4,792 research outputs found
Tuning the electronic band structure of PCBM by electron irradiation
Tuning the electronic band structures such as band-edge position and bandgap of organic semiconductors is crucial to maximize the performance of organic photovoltaic devices. We present a simple yet effective electron irradiation approach to tune the band structure of [6, 6]-phenyl-C61-butyric acid methyl ester (PCBM) that is the most widely used organic acceptor material. We have found that the lowest unoccupied molecular orbital (LUMO) level of PCBM up-shifts toward the vacuum energy level, while the highest occupied molecular orbital (HOMO) level down-shifts when PCBM is electron-irradiated. The shift of the HOMO and the LUMO levels increases as the irradiated electron fluence increases. Accordingly, the band-edge position and the bandgap of PCBM can be controlled by adjusting the electron fluence. Characterization of electron-irradiated PCBM reveals that the variation of the band structure is attributed to the molecular structural change of PCBM by electron irradiation
Improvement in the photoelectrochemical responses of PCBM/TiO2 electrode by electron irradiation
The photoelectrochemical (PEC) responses of electron-irradiated [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/TiO2 electrodes were evaluated in a PEC cell. By coating PCBM on TiO2 nanoparticle film, the light absorption of PCBM/TiO2 electrode has expanded to the visible light region and improved the PEC responses compared to bare TiO2 electrode. The PEC responses were further improved by irradiating an electron beam on PCBM/TiO2 electrodes. Compared to non-irradiated PCBM/TiO2 electrodes, electron irradiation increased the photocurrent density and the open-circuit potential of PEC cells by approximately 90% and approximately 36%, respectively at an optimum electron irradiation condition. The PEC responses are carefully evaluated correlating with the optical and electronic properties of electron-irradiated PCBM/TiO2 electrodes
Single-Copy Certification of Two-Qubit Gates without Entanglement
A quantum state transformation can be generally approximated by single- and
two-qubit gates. This, however, does not hold with noisy intermediate-scale
quantum technologies due to the errors appearing in the gate operations, where
errors of two-qubit gates such as controlled-NOT and SWAP operations are
dominated. In this work, we present a cost efficient single-copy certification
for a realization of a two-qubit gate in the presence of depolarization noise,
where it is aimed to identify if the realization is noise-free, or not. It is
shown that entangled resources such as entangled states and a joint measurement
are not necessary for the purpose, i.e., a noise-free two-qubit gate is not
needed to certify an implementation of a two-qubit gate. A proof-of-principle
demonstration is presented with photonic qubits.Comment: 8 pages. arXiv admin note: text overlap with arXiv:1812.0208
Comparative analysis of multiple classification models to improve PM10 prediction performance
With the increasing requirement of high accuracy for particulate matter prediction, various attempts have been made to improve prediction accuracy by applying machine learning algorithms. However, the characteristics of particulate matter and the problem of the occurrence rate by concentration make it difficult to train prediction models, resulting in poor prediction. In order to solve this problem, in this paper, we proposed multiple classification models for predicting particulate matter concentrations required for prediction by dividing them into AQI-based classes. We designed multiple classification models using logistic regression, decision tree, SVM and ensemble among the various machine learning algorithms. The comparison results of the performance of the four classification models through error matrices confirmed the f-score of 0.82 or higher for all the models other than the logistic regression model
Improved conversion efficiency of Ag2S quantum dot-sensitized solar cells based on TiO2 nanotubes with a ZnO recombination barrier layer
