCD power amplifier composed of matching circuit with chip capacitor and micro strip line using FR4 dielectric substance of specific inductive capacity(${\varepsilon}r$) 4.6, dielectric substance height(H) 30 Mills, and 2.68 Mills(2 oz) of copper plate thickness(T). Experiment result satisfied specification of amplifier with gains are 57.03 dB in 2.11 ~ 2.17 GHz, 3GPP frequency band, PEP output is 50.30 dBm, W-CDMA average power is 47.01 dBm, and ACLR characteristics at 5MHz offset frequency band station is -40.45 dBc. Especially, 3-way DCHD power amplifier showed excellence efficiency performance improvement in same ACLR than general doherty power amplifier.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2007.05a
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• pp.33-55
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• 2007

This article portrays special cellulose fibers, which are designed to be a functional additive and a carrier for papermaking chemicals. The first part of the presentation deals with the micronized $ARBOCEL^{(R)}$ cellulose fibers, which are used as a functional paper/paperboard additive. In particular as a bulk and speed aid. The detailed description of the micronized $ARBOCEL^{(R)}$ fibers, their function and effects on papermaking process and paper products are given. The second part of the study describes the concept of fiber-based papermaking chemicals. A new generation of fiber-based papermaking chemicals were presented for the first time at the PTS Pulp Technology Symposium 2005, and then several articles were published in various magazine in Asia ("Paper Asia"), the US ("Pulp & Paper"). and Europe ("Wochenblatt fuel Papierfabrikation"). The information generated quite an interest in the paper industry. Extensive studies of these papermaking additives have been made recently, new information obtained, and the compounds have gained more recognition in the industry. The company J. Rettenmaier und Soehne developed a group of fiber-based papermaking additives. They include combination of fibers with sizing agents, starch, fluorochemicals, minerals, biocides and some others. This article presents in-depth study of the AKD modified micronized cellulose as an example of the fiber-based papermaking chemicals concept. The material of the present paper is based mostly on the results of the pilot paper machine study at the Paper Research Institute PTS (Heidenau, Germany), and includes case studies from the mills, which used $ARBOCELPLUS^{(R)}-AKD$ compounds. It should be noted that the $ARBOCELPLUS^{(R)}$ compounds were not designed to replace traditional additives in paper industry. They should rather be used in those areas, where application of "normal" chemicals is especially problematic

• Korean Journal of Agricultural Science
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• v.10 no.2
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• pp.334-344
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• 1983

This study was conducted to investigate the variables affecting the performance of hammer mills by the theoretical and dimensional analysis, and evaluate the power requirements of hammer mills for farm use in Korea. From the theoretical analysis, 16 variables affecting the performance of hammer mills were defined. In order to develop the mathematical relationships among the variables, the dimensional analysis was made for power requirements and $12{\pi}$ parameters were obtained. For the evaluation of the power requirements of hammer mills, approximate rates of grinding for 1HP, 3HP, 5HP, 6HP, 8HP, and 10HP were analyzed. Then, the fineness of grinding recommendation and average feeding rate of grain for livestock which is native cattle, dairy cattle, beef cattle, swine, broilers, and layers, were estimated. Finally number of livestock feeding shelled corn and barley were estimated from the above for one hour's hammer mill operation having the various power requirements. From this study it is known that 5HP is considered as an enough power for feed grinding of any kinds of livestock of Korean farm, as far as the grinding capacity is concerned.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.2
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• pp.233-239
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• 1997

A mammary epithelial cell line (MAC-T) established as a model for lactation was utilized to identify and characterize effects of various hormones upon insulin-like growth factor binding protein secretion. Ligand and immunoblot analyses of conditioned media indicated that insulin-like growth factor binding protein-2 was secreted by MAC-T cells. Insulin-like growth factor-I stimulated insulin-like growth factor binding protein-2 secretion in a dose-dependent manner, but prolactin and bovine somatotropin did not alter insulin-like growth factor binding protein-2 secretion. Insulin increased and cortisol decreased insulin-like growth factor binding protein-2 secretion. Effects of insulin-like growth factor-I on insulin-like growth factor binding protein-2 secretion support previous studies using primary cultures of bovine mammary cells and bovine fibroblasts. Effects of cortisol and insulin on insulin-like growth factor binding protein-2 secretion may be explained by changes in protein synthesis. In addition, supraphysiological doses of insulin can cross-react with the insulin-like growth factor-I receptor and stimulate insulin-like growth factor binding protein-2 secretion. MAC-T cells provide a model system to study mechanisms that regulate local insulin-like growth factor-I bioactivity.