scholarly journals Fabrication of metal-dielectric nanoparticles from a bi-layer gold-silicon film by femtosecond laser-induced dewetting

2021 ◽  
Vol 2015 (1) ◽  
pp. 012071
Author(s):  
S. V. Koromyslov ◽  
E.I. Ageev ◽  
E. Yu. Ponkratova ◽  
D. A. Zuev
Keyword(s):  
White Light ◽  
Communication Systems ◽  
High Efficiency ◽  
Silicon Film ◽  
Spectral Width ◽  
Single Step ◽  
Light Sources ◽  
World Demand ◽  
Efficient Information ◽  
Low Efficiency

Abstract Today the world demand for the creation of highly efficient nanoscale white light sources is growing. It happens because energy-efficient information and communication systems are being developed, in which optical signals are replacing electrical signals. For the fabrication of such devices, creating efficient nanoscale white light sources with high efficiency is very acute. Such structures obtained by current methods have a common disadvantages: a small spectral width and low efficiency. Here we demonstrate the development of metal-dielectric structures exploiting the single-step and lithography-free laser-induced dewetting of bi-layer gold silicon films and study their broadband photoluminescence.

scholarly journals High efficiency Doherty power amplifiers for modern wireless communication systems: A brief review

2021 ◽  
Vol 23 (3) ◽  
pp. 1855
Author(s):  
Mussa Mabrok ◽  
Zahriladha Zakaria ◽  
Tole Sutikno
Keyword(s):  
Wireless Communication ◽  
Power Amplifiers ◽  
Communication Systems ◽  
High Performance ◽  
High Efficiency ◽  
Average Power ◽  
Wireless Communication Systems ◽  
Saturation Power ◽  
Low Efficiency ◽  
Suitable Technique

Due<span lang="EN-MY">to the high peak to average power ratio (PAPR) of modern modulated signals, power amplifiers (PAs) have been forced to operate at the back-off (BO) region of their saturation power in order to avoid signal clipping and distortion. However, classical PAs suffer from low efficiency in the BO region operation. Therefore, efficiency has to be enhanced in that region. Many techniques have been proposed. Among them, the Doherty power amplifier (DPA) is considered as the most suitable technique due to its simple structure and high performance. However, its conventional design is limited to a 6 dB BO level, which does not satisfy the requirements of modern communication systems. In this paper, a brief review of the most significant techniques of high-efficiency DPA is presented. First, DPA topology and its operation principles are briefly discussed. Second, efficiency enhancement techniques such as an asymmetrical DPA, output combiner modification, gate bias adaption, offset line optimization, and multi-way DPA were discussed. The study shows that the most suitable, simple, and effective solution is an asymmetrical approach. However, it needs to be investigated in terms of bandwidth in order to meet the efficiency-bandwidth requirements of modern wireless communication systems such as </span>5G.

Exafs and X-ray Ctr Scattering Characterization of Er Doped in InP by Omvpe

1996 ◽  
Vol 422 ◽  
Author(s):  
M. Tabuchi ◽  
D. Kawamura ◽  
K. Fujita ◽  
N. Matsubara ◽  
N. Yamada ◽  
...  
Keyword(s):  
Optical Communication ◽  
Communication Systems ◽  
High Efficiency ◽  
Absorption Region ◽  
Doped Semiconductors ◽  
X Ray ◽  
Optical Communication Systems ◽  
Low Efficiency ◽  
Er Doped

AbstractEr-doped semiconductors are considered to be important for optical communication systems since one of the prominent luminescent peaks of Er is in the minimum absorption region of silica based fiber and wavelength of the luminescence is insensitive to the ambient temperature. In this work, OMVPE grown InP samples uniformly and δ-doped with Er were investigated by EXAFS and X-ray CTR measurements. The EXAFS measurement revealed that the uniformly doped Er atoms in InP grown at 580°C formed NaCl-structure ErP, and at 530°C occupied the In-sites. The X-ray CTR measurement revealed that the δ-doped Er atoms in InP at 530'C formed NaCl-structure ErP. In the sample, the total number of Er was analyzed to be about 0.171ML(monolayer), and the FWHM of Er distribution was about 5ML. By comparing the results of PL measurement with those of the EXAFS and the X-ray CTR measurements, it was suggested that the Er atoms on In-sites show high efficiency of luminescence and the Er atoms in the NaCl-structure ErP low efficiency.

scholarly journals CHROMOSOMAL BASIS OF THE MEROZYGOSITY IN A PARTIALLY DIPLOID MUTANT OF PNEUMOCOCCUS

Genetics ◽  
1975 ◽  
Vol 80 (4) ◽  
pp. 667-678
Author(s):  
Mary Lee S Ledbetter ◽  
Rollin D Hotchkiss
Keyword(s):  
High Efficiency ◽  
Point Mutations ◽  
Resistant Mutant ◽  
Chromosomal Marker ◽  
Structural Abnormality ◽  
C Cells ◽  
Wild Type ◽  
Chromosomal Locus ◽  
Low Efficiency ◽  
Derivatives Of

ABSTRACT A sulfonamide-resistant mutant of pneumococcus, sulr-c, displays a genetic instability, regularly segregating to wild type. DNA extracts of derivatives of the strain possess transforming activities for both the mutant and wild-type alleles, establishing that the strain is a partial diploid. The linkage of sulr-c to strr-61, a stable chromosomal marker, was established, thus defining a chromosomal locus for sulr-c. DNA isolated from sulr-c cells transforms two mutant recipient strains at the same low efficiency as it does a wild-type recipient, although the mutant property of these strains makes them capable of integrating classical "low-efficiency" donor markers equally as efficiently as "high efficiency" markers. Hence sulr-c must have a different basis for its low efficiency than do classical low efficiency point mutations. We suggest that the DNA in the region of the sulr-c mutation has a structural abnormality which leads both to its frequent segregation during growth and its difficulty in efficiently mediating genetic transformation.

