排序方式: 共有56条查询结果,搜索用时 15 毫秒
31.
We report direct generation of 81 nJ chirped pulses from a room-temperature, Kerr lens mode-locked Cr??:forsterite oscillator operating at 1258 nm. To increase the pulse energy, the pulse repetition rate of the short x-type resonator was lowered from 143 to 4.9 MHz by the addition of a q-preserving multipass cavity, which provided an additional effective optical path length of 59.4 m. The duration of the chirped pulses was around 5.5 ps with a spectral width of 21 nm. The pulses were externally compressed to 607 fs by using a diffraction grating pair. To our knowledge, this is the highest reported pulse energy directly generated from a room-temperature mode-locked Cr??:forsterite laser. 相似文献
32.
Enhancing Multiple Routing Configurations through systematic analysis of topological characteristics
Selcuk Cevher Mustafa Ulutas Ibrahim Hokelek 《International Journal of Network Management》2016,26(3):176-198
Previous studies show that topological characteristics in IP networks significantly influence the performance of networking algorithms, which therefore should be systematically analyzed using diverse topologies prior to their deployments. In this paper, we present an elaborate topological dependency analysis of a multi‐topology routing‐based IP fast re‐route technology, namely, Multiple Routing Configurations (MRC), using a large topology pool with diverse properties. Through an extensive analysis using our automated topological analysis tool, we discover a significant correlation between the performance of MRC and topological characteristics. MRC needs to construct a higher number of virtual topologies to provide full alternate path coverage if a network topology tends to have more hub nodes, whose degree is much higher than the rest of the network. Inspired by our topological analysis results, we propose a new heuristic algorithm enhancing MRC. Numerical experiments demonstrate that our heuristic significantly improves the performance of MRC confirming the effectiveness of the systematic analysis of topological characteristics. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
33.
The Ramanujan Journal - Let $$k ge 2$$ and N be positive integers and let $$chi $$ be a Dirichlet character modulo N. Let f(z) be a modular form in $$M_k(Gamma _0(N),chi )$$ . Then we have a... 相似文献
34.
Amir Zarean Afshord Bahri Eren Uzuner Wiria Soltanpoor Salar H. Sedani Tom Aernouts Gorkem Gunbas Yinghuan Kuang Selcuk Yerci 《Advanced functional materials》2023,33(31):2301695
Wide-bandgap perovskite solar cells (WBG-PSCs), when partnered with Si bottom cells in tandem configuration, can provide efficiencies up to 44%; yet, the development of stable, efficient, and scalable WBG-PSCs is required. Here, the utility of the hybrid evaporation-solution method (HESM) is investigated to meet these demanding requirements via its unique advantages including ease of control and reproducibility. A PbI2/CsBr layer is co-evaporated followed by coating of organic-halide solutions in a green solvent. Bandgaps between 1.55–1.67 eV are systematically screened by varying CsBr and MABr content. Champion efficiencies of 21.06% and 20.35% in cells and 19.83% and 18.73% in mini-modules (16 cm2) for perovskites with 1.64 and 1.67 eV bandgaps are achieved, respectively. Additionally, 18.51%-efficient semi-transparent WBG-PSCs are implemented in 4T perovskite/bifacial silicon configuration, reaching a projected power output of 30.61 mW cm−2 based on PD IEC TS 60904-1-2 (BiFi200) protocol. Despite similar bandgaps achieved by incorporating Br via MABr solution and/or CsBr evaporation, PSCs having a perovskite layer without MABr addition show significantly higher thermal and moisture stability. This study proves scalable, high-performance, and stable WBG-PSCs are enabled by HESM, hence their use in tandems and in emerging applications such as indoor photovoltaics are now within reach. 相似文献
35.
Lidón Gil-Escrig Isidora Susic İlker Doğan Valerio Zardetto Mehrdad Najafi Dong Zhang Sjoerd Veenstra Salar Sedani Bulent Arikan Selcuk Yerci Henk J. Bolink Michele Sessolo 《Advanced functional materials》2023,33(31):2214357
Wide bandgap perovskites are being widely studied in view of their potential applications in tandem devices and other semitransparent photovoltaics. Vacuum deposition of perovskite thin films is advantageous as it allows the fabrication of multilayer devices, fine control over thickness and purity, and it can be upscaled to meet production needs. However, the vacuum processing of multicomponent perovskites (typically used to achieve wide bandgaps) is not straightforward, because one needs to simultaneously control several thermal sources during the deposition. Here a simplified dual-source vacuum deposition method to obtain wide bandgap perovskite films is shown. The solar cells obtained with these materials have similar or even larger efficiency as those including multiple A-cations, but are much more thermally stable, up to 3500 h at 85 °C for a perovskite with a bandgap of 1.64 eV. With optimized thickness, record efficiency of >19% and semitransparent devices with stabilized power output in excess of 17% are achieved. 相似文献
36.
Osman Kurnaz Selcuk Helhel 《AEUE-International Journal of Electronics and Communications》2014,68(10):944-950
A propagation model experimentally derived from both free space and near ground plane earth path loss models for pine tree forest with foliage depth lower than 400 m has been proposed. It is a piecewise model taking foliage depth of 200 m as a boundary. The model is compared with several well-known models, namely Weissberger, ITU-R and COST235. Different from other models, the proposed one takes into account trunk height gain k. Observed average error is about 6 dB for proposed model whereas it is about 32 dB, 16 dB and 20 dB for COST235, Weissberger and ITU-R models, respectively. Also, it is observed that COST235 estimates the highest path loss among the models and it has the highest absolute errors especially in a forest with low foliage density. 相似文献
37.
Ozge Selcuk Cem Erkmen Dr. Burcin Bozal-Palabiyik Prof. Dr. Bengi Uslu 《Electroanalysis》2021,33(5):1290-1298
In this study, a differential pulse voltammetry method was designed for the simultaneous determination of etodolac and thiocolchicoside in a tablet dosage form. This method is a sensitive, costless and reproducible one initially designed for the simultaneous determination of etodolac and thiocolchicoside using bare/unmodified glassy carbon electrode in the presence of sodium dodecyl sulfate. At optimized conditions, the method showed linear responses with etodolac and thiocolchicoside concentration in the range of 1 μM to 80 μM. The limits of detection and quantification were calculated as 0.11 μM and 0.38 μM for etodolac and 0.20 μM and 0.67 μM for thiocolchicoside, respectively. 相似文献
38.
It is pointed out that a slight modification of the relativistic quantum theory of a free electron in a uniform wiggler field enables the study of motion in a tapered wiggler field of the form which merits attention. The lower limit of z is 800 cm. The exact relativistic quantum mechanical calculation shows an enhancement in the gain for single pass. The frequencies are up-shifted by amounts depending on the parameter b. 相似文献
39.
Selcuk Demir Veysel T. Yilmaz Omer Andac William T. A. Harrison 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(7):o407-o408
The title compound, C4H14N2O2+·HPO42?·H2O, contains alternating interleaved layers of hydrogenphosphate and N‐(2‐hydroxyethyl)ethylenediammonium moieties. The water molecules are associated with channel‐like voids in the structure and a network of hydrogen bonds stabilizes the crystal packing. 相似文献
40.