• KIEAE Journal
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• v.10 no.5
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• pp.139-150
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• 2010

Until now, the eco-friendly construction (green construction) has been focused on reducing environmental impacts in use(operation and maintenance) phase. Considering the environmental influence along the life cycle of construction project, the impact in execution phase is rather lower than that in use phase. However, that impact is thought to be greatly decreased by well-organized activities. Based on its urgency and requirement for timely action, this study aimed to discuss the greenhouse gas (GHG) reduction plan in execution phase from a broad perspective. To achieve this purpose, the green building rating systems in domestic and foreign countries have been reviewed, and the practice in Japan was investigated. In order to improve current on-site greenhouse gas management, the integration among construction phases, participants, and environmental factors, and institutional supports are required as well as the contractor's efforts.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.85-89
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• 2021

AlGaN-based UV-C light-emitting diodes (LEDs) were applied for p-type activation by electrochemical potentiostatic activation (EPA). The p-type activation efficiency was increased by removing hydrogen atoms through EPA treatment using a neutral Mg-H complex that causes high resistance and low conductivity. A neutral Mg-H complex is decomposed into Mg^- and H⁺ depending on the key parameters of solution, voltage, and time. The improved hole carrier concentration was confirmed by secondary ion mass spectroscopy (SIMS) analysis. This mechanism eventually improved the internal quantum efficiency (IQE), the light extraction efficiency, the leakage current value in the reverse current region, and junction temperature, resulting in better UV-C LED lifetime. For systematic analysis, SIMS, Etamax IQE system, integrating sphere, and current-voltage measurement system were used, and the results were compared with the existing N₂-annealing method.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.2
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• pp.119-126
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• 2017

Purpose: The aim of the present study was to compare clinical antiplaque and antigingivitis effect between Light Emitting Diode (LED) electronic toothbrush and electronic toothbrush without LED for gingivitis and mild periodontitis patients. Materials and Methods: 30 patients included in this study. 15 patients in experimental group used LED electronic tooth brush which has red and white LED within its head, and other 15 patients in control group used same product which specially modified that function without LED. Clinical parameters ($L{\ddot{o}}e-Silness$ gingival index (GI), Quigley-Hein plaque index (PI)) were measured at the baseline, 2 weeks and 4 weeks later. Wilcoxon signed rank test and Mann-Whitney test were used for statistical analysis. Results: Compare of GI change between experimental and control group with time, both groups showed that reduced GI, but lower GI values detected at 2 weeks and 4 weeks later in experimental group than control group. And lower PI values detected at 4 weeks later in experimental group than control group, but not statistically significant. Conclusion: Based on these results and within the limits of this study, the electronic toothbrush with LED could reducing gingivitis in a short period and infer that decreasing plaque accumulation in a long period.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6925-6931
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• 2015

LED(Light Emitting Diode) is used in various filed like a display because of low power consuming, long life span, high brightness, rapid response time and environmental-friendly characteristic. General fabrication method is combination blue light LED chip with yellow fluorescent substance. Because this way is suitable for industry field in terms of convenience, economic, efficiency. In white light LED packaging process, encapsulation process that is dispensing fluorescent substance with silicon to blue light LED chip is most important. So, in this paper we develop EHD pump system using voice coil motor and electrostatic pump for dispensing fluorescent substance. For these things we conduct basic test about liquid surface profiles by voltage and process time. Through this data we decide optimal process condition and verify the optimal condition using design of experiment method. And to confirm uniformity of the condition, we conduct repeat dispensing test.

• Analytical Science and Technology
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• v.6 no.3
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• pp.319-328
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• 1993

Energy transfer process between $Tb^{3+}$ and $Ce^{3+}$ has been studied in LaOCl host. The energy absorbed by $Ce^{3+}$ transfers to $Tb^{3+}$ which has levels emitting strong fluorescence. The probability of energy transfer depends strongly on the concentration or the distance of activator ions. While the energy transferred on $Tb^{3+}$ emits from $^5D_3$ level at low concentration of $Ce^{3+}$, the energy goes back to $Ce^{3+}$(Back Transfer) and then emits from low levels of $Ce^{3+}$ and $Tb^{3+}$ at the high concentration. The Back Transfer process has been identified by the experiment with varying the concentration of the activator, $Ce^{3+}$. The relaxation is more effective if $Ce^{3+}$ intermediates than if not.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1735-1737
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• 1999

In this study, several lanthanide complexes such as Eu$(TTA)_3$(Phen). Tb$(ACAC)_3$(Cl-Phen) were synthesized and the white-light electroluminescence (EL) characteristics of their thin films were investigated. where the devices having structures of anode/TPD/Tb$(ACAC)_3$(Cl-Phen)/Eu$(TTA)_3$(Phen)/$Alq_3$ or $Bebq_2$/ cathode and the low work function metal alloy such as Li:Al was used as the electron injecting electrode (cathode). Details on the white-light-emitting characteristics of these device structures were explained by the energy band diagrams of various materials used in these structures, where the energy levels of new materials such as ionization potential (IP) and electron affinity (EA) were measured by cyclic voltametric method.

