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- 摘要
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- 实验方案
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Direct dynamic evidence of charge separation in a dyea??sensitized solar cell under operando conditions by Raman spectroscopy
摘要： Interfaces play an important role in enhancing the energy conversion performance of dye-sensitized solar cells (DSCs). The interface effects have been studied by many techniques, but almost all studies only performed on a portion of DSC, rather than on a complete solar cell. Hence, monitoring the interface evolution of a DSC is still very challenging. Here, in situ/operando resonance Raman (RR) spectroscopic analyses were carried out to monitor the dynamic observations of the photovoltaic conversion process from a DSC. We observed the creation of new species (i.e., polyiodide and iodine aggregates) in the photosensitization process. We also successfully identified molecular-scale dynamic evidence that the bands from the C═C of 2,2’-bipyridyl (bpy), the S═C═N of NCS ligand and photochemical products show reasonably strong intensity and frequency changes, which clearly demonstrates that they are important pathways of charge separation. Furthermore, RR spectroscopy also be applicable to quickly evaluate the performance of DSCs.
关键词： dye-sensitized solar cell,semiconductor,TiO2 nanotube array,Raman spectroscopy,charge transfer
更新于2025-09-23 15:19:57
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A Solution of Implicit Model of Series-Parallel Photovoltaic Arrays by Using Deterministic and Metaheuristic Global Optimization Algorithms
摘要： The implicit model of photovoltaic (PV) arrays in series-parallel (SP) configuration does not require the LambertW function, since it uses the single-diode model, to represent each submodule, and the implicit current-voltage relationship to construct systems of nonlinear equations that describe the electrical behavior of a PV generator. However, the implicit model does not analyze different solution methods to reduce computation time. This paper formulates the solution of the implicit model of SP arrays as an optimization problem with restrictions for all the variables, i.e., submodules voltages, blocking diode voltage, and strings currents. Such an optimization problem is solved by using two deterministic (Trust-Region Dogleg and Levenberg Marquard) and two metaheuristics (Weighted Differential Evolution and Symbiotic Organism Search) optimization algorithms to reproduce the current–voltage (I–V) curves of small, medium, and large generators operating under homogeneous and non-homogeneous conditions. The performance of all optimization algorithms is evaluated with simulations and experiments. Simulation results indicate that both deterministic optimization algorithms correctly reproduce I–V curves in all the cases; nevertheless, the two metaheuristic optimization methods only reproduce the I–V curves for small generators, but not for medium and large generators. Finally, experimental results confirm the simulation results for small arrays and validate the reference model used in the simulations.
关键词： partial shading,global optimization,series–parallel,deterministic optimization algorithm,implicit model solution,metaheuristic optimization algorithm,photovoltaic array
更新于2025-09-23 15:19:57
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Enhancing electrostatic coupling in silicon quantum dot array by dual gate oxide thickness for large-scale integration
摘要： We propose a structure with word/bit line control for a two-dimensional quantum dot array, which allows random access for arbitrary quantum dots with a small number of control signals. To control multiple quantum dots with a single signal, every quantum dot should have a wide operating voltage allowance to overcome the property variations. We fabricate two-dimensional quantum dot arrays using silicon-complementary-metal-oxide-semiconductor technology with an alternating dual-standard gate oxide thickness. The quantum dots are designed to have an allowable operating voltage window of 0.2 V to control the number of electrons, which is a window one order of magnitude wider than that of previous works. The proposed structure enables both easy fabrication and operation for multiple quantum dots and will pave the way for practical use of large-scale quantum computers.
关键词： electrostatic coupling,dual gate oxide thickness,quantum dot array,large-scale integration,silicon-complementary-metal-oxide-semiconductor technology
更新于2025-09-23 15:19:57
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Nanodot array deposition via single shot laser interference pattern using laser-induced forward transfer
摘要： Laser-induced forward transfer (LIFT) is a direct-writing technique capable of depositing a single dot smaller than the laser wavelength at small shot energy through the laser-induced dot transfer (LIDT) technique. To deposit a single nanodot in a single shot of laser irradiation, a liquid nanodrop is transferred from donor to receiver and finally solidified via a solid-liquid-solid (SLS) process. In conventional LIDT experiments, multi-shots with step scanning have been used to form array structures. However, interference laser processing can achieve an arrayed process and generate a periodic structure in a single shot. In this study, a femtosecond laser interference pattern was first applied to LIDT, and an array of nanodots was successfully deposited in a single shot, producing the following unit structures: a single dot, adjoining dots, and stacking dots. The diameter of the smallest nanodot was 355 nm, and the narrowest gap between two adjoining nanodots was 17.2 nm. The LIDT technique produces high-purity, catalyst-free that do not require post-cleaning or alignment processes. Given these significant advantages, LIDT can expand the usability of nanodots in a wide range of fields.
