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Nanotube-based Dye-sensitized Solar Cells

  • Kim, Jae-Yup;Park, Sun-Ha;Choi, Jung-Woo;Shin, Jun-Young;Sung, Yung-Eun
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.71-71
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    • 2011
  • Dye-sensitized solar cells (DSCs) have drawn great academic attention due to their potential as low-cost renewable energy sources. DSCs contain a nanostructured TiO2 photoanode, which is a key-component for high conversion efficiency. Particularly, one-dimensional (1-D) nanostructured photoanodes can enhance the electron transport for the efficient collection to the conducting substrate in competition with the recombination processes. This is because photoelectron colletion is determined by trapping/detrapping events along the site of the electron traps (defects, surface states, grain boundaries, and self-trapping). Therefore, 1-D nanostructured photoanodes are advantageous for the fast electron transport due to their desirable features of greatly reduced intercrystalline contacts with specified directionality. In particular, anodic TiO2 nanotube (NT) electrodes recently have been intensively explored owing to their ideal structure for application in DSCs. Besides the enhanced electron transport properties resulted from the 1-D structure, highly ordered and vertically oriented nanostructure of anodic TiO2 NT can contribute additional merits, such as enhanced electrolyte diffusion, better interfacial contact with viscous electrolytes. First, to confirm the advantages of 1-D nanostructured material for the photoelectron collection, we compared the electron transport and charge recombination characteristics between nanoparticle (NP)- and nanorod (NR)-based photoanodes in DSCs by the stepped light-induced transient measurements of photocurrent and voltage (SLIM-PCV). We confirmed that the electron lifetime of the NR-based photoanode was much longer than that of the NP-based photoanode. In addition, highly ordered and vertically oriented TiO2 NT photoanodes were prepared by electrochemical anodization method. We compared the photovoltaic properties of DSCs utilizing TiO2 NT photoanodes prepared by one-step anodization and two-step anodization. And, to reduce the charge recombination rate, energy barrier layer (ZnO, Al2O3)-coated TiO2 NTs also applied in DSC. Furthermore, we applied the TiO2 NT photoanode in DSCs using a viscous electrolyte, i.e., cobalt bipyridyl redox electrolyte, and confirmed that the pore structure of NT array can enhance the performances of this viscous electrolyte.

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A Data Quality Improvement Method in Integrations of Distributed Data: National Science & Technology Information Services (분산 데이터의 통합시 데이터의 품질향상 방안: 국가과학기술종합정보시스템)

  • Shon, Kang-Ryul
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.8
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    • pp.1623-1636
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    • 2009
  • A currently domestic governmental R&D business is early to 100. And this is each managed individually in 15 professional organizations of research and management by characteristics of a business. For this Reason, A redundant investment issue regarding national R&D occurs, and an issue regarding efficiency of R&D investment by insufficiency of systematic R&D research project and result management is continuously raised. Ministry of Education Science and Technology establishing National Science & Technology Information Service(NTIS) in order to solve these issues. NTIS is the national R&D Portal System which can support efficiency of research and development to result utilization in planning of national research and development. As data of the same meaning are named particularly in each organizations, and that made to different data types, It is an issue to be difficult to achieve high level qualify, accuracy of integrated data in case of integration of distributed data like NTIS In this paper We consider integrated DB constructions and Information Linking of R&D Participants/Projects/Results information in a NTIS system for data qualify Improvement, and then We analyze the cause of the data quality problem, and we propose the improvement plan for data quality elevation of NTIS system.

CdS-Titania-Nanotube Composite Films for Photocatalytic Hydrogen Production (CdS/Titania-나노튜브 복합 막을 이용한 광촉매적 수소제조)

  • Lee, Hyun-Mi;So, Won-Wook;Baeg, Jin-Ook;Kong, Ki-Jeong;Moon, Sang-Jin
    • Transactions of the Korean hydrogen and new energy society
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    • v.18 no.3
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    • pp.230-237
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    • 2007
  • Titania nanotube(TiNT) and CdS sol were synthesized by hydrothermal reaction under strongly basic condition and by precipitation reaction of $Cd(N0_3)_2$ and $Na_2S$ aqueous solutions, respectively. After preparing a series of CdS-TiNT composite films on $F:SnO_2$ conducting glass with variation of the mole ratio (r) of TiNT/(CdS+TiNT), their visible light absorption, photocatalytic activities for hydrogen production, and the photocurrent generation were examined. In general, this CdS-TiNT series showed lower photocatalytic activities and photocurrent generation under Xe light irradiation compared to their counterparts, i.e., CdS-$TiO_2$ particulate series. It appeared that TiNTs are not so effective photocatalyic material in spite of their larger specific surface areas compared to $TiO_2$ nanoparticles, because they indicate a poor crystallinity and less intimate interaction or contact with CdS particles owing to the tubular morphology and an easy agglomeration among themselves.

Optical properties of Yb3+ doped Y3Al5O12 single crystals derived by the Czochralski method according to growth atmosphere and doping concentration (Czochralski 법으로 성장된 Yb3+ doped Y3Al5O12 단결정의 성장 분위기 및 도핑 농도에 따른 광학적 특성)

  • Shim, Jang Bo;Lee, Young Jin;Kang, Jin Ki;Lee, Young Kuk
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.25 no.2
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    • pp.68-73
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    • 2015
  • Single crystals of $Yb^{3+}$ doped $Y_3Al_5O_{12}$ up to 25 at.% were grown by the Czochralski method. Using the pulling rate of 0.8 mm/h and the rotation rate of 10 rpm, single crystals with diameters of up to 40 mm and lengths up to 160 mm were obtained. The growth atmosphere was either pure nitrogen or the mixture of nitrogen and oxygen. The crystal was bluish green when using pure nitrogen and the crystal was colorless when using the mixture of 99 % nitrogen and 1 % oxygen. The concentration of $Yb^{3+}$ ions decreased with increasing the length of the crystal and $Yb^{3+}$ concentration of core area was slightly higher than the other areas in the compositional analysis. The fluorescence lifetime decreased with increasing the doping concentration of $Yb^{3+}$ ions.

