• Journal of the Korean Institute of Gas
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• v.2 no.2
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• pp.55-60
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• 1998

In this study, we investigated the dust explosion characteristics by determining minimum ignition energy and explosion limit for this experiment, we used pine-tree dust which was used widely for the filler of thermosetting resin. The experiment was accomplished according to the variation of discharge gap, dust concentration, particle size and humidity. The result of this experiment are as follows; (1) The relation between the discharge gap and ignition energy was that ignition energy decreased according as the discharge gap became small, but increased when the discharge gap was below 4mm and suddenly became infinite when the discharge gap was below. So, we knew that this infinite value was limit discharge gap. (2) When the dust concentration increase and the particle size became microscopic it was easy to explore and in the same particle size, if the humidity increase the minimum ingnition energy decreased.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4005-4012
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• 2022

As high-level radioactive waste (HLW) generated from nuclear power plants is harmful to the human body, it must be safely disposed of by an engineered barrier system consisting of disposal canisters and buffer and backfill materials. A gap exists between the canister and buffer material in a HLW repository and between the buffer material and natural rock-this gap may reduce the water-blocking ability and heat transfer efficiency of the engineered barrier materials. Herein, the basic characteristics and thermal properties of granular bentonite, a candidate gap-filling material, were investigated, and their effects on the temperature change of the buffer material were analyzed numerically. Heat transfer by air conduction and convection in the gap were considered simultaneously. Moreover, by applying the Korean reference disposal system, changes in the properties of the buffer material were derived, and the basic design of the engineered barrier system was presented according to the gap filling material (GFM). The findings showed that a GFM with high initial thermal conductivity must be filled in the space between the buffer material and rock. Moreover, the target dry density of the buffer material varied according to the initial wet density, specific gravity, and water content values of the GFM.

• Journal of the Korean Ceramic Society
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• v.40 no.3
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• pp.213-218
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• 2003

Band gap energies of SrTiO$_3$(STO) thin film on glass substrates were studied in terms of annealing temperature. The STO thin film was fabricated by our newly developed method based on the combination of the Self-Assembled Monolayer(SAM) technique and the Liquid Phase Deposition(LPD) method. The as-deposited film demonstrated a direct band gap energy of about 3.65 eV, which further increased to 3.73 eV and 3.78 eV by annealing at 40$0^{\circ}C$ and 50$0^{\circ}C$, respectively. The band gap energy saturated at about 3.70 eV for the crystallized film which was obtained by annealing at 600-$700^{\circ}C$. The relatively large band gap energies of our crystallized films were due to the presence of minor amorphous phase, grain boundaries and oxygen vacancies generated by annealing in air.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.262-264
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• 2009

Ternary oxides with controlled band gap energy and reduced reactivity against moisture and carbon dioxide gas were designed and studied as a potential material for protective layer of ac-PDPs. The results showed a significant reduction in firing voltage and improved environmental stability.

• Asia Pacific Journal of Business Review
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• v.3 no.1
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• pp.19-38
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• 2018

The energy intensity of Nepal is economically not worthy, lacks eco-friendly and importantly not sustainable, and almost four times the average global energy intensity. Considerable efforts have been exercised to reduce the energy gap yet, it is still much to achieve. Nation priority on energy sector was envisaged with promulgation of investment friendly rules and law in hydropower and renewable technology even though, could not harness the sufficient energy. In amid of this acute energy crisis, the government launched the Nepal Energy Efficiency Programme (NEEP) with technical assistance from German International Cooperation (GIZ). Energy Efficiency (EE) practice is the most cost-effective method to reduce the supply and demand gap, reduce on greenhouse gases and pollution, and deter on import of petroleum products which finally improves on trade imbalance. This paper had proposed a framework of energy management team to promote energy efficient technologies in residential consumer. The energy management teams study the past records of energy use pattern of consumers and suggest appropriate technology for energy saving options. The paper provides some reviews of energy efficiency initiatives undertaken by the concern regulatory body which highlights the current status. The comprehensive knowledge acquired through exploratory research is implemented in this paper to identify the various barriers that domestic consumer is experiencing towards the active participation in energy efficiency program launched by the Government of Nepal.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.08a
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• pp.31-36
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• 2002