关键词： array,laser-induced dot transfer (LIDT),interference laser processing,nanodot,femtosecond laser,Au,solid-liquid-solid (SLS) mechanism
更新于2025-09-23 15:19:57
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Full-spectrum periodic nonlinear Fourier transform optical communication through solving the Riemann-Hilbert problem
摘要： An algorithm is proposed for the detection and joint estimation of target parameters for a radar with a two-element rotating antenna. Rotation of the antenna introduces unwanted effects, which may cause inaccuracy in the parameter estimation. Target detection is performed by adding the processed data from two sensors. Joint estimation of range, Doppler, and direction of arrival (DOA) is carried while compensating the effects of antenna rotation. The detection performance is analyzed in terms of the receiver operating characteristics. Analytical expressions of Cramer–Rao Bound for Doppler, the range and DOA are derived. Computational complexity is also discussed. A simulation demonstrates and veri?es the proposed algorithm and its analyses.
关键词： target detection,parameter estimation,rotation compensation,Radar array processing,Cramer-Rao bound
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE Asia-Pacific Microwave Conference (APMC) - Singapore, Singapore (2019.12.10-2019.12.13)] 2019 IEEE Asia-Pacific Microwave Conference (APMC) - Two-Dimensional Electronically Controlled Scanning Phased Array Antenna Based on Liquid Crystal Material
摘要： In this paper, a two-dimensional electronically controlled scanning phased array antenna based on liquid crystal material is introduced. The structure consists of a 2×2 microstrip patch antenna array, a continuously variable helical folded delay line phase shifter, a RF feed and a bias network. The suspended stripline power divider, ground coplanar waveguide-suspended stripline transition structure and broadband patch antenna are studied respectively. The Ka-band LC passive phased array is developed by cascading the above circuits. The simulation results show that by tuning the excitation phases of each unit, the two-dimensional phase scan of the array is realized, the scanning angle is greater than ±30°, and the -10dB bandwidth of the array is larger than that of 4GHz.
关键词： Phased array,electronic scanning,liquid crystal
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 2nd International Conference on Renewable Energy and Power Engineering (REPE) - Toronto, ON, Canada (2019.11.2-2019.11.4)] 2019 IEEE 2nd International Conference on Renewable Energy and Power Engineering (REPE) - The Potential and analysis of Grid-connected Photovoltaic System in residential houses in Libya : Near-term solution of electricity shortage: A case study in Tripoli
摘要： Reducing the capacitance of programmable capacitor arrays (PCAs), commonly used in analog integrated circuits, is necessary for low-energy applications. However, limited mismatch data are available for small capacitors. We report mismatch measurement for a 2-fF poly–insulator–poly (PIP) capacitor, which is the smallest reported PIP capacitor to the best of the authors’ knowledge. Instead of using complicated custom on-chip circuitry, direct mismatch measurement is demonstrated and veri?ed using Monte Carlo simulations and experimental measurements. Capacitive test structures composed of 9-bit PCAs are implemented in a low-cost 0.35-μm CMOS process. Measured data are compared to the mismatch of large PIP capacitors, theoretical models, and recently published data. Measurement results indicate an estimated average relative standard deviation of 0.43% for the 2-fF unit capacitor, which is better than the reported mismatch of metal–oxide–metal (MOM) fringing capacitors implemented in an advanced 32-nm CMOS process.
