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[IEEE 2017 IEEE International WIE Conference on Electrical and Computer Engineering (WIECON-ECE) - Dehradun (2017.12.18-2017.12.19)] 2017 IEEE International WIE Conference on Electrical and Computer Engineering (WIECON-ECE) - Hybrid Beamforming Utilization Perspective for Future 5G Millimeter Wave Communication
摘要： This paper presents hybrid beamforming perspective which will play a vital role in upcoming 5G millimeter wave communication systems. Windowing techniques are implemented in this paper which helps in suppression of sidelobes of the beam. Analysis of directivity with respect to number of antenna elements with combination of windowing techniques has also been observed in this paper. Thus in this paper analysis for future technology has been provided which will act as building blocks for millimeter wave communications.
关键词： SLL (Side Lobe Level),BER (Bit Error Rate),MRA (Maximum Response Angle),MLW (Main Lobe Width),ULA(Uniform Linear Array)
更新于2025-09-09 09:28:46
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Titanium coverage for plasma-induced uniform HfSiON film from Hf nanoscale islands on SiO <sub/>2</sub> /Si
摘要： Signi?cant improvement of the in-plane uniformity of an HfSiON ?lm is enabled by a Ti coverage over Hf islands on an SiO2/Si substrate. Surface diffusion of Hf during an HfSiON ?lm growth from Hf (island)/SiO2/Si structure induced by a nitrogen inductively coupled plasma (ICP) exposure is effectively suppressed by the Ti coverage. The nitrogen ICP exposure to the Ti/Hf (island)/SiO2/Si surface forms a TiN layer, which suppresses the surface diffusion of Hf by lowering the surface energy. Even a small Ti coverage of 5% is effective for the uniform Hf concentration in the HfSiON ?lm. The uniformity of the ?lm is monitored by an in vacuo noncontact AFM and a cross-sectional SEM imaging. An ex situ XPS analysis indicates that the TiN layer is sputtered by the ion bombardment and the Ti content in the ?lm decreases less than 1%. The intermixing of Si with Hf and the subsequent nitridation of the ?lm is successfully performed even the surface is covered with TiN. The mercury probe measurement revealed that the improved uniformity by the Ti coverage increases the capacitance and reduces the leakage current of the high-k dielectric ?lm.
关键词： uniform film,capacitance,HfSiON,Ti coverage,leakage current,nitrogen ICP,surface diffusion,plasma-induced,TiN layer
更新于2025-09-09 09:28:46
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A Reconfiguration Method for Extracting Maximum Power from Non-Uniform Aging Solar Panels
摘要： Aging affects different photovoltaic (PV) modules in a PV array in a non-uniform way, thereby leading to non-uniform working conditions of the PV modules and resulting in variations in the power outputs of the PV array. In this paper, an algorithm is developed for optimising the electrical con?guration of a PV array during the non-uniform aging processes amongst the PV modules. A new PV array recon?guration method is proposed to maximize the power generation from non-uniformly aged PV arrays through rearrangements of the positions of the PV modules without having to replace the aged PV modules with new ones, thereby saving on maintenance costs. This recon?guration strategy requires information about the electrical parameters of the PV modules in an array, so as to choose the optimal recon?guration topology. In this algorithm, the PV modules are sorted iteratively in a hierarchy pattern to reduce the effect of mismatch due to the non-uniform aging processes amongst PV modules. Computer simulation and analysis have been carried out to evaluate the effectiveness of the proposed method for different sizes of non-uniform aged PV arrays (4 × 4, 10 × 10, and 100 × 10 arrays) with MATLAB. The results show an improvement in the power generation from a non-uniformly aged PV array and can be applied to any size of PV array.
关键词： non-uniform aging,rearrangement,MPPT,solar PV
更新于2025-09-09 09:28:46
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Humidity sensors based on AlN microcantilevers excited at high-order resonant modes and sensing layers of uniform graphene oxide
摘要： Resonant humidity sensors base on interdigital transducers (IDTs) excited microcantilevers are proposed for high sensitivity. The microcantilevers are coated with uniform graphene oxide (GO) thin films as sensing layers. For the first time, IDTs are used to excite piezoelectric microcantilevers to operate at very high-order resonant modes with intense signal. A small temperature coefficient of frequency (-23.6 ppm/?C) of the microcantilvers is obtained by using AlN/Si (surface highly doped) layered structure. Uniform and thickness-controllable GO films covering the surface of microcantilevers are formed by vacuum filtration. Compared with the normal electrodes excited sensor with the same structure size, the sensitivity of the IDTs excited sensor is increased from 9.67 to 84.41 Hz/%RH. The thicker GO film, the higher sensitivity of the humidity sensor. Very little humidity hysteresis (< 3%RH) of the sensors is observed in a wide test range from 10%RH to 90%RH. Moreover, the sensors have excellent short term repeatability, fast response and short recovery time (about 10 s).
