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- 2018
- Solar Photovoltaic (SPV)
- Fuzzy Logic Control (FLC)
- MATLAB/Simulink
- Simulation
- Variable Step Size Incremental Conductance (VSS InC)
- Maximum Power Point Tracking (MPPT)
- Electrical Engineering and Automation
- Cochin University College of Engineering
- T.K.M College of Engineering
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To the Theory of the Polarized Radiation Absorption in a Semiconductor (001) Quantum Well
摘要： The paper considers absorption of linearly polarized radiation in a semiconductor size-quantized well related to optical transitions both between the branches of light and heavy holes and between the size-quantized subbands. Main features of the light absorption in an infinitely deep symmetric well are elucidated. These features are characterized by intraband absorption of light and associated with the direct optical transitions of holes between the subbands of the semiconductor valence band formed due to the size quantization.
关键词： optical transition,semiconductor,size quantization,light absorption coefficient,polarized light,holes
更新于2025-09-23 15:23:52
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Effect of multi stage abrasive slurry jet polishing on surface generation in glass
摘要： The polishing process is used to produce a smooth surface with a required geometrical figure for the optical component. The abrasive slurry jet polishing process is one of the non-traditional polishing process, which is used to polish freeform optics with the nano-level surface finish. In the abrasive slurry jet polishing process, the saturation in surface roughness is observed with a jet exposure time or polishing time. Once the saturation limit is reached a further reduction in surface roughness without the modification of processing conditions and the size of the abrasive particles is not possible. Hence to achieve the required surface roughness a different polishing strategy has to be adapted. In this work, an attempt was carried out to yield a considerable reduction in surface roughness using a multistage polishing concept. In this concept, the impact angle, the traverse speed of the nozzle, the type and size of the abrasive particle were changed after the first stage of polishing. The surface generation has been studied by measuring the surface roughness at each stage of polishing, and the Scanning Electron Microscope (SEM) analyses have been done to understand the changes in surface texture, after polishing. From the experiments, the large size Al2O3 particle in the first stage of polishing and then small size Al2O3 particle in the remaining stages of polishing yields a considerable reduction in surface roughness. The combination of parameters with the type and size of the abrasive particles to be used to achieve the required surface characteristics were demonstrated. Thus, the multistage polishing concept can be floated as a viable strategy to achieve a high reduction in surface roughness on the optical component.
关键词： Abrasive,Particle size,Traverse speed,Slurry,Multistage Polishing,Glass
更新于2025-09-23 15:23:52
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Research on Micro-Size Electrical Discharge Machining Polycrystalline Diamond
摘要： With the demand of modern cutting technology for ‘high efficiency, precise, flexibility and green manufacturing’, polycrystalline diamond materials as cutting tools have been widely used in automobile, aerospace and non-metal processing. Electro-spark erosion is one of the most effective ways to machine polycrystalline diamond materials. Single pulse discharge is one of the research foundations of micro-EDM. Using 2 micron granularity polycrystalline diamond as experiment material, the influence of single pulse discharge technology on the removal efficiency of materials was studied, such as pit radius, pit depth and radius-depth ratio, etc. The experimental results show that, with the extension of the pulse duration, the radius of the discharge pit begins to increase rapidly, then slowly increases, and finally to slow down; while the radius of thermal influence zone increases rapidly and then continues to increase slowly. With the extension of pulse duration, the ratio of pit depth to radius changes within the range of 0.05 ~ 0.25, which shows a downward trend basically.
关键词： Single pulse,Micro-size,Polycrystalline diamond (PCD),Electrical Discharge Machining (EDM),Corrosion pit size
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Information and Communication Technology Convergence (ICTC) - Jeju (2018.10.17-2018.10.19)] 2018 International Conference on Information and Communication Technology Convergence (ICTC) - High Accuracy Real Time Machine Vision for Diameter Measurement Using Simpson Algorithm
摘要： Diameter is one of the important parameters for quality measurement. Fruit classification, for example, takes diameter as one important indicator, apart from other indicators. Precision measurement has been observed and experimented for example it can be done using laser technology, however the instrument requires a lot of space, therefore mobility is almost impossible. When speed is necessity while doing measurement, a real-time measurement using camera and image processing can give a lot of contribution compared to manual measurement. This paper introduces a diameter measurement method using Simpson algorithm in real-time, using regular camera. Simpson algorithm gave high accuracy measurement with high computation speed. The design indicated good result with accuracy ranged from 93% to 99% depending on calibration.
关键词： size measurement,automatic measurement,camera vision,simpson algorithm,size classification
更新于2025-09-23 15:22:29
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Compact L/S-Band Circularly Polarized Microstrip Antenna over Reactive Impedance Surface
摘要： A compact LIS-band circularly polarized (CP) antenna over the reactive impedance surface (RIS) is designed, fabricated, and measured. This dual-band CP antenna is excited by two probes and fed by two grounded coplanar waveguides. The CP radiation with very compact antenna size is achieved by stacking a square ring slotted truncated corner square patch and a truncated corner square patch over the RIS. The measured results show that the 3-dB axial ratio bandwidth of the antenna is 0.9% (1.787-1.803 GHz) for the lower band and 1.1% (2.685-2.715 GHz) for the upper band, while the 10-dB return loss bandwidth is 5.9% (1.746-1.852 GHz) and 7.3% (2.586-2.784 GHz), respectively. The antenna gain at boresight is 1.9 dBic for the lower band, and 1.94 dBic for the upper band. The overall volume of the dual-band CP antenna is 0.235 x 0.235 x 0.042λ at 1.765 GHz.