We improve the conversion efficiency of Ag2S quantum dot (QD)-sensitized TiO2 nanotube-array electrodes by chemically depositing ZnO recombination barrier layer on plain TiO2 nanotube-array electrodes. The optical properties, structural properties, compositional analysis, and photoelectrochemistry properties of prepared electrodes have been investigated. It is found that for the prepared electrodes, with increasing the cycles of Ag2S deposition, the photocurrent density and the conversion efficiency increase. In addition, as compared to the Ag2S QD-sensitized TiO2 nanotube-array electrode without the ZnO layers, the conversion efficiency of the electrode with the ZnO layers increases significantly due to the formation of efficient recombination layer between the TiO2 nanotube array and electrolyte
Fabrication of complete titania nanoporous structures via electrochemical anodization of Ti
We present a novel method to fabricate complete and highly oriented anodic titanium oxide (ATO) nano-porous structures with uniform and parallel nanochannels. ATO nano-porous structures are fabricated by anodizing a Ti-foil in two different organic viscous electrolytes at room temperature using a two-step anodizing method. TiO2 nanotubes covered with a few nanometer thin nano-porous layer is produced when the first and the second anodization are carried out in the same electrolyte. However, a complete titania nano-porous (TNP) structures are obtained when the second anodization is conducted in a viscous electrolyte when compared to the first one. TNP structure was attributed to the suppression of F-rich layer dissolution between the cell boundaries in the viscous electrolyte. The structural morphologies were examined by field emission scanning electron microscope. The average pore diameter is approximately 70 nm, while the average inter-pore distance is approximately 130 nm. These TNP structures are useful to fabricate other nanostructure materials and nanodevices
Implementation Mechanism of the Four-Group Shift System at Yuhan-Kimberly
Research has long reported the difficulty of adopting a new system into
an organization. Therefore, we have examined the introduction process of
a new system through Yuhan-Kimberlys case for finding the solution. The
new system such as the four-group shift of Yuhan-Kimberly is an effective
combination of technological skills and HR management skills respecting
human beings. It also generates competitive advantages contributing to the
formation of lifelong education, decreased safety-related accidents, and increased product quality and productivity. This system allows employees to
trust that the company regards its employees as true companions. From the
Yuhan-Kimberlys case, we could reveal the secret of the successful introduction
of a new system via a mechanism framework.This work was supported by the second stage of the Brain Korea 21 Project in
2007
Gene loss in keratinization programs accompanies adaptation of cetacean skin to aquatic lifestyle.
Importùncia dos Saca-Rabos (Herpestes Ichneumon) como Reservatório de Mycobacterium avium subsp. paratuberculosis. Deteção por Técnicas Tradicionais e Moleculares
Poster apresentado nas IV Jornadas de GenĂ©tica, realizadas na UTAD, Vila Real, nos dias 1,2 e 3 de Março de 2012.Os saca-rabos (Herpestes ichneumon) tambĂ©m conhecidos por mangustos, sĂŁo carnĂvoros diurnos selvagens que juntamente com a geneta (Genetta genetta) representam os exemplares da famĂlia Viverridae em Portugal. Ă uma espĂ©cie cinegĂ©tica de caça menor que se alimenta de coelhos, roedores, aves, cobras, insectos e ovos.
Neste estudo colheram-se amostras de 8 animais mortos por atropelamento e em açÔes de controlo de predadores, durante os anos de 2010 e 2011, nos concelhos de Idanha-a-Nova e Penamacor do distrito de Castelo Branco. As amostras colhidas foram fĂgado, pulmĂŁo, baço, intestino, rim, gĂąnglio mesentĂ©rico, retrofarĂngeo, mediastĂnico, amĂgdalas e fezes. As amostras foram submetidas Ă tĂ©cnica de PCR e a cultura microbiolĂłgica em meios especĂficos.
Em trĂȘs saca-rabos (37,5%) detectou-se Mycobacterium avium subsp. paratuberculosis (Map) atravĂ©s da tĂ©cnica de biologia molecular. Dois eram machos e um era fĂȘmea. Map foi confirmado tambĂ©m em cultura nos dois machos. Sete saca-rabos (87,5%) apresentaram bactĂ©rias ĂĄlcool-ĂĄcido resistentes compatĂveis com Map em esfregaços de diferentes tecidos, quando corados pelo mĂ©todo de Ziehl-Neelsen.
Estes resultados preliminares confirmam os saca-rabos como reservatĂłrio de Map no nosso paĂs. Atualmente, estĂŁo a ser desenvolvidos mais estudos para a avaliação dos saca-rabos na dinĂąmica da infeção de Map em mamĂferos selvagens
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