- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
All-optical regenerative technique for width-tunable ultra-wideband signal generation
摘要： We demonstrate all-optical generation of width-tunable mono-cycle pulses for ultra-wideband communication. It has been shown that the width of the mono-cycle pulses can be tuned dynamically by simply varying the power of the optical signal. We also investigate the regenerative property of the nonlinear medium-based technique for the generation of mono-cycle pulses. For the purpose of comparison, ultra-wideband mono-cycle pulses are also generated through the optical delay line-based technique. It has been demonstrated through numerical simulations that the nonlinear medium-based technique is highly resilient to amplified spontaneous emission noise that is induced over the optical signal. Furthermore, we have shown that the highly nonlinear fiber-based nonlinear medium performs better than the semiconductor optical amplifier-based medium. Bit error rate measurements are taken for different values of optical signal-to-noise ratios in order to elaborate our work.
关键词： Gaussian mono-cycle pulses,Ultra-wideband over fiber,Semiconductor optical amplifier,Pulse width tuning,Highly nonlinear fiber
更新于2025-09-23 15:22:29
-
[IEEE 2018 IEEE 6th Workshop on Advances in Information, Electronic and Electrical Engineering (AIEEE) - Vilnius, Lithuania (2018.11.8-2018.11.10)] 2018 IEEE 6th Workshop on Advances in Information, Electronic and Electrical Engineering (AIEEE) - 18-pulse Rectifier with Electronic Phase Shifting with Autotransformer in Inverter and Rectifier Mode
摘要： To reduce harmonic distortion of the input current, multipulse rectifiers are used. They require the presence of phase-shifting transformers or autotransformers. Elimination of electromagnetic phase-shifting devices while maintaining small harmonic distortion of the input current and obtaining a power factor close to unity is possible with the use of electronic phase shift. The electronic phase shift is realized by means of the rectifier itself: the introduction of positive and negative control angles in the pairs of rectifiers’ modules. At present, 12-pulse rectifiers with electronic phase shift are known. Unlike classic rectifiers, they do not use phase-shifting transformers and have a unit power factor. Increasing of the rectifier’s pulse makes it possible to improve the harmonic composition of the input current. The use of the principle of electronic phase shift in 18-pulse rectifier leads to different levels of constant voltage at the output of the rectifiers. In this case, to equalize the currents of rectifiers’ modules, one can use both an increase the voltage at the input of rectifiers operating with large control angles and a decrease the input voltage of the rectifiers operating with smaller control angles. The principles of constructing of matching autotransformers for the 18-pulse rectifier with an electronic phase shift are considered in the article. Comparison of 18-pulse rectifiers with use of step-up and step-down autotransformers is made. Data on the installed capacity of autotransformers, power losses are obtained. The results of thermophysical modeling are presented. When comparing the parameters of the matching magnetic elements, it can be concluded that it is more appropriate to use a step-down autotransformer.
关键词： pulse-width modulation,magnetic elements,electronic phase shifting,rectifiers,power factor
更新于2025-09-23 15:22:29
-
A flexible procedure to avoid the boundary materials singularities in 2D transformation-based cloaks
摘要： An out-of-plane coordinate transformation can avoid singular materials in a two-dimensional electromagnetic cloak. Based on numerical simulations of elliptical cylinders, in this paper we show that the use of two different constants to define the out-of-plane stretching can result in anisotropic materials with lower values and yet with a better scattering reduction for a given incident wave direction.
关键词： scattering cross-width,Cloaking,coordinate transformation,electromagnetic metamaterials
更新于2025-09-23 15:21:21
-
[IEEE 2020 7th International Conference on Signal Processing and Integrated Networks (SPIN) - Noida, India (2020.2.27-2020.2.28)] 2020 7th International Conference on Signal Processing and Integrated Networks (SPIN) - Active Power Filter for Harmonic Mitigation of Power Quality Issues in Grid Integrated Photovoltaic Generation System
摘要： Single phase tied with Photovoltaic arrangement (PV) employed on perturbed & observed (P&O) maximum energy point tracking technique with shunt active power filter allied to a rectifier feed R-L nonlinear load. The traditional Perturbed & Observed technique maximum energy point tracking topology is applied to attained maximum output power from Photovoltaic array(PVA), Proportional Integral conventional controller with phase detector (PLL) (PD) phase synchronization are executed to produce reference current. It provide at control unit of pulse width modulation topology( PWM) is utilized in inverter to get steady output voltage. Self supported DC bus PWM converter is regulated from PV array. In proposed architecture is minimized total harmonic pollution existing in supply current owing to power electronic load is (PEL). Total current harmonic pollution (THDi) factor obtain better than compensated using dynamic filter shunt active power filter (SAPF) and power compensation. Hence, reactive power (KVAR) is delivered through system decrease and active power (KW) enhance. The suggested scheme has been implemented by way of MATLAB/SIMULINK 2015(a) environment.
