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- 摘要
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In-Situ Observation of Coulomb Fission of Individual Plasmonic Nanoparticles
摘要： Reshaping plasmonic nanoparticles with laser pulses has been extensively researched as a tool for tuning their properties. However, in the absence of direct observations of the processes involved, important mechanistic details have remained elusive. Here, we present an in-situ electron microscopy study of one such process that involves Coulomb fission of plasmonic nanoparticles under femtosecond laser irradiation. We observe that gold nanoparticles encapsulated in a silica shell fission by emitting progeny droplets comprised of about 10-500 atoms, with ejection preferentially occurring along the laser polarization direction. Under continued irradiation, the emitted droplets coalesce into a second core within the silica shell, and the system evolves into a dual-core particle. Our findings are consistent with a mechanism in which electrons are preferentially emitted from the gold core along the laser polarization direction. The resulting anisotropic charge distribution in the silica shell then determines the direction in which progeny droplets are ejected. In addition to yielding insights into the mechanism of Coulomb fission in plasmonic nanoparticles, our experiments point towards a facile method for forming surfaces decorated with aligned dual-gold-core silica shell particles.
关键词： single-particle observation,gold-core silica shell particles,plasmonic nanoparticles,in-situ,nanoparticle reshaping,Coulomb fission,transmission electron microscopy
更新于2025-09-11 14:15:04
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Tracking Unmanned Aerial Vehicle CTU FTS - Application of equipment
摘要： Article which is about the Tracking Unmanned Aerial Vehicle continues in the description of the project development dealing with the utilization of the UAV (unmanned aerial vehicle). Documentation of the project progresses builds on the previous article. In that article the selection of observation and transmission equipment was summarized. In the article, the reader learns about an installation of the equipment on the UAV (helicopter), about an interconnection of the equipment to create complete and functional system, about testing of the UAV, about the solutions of the problems which came into being during the equipment against testing and about protection of unfavourable effects. The unmanned vehicle was chosen after a considering of several the parameters. These parameters are preservation of functionality or an influence to the balance. To find out how the added equipment affect the centre of gravity of the UAV the tabular method of the centre of gravity calculation was used. The results of the existing work on the project are location and attaching of the equipment to the unmanned vehicle, balance of the unmanned vehicle, solutions of the problems coming into being during the testing and design of the equipment protection against unfavourable effects.
关键词： Tracking Unmanned Aerial Vehicle CTU FTS,application of equipment,UAV,observation and transmission equipment,RPAS
更新于2025-09-11 14:15:04
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The Improved Image Scrambling Algorithm for the Wireless Image Transmission Systems of UAVs
摘要： With the deepening of modern military reforms, information has become the key to winning modern warfare. The use of unmanned aerial vehicle (UAV) to capture image information has become an important means of reconnaissance in modern warfare and plays an irreplaceable role. The image information usually uses a wireless image transmission system, since image information is intercepted or stolen easily during the information transmission, encrypting an image is a common method for ensuring image security. However, traditional encryption algorithms have some deficiencies in terms of efficiency and security. In order to overcome these shortcomings, a new algorithm is proposed in this paper-an improved image scrambling encryption algorithm based on Fibonacci-p coding. The first new idea of the algorithm is to separate the positive and negative signs and data of the scrambled DCT coefficients, then form the symbol matrix and the data matrix respectively, perform the scrambling encryption operation on the symbol matrix. The second new idea is to encrypt the color RGB image by converting the R, G, and B colors into Y, Cb, and Cr, and converting the normal image operation into operations on Y, Cb, and Cr, thereby implementing the encryption operation. The comprehensive performance of the algorithm is optimal with different image information. Experiments results validate the favorable performance of the proposed improved encryption algorithm.