scholarly journals A Brief Review on Solvent-Free Synthesis of Zeolites

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 788
Author(s):  
Jinlin Mei ◽  
Aijun Duan ◽  
Xilong Wang
Keyword(s):  
High Efficiency ◽  
Raw Materials ◽  
Solvent Free ◽  
High Yield ◽  
Control Synthesis ◽  
Mechanical Mixing ◽  
Synthesis Mechanism ◽  
Wastewater Pollution ◽  
Low Efficiency ◽  
Solvent Free Synthesis

The traditional hydrothermal method to prepare zeolite will inevitably use a large amount of water as a solvent, which will lead to higher autogenous pressure, low efficiency, and wastewater pollution. The solvent-free method can be used to synthesize various types of zeolites by mechanical mixing, grinding, and heating of solid raw materials, which exhibits the apparent advantages of high yield, low pollution, and high efficiency. This review mainly introduces the development process of solvent-free synthesis, preparation of hierarchical zeolite, morphology control, synthesis mechanism and applications of solvent-free methods. It can be believed that solvent-free methods will become a research focus and have enormous industrial application potential.

Crystalline Silicon White Light Sources Driven by Optical Resonances

Nano Letters ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2397-2405
Author(s):  
Jin Xiang ◽  
Mincheng Panmai ◽  
Shuwen Bai ◽  
Yuhao Ren ◽  
Guang-Can Li ◽  
...  
Keyword(s):  
White Light ◽  
Crystalline Silicon ◽  
Light Sources ◽  
Optical Resonances

scholarly journals Inflight Transmission of COVID-19 Based on Experimental Aerosol Dispersion Data

2021 ◽  
Author(s):  
Zhaozhi Wang ◽  
Edwin R Galea ◽  
Angus Grandison ◽  
John Ewer ◽  
Fuchen Jia
Keyword(s):  
High Efficiency ◽  
Face Mask ◽  
Generation Rate ◽  
Aviation Industry ◽  
Filtration System ◽  
Dispersion Data ◽  
Low Probability ◽  
Meal Service ◽  
Low Efficiency ◽  
Aerosol Dispersion

Abstract Background An issue of concern to the travelling public is the possibility of in-flight transmission of COVID-19 during long- and short-haul flights. The aviation industry maintains that the probability of contracting the illness is small based on reported cases, modelling and data from aerosol dispersion experiments conducted on-board aircraft. Methods Using experimentally derived aerosol dispersion data for a B777–200 aircraft and a modified version of the Wells-Riley equation we estimate inflight infection probability for a range of scenarios involving quanta generation rate and face mask efficiency. Quanta generation rates were selected based on COVID-19 events reported in the literature while mask efficiency was determined from the aerosol dispersion experiments. Results The MID-AFT cabin exhibits the highest infection probability. The calculated maximum individual infection probability (without masks) for a 2-hour flight in this section varies from 4.5% for the ‘Mild Scenario’ to 60.2% for the ‘Severe Scenario’ although the corresponding average infection probability varies from 0.1% to 2.5%. For a 12-hour flight, the corresponding maximum individual infection probability varies from 24.1% to 99.6% and the average infection probability varies from 0.8% to 10.8%. If all passengers wear face masks throughout the 12-hour flight, the average infection probability can be reduced by approximately 73%/32% for high/low efficiency masks. If face masks are worn by all passengers except during a one-hour meal service, the average infection probability is increased by 59%/8% compared to the situation where the mask is not removed. Conclusions This analysis has demonstrated that while there is a significant reduction in aerosol concentration due to the nature of the cabin ventilation and filtration system, this does not necessarily mean that there is a low probability or risk of in-flight infection. However, mask wearing, particularly high-efficiency ones, significantly reduces this risk.

Ultra-High Efficiency White Light Emitting Diodes

2006 ◽  
Vol 45 (No. 41) ◽  
pp. L1084-L1086 ◽  
Author(s):  
Yukio Narukawa ◽  
Junya Narita ◽  
Takahiko Sakamoto ◽  
Kouichiro Deguchi ◽  
Takao Yamada ◽  
...  
Keyword(s):  
White Light ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
White Light Emitting Diodes

scholarly journals Photocatalytic Performance of ZnO: Al Films under Different Light Sources

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Prashant Pradhan ◽  
Juan Carlos Alonso ◽  
Monserrat Bizarro
Keyword(s):  
White Light ◽  
Irradiation Time ◽  
Zno Films ◽  
Light Sources ◽  
X Ray Diffraction ◽  
Treatment Processes ◽  
Vis Spectroscopy ◽  
Doped Zno ◽  
Very High ◽  
High Degradation Rate

ZnO and Al doped ZnO films were produced by spray pyrolysis. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis spectroscopy, and photoluminescence. Their photocatalytic activity was evaluated by the decomposition of the methyl orange dye using different light sources: ultraviolet light, artificial white light, and direct sunlight. The films were also tested under darkness for comparison. The ZnO films were able to degrade the test pollutant under UV and sunlight in more than a 60% after 180 min of irradiation and a scarce degradation was obtained using white light. However, the Al doped ZnO films presented a very high degradation rate not only under UV and sunlight (100% degradation), but also under white light (90% degradation after the same irradiation time). An unexpected high degradation was also obtained in the dark, which indicates that a nonphotonic process is taking place parallel to the photocatalytic process. This can be due to the extra electrons—provided by the aluminum atoms—that migrate to the surface and produce radicals favoring the decomposition process even in the dark. The high activity achieved by the ZnO: Al films under natural conditions can be potentially applied to water treatment processes.

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