关键词： Pulse width Modulated (PWM) Converter,Proportional Integral controller,Maximum Power Point Tracking (P & O) Scheme,Shunt Active Power Filter (SAPF),Photovoltaic Array (PVA)
更新于2025-09-23 15:21:01
-
Relativistic Self Focusing and Frequency Shift of super-Gaussian Laser Beam in Plasma
摘要： Relativistic self focusing and frequency shift of laser beam having super-Gaussian profile in space and Gaussian profile in time is studied in a plasma. The relativistic mass nonlinearity is found to cause time dependent self focusing of the laser pulse and the saturation effect of nonlinearity avoids point focusing of the beam. For ultrashort laser pulse, the front of the pulse undergoes frequency down shift while that of the tail undergoes up shift. Frequency shift increases and self focusing becomes stronger for higher intensity of the laser. The self focusing is also stronger for the laser beam carrying larger wavelength.
关键词： Beam width parameter,Self focusing,Frequency shift,super-Gaussian laser,Moment Theory,Relativistic nonlinearity
更新于2025-09-23 15:21:01
-
[IEEE 2019 41st Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC) - Berlin, Germany (2019.7.23-2019.7.27)] 2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Electrode design on plastic substrates using laser patterned double-sided tape and gold leaf
摘要： The production of electrodes and sensors using plastic substrates has increased substantially for the last decades. Although devices are fabricated using plastic substrates suitable for the purpose of each device, it is difficult to find a process that can be used commonly for most types of plastics. In this paper, two kinds of electrode fabrication process that can be applied to most plastic films using kapton double sided tape and gold leaf are proposed. One is for the plastic film with adhesive and the other is for the film without adhesive. First, the kapton double-sided tape was patterned using a CO2 laser. After transfer double-sided tape to desired substrate, release paper was detached and gold leaf was attached on the exposed side of the tape. Then, the tape was appropriately removed according to the presence or absence of the adhesive. After that, the packaging was performed using an adhesive when the used film has adhesive, and otherwise, heat press was used for packaging. These processes have a variety of advantages such as inexpensive, fast-running and commonly applicable to many plastics. To prove its usability, impedance and minimum line width was measured.
关键词： electrode fabrication,CO2 laser,kapton double-sided tape,plastic substrates,minimum line width,impedance,gold leaf
更新于2025-09-23 15:21:01
-
A hybrid output multiport converter for standalone loads and photovoltaic array integration
摘要： Multiport converters (MPCs) are relatively recent power converter structures, which bestow the merits such as the omission of redundant power stages, centralized control, compact packaging, enhanced efficiency, improved reliability, and so on and have larger potential in domestic applications. They have the ability to amalgamate energy sources such as photovoltaic (PV) sources and battery storages, and can accommodate hybrid (ac and dc) domestic loads (bulbs, fans, induction stoves, and electric bike chargers). Hence, they can replace the conventional off-line uninterruptible power supplies, which are habitually used in domestic applications. The unique feature of MPCs is the ability to transfer the power between multiple sources and loads concurrently/independently. This article proposes cascaded sources switched tapping multi-level DC-link inverter (CSSTMLDCLI) involved hybrid loads MPC, which can integrate PV sources and feed above mentioned hybrid domestic loads. The involved novel seven level multilevel inverter structure, the CSSTMLDCLI has reduced component count to offer a high quality ac output, while the dc output is synthesized by a forward converter structure. The working principle of the CSSTMLDCLI along with the systematic design procedure is presented. The validity and effectiveness of the proposed converter are ratified through both MATLAB? Simulink R2016a simulation and the experimentation for a typical solar, battery, and grid supported domestic power backup. The system is managed for a lesser energy purchase using a developed minimal grid usage energy management system, which is implemented using ALTERA QUARTUS II 12.0SP2, field-programmable gate array processor.
