• Journal of the Korean Solar Energy Society
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• v.40 no.1
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• pp.25-33
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• 2020

It has been reported about the energy saving performance of UFAD(under floor air distribution) system and NPC(night purge cooling) system respectively which are applied for commercial buildings. However, when two systems are used at the same time, the effect of heat transfer from floor plenum to slab may vary depending on the operating conditions of NPC. In this study, cooling energy demands were analyzed for building models with UFAD and NPC by using TRNSYS 17 program. UFAD was applied as a cooling system of the base building model, and the cooling energy demands were compared for 64 cases in which the operating time, supply airflow rate, and outdoor air temperature(T_o) of NPC. As a result, it was confirmed that the cooling energy demands were reduced to 30 ~ 80% level compared to UFAD alone, and in particular, the energy demand was reduced in proportion to the supply airflow rate or the operating time while T_o was 16 ~ 20℃. However, when T_o was 22℃, the increase in the supply airflow rate or the operating time results in a disadvantage in terms of cooling energy demands. In addition, the cooling energy demands for UFAD+NPC model were analyzed by applying weather data from three regions with different average outdoor air temperatures. As a result, the cooling energy demand of operating NPC only when T_o was below 20℃ was reduced by 27% compared to that of operating NPC continuously for 8 hours.

• 한국초전도학회:학술대회논문집
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• v.12
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• pp.85-85
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• 2002

• The Journal of Asian Finance, Economics and Business
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• v.8 no.4
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• pp.613-624
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• 2021

This paper analyzes the relationship between income distribution and energy consumption from a Pareto optimal approach. For this purpose, the causality relationship between electricity consumption per capita (kWh) with respect to country groups and energy consumption per capita (kg of oil equivalent) along with gross domestic product per capita was analyzed. In addition to this purpose, a Pareto analysis was conducted to determine the countries with the highest per capita national income, how much of the world total energy they consume, and whether the law of power in the energy and electricity markets exists. Finally, the impact of official development assistance provided to low-income countries by high-income countries on the low-income countries' electricity and energy consumption was analyzed. In other words, it was questioned whether pareto redistribution policies serve the purpose or not. The Engle-Granger causality approach was used in the analysis of the causality relationship between variables. Our analysis indicated that, first, the energy data of the country groups may be inadequate in revealing income inequalities. Second, the existence of Pareto law of power and global income inequality can be explained based on energy data. Finally, Pareto optimal redistribution policies to eliminate income inequality remain inadequate in practice.

• Journal of Nutrition and Health
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• v.25 no.7
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• pp.617-627
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• 1992

This study was attempted to observe the possibility of body fat distribution and fasting serum insulin as potential predictive factors for obesity and energy intake. Subjects participated in this study were seventeen pairs of upper body type women and lower body type women whose age weight BMI daily energy expenditure per body weight were equally matched, Waist to hip girth ratio(WHR) was measured as a criteria of body fat distribution. Comparison of eating behavior between upper body type and lower body type women did not show any significant differences in meal size meal duration and energy intake per minute While serum free fatty acid level was lower in upper body type women percentage of body fat and fasting serum insulin triglycerde level of upper body type women were statistically higher than those of lower body type women(p<0.05) Our data may indicate the possibility that sympathetic nervous system activity was suppressed in upper body type women which needs ti be examined in future studies. In addition since the upper body type women were dieting over the period of survey with the intention of weigh loss we can conclude that upper body type women had larger variabilities than lower body type women in terms of daily energy intake level.

• Nuclear Engineering and Technology
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• v.38 no.7
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• pp.675-680
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• 2006

The neutron transmutation doping of silicon (NTD), as a method to produce a high quality semiconductor, utilizes the transmutation of a silicon element into phosphorus by neutron absorption in a silicon single crystal. In this paper, we present the design of a neutron screen for a 6' Si ingot irradiation in the NTD2 hole of HANARO. The goal of the design is to achieve an even flat axial distribution of the resistivity, or $Si^{30}(n,{\gamma})Si^{31}$ reaction rate, in the irradiated Si ingot. We used the MCNP4C code to simulate the neutron screen and to calculate the reaction rate distribution in the Si ingot. The fluctuations in the axial distribution were estimated to be within ${\pm}2.0%$ from the average for the final neutron screen design; thus, they satisfy the customers' requirement for uniform irradiation. On the other hand, we determined the optimal insertion depths of the Si ingots by varying the critical control rod position, which greatly affects the axial flux distribution.