关键词： Humidity sensors,interdigital transducers,uniform graphene oxide films,microcantilevers,high-order resonant mode
更新于2025-09-09 09:28:46
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[Lecture Notes in Mechanical Engineering] Numerical Heat Transfer and Fluid Flow (Select Proceedings of NHTFF 2018) || Combined Influence of Radiation Absorption and Hall Current on MHD Free Convective Heat and Mass Transfer Flow Past a Stretching Sheet
摘要： The present article investigates the combined in?uence of thermal radi- ation, radiation absorption, Soret and Dufour effect, and non-uniform heat source on the steady convective heat and mass transfer ?ow of a viscous incompressible ?uid past a stretching sheet. The non-linear equations governing the ?ow, heat and mass transfer have been solved by using a Runge–Kutta ?fth-order together with shooting technique. The in?uence of Sr/Du, A1, B1 on all ?ow characteristics has been analysed.
关键词： Stretching sheet,Hall current,Cross diffusion,Non-uniform heat source/sink
更新于2025-09-04 15:30:14
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[ASME ASME 2017 Power Conference Joint With ICOPE-17 collocated with the ASME 2017 11th International Conference on Energy Sustainability, the ASME 2017 15th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2017 Nuclear Forum - Charlotte, North Carolina, USA (Monday 26 June 2017)] Volume 2: I&C, Digital Controls, and Influence of Human Factors; Plant Construction Issues and Supply Chain Management; Plant Operations, Maintenance, Aging Management, Reliability and Performance; Renewable Energy Systems: Solar, Wind, Hydro and Geothermal; Risk Management, Safety and Cyber Security; Steam Turbine-Generators, Electric Generators, Transformers, Switchgear, and Electric BOP and Auxiliaries; Student Competition; Thermal Hydraulics and Computational Fluid Dynamics - Heat Transfer Performance of LiF–NaF–KF Salt in a Corrugated Receiver Tube With Non-Uniform Solar Flux
摘要： The heat flux on the receiver tube is non-uniform because of uneven solar flux and receiver structure, which causes overheating and thermal stress failure of receiver and affected safe operations of the Concentrated Solar Power(CSP) system. In order to reduce the temperature difference in receiver tube wall and improve the efficiency of CSP system, the ternary eutectic salt LiF–NaF–KF (46.5–11.5–42 wt.%, hereafter FLiNaK), which has a better high thermal stability than that of nitrate salts at operating temperature of 900 °C, is selected as HTF, and heat transfer performance of FLiNaK in a corrugated receive tube with non-uniform heat flux is simulated by CFD software in the present work. The numerical results reveal that the non-uniform heat flux has a great influence on the temperature distributions of the receive tube and FLiNaK salt. Compared with the result of bare tube, the corrugated tube can not only significantly reduce the temperature difference in tube wall and salt by improving the uniformity of temperature distribution but also enhance the heat transfer of the salt, where the heat transfer coefficient increases with the Reynolds number and heat flux. Moreover, the enhanced effect of the corrugated tube depends on both the pitch and the height of ridges. It is found that the heat transfer coefficient of the salt gets a maximum when the ratio of the height of ridge to the pitch is 0.2. The research presented here may provide guidelines for design optimization of receiver tube in CSP system.
关键词： heat transfer,FLiNaK,non-uniform heat flux,corrugated tube,Concentrated Solar Power
更新于2025-09-04 15:30:14
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EFFICIENT LOCALIZATION ALGORITHM OF MIXED FAR-FIELD AND NEAR-FIELD SOURCES USING UNIFORM CIRCULAR ARRAY
摘要： An e?cient algorithm based on high-order cumulant is addressed for the scenarios where both far-?eld and near-?eld narrow-band signals may exist synchronously. The ?rst matrix built by four-order cumulant is utilized to estimate the two dimensional direction-of-arrivals (DOAs) using the orthogonal projection matrix of the signal subspace and the virtual steering matrix. Then, the second matrix built by four-order cumulant is decomposed to get the noise subspace using the eigen decomposition. Meanwhile, a virtual steering matrix is used to distinguish far-?eld signals (FFSs) from near-?eld signals (NFSs). And one-dimensional MUSIC algorithm is used to estimate the range of the NFSs. Compared to the TSMUSIC, the proposed algorithm can provide high resolution for the DOAs. In addition, there is higher accuracy for the DOA of NFS in the proposed algorithm than that in TSMUSIC and in TSMD. Simulation results are carried out to certify the performance of the proposed algorithm.
关键词： near-field signals,MUSIC algorithm,high-order cumulant,uniform circular array,far-field signals,DOA estimation
更新于2025-09-04 15:30:14