• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.91-99
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• 2017

In order to meet the thermal performance analysis accuracy requirements of high density permanent magnet synchronous motor (PMSM), a method of multi physical domain coupling thermal analysis based on control circuit, electromagnetic and thermal is presented. The circuit, electromagnetic, fluid, temperature and other physical domain are integrated and the temperature rise calculation method that considers the harmonic loss on the frequency conversion control as well as the loss non-uniformly distributed and directly mapped to the temperature field is closer to the actual situation. The key is to obtain the motor parameters, the realization of the vector control circuit and the accurate calculation and mapping of the loss. Taking a 48 slots 8 poles high density PMSM as an example, the temperature rise distribution of the key components is simulated, and the experimental platform is built. The temperature of the key components of the prototype machine is tested, which is in agreement with the simulation results. The validity and accuracy of the multi physical domain coupling thermal analysis method are verified.

• 수산해양기술연구
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• 제35권3호
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• pp.267-276
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• 1999

In order to investigate the properties in distribution and movement of anchovy school catches by the lift net in the Kamak bay and their relation to the environmental factors, i.e., the water temperature and the salinity were observed form June to August in 1997 and compared with the catch of anchovy by the lift net. The results obtained are summarized as follows;1) The water temperature and salinity ranged form 20.0 to $27.0^{\circ}C\;and\;from\;31.2\;to\;33.8\texperthousand$, respectively. The water temperature and salinity at the fishing points ranged form 19.7 to $27.2^{\circ}C\;and,\;from\;30.5\;to\;33.8^{\circ}C$ respectively.2) The water temperature influenced remarkably on the distribution and movement of anchovy school. But the salinity influenced little on the distribution and movement. 3) The catch of anchovy was highest on July, poor second on August, and lowest on June. Anchovy school can be presurmed, they are come from north of bay, visited and distributed through east of bay at the middle of June. Moreover, they spreaded in all bay. Then gradually, when July arrive, they go to the south th nearest the coasts, and they are outflow through the south entrance of bay at the end of August.

• The Korean Journal of Ecology
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• 제8권2호
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• pp.89-98
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• 1985

Correlations between horizontal distributions of bamboos (Bambusaceae) in the Korean peninsula and environmental factors were studied using taxanomic and geographical literatures, both old and current. The vertical distributions of bamboos on Mt. Chiri were also studied, and environmental factors limiting horizontal and vertical distributions were compared. There are 18 species of bamboos (belonging to 5 genera) distributed in the Korean peninsula. The distributional range of each genus were distinct, although overlapped. Northern limit of bamboos of any species was marked by the line connecting Paikryung Island (124。40'E, 38。00'N), Mt. Changsoo, Mt. Myungji, Mt. Myohyung and Myungchum (129。40'E, 41。10'N). The optimum range of bamboos was concluded to be restricted to several southern province, with annual precipitation over 1,200 mm. The limiting factors on the distribution were inferred to be low temperature and duration of it. Mean daily minimum temperature of January and the number of days with daily mean temperatures below zero during January showed close associations with the distributional range, and an environmental factors favouring the distributrion of bamboos appeared to be vicinity of warm sea current, deep and extended snow acculation and southern exposure. The vertical distribution of bamboos on Mt. Chiri was limited by low temperature, unfavorable topographic and edaphic conditions caused by steep slope. Difference in the vertical limits between SE and NW slopes are caused by the differences in temperature and precipitation between the slopes. Bamboos were more abundant in valleys than on the ridge, apparently because the deeper snow in the valleys protected the plants from low temperature, heavy winter winds and desiccation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1358-1362
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• 2005

The Ni-base superalloy GTD-111DS was designed in the 1970s and is widely used as the material of the first stage blade under a severe combination of temperature and pressure in gas turbines. But because GTD-111DS is distributed in the shape of blade and blade has a unique figure and many cooling channels, it is hard to manufacture the test specimen. In this reason, there are little data on the microstructure and mechanical properties of the alloy. Therefore through the microstructure analysis, present paper observed that the shape of $\gamma{'}$ did not change even if aging time was increased but the amount and volume of the deposition of secondary $\gamma{'}\;rose\;and\;secondary\;\gamma{'}\;grew\;among\;primary\;\gamma{'}$. Also, by tensile test for different temperature, there was difference between yield strength and tensile strength in room temperature on heat treatment and extracting region but the more increasing temperature, the more decreasing difference between yield strength and tensile strength.

• Structural Engineering and Mechanics
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• 제53권3호
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• pp.497-517
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• 2015

In this study, nonlocal nonlinear buckling analysis of embedded polymeric temperature-dependent microplates resting on an elastic matrix as orthotropic temperature-dependent elastomeric medium is investigated. The microplate is reinforced by single-walled carbon nanotubes (SWCNTs) in which the equivalent material properties nanocomposite are estimated based on the rule of mixture. For the carbon-nanotube reinforced composite (CNTRC) plate, both cases of uniform distribution (UD) and functionally graded (FG) distribution patterns of SWCNT reinforcements are considered. The small size effects of microplate are considered based on Eringen's nonlocal theory. Based on orthotropic Mindlin plate theory along with von K$\acute{a}$rm$\acute{a}$n geometric nonlinearity and Hamilton's principle, the governing equations are derived. Generalized differential quadrature method (GDQM) is applied for obtaining the buckling load of system. The effects of different parameters such as nonlocal parameters, volume fractions of SWCNTs, distribution type of SWCNTs in polymer, elastomeric medium, aspect ratio, boundary condition, orientation of foundation orthtotropy direction and temperature are considered on the nonlinear buckling of the microplate. Results indicate that CNT distribution close to top and bottom are more efficient than those distributed nearby the mid-plane for increasing the buckling load.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1781-1786
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• 2005