• Proceedings of the Korean Magnestics Society Conference
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• 2012.11a
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• pp.104-105
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• 2012

The temperature dependence of the effective magnetic anisotropy constant K(T) of ferrite nanoparticles is obtained based on the measurements of SQUID magnetometry. For this end, a very simple but intuitive and direct method for determining the temperature dependence of anisotropy constant K(T) in nanoparticles is introduced in this study. The anisotropy constant at a given temperature is determined by associating the particle size distribution f(r) with the anisotropy energy barrier distribution $f_A(T)$. In order to estimate the particle size distribution f(r), the first quadrant part of the hysteresis loop is fitted to the classical Langevin function weight-averaged with the log?normal distribution, slightly modified from the original Chantrell's distribution function. In order to get an anisotropy energy barrier distribution $f_A(T)$, the temperature dependence of magnetization decay $M_{TD}$ of the sample is measured. For this measurement, the sample is cooled from room temperature to 5 K in a magnetic field of 100 G. Then the applied field is turned off and the remanent magnetization is measured on stepwise increasing the temperature. And the energy barrier distribution $f_A(T)$ is obtained by differentiating the magnetization decay curve at any temperature. It decreases with increasing temperature and finally vanishes when all the particles in the sample are unblocked. As a next step, a relation between r and $T_B$ is determined from the particle size distribution f(r) and the anisotropy energy barrier distribution $f_A(T)$. Under the simple assumption that the superparamagnetic fraction of cumulative area in particle size distribution at a temperature is equal to the fraction of anisotropy energy barrier overcome at that temperature in the anisotropy energy barrier distribution, we can get a relation between r and $T_B$, from which the temperature dependence of the magnetic anisotropy constant was determined, as is represented in the inset of Fig. 1. Substituting the values of r and $T_B$ into the $N{\acute{e}}el$-Arrhenius equation with the attempt time fixed to $10^{-9}s$ and measuring time being 100 s which is suitable for conventional magnetic measurement, the anisotropy constant K(T) is estimated as a function of temperature (Fig. 1). As an example, the resultant effective magnetic anisotropy constant K(T) of manganese ferrite decreases with increasing temperature from $8.5{\times}10^4J/m^3$ at 5 K to $0.35{\times}10^4J/m^3$ at 125 K. The reported value for K in the literatures is $0.25{\times}10^4J/m^3$. The anisotropy constant at low temperature region is far more than one order of magnitude larger than that at 125 K, indicative of the effects of inter?particle interaction, which is more pronounced for smaller particles.

• Korean Journal of Acupuncture
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• v.26 no.4
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• pp.1-11
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• 2009

Objectives : The object of this study is measuring energy (skin capacitance) distribution on the specific acupionts and analyzing change patterns of meridian energy according to time or synchronous time. Methods : To check energy distribution using the meridian energy measurement system(DMM-1000), ten specific acupoints(ST34, ST36, ST40, ST41, ST42, ST43, ST44, ST45, BL21, CV12) were chosen. We checked the energy distribution and analyzed the change patterns before and after meal. We checked the state of the energy of ST meridian which is considered to have relation to stomach organ activity. Based on the hypothesis regarding energy difference due to Qi flowing, we compared energy potential on 10 specific acupoints. Results and Conclusions : Electric energy of each specific acupoint was different according to subjects and time. Through this study, we proposed an indispensable condition of energy difference due to Qi flowing through meridian.

• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.72-77
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• 2021

The radial distribution of etch rate was analyzed using the ion energy flux model in VHF-CCP. In order to exclude the effects of polymer passivation and F radical depletion on the etching. The experiment was performed in Ar/SF6 plasma with an SF6 molar ratio of 80% of operating pressure 10 and 20 mTorr. The radial distribution of Ar/SF6 plasma was diagnosed with RF compensated Langmuir Probe(cLP) and Retarding Field Energy Analyzer(RFEA). The radial distribution of ion energy flux was calculated with Bohm current times the sheath voltage which is determined by the potential difference between the plasma space potential (measured by cLP) and the surface floating potential (by RFEA). To analyze the etch rate uniformity, Si coupon samples were etched under the same condition. The ion energy flux and the etch rate show a close correlation of more than 0.94 of R² value. It means that the etch rate distribution is explained by the ion energy flux.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.05a
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• pp.83-86
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• 2001

This paper aims to make a feasibility study and to propose a master plan for the development of "integrated ocean energy utilization system", which utilizes various renewable ocean energies. Fossils energy, as the most important energy resources which are inevitable for the living and industrial development, becomes exhausted and its consumption creates serious environmental problem. It is important to utilize renewable ocean energy for a sustainable and environmentally friendly development. We survey the integrated utilization of ocean energy based on surveyed energy density distribution and propose concepts of integrated ocean energy utilization plant for both onshore and offshore system. The results of this study can support national effort for renewable energy development utilizing integrated ocean energy and refer as a guideline for the technical development of sustainable integrated ocean energy.

• Wind and Structures
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• v.28 no.6
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• pp.369-380
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• 2019

Statistical distributions are very useful in describing wind speed characteristics and in predicting wind power potential of a specified region. Although the Weibull distribution is the most popular one in wind energy literature, it does not seem to be able to perfectly fit all the investigated wind speed data in nature. Thus, many studies are still being conducted to find flexible distribution for modelling wind speed data. In this study, we propose a new Odd-Burr Rayleigh distribution for wind speed characterization. The Odd-Burr Rayleigh distribution with two shape parameters is flexible enough to model different shapes of wind speed data and thus it can be an alternative wind speed distribution for the assessment of wind energy potential. Therefore, suitability of the Odd-Burr Rayleigh distribution is investigated on real wind speed data taken from different regions in the South Africa. Numerical results of the conducted analysis confirm that the new Odd-Burr Rayleigh distribution is suitable for modelling most of the considered real wind speed cases and it also can be used for predicting wind power.