关键词： improved image scrambling encryption algorithm,Fibonacci-p coding,high-definition long-distance wireless digital image transmission system,UAV
更新于2025-09-10 09:29:36
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[IEEE 2018 International Conference on Information , Communication, Engineering and Technology (ICICET) - Pune, India (2018.8.29-2018.8.31)] 2018 International Conference on Information , Communication, Engineering and Technology (ICICET) - New Control Technique to Improve the Grid Power by Using PV-STATCOM
摘要： This paper introduces novel control method to utilize the solar plant inverter as static synchronous compensator (STATCOM) which is also called as PV-STATCOM to improve the power transmission capacity of the grid. The solar farm is ideal for the nighttime and it produces less power in morning period and late afternoon period. Therefore these are the expensive assets which are remaining unutilized during this period of 24hrs. To overcome these problems solar plant along with maximum power point tracking [MPPT] produces active power during daytime and full capacity of solar plant inverter which is not used in night period is used with help of point of common coupling [PCC] voltage controller and damping controller to improve the power transmission capacity of line and also power factor of the grid line. The inverter capacity which is left after the real power generation is used to perform the given objective. This new control technique is used to increase the grid transfer capacity for which other alternatives are used like FACT devices.
关键词： flexible alternating current transmission system,inverter,solar system,damping controller,MPPT,STATCOM,dc voltage regulator,voltage controller
更新于2025-09-10 09:29:36
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Atomic Structure and Electrical Activity of Grain Boundaries and Ruddlesden-Popper Faults in Cesium Lead Bromide Perovskite
摘要： To evaluate the role of planar defects in lead-halide perovskites—cheap, versatile semiconducting materials—it is critical to examine their structure, including defects, at the atomic scale and develop a detailed understanding of their impact on electronic properties. In this study, postsynthesis nanocrystal fusion, aberration-corrected scanning transmission electron microscopy, and first-principles calculations are combined to study the nature of different planar defects formed in CsPbBr3 nanocrystals. Two types of prevalent planar defects from atomic resolution imaging are observed: previously unreported Br-rich [001](210)∑5 grain boundaries (GBs) and Ruddlesden–Popper (RP) planar faults. The first-principles calculations reveal that neither of these planar faults induce deep defect levels, but their Br-deficient counterparts do. It is found that the ∑5 GB repels electrons and attracts holes, similar to an n–p–n junction, and the RP planar defects repel both electrons and holes, similar to a semiconductor–insulator–semiconductor junction. Finally, the potential applications of these findings and their implications to understand the planar defects in organic–inorganic lead-halide perovskites that have led to solar cells with extremely high photoconversion efficiencies are discussed.
关键词： Ruddlesden–Popper faults,lead-halide perovskites,scanning transmission electron microscopy,density-functional theory,grain boundaries
更新于2025-09-10 09:29:36
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[Lecture Notes in Electrical Engineering] Engineering Vibration, Communication and Information Processing Volume 478 (ICoEVCI 2018, India) || Design of an Energy Harvesting System for Wireless Power Transmission Using Microstrip Antenna
摘要： Power supply drives technological devices. As the wired world looks long antiquated, it is imperative transition towards wireless power transmission (WPT). WPT has been lately enticing in a varying range of applications in numerous ?elds and has also become a very alluring area of research activity because of the potential it has in providing solutions to our daily requirement, so the need arises to delve into it to explore new, innovative and ef?cient means of energy transmission. WPT will be indispensable in the imminent future, as this technology assists in the transmission of electrical energy to any device from the power source using air as the transmission medium without the use of any conductors. In this paper, an energy harvesting device is proposed to convert ambient electromagnetic waves, predominantly from the 2.4 GHz ISM radio frequency (RF) channel into direct current (DC) electricity. A microstrip antenna is designed along with a booster circuit to help charge devices wirelessly. This novel technology could be used for charging phone batteries on-the-go, thereby eliminating the hassles of wired connections.