In sensor network systems, all the nodes are interconnected and the positional information of each sensor is essential. To measure the temperature, position detection and communication functions are required. Many sensor nodes are distributed to a measurement field, and these sensors have three main functions: they measure the distance to the other nodes, the data of which are used to determine the position of each node; they communicate with other nodes; and they measure the temperature of each node. A novel range measurement method using the difference between light and sound propagation speed is proposed. The experimental results show the temperature distribution as measured with the aid of the determined positions. The positions of every node were calculated with a PC program. Eight nodes were manufactured and their fundamental functions were tested. The results of the range measurement method, which takes relatively accurate measurements, contribute significantly to the accuracy of the position determination. Future studies will focus on 3-D position determination and on the architecture of appropriate sensors and actuators.

• 한국의류산업학회지
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• 제12권4호
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• pp.513-522
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• 2010

The aim of this study is to investigate the actual state for the development of the thermally comfortable uniform for workers on a low temperature storage. Observation, interview and survey were executed focusing on the environment, clothing, and human factors which have effects on the comfort of workers. Of 400 distributed, 253 questionnaires were analyzed through descriptives, frequency, ANOVA, t-test, multi-response analysis, correlation analysis with SPSS 12.0. The results are following. Coming and going between a selling area and cold storages, the workers showed to experience a big temperature gap. They indicated to feel cold on face and hands which were not covered by clothing and have got sick because of low temperature. The workers wanted the uniform made of functional fabrics, especially heat insulation fabrics. Female workers rather than male workers, the older, and the longer their working period were, the more uncomfortable they revealed to feel. The workers who works on the daily products part or mainly on the freezer appeared to feel cold more than any other workers. In conclusion, it was found that the uniform which consider steady state and unsteady state heat transfer together must be developed.

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1345-1348
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• 2013

We investigated the tribochemical and wear properties of Polytetrafluoroethylene (PTFE) based polymer matrix composites with nanoceramic (NC) ${\beta}$-sialon, and $Al_2O_3$ particles for the mechanical seal applications at low temperature. SEM showed that NC particles were homogeneously distributed in the polymer matrix and initiated the formation of the supramolecular spherulites around NC. From the temperature stimulated depolarization (TSD) current results, it was analyzed that the surface charge on nanoceramic affected the formation of the spherulites structure. 2 wt % $Al_2O_3$ NC did not degrade the mechanical properties of PTFE so that composites showed the similar values of tensile strength, elongation at the rupture and friction coefficient as those of neat PTFE. However, the composite with 2 wt % $Al_2O_3$ NC revealed the improved wear resistance, wear rate of 0.4-1.2 mg/h at room temperature and 0.28 mg/h at $-40^{\circ}C$, respectively, while the neat PTFE the 70-75 mg/h at room temperature and 70.3 mg/h at $-40^{\circ}C$.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권2호
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• pp.62-67
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• 2000

The uniformity of temperature on a wafer is one of the most important parameters to control the RTP (Rapid Thermal Process) with proper input signals. Since it is impossible to achieve the uniformity of temperature without exact estimation of temperature at all points on the wafer, the difficulty of understanding internal dynamics and structural complexities of the RTP is a primary obstacle to accurately measure the distributed temperatures on the wafer. Furthermore, it is also hard to accomplish desirable estimation because only few pyrometers have been commonly available in the general equipments. In the paper, a thermal model based on the chamber geometry of the AST SHS200 RTP system is developed to effectively control the thermal uniformity on the wafer. First of all, the estimation method of one-point measurement is developed, which is properly extended to the case of multi-point measurements. This thermal model is validated through certain simulation and experiments. The work can be usefully contributed to building a run-by-run or a real-time controls of the RTP.

• 통합자연과학논문집
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• 제4권1호
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• pp.58-71
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• 2011

The precambrian gneisses are widely distributed in the Jangsu area. This study focuses on the metamorphic mineral assemblages and metamorphic P-T conditions of the gneiss. We have analyzed garnet, biotite and plagioclase among the gneiss through the EPMA analysis, and calculated the metamorphic temperature and pressure accordingly. The metamorphic temperature was estimated by the average of values from the garnet and biotite formulas, and the metamorphic pressure by value of the Hoisch(1990) geopressured on garnet-biotite-plagioclase. The mineral sample we examined shows garnet-biotite-plagioclase-quartz composite and garnet-plagioclase-orthoclase-quartz composite. Garnet shows almandine-pyrope solid solution in general, while porphyroblastic gneiss shows almandine-grossluar solid solution. The fact that the abundances, observed by garnet profile, are almost identical in both the central region and the outer egion indicates that the crystal was developed uniformly. There is almost negligible variance in biotite on metamorphic grade, and andesine is observed in plagioclase. The metamorphic temperature and pressure from EPMA analysis and its indications are as follows: the middle-temperature, high-pressure metamorphism ($500-650^{\circ}C$, 6.9-10 kbar) ensued in the beginning, and then was followed by the high-temperature, middle-pressure($600-740^{\circ}C$, 2.7-5.9 kbar) to ($500-540^{\circ}C$, 3.1 kbar) retrograde metamorphism.