关键词： reactive impedance surface,circularly polarized antenna,size miniaturization,dual band
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Design of Compact SIW Bandpass Filter for Millimeter-Wave Applications
摘要： this paper presents the design of two structures of substrate integrated waveguide (SIW) bandpass filter (BPF) for millimeter-wave application. By approaching the cruciform slot and ground vias, the numbers of resonance frequency was increased, and the filter structure can be miniaturized. Finally, the filter is designed to work at the center frequency of 22 GHz with the bandwidth of 1.4 GHz, and the numerical simulations shows good performance in the pass band and stopband.
关键词： Compact size,Bandpass,Millimeter wave,SIW
更新于2025-09-23 15:22:29
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Scaling up electrodes for photoelectrochemical water splitting: fabrication process and performance of 40 cm2 LaTiO2N photoanodes
摘要： A scalable process for particle-based photoanodes is developed. The electrodes are versatilely made of photocatalytically active semiconductor particles, here LaTiO2N, and optionally coated with co-catalysts and protecting components, all immobilized on a conducting substrate. The involved fabrication steps are restricted to scalable processes like electrophoretic deposition, annealing in air and dip coating. Special care is taken to ensure charge transport in between particles and to the substrate by adding conducting connectors. Adapting the fabrication steps, the geometrical electrode dimension is increased from the size of a typical lab electrode of 1 cm2 to 40 cm2. The quality of the scale up process is characterized by comparing the photoanodes in terms of thickness, light absorption properties and morphology. For several compositions, the electrochemical performance of both electrode sizes is assessed by measuring photocurrents and Faraday efficiencies. The comparison revealed a complex upscaling behavior and showed that photoelectrode size affected performance already on the 0.1 m scale.
关键词： photoelectrodes,energy conversion,LaTiO2N,electrode size,water splitting
更新于2025-09-23 15:22:29
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Size-Dependent Buckling and Vibrations of Piezoelectric Nanobeam with Finite Element Method
摘要： In the present paper, a finite element method is used to study the vibrations and buckling of a piezoelectric nanobeam. The beam theory used here is Bernoulli–Euler model. In order to achieve the goal, first, the governing equations of the piezoelectric nanobeam were obtained via the Hamilton principle, based on the higher-order theory such as modified couple stress. The shape functions were embedded in these equations, and the matrix form of the equations was obtained. In other words, the governing equations were discretized by the finite element method. By calculating the matrix form of equations, mass matrices, mechanical stiffness and electrical stiffness of the beam were obtained. It should be noted that when calculating stiffness matrices, first, the definition of a new element must be added to the effects of the electric field in the elements of the beam, and the effects of the gradient of strain should be added in the form of non-classical matrix to the stiffness matrix. With the aid of these critical load matrices, the buckling force and voltage and the natural frequency of the piezoelectric nanobeam have been calculated. Numerical results show that this method can involve the size effects.
关键词： Size effect,Piezoelectric,Buckling voltage,Couple stress theory,Free vibration,Buckling load
更新于2025-09-23 15:22:29
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The Size Effect of Exfoliated MoS <sub/>2</sub> Based Thin Film Humidity Sensor
摘要： Layered two-dimensional nanomaterials such as MoS2 show great potential for sensor application owing to their distinct nature that most atoms are surface atoms. The difficult in mass production of exfoliated MoS2 hinders its practical application. In this study, we investigate the ultrasound assisted liquid method to efficiently exfoliate MoS2 into nanosheets and nanoparticles. The dependence of ultrasonic dosing, e.g., ultrasonic time, on the morphology and yield of final products are studied. The exfoliated MoS2 nanomaterials are fabricated into thin film sensors and examined with humidity gas. The sensors exhibit excellent and quick response toward humidity gas. We find the sensor prepared with longer ultrasonic treatment presents higher response owing to that the longer ultrasonic irradiation exposes more active edge sites.
关键词： Exfoliation,Humidity Sensor,MoS2,Size Effect,Thin Film
更新于2025-09-23 15:22:29
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Quality factor assessment of finite-size all-dielectric metasurfaces at the magnetic dipole resonance
摘要： Recently there has been a large interest in achieving metasurface resonances with large quality factors. In this article, we examine metasurfaces that comprised a finite number of magnetic dipoles oriented parallel or orthogonal to the plane of the metasurface and determine analytic formulas for their resonances’ quality factors. These conditions are experimentally achievable in finite-size metasurfaces made of dielectric cubic resonators at the magnetic dipole resonance. Our results show that finite metasurfaces made of parallel (to the plane) magnetic dipoles exhibit low quality factor resonances with a quality factor that is independent of the number of resonators. More importantly, finite metasurfaces made of orthogonal (to the plane) magnetic dipoles lead to resonances with large quality factors, which ultimately depend on the number of resonators comprising the metasurface. In particular, by properly modulating the array of dipole moments by having a distribution of resonator polarizabilities, one can potentially increase the quality factor of metasurface resonances even further. These results provide design guidelines to achieve a sought quality factor applicable to any resonator geometry for the development of new devices such as photodetectors, modulators, and sensors.
关键词： dipole approximation,Mie resonances,magnetic dipole resonance,finite-size metasurfaces,High quality factor
更新于2025-09-23 15:22:29