Analysis of surface defect in RE : YAG (RE = Nd3+, Er3+, Yb3+) single crystal using chemical polishing and etching (화학적 polishing 및 etching을 통한 RE : YAG (RE = Nd3+, Er3+, Yb3+) 단결정의 표면 결함 분석)

  • Shim, Jang Bo;Kang, Jin Ki;Lee, Young Kuk
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.26 no.4
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    • pp.131-134
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    • 2016
  • The conditions for chemical polishing and etching technique were investigated to reveal surface defects in RE : YAG ($RE=Nd^{3+},\;Er^{3+},\;Yb^{3+}$) single crystals grown by Czochralski method. The optimal condition for chemical polishing was in 85 % $H_3PO_4$ solution at $330^{\circ}C$ for 30 minutes with a specimen fixed in the vertical direction. In addition, the optimal condition for chemical etching was in 85 % $H_3PO_4$ solution at $260^{\circ}C$ for 1 hour, and $70{\sim}80{\mu}m$ sized triangular etch pits were observed on (111) face. As a result of defect density analysis, $1.9{\times}10^3/cm^2$ for Nd(1 %) : YAG, $4.3{\times}10^2/cm^2$ for Er(7.3 %) : YAG, and $5.1{\times}10^2/cm^2$ for Yb(15 %) : YAG were measured.

Trademark Protection In The Fashion Industry with ICT Issues (패션산업의 상표권 보호 및 ICT 쟁점 - Louboutin 사건, Levi 사건에 대한 분석을 중심으로 -)

  • Lee, Jae-Kyoung
    • Journal of Legislation Research
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    • no.44
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    • pp.185-209
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    • 2013
  • With the broader range of information and communications technology, of which fashion is a foundational medium, to analyze fashion as an information technology in order to better understand the industry's desire for intellectual property protection, popular resistance to such protection, and the most efficacious balance between them in terms of creative expression. It is, therefore to be focused on cultural and historical reasons for the limited degree of intellectual property protection extended in the past to certain categories of human creativity, including fashion design. So, the question of why some tension still exists between creators and consumers of fashion, how information theory can contribute to an explanation for that tension, and what role law can play in its resolution with Louboutin case and Levi case. Consumers and designers alike are better served by promotion of fair competition, lower litigation costs, and the inventive synergy of the fashion industry. Louboutin shows the comfortable, respectful limits of trademark law, while Levi illustrates the dangerous, overreaching deference that a few circuits have granted to famous marks. The Supreme Court could clarify the standard for dilution claims, requiring that a junior mark be "identical or nearly identical" or even "significantly similar" to a senior mark. Courts should need a deference in making dilution determinations and can choose to make this factor quite subjective with the highest degree of similarity.

Surgical Treatment of Thoracoabdominal Aortic Aneurysm (흉복부 대동맥류의 외과적 치료)

  • Ahn, Hyuk;Kim, Jun-Seok
    • The Korean Journal of Thoracic and Cardiovascular Surgery
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    • v.29 no.2
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    • pp.177-184
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    • 1996
  • Between 1987 and 1994, 21 patients were treated surgically for aortic aneurysm involving the thoracoabdominal aorta. There were 11 males and 10 females, and their age ranged from 20 to 67 years old and mean age was 41.5 years. Many complained of back pain, chest pain or discomfort, and flank pain, but three patients were asymptomatic. 15 patients had chronic dissection (71.4%) and 6 had nondissecting fusiform or saccular aneurysm(28.5%), and of those 15 patients with chronic dissection, 6(28.5%) had atherosclerosis assniated with hypertension, 5 (23.8%) were Martian syndrome, and 2 (9.5%) were associated with pregnancy. The diameter of an aneurysm ranged from 6cm to 12cm, and their extent was classified as type I in 7(33.3%), type II in 8(38.1%), type III in 3(14.3%), and type IV in 3(14.3%) patients based on Crawford classification for TAA . Diseased aorta was replaced with artificial vascular graft in all but one patient. In whom the aortic tear site due to pseudoaneurysm was closed by primary suture. For the spinal cord protection during the operation, we used partial cardiopulmonary bypass (FV-FA or PA-FA bypass) in 12 patients (57.1%), Biopump (LA-FA bypass) in 4(19.0%), total circulartory arrest and CPB in 2 (9.5%), Gott's heparinized shunt in 1(4.7%), and simple aortic cross clamping in 2 (9.5%). The most common complication after the operation was hoarseness due to unilateral vocal cord palsy which onured in 5 patients (23.8%), and the next common complication was wound infection in 4 patients(19.0%), paraplegia in 2 patients (9.5%), chylothorax in 1 patient(4.7%). The hospital mortality rate was 9.5% (2deaths), and there was no late death. Our experience shows that the graft replacement of TAAA had reasonable rate of mortality, low rate of serious complication, and provided good post operative state of the pati nts, and since the thoracoabdominal aortic operation is not a high risky procedure anymore, we recommend a radical operation for the indicated patients.

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