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31.
Nanotextured multicrystalline Al‐BSF solar cells reaching 18% conversion efficiency using industrially viable solar cell processes 下载免费PDF全文
Bishal Kafle Abdul Mannan Timo Freund Laurent Clochard Edward Duffy Marc Hofmann Jochen Rentsch Ralf Preu 《固体物理学:研究快报》2015,9(8):448-452
We report recent achievements in adapting industrially used solar cell processes on nanotextured surfaces. Nanostructures were etched into c‐Si surfaces by dry exothermic plasma‐less reaction of F species with Si in atmospheric pressure conditions and then modified using a short post‐etching process. Nanotextured multicrystalline wafers are used to prepare Al‐BSF solar cells using industrially feasible solar cell proc‐ essing steps. In comparison to the reference acidic textured solar cells, the nanostructured cells showed gain in short circuit current (Jsc) of up to 0.8 mA/cm2 and absolute gain in conversion efficiency of up to 0.3%. The best nanotextured solar cell was independently certified to reach the conversion efficiency of 18.0%. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
32.
Cell Tracking with Caged Xenon: Using Cryptophanes as MRI Reporters upon Cellular Internalization 下载免费PDF全文
Stefan Klippel Jörg Döpfert Dr. Jabadurai Jayapaul Martin Kunth Federica Rossella Matthias Schnurr Dr. Christopher Witte Dr. Christian Freund Dr. Leif Schröder 《Angewandte Chemie (International ed. in English)》2014,53(2):493-496
Caged xenon has great potential in overcoming sensitivity limitations for solution‐state NMR detection of dilute molecules. However, no application of such a system as a magnetic resonance imaging (MRI) contrast agent has yet been performed with live cells. We demonstrate MRI localization of cells labeled with caged xenon in a packed‐bed bioreactor working under perfusion with hyperpolarized‐xenon‐saturated medium. Xenon hosts enable NMR/MRI experiments with switchable contrast and selectivity for cell‐associated versus unbound cages. We present MR images with 103‐fold sensitivity enhancement for cell‐internalized, dual‐mode (fluorescence/MRI) xenon hosts at low micromolar concentrations. Our results illustrate the capability of functionalized xenon to act as a highly sensitive cell tracer for MRI detection even without signal averaging. The method will bridge the challenging gap for translation to in vivo studies for the optimization of targeted biosensors and their multiplexing applications. 相似文献
33.
Back Cover: Cell Tracking with Caged Xenon: Using Cryptophanes as MRI Reporters upon Cellular Internalization (Angew. Chem. Int. Ed. 2/2014) 下载免费PDF全文
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The application of a variety of “surface‐science” techniques to elucidate surface structures and mechanisms of chemical reactions at zeolite surfaces has long been considered as almost impossible because of the poor electrical and thermal conductivity of those materials. Here, we show that the growth of a thin aluminosilicate film on a metal single crystal under controlled conditions results in adequate and well‐defined model systems for zeolite surfaces. In principle, silicate films that contain metals other than Al (e.g. Ti, Fe, etc) may be prepared in a similar way. We believe that this approach opens up a new playground for experimental and theoretical modeling of zeolites, aimed at a fundamental understanding of structure–reactivity relationships in such materials. 相似文献
37.
The critical points of generic paraxial ellipse fields consist of singular points of circular polarization, called C -points, and azimuthal stationary points, i.e., maxima, minima, and saddle points. We define these stationary points here and review their properties. The sign rule for ellipse fields requires that the sign of the singularity indices I(C)=+/-1/2 of the C -points on non-self-intersecting lines of constant azimuthal ellipse orientation (modulo pi/2), i.e., a -lines, alternate along the line. We verify this rule experimentally, using a newly developed interferometric technique to measure C -points and a -lines in an elliptically polarized random optical field. 相似文献
38.
We study a new type of walk with memory which might serve as a toy model for the behavior one must adopt to avoid exhaustion of resources and attraction of parasites and predators. The walk takes place on a regular square lattice with periodic boundary conditions. Although the walk is completely deterministic, it mimics a “true” self-avoiding walk, i.e. a random walk with weak autocorrelation. This shows that the Red Queen effect can lead to aperiodic behavior. In addition to the case of single walkers in a flat landscape we also study the cases of hilly landscapes and of several walkers performing simultaneous walks. 相似文献
39.
The rapid growth of a through-the-thickness crack in a nominally elastic plate under Mode I conditions is considered, with emphasis on the three-dimensional aspects of the elastodynamic crack growth process. For points near the crack edge, the assumptions on stress state consistent with plane stress analysis are not valid, and the possibility of an inertial effect associated with rapid lateral contraction must be considered. The steady crack growth process is analyzed here by means of the finite element method, and the degree to which the local fields are described by plane stress analysis is established. In addition, synthetic shadow spot patterns are generated from the numerical three-dimensional solutions. The inferred values of stress intensity factor are compared with the values of the corresponding plane stress dynamic stress intensity factor. 相似文献
40.
Surface chemistry of carbon dioxide 总被引:5,自引:0,他引:5
The review discusses how CO2 surface chemistry has developed since the early 1950s. Emphasis is given to studies of well-characterized surfaces of metals, oxides and some more complex systems involving in particular alkali modified surfaces and also of coadsorbed molecules. 相似文献