In this work $Cd_{4}GeSe_{6}$ and $Cd_{4}GeSe_{6}:Co^{2+}$ single crystals were grown by the chemical transport reaction method and the structure of $Cd_{4}GeSe_{6}$ and $Cd_{4}GeSe_{6}:Co$ single crystals were monoclinic structure. The temperature dependence of optical energy gap was fitted well to Varshni equation. Also, the entropy, enthalpy and heat capacity were deduced from the temperature dependence of optical energy gap.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.37-37
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• 2009

박막태양전지는 p-i-n substrate형과 n-i-p substrate형 두가지구조로 제조된다. 각 layer에서 activation energy와 band gap energy를 ASA simulator를 통해 조절해보았다. Simulation결과 p-i-n substrate형에서 p-layer와 n-i-p substrate형 n-layer에서 동일하게 activation energy 0.2eV, band gap energy 1.80eV에 최고효율 나왔고 각각 10.07%, 10.17%의 최고효율을 구할 수 있었다. 최적화 과정을 통하여 같은 조건에서 p-i-n substrate형 보다 n-i-p substrate형이 보다 높은 효율을 낸다는 것을 알 수 있었으며 본 연구를 통해 각 구조의 차이를 알 수 있었고 이는 높은 효율의 박막태양전지 설계에 도움이 될 것 이다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.12a
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• pp.39-42
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• 2006

Titania sols or powders were are very promising materials for environment as photocatalyst. The band gap energy of $TiO_2$ has been known to be 2.8 to 3.2 eV. But the measuring system of its band gap is usually depend on absorption properties. Thus, in this study, absorption properties of $TiO_2$ sols prepared by hydrothermal process were researched with the effect of various particle sizes and concentrations. The mean particle size in $TiO_2$ sols increased as 15 nm to 60 nm, absorption graph measured by UV-Vis spectrometer shows to move red-shift. When dilute solution added with $2^n$ in $TiO_2$, the band gap energy increases as linear function.

• Coupled systems mechanics
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• v.2 no.2
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• pp.147-157
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• 2013

We numerically investigate the electronic band structure of carbon nanotubes (CNTs) under radial corrugation. Hydrostatic pressure application to CNTs leads to a circumferential wave-like deformation of their initially circular cross-sections, called radial corrugations. Tight-binding calculation was performed to determine the band gap energy as a function of the amplitude of the radial corrugation. We found that the band gap increased with increasing radial corrugation amplitude; then, the gap started to decline at a critical amplitude and finally vanished. This non-monotonic gap variation indicated the metal-semiconductor-metal transition of CNTs with increasing corrugation amplitude. Our results provide a better insight into the structure-property relation of CNTs, thus advancing the CNT-based device development.

• Korean Management Science Review
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• v.34 no.3
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• pp.1-14
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• 2017

This study empirically analyzes the impact of inventory management performance on the energy efficiency in Korean petrochemical companies. The concept of the distance function is used to define the energy efficiency and the estimation of the distance function is performed using the stochastic frontier analysis. The inventory turnover is selected as the variable indicating the inventory management performance of the company. The main results of this study are as follows. First, the inventory turnover has a positive impact on energy efficiency. Second, during the period over 2011~2015, while the gap in energy efficiency among the companies expanded, the average energy efficiency decreased. Third, the average energy efficiency in upstream process companies was greater than downstream process companies and the gap in energy efficiency among downstream process companies was greater than upstream process companies. Fourth, the average marginal effect of inventory turnover on energy efficiency increased gradually from 2011 to 2015. Finally, the average marginal effect of inventory turnover in downstream process companies was greater than upstream process companies, and the gap in the marginal effect of inventory turnover among downstream process companies was greater than upstream process companies. These results together imply the importance of inventory management in terms of energy efficiency.