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排序方式: 共有97条查询结果,搜索用时 15 毫秒
31.
Ivan A. Velasco-Davalos Mathieu Moretti Mischa Nicklaus Christian Nauenheim Shun Li Riad Nechache Carlos Gomez-Yanez Andreas Ruediger 《Applied Physics A: Materials Science & Processing》2014,115(3):1081-1085
Multiferroic bismuth ferrite (BiFeO3) has attracted considerable attention due to applications related to the bulk photovoltaic effect in which the direction of polarization determines the direction of the photocurrent. Epitaxial thin films are produced by means of techniques that usually require high temperature processes. The hydrothermal method can be seen as an alternative route to obtain highly textured thin films in quantities compatible with batch processing; nevertheless, the structural, dielectric and electric properties are generally affected by the presence of hydrogen and other reaction by-products. In this work, functional and highly textured BiFeO3 films were successfully produced on metallic SrTiO3:Nb (0.5 wt.%) (100) substrates via hydrothermal synthesis. X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) were used to analyze the structural properties of the films. Piezoresponse Force Microscopy (PFM) and Photoconductive Atomic Force Microscopy (Pc-AFM) were used to determine their functional properties. We show the polarization switching and confirm the presence of the bulk photovoltaic effect for the first time in hydrothermally synthesized BiFeO3. 相似文献
32.
Nacera Naar Saad Lamouri Isabelle Jeacomine Adam Pron Marguerite Rinaudo 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):897-905
Soluble emeraldine-base (PANI-EB) was prepared and its structure was characterized using 1H, 13C and 2D (COSY, HMQC and HMBC) NMR. The solubility of the polymer in two solvents (N-methylpyrrolidone (NMP) and dimethyl sulfoxide (DMSO), the structure of the solution (aggregation) and the behavior of polyaniline were studied by viscometry and by dynamic light scattering (DLS) in dilute solution. Viscometric behavior in NMP and Huggins constant determination confirm supramolecular interactions also evidenced by DLS; at end, the molecular weight of the soluble fraction of PANI-EB is determined. 相似文献
33.
We investigate the mechanisms involved in the funneling of optical energy into subwavelength grooves etched on a metallic surface. The key phenomenon is unveiled thanks to the decomposition of the electromagnetic field into its propagative and evanescent parts. We unambiguously show that the funneling is not due to plasmonic waves flowing toward the grooves, but rather to the magnetoelectric interference of the incident wave with the evanescent field, this field being mainly due to the resonant wave escaping from the groove. 相似文献
34.
Sid Ali Kaoua Kamel Taibi Nacera Benghanem Krimo Azouaoui Mohammed Azzaz 《Applied Mathematical Modelling》2011,35(3):1378-1387
This paper presents a 3D geometric modelling of a twin helical spring and its finite element analysis to study the spring mechanical behaviour under tensile axial loading. The spiralled shape graphic design is achieved through the use of Computer Aided Design (CAD) tools, of which a finite element model is generated. Thus, a 3D 18-dof pentaedric elements are employed to discretise the complex “wired-shape” of the spring, allowing the analysis of the mechanical response of the twin spiralled helical spring under an axial load. The study provides a clear match between the evolution of the theoretical and the numerical tensile and compression normal stresses, being of sinusoidal behaviour. The overall equivalent stress isovalues increases radially from 0° to 180°, being maximal on the internal radial zone at the section 180°. On the other hand, the minimum stress level is located in the centre of the filament cross section. 相似文献
35.
Megouda N Cofininier Y Szunerits S Hadjersi T Elkechai O Boukherroub R 《Chemical communications (Cambridge, England)》2011,47(3):991-993
The communication reports on the high performance of hydrogen-terminated silicon nanowires and silicon nanowires coated with metal (Ag, Cu) nanostructures for the photodegradation of rhodamine B under UV and visible light irradiation. 相似文献
36.
NM Al-Daghri KM Alkharfy A Al-Othman SM Yakout Y Al-Saleh MA Fouda R Sulimani S Sabico 《Molecules (Basel, Switzerland)》2012,17(7):8408-8418
Biochemical bone turnover markers (BTMs) provide important information on the diagnosis, therapy and monitoring of metabolic bone diseases. They are evident before measurable changes in bone mineral density (BMD) take place. A total of 35 adult Saudi patients (23 males; 12 females) with type 2 diabetes and diagnosed to be vitamin D deficient were recruited in this prospective study. Here we investigated the effects of gender, season, and vitamin D status on bone biochemical markers of bone remodeling. Anthropometry and blood samples were collected at different intervals. Metabolic parameters and bone biomarkers were measured routinely and by ELISA. Both males and females had a significant increase in their vitamin D status over time, but no significant changes in the bone biomarkers were observed in females. In males there was a significant increase in circulating levels of corrected calcium and OPN (p = 0.004 and 0.01 respectively) and a significant decrease in crosslaps (p = 0.005). In all subjects there was a modest but significant positive relationship between vitamin D status and OC (R = 0.34; p = 0.04). In conclusion, our study demonstrates that changes in bone remodeling markers are affected by season, gender, and possibly vitamin D status. This gender difference may well reflect the physiologic pathway responsible for the higher peak bone mass achieved in males compared to females. 相似文献
37.
Raybaut M Godard A Haïdar R Lefebvre M Kupecek P Lemasson P Rosencher E 《Optics letters》2006,31(2):220-222
We report what we believe to be the first demonstration of mid-infrared generation (approximately 9 microm) by self-difference frequency generation in Fresnel birefringence quasi-phase-matched Cr:ZnSe laser slabs. 相似文献
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