关键词： Rectenna,Wireless power transmission,Energy harvesting,Wireless charging,Microstrip patch antenna
更新于2025-09-10 09:29:36
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The Modeling and Analysis of a Power Transmission Line Supplied by a Solar Power Plant
摘要： This article deals with the energy transmission line system which feeds from solar energy at the MATLAB Simulink. So, direct voltage is considered to be converted as an alternating voltage by a 35-level inverter after the solar power plant which has the power of 110 MW produce 360 kV of direct voltage. A line which covers 240 km of distance is preferred to transmit electrical power from the A1 point to an A2 point. Due to this, the required mathematical equations are calculated with a circuit analyzing method for the line modeling in the simulation. Experiments on the model are carried out at the MATLAB Simulink after the creation of an energy transmission line. After that, when measurements are made taking into consideration the A2 node; the capacitor voltage, the transformer current, the A2 node current, and the fault current, values are given according to the converted voltage at the frequencies of 100 Hz, 80 Hz, and 50 Hz. The obtained results demonstrate the success of the proposed line system, while power is distributed with eliminated fault at a long distance at different frequencies.
关键词： mathematical model of the line,simulation model of the transmission line,35-level inverter
更新于2025-09-10 09:29:36
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A novel compact wideband filter using three-mode dual-ring resonator
摘要： A novel compact wideband filter using three-mode dual-ring resonator is presented in this article. The resonator is constructed by two quarter wavelength transmission lines and a cascaded half wavelength dual-ring. Formulae based on even- and odd-mode analysis are derived to analyze the locations of the transmission poles and zeros of the resonator. Due to the transmission zeros in the lower and upper stopbands, the proposed filter exhibits sharp attenuations near the passband as well as very wide stopband. The filter is successfully realized by full wave EM simulation and fabricated. The measured responses of the filter agree well with the design simulation, and show that the fabricated filter has an insertion loss of better than 1.5 dB in the passband and two rejections of greater than 20 dB in the stopbands from 0 to 10GHz.
关键词： even- and odd-mode analysis,dual-ring resonator,wideband filter,transmission zeros,three-mode
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu, China (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Multiple Orbital Angular Momentum Vortex Electromagnetic Waves Multiplex Transmission and Demultiplex Reception Analysis
摘要： We investigated the multiplexing transmission and demultiplexing reception properties of vortex electromagnetic wave with multiple orbital angular momentum (OAM) modes. In this paper, a uniform circular array (UCA) antenna model at 10GHz is designed for generating multiple OAM modes vortex electromagnetic wave, and both the transmission characteristics, i.e., the field distribution in the space, and the reception characteristics are analyzed. The whole aperture sampling receiving (WASR) scheme is used for the reception. And the radius of the reception aperture that influences the multiple OAM modes demultiplex reception effects is analyzed. Some numerical calculation simulation experiments are performed and a simple expression is defined as mode percent for measuring the reception effects.
关键词： Demultiplex reception,UCA antenna,whole aperture sampling receiving (WASR),multiplex transmission,multiple OAM modes,vortex electromagnetic wave
更新于2025-09-10 09:29:36
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[Springer Series in Optical Sciences] Fano Resonances in Optics and Microwaves Volume 219 (Physics and Applications) || Resonant-State Expansion of the Fano Peak in Open Quantum Systems
摘要： We describe the Fano asymmetry by expanding the transmission amplitude with respect to states with point spectra (discrete eigenstates), including not only bound states but also resonant states with complex eigenvalues. We ?rst introduce a novel complete set that spans the Hilbert space of the central part of an open quantum-dot system. This complete set contains all states of point spectra, but does not contain any states of continuous spectra. We thereby analytically expand the conductance of the dot in terms of all discrete states without any background integrals. This expansion implies that the resonant states produce the main contributions to the electron transmission. We then explain the Fano peak as an interference effect involving resonant states. We ?nd that there are three types of Fano asymmetry according to their origins: the interference between a resonant state and an anti-resonant state, that between a resonant state and a bound state, and that between two resonant states. We derive microscopic expressions of the Fano parameters that describe the three types of Fano asymmetry. We show that the last two types display the asymmetric energy dependence given by Fano, but the ?rst one shows a slightly different form.
关键词： transmission amplitude,Fano asymmetry,discrete eigenstates,resonant states,quantum-dot system
更新于2025-09-10 09:29:36