关键词： programmable capacitor array (PCA),Analog-to-digital converter (ADC),energy-ef?cient circuits,mismatch characterization,capacitance-to-digital converter (CDC),capacitor mismatch
更新于2025-09-23 15:19:57
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[IEEE 2020 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus) - St. Petersburg and Moscow, Russia (2020.1.27-2020.1.30)] 2020 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus) - Investigation of the Laser Radiation Effect on the Viability and Functional Activity of Prokaryotic and Eukaryotic Cells
摘要： In bistatic multiple input multiple output (MIMO) radar, more number of detectable incident signals and a higher angle estimation performance can be obtained by using conjugate estimation of signal parameters via rotational invariance techniques (ESPRITs) with the characteristic of noncircularity. The result is achieved under the assumption that all the received signals are noncircular. When the incident signals are the coexistence of noncircular and circular signals, the conjugate ESPRIT will not valuable. Therefore, this paper proposes a method of the joint of direction of departure (DOD) and direction of arrival (DOA) estimation, which is appropriate for the coexistence of noncircular and circular signals in bistatic MIMO radar. First, the received data model of the bistatic MIMO radar is given. Second, we modify the received signal model by the use of noncircularity characteristic. Third, we derive out the equation of spatially rotational invariant containing the DOD and DOA information. Last, we solve the equation to obtain the DOD and DOA by means of total least squares technology. The proposed algorithm has the three advantages. One is that it has better angle estimation accuracy than that of method which does not use the noncircularity characteristic. Another one is that it has more number of detectable incident signals. The last one is that the more number of noncircular signals, the higher angle estimation accuracy will be. Results from numerical experiments are used to show the effectiveness of our proposed algorithm.
关键词： noncircular,MIMO radar,ESPRIT,Array signal processing,DOA estimation
更新于2025-09-23 15:19:57
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Method for Measuring the Absolute Spectral Response of Infrared Photodetector Arrays
摘要： Physical and technical aspects of the implementation of an alternative method for measuring the absolute spectral response of infrared photodetector arrays (IR PDA) (current sensitivity spectrum, voltage sensitivity, and quantum efficiency) without the use of spectral instruments are considered. The method is based on multiple measurements of the output signal of all IR array’s photosensitive elements (PSEs) generated by modulated black-body radiation at different temperatures of the black body (BB). The signal is measured against the sum of constant signals from the background radiation, the detector input optical window, the BB radiation modulator, the PSE dark current, and the constant signal of the LSI multiplexer. A system of Fredholm integral equations of the first kind is constructed based on the measured PSE signals. Its left side includes measured BB signals and, the right side, analytical expressions describing these signals. The solution of the system are the absolute values of the above-mentioned spectral components of all PSEs of PDAs. The block diagram of the measurement setup is considered, functional features of its operation are analyzed, and requirements for its blocks are substantiated. Additional advantages of the new method in comparison with the existing methods are presented.
关键词： useful and stray irradiation,current and voltage sensitivity spectra,PSE red boundary histogram,PSE red boundary distribution on IR array area,BB radiation modulation,IR PDA output signal,quantum efficiency spectrum
更新于2025-09-23 15:19:57
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Hierarchical Core-Shell Structure of 2D VS2@VC@N-Doped Carbon Sheets Decorated by Ultrafine Pd Nanoparticles: Assembled in 3D Rosette-like Array on Carbon Fiber Microelectrode for Electrochemical Sensing
摘要： The development of two-dimension (2D) nanohybrid materials with heterogeneous component in nanoscale and three-dimension (3D) well-ordered assembly in microscale has been regarded as an effective way to improve their overall performances by synergistic coupling of the optimized structure and composition. In this work, we reported the design and synthesis of a new type of hierarchically core-shell structure of 2D VS2@VC@N-doped carbon (NC) sheets decorated by ultrafine Pd nanoparticles (PdNPs), which were vertically grown on carbon fiber (CF) and assembled into a unique 3D rosette-like array. The resultant VS2@VC@NC-PdNPs modified CF microelectrode integrated the structural and electrochemical properties of the heterogeneous hybridization of core-shell VS2@VC@NC-PdNPs sheets with unique rosette-like array structure, and gave rise to a significant improvement in terms of electron transfer ability, electrocatalytic activity, stability and biocompatibility. Under the optimized conditions, the VS2@VC@NC-PdNPs modified CF microelectrode demonstrated excellent electrochemical sensing performance towards biomarker hydrogen peroxide (H2O2) including high sensitivity of 152.7 μA cm-2 mM-1, low detection limit of 50 nM (a signal-to-noise ratio of 3:1), as well as good reproducibility and anti-interference ability, which could be used for real-time in situ electrochemical detection of H2O2 in live cancer cells and cancer tissue. The remarkable performances of the proposed nanohybrid microelectrode will have a profound impact on the design of diverse 2D layered materials as promising candidate for electrochemical biosensing applications.
关键词： electrochemical sensing,hierarchical core-shell structure,three-dimension rosette-like sheets array,Two-dimension layered nanomaterials,cancer biomarker detection
更新于2025-09-23 15:19:57