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排序方式: 共有172条查询结果,搜索用时 10 毫秒
161.
162.
Wenjun Chen Joshua Castro Seungbae Ahn Xiaochen Li Oscar Vazquez‐Mena 《Advanced materials (Deerfield Beach, Fla.)》2019,31(14)
Charge collection is critical in any photodetector or photovoltaic device. Novel materials such as quantum dots (QDs) have extraordinary light absorption properties, but their poor mobility and short diffusion length limit efficient charge collection using conventional top/bottom contacts. In this work, a novel architecture based on multiple intercalated chemical vapor deposition graphene monolayers distributed in an orderly manner inside a QD film is studied. The intercalated graphene layers ensure that at any point in the absorbing material, photocarriers will be efficiently collected and transported. The devices with intercalated graphene layers have superior quantum efficiency over single‐bottom graphene/QD devices, overcoming the known restriction that the diffusion length imposes on film thickness. QD film with increased thickness shows efficient charge collection over the entire λ ≈ 500–1000 nm spectrum. This architecture could be applied to boost the performance of other low‐cost materials with poor mobility, allowing efficient collection for films thicker than their diffusion length. 相似文献
163.
Langergraber G Giraldi D Mena J Meyer D Peña M Toscano A Brovelli A Korkusuz EA 《The Science of the total environment》2009,407(13):3931-5004
Numerical modelling of subsurface flow constructed wetlands (CWs) gained increasing interest during the last years. The main objective of the modelling work is, on the one hand, to increase the insight in dynamics and functioning of the complex CW system by using mechanistic or process based models that describe transformation and degradation processes in detail. As these mechanistic models are complex and therefore rather difficult to use there is, on the other hand, a need for simplified models for CW design. The design models should be premium to the currently used design guidelines that are mainly based on rules of thumb or simple first-order decay models. This paper presents an overview of the current developments on modelling of subsurface flow CWs based on the modelling work and model developments presented at the WETPOL 2007 symposium. Three kinds of models have been presented: simple transport and first-order decay models, complex mechanistic models, and a simplified model that has been developed for design of CWs. The models are presented and selected results are shown and discussed in relation to the available literature. 相似文献
164.
Ángel Mena Fernando López José Manuel Framiñan Francisco Flores Juan Manuel Gallego 《Automation in Construction》2010,19(2):270-282
In this paper we discuss the results of a research project called eXtensible Project Documentation Reporting Language (XPDRL). The main objective of this project is to improve the quality of the core project documentation that serves for supporting the construction works in Spain and to facilitate an efficient exchange of information between the stakeholders in the Spanish Architectural Engineering and Construction sector, in particular their relationship with the Professional Associations and Spanish control public bodies. Starting from the premise that high quality project documentation is the basic precondition for a good quality in all the phases of the whole buildings and facilities life cycle, the project is based on Internet, XBRL (eXtensible Business Reporting Language) and the new Spanish standards about the quality in the project documentation (UNE 157000 series). As a result, a new set of XBRL taxonomies has been developed to support the processes of elaboration, verification, sending to the Professional Association, digital stamping, delivery, control, compulsory registration and storage of the construction project core documentation by the public authorities. Our proposal can be extended to other countries, particularly in Europe, since regulations are becoming similar in all EU countries. The potential for spin-off technology utilization is also significant in the areas of insurance, inspection chamber, digital reporting and project management. 相似文献
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167.
(1)H-high resolution magic angle spinning-nuclear magnetic resonance spectroscopy was employed to gain the metabolic profile of longissimus dorsi and semitendinosus muscles of four different breeds: Chianina, Holstein Friesian, Maremmana and Buffalo. Principal component analysis, partial least squares projection to latent structure - discriminant analysis and orthogonal partial least squares projection to latent structure - discriminant analysis were used to build models capable of discriminating the muscle type according to the breed. Data analysis led to an excellent classification for Buffalo and Chianina, while for Holstein Friesian the separation was lower. In the case of Maremmana the use of intelligent bucketing was necessary due to some resonances shifting allowed improvement of the discrimination ability. Finally, by using the Variable Importance in Projection values the metabolites relevant for the classification were identified. 相似文献
168.
Mena Abdel-Nour Carla Duncan Donald E. Low Cyril Guyard 《International journal of molecular sciences》2013,14(11):21660-21675
Legionellosis is mostly caused by Legionella pneumophila and is defined as a severe respiratory illness with a case fatality rate ranging from 5% to 80%. L. pneumophila is ubiquitous in natural and anthropogenic water systems. L. pneumophila is transmitted by inhalation of contaminated aerosols produced by a variety of devices. While L. pneumophila replicates within environmental protozoa, colonization and persistence in its natural environment are also mediated by biofilm formation and colonization within multispecies microbial communities. There is now evidence that some legionellosis outbreaks are correlated with the presence of biofilms. Thus, preventing biofilm formation appears as one of the strategies to reduce water system contamination. However, we lack information about the chemical and biophysical conditions, as well as the molecular mechanisms that allow the production of biofilms by L. pneumophila. Here, we discuss the molecular basis of biofilm formation by L. pneumophila and the roles of other microbial species in L. pneumophila biofilm colonization. In addition, we discuss the protective roles of biofilms against current L. pneumophila sanitation strategies along with the initial data available on the regulation of L. pneumophila biofilm formation. 相似文献
169.
Roland Fitzner Egon Reinold Amaresh Mishra Elena Mena‐Osteritz Hannah Ziehlke Christian Körner Karl Leo Moritz Riede Matthias Weil Olga Tsaryova André Weiß Christian Uhrich Martin Pfeiffer Peter Bäuerle 《Advanced functional materials》2011,21(5):897-910
Efficient synthesis of a series of terminally dicyanovinyl (DCV)‐substituted oligothiophenes, DCVnT 1–6, without solubilizing side chains synthesized via a novel convergent approach and their application as electron donors in vacuum‐processed m‐i‐p‐type planar and p‐i‐n‐type bulk heterojunction organic solar cells is described. Purification of the products via gradient sublimation yields thermally highly stable organic semiconducting materials in single crystalline quality which allows for X‐ray structure analysis. Important insights into the packing features and intermolecular interactions of these promising solar cell materials are provided. Optical absorption spectra and electrochemical properties of the oligomers are investigated and valuable structure–property relationships deduced. Photovoltaic devices incorporating DCVnTs 4–6 showed power conversion efficiencies up to 2.8% for planar and 5.2% for bulk heterojunction organic solar cells under full sun illumination (mismatch corrected simulated AM 1.5G sunlight). The 5.2% efficiency shown here represents one of the highest values ever reported for organic vacuum‐deposited single heterojunction solar cells. 相似文献
170.
Pablo Zorzi Christophe Granet Franco Colleoni Nicolas Reyes Jose Pizarro Fausto-Patricio Mena Leonardo Bronfman 《Journal of Infrared, Millimeter and Terahertz Waves》2012,33(1):17-24
A corrugated spline-profile horn has been designed to meet the stringent specifications and constraints of a receiver for
Band 1 (31.3–45 GHz) of the Atacama Large Millimeter Array (ALMA). Given the physical restrictions of the receiver, the horn
will be located behind a focusing lens placed 191 mm over its aperture. After this first focusing stage, the horn must have
a reflection coefficient less than −20 dB and the cross-polarization not exceeding the −30 dB level in the entire frequency
range. The side-lobes should be less than −25 dB at all frequencies and its half power beamwidth must be approximately 24°
at 31.3 GHz and 16° at 45 GHz. The horn has been constructed using the split-block technique and characterized in a near-field
scanner setup. The results show an excellent performance complying with all the requirements. 相似文献