• Journal of the Korean Ceramic Society
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• v.42 no.5 s.276
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• pp.333-337
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• 2005

In order to improve the performance of green emitting phosphors for plasma display panel, the $Zn_2SiO_4:Mn,Al$ phosphors were synthesized using sol-gel technique and studied using SEM and VUV photoluminescence spectrometer. pH values of the starting solutions (pH = 0.5$\~$2.34) were controled by HCl as the catalysis of hydrolysis and wet gels were dried at $80^{\circ}C$ and $120^{\circ}C$, respectively. We investigated the effects of pH and drying temperatures during sol-gel processes. The results indicated that the phosphor prepared at pH = 1 showed the maximum emission intensity in both drying conditions and the effect of pH of the starting solution on morphology were increased with particle size as HCl and phosphor dried at high temperature showed more spherical and smaller particles than at low.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.99-99
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• 2010

Recently, amorphous transparent oxide semiconductors (TOS) have been widely studied for many optoelectronic devices such as AM-OLED (active-matrix organic light emitting diodes). The TOS TFTs using a-IGZO channel layers exhibit a high electron mobility, a smooth surface, a uniform deposition at a large area, a high optical transparency, a low-temperature fabrication. In spite of many advantages of the sputtering process such as better step coverage, good uniformity over large area, small shadow effect and good adhesion, there are not enough researches about characteristics of a-IGZO thin films. In this study, therefore, we focused on the electrical properties of a-IGZO thin films as a channel layer of TFTs. TFTs with the a-IGZO channel layers and Y2O3 gate insulators were fabricated. Source and drain layers were deposited using ITO target. TFTs were deposited on unheated non-alkali glass substrates ($5cm{\times}5cm$) with a sintered ceramic IGZO disc (3 inch $\varnothing$, 5mm t), Y2O3 disc (3 inch $\varnothing$, 5mm t) and ITO disc (3 inch $\varnothing$, 5mm t) as a target by magnetron sputtering method. The O2 gas was used as the reactive gas. Deposition was carried out under various sputtering conditions to investigate the effect of sputtering process on the characteristics of a-IGZO thin films. Correlation between sputtering factors and electronic properties of the film will be discussed in detail.

• Korean Journal of Materials Research
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• v.14 no.6
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• pp.399-401
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• 2004

InGaAs/GaAs quantum wire structures were grown by low pressure metalorganic chemical vapor deposition by using selective area epitaxy.$ In_{ 0.2}$$Ga_{0.8}$ As/GaAs quantum wire structures were grown on a $SiO_2$ masked GaAs substrate. Quantum wire structures with sharp tips and smooth side walls were grown. We have grown InGaAs/GaAs quantum wire structures using variously opened width of the $SiO _2$ mask. Even though the opening widths of $SiO_2$ masked GaAs substrate were different, similar shapes of triangular structures were grown. Using various kinds of differently opened $SiO_2$ masked area, it would be possible to grow quantum wire structures with various thicknesses. The quantum wire structures are formed near the pinnacle of the triangular structure. Therefore, the fabrication of the uniquely designed integrated optical devices which include light emitting sources of multiple wavelength is possible.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1999.04a
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• pp.53-61
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• 1999

Radiation therapy has been used for the cancer treatment and radiation synovectomy$\^$1-3)/. There are two kinds of radiation therapy; the external radiation therapy and the internal radiation therapy. Hitherto, the external radiation therapy has been widely used, but for the lack of its selectivity it requires strong radiation dose and causes the irritation and damage of the normal tissue or organ. Therefore many researchers give their interests to the internal radiation therapy in which the radioactive materials are injected directly into the target organ or tissue. Many ${\beta}$-emitting radionuclides have been studied for the application of the internal radiation theraily. Among them, Holmium-166 has the many beneficial physical characteristics for the internal radiation therapy such as appropriate half life (26.8hr), high ${\beta}$ energy (max. 1.85 MeV(51%), 1.77 MeV (48%), mean 0.67MeV), and low ${\gamma}$ energy (0.081MeV) easily detected by ${\gamma}$-camera. In the internal radiation therapy, the administered radioactive materials should be retained in the target long enough to increase the therapeutic effects and avoid the damage in the normal tissue or organ. For this purpose, radionuclides are used as complex form with carriers. Carriers should have a high affinity with radionuclides in vivo and in vitro, so the complex can be evenly distributed in the lesion but can not be leaked out from the lesion.