关键词： hybrid load MPC (HLMPC),photovoltaic (PV),cascaded sources switched tapping multilevel DC-link inverter (CSSTMLDCLI),multilevel inverters (MLI),pulse width modulation (PWM),multiport converters (MPC)
更新于2025-09-23 15:21:01
-
Anion-Substituted Garnets Ca3Mn2 – x(Ni, Co)xVyGe3 – yO12 (x = 0, 1; y = 0, 1, 2): Preparation and Characterization
摘要： Garnets with the structure similar to that of Ca3Mn2Ge3O12 have been prepared with simultaneous substitutions of Ge4+ by V5+ in tetrahedra and of Mn3+ by Ni2+ or Co2+ in octahedra. X-ray photoelectron spectroscopy (XPS) proved the absence of V4+ in tetrahedra of the lattice of the compounds prepared and determined the valences of elements in octahedral sites. The increasing d-cation size in octahedra is accompanied by an increase in unit cell volume regardless of the composition of tetrahedra (VyGe3 – y)O12. The electrical conductivity of Ca3Mn2 – x(Ni, Co)xVyGe3 – yO12 (x = 0, 1; y = 0, 1, 2) garnet ceramic samples and the calculated bandgap widths make it possible to classify them with medium-gap semiconductors.
关键词： garnet,crystallographic radius,tetrahedron,electrical conductivity,octahedron,bandgap width,d elements
更新于2025-09-23 15:21:01
-
Rapid detection of building cracks based on image processing technology with double square artificial marks
摘要： In order to measure the crack width of dangerous buildings quickly and accurately, this article presents a new crack width measurement method, which is based on image processing technology, using double square artificial markers to identify building cracks and calculate crack width. It makes two 10 mm 3 10 mm black square artificial marks and places them near the sides of the crack. Then it uses a camera to collect crack images and transfer photos to a computer. The crack image is subjected to image graying, binarization, denoising, image segmentation, and pixel calibration based on the image processing technique. Finally, the actual length value of the unit pixel is calculated. Then it can calculate the actual width of the crack according to the number of pixels included in the test crack. The calculation results show that the accuracy of the proposed method is 98.56% compared with the measured data. The calculation method can accurately and effectively detect the crack width of dangerous buildings and improve work efficiency. At the same time, it can avoid long hours of work in dangerous operating environments.
关键词： building cracks,digital image processing,safety,MATLAB,double square artificial marks,crack width
更新于2025-09-23 15:21:01
-
Dependence of the Optimization of the Front Grid Design in Passivated Emitter and Rear Contact c-Si Solar Cells on the Finger Width and the Aspect Ratio
摘要： In this research, modeling was performed to optimize the grid of the front surface of a solar cell with the passivated emitter and rear contact (PERC) structure by considering the recombination characteristics. The front surface recombination velocity can be reduced in two main ways. The first method is to reduce the emitter Auger recombination by lowering the surface doping concentration during emitter formation, and the second method is to reduce the recombination that occurs at the surface when the electrode and the silicon are in contact, which is called metal-induced recombination and is represented by J0.metal. Because J0.metal increases in proportion to the area of the front electrode, minimizing the finger width and number by optimizing the electrode design is important. Therefore, the front electrode grid should be designed considering the emitter characteristics, J0.metal, according to the number of fingers and the resistance. In this research, the front grid of the solar cell was optimized via modeling using equations to calculate the number of fingers and the resistance. According to the finger width, the number of busbars, the sheet resistance, the aspect ratio, and the number of fingers corresponding to the maximum efficiency were identified. As a result, this modeling enabled us to optimize the front grid to the desired conditions, and we found that an increase in the number of busbars plays an important role in improving the efficiency of solar cells. In addition, the efficiency change with increasing number of busbars can be seen to be affected by the width of the finger and the resolution of the printed finger rather than the aspect ratio.
关键词： Aspect ratio,Finger width,Resistance,Front grid optimization,Crystalline silicon solar cells
更新于2025-09-23 15:21:01