- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2019 4th International Conference on Mechanical, Control and Computer Engineering (ICMCCE) - Hohhot, China (2019.10.24-2019.10.26)] 2019 4th International Conference on Mechanical, Control and Computer Engineering (ICMCCE) - Evaluation of Distributed Photovoltaic Consumption Capacity of Distribution Network Based on Cuckoo Search Algorithm
摘要： In this communication, the computation of the perturbation-based electric field integral equation of the form Rn?1, n = 0, 1, 2, . . . , is accelerated by using fast Fourier transform (FFT) technique. As an effective solution of the low-frequency problem, the perturbation method employs the Taylor expansion of the scalar Green’s function in free space. However, multiple impedance matrices have to be solved frequency orders, and the computational cost becomes at different extremely high, especially for large-scale problems. Since the perturbed kernels still satisfy Toeplitz property on the uniform Cartesian grid, incorporated the FFT based on Lagrange interpolation can be well to accelerate the multiple matrix vector products. Because of the nonsingularity property of high-order kernels when n ≥ 1, we do not need to do any near field amendment. Finally, the efficiency of the proposed method is validated in an iterative solver with numerical examples.
关键词： perturbation method,integral equation (IE),Fast Fourier transform (FFT),low frequency
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Curve Correction of the Energy Yield by Flexible Photovoltaics for VIPV and BIPV Applications Using a Simple Correction Factor
摘要： High-power grinding mills are used in the cement and mining industries to crush clinker or copper ore and grind these materials to fine powder. The multi-megawatt speed-controlled mill drives operate at a very low angular speed. Synchronous motors with a high number of pole pairs are used as the prime movers. They are traditionally fed by load-commutated thyristorized cycloconverters. These are prone to failure modes that can lead to excessive torque pulsations and high overcurrents. The huge stator, which was built as a separate ring-shaped structure around the tubular mill, may then get mechanically displaced, and the operation of the plant is interrupted. A novel and reliable direct drive uses a voltage source inverter that operates at the unity power factor for increased efficiency. Synchronous optimal pulsewidth modulation ensures a low harmonic current distortion and reduced switching losses at a very low switching frequency. The optimization of the pulse patterns takes the anisotropic magnetic properties of a separately excited synchronous motor into account. The implementation in a 23-MW semiautonomous grinding mill installed in a Zambian copper mine is intended.
关键词： Alternators,ball milling,pulse width modulation inverters,gradient methods,software algorithms,variable speed drives,Fourier transform
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Temperature-insensitive Fiber Twist Sensor Based on A Reflective Microfiber Coupler
摘要： A temperature-insensitive fiber twist sensor based on a reflective microfiber coupler with a high sensitivity of 2621.08 (a.u.)/(rad/m) is demonstrated. Modal interference of the sensor is analysed by Fast Fourier transform algorithm.
关键词： Microfiber coupler,Twist sensor,Fast Fourier transform
更新于2025-09-16 10:30:52
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Postmortem Diagnosis of Fatal Hypothermia by Fourier Transform Infrared Spectroscopic Analysis of Edema Fluid in Formalin‐Fixed, Paraffin‐Embedded Lung Tissues
摘要： The goal of this study was to investigate whether pulmonary edema could become a specific diagnostic marker for fatal hypothermia using Fourier transform infrared (FTIR) spectroscopy in combination with chemometrics. The spectral profile analysis indicated that hypothermia fatalities associated with pulmonary edema fluid contained more b-sheet protein conformational structures than the control causes of death, which included sudden cardiac death, brain injury, cerebrovascular disease, mechanical asphyxiation, intoxication, and drowning. Subsequently, the results of principal component analysis (PCA) further revealed that the content of b-sheet protein conformational structures in the pulmonary edema fluid was the main discriminatory marker between fatal hypothermia and the other causes of death. Ultimately, a robust postmortem diagnostic model for fatal hypothermia using a partial least-squares discriminant analysis (PLS-DA) algorithm was constructed. Pulmonary edema fluid spectra collected from eight new forensic autopsy cases that did not participate in the construction of the diagnostic model were predicted using the model. The results showed the causes of death of all these eight cases were correctly classified. In conclusion, this preliminary study demonstrates that FTIR spectroscopy in combination with chemometrics could be a promising approach for the postmortem diagnosis of fatal hypothermia.
关键词： postmortem diagnosis,fatal hypothermia,chemometrics,pulmonary edema fluid,Fourier transform infrared microspectroscopy,partial least-squares discriminant analysis
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Buildup of Noise-Like Pulses in Ultrafast Fiber Lasers
摘要： Noise-like pulses (NLP) - the emission of sub-nanosecond incoherent pulses in ultrafast lasers - are a topic of widespread attention, owing to their fundamental and applied interest [1]. Their existence seems paradoxical, combining the high temporal localization of circulating pulses akin to mode-locking, with a fundamental instability that entails large fluctuations [2]. NLPs can be considered as incoherent dissipative solitons [3]. It is therefore of considerable interest to investigate the self-emergence of these pulses in the laser. We undertake this study experimentally using the time-stretch dispersive Fourier transform (DFT), recording the pulse spectral and temporal information in real time over successive cavity roundtrips [4]. The buildup dynamics of noise-like pulses in both anomalous and normal-dispersion fiber lasers are compared, revealing markedly different stages and timescales in the evolution process.
关键词： anomalous dispersion,normal dispersion,Noise-like pulses,ultrafast fiber lasers,dispersive Fourier transform
更新于2025-09-16 10:30:52
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Polarization Dependent Reflectivity and Transmission for Cd1-Xznxte/GaAs(001) Epifilms in the Far-Infrared and Near-Infrared to Ultraviolet Region
摘要： The results of a comprehensive experimental and theoretical study is reported to empathize the optical properties of binary GaAs, ZnTe, CdTe and ternary Cd1-xZnxTe (CZT) alloys in the two energy regions: (i) far-infrared (FIR), and (ii) near-infrared (NIR) to ultraviolet (UV). A high resolution Fourier transform infrared spectrometer is used to assess the FIR response of GaAs, ZnTe, CdTe and CZT alloys in the entire composition 1.0 ≥ x ≥ 0 range. Accurate model dielectric functions are established appositely to extort the optical constants of the binary materials. The simulated dielectric functions are meticulously appraised in the FIR → NIR → UV energy range by comparing them against the existing spectroscopic FTIR and ellipsometry data. These outcomes are expended eloquently for evaluating the polarization dependent reflectivity R(λ) and transmission T(λ) spectra of ultrathin CZT/GaAs (001) epifilms. A reasonably accurate assessment of the CZT film thickness by reflectivity study has offered a credible testimony for characterizing any semiconducting epitaxially grown nanostructured materials of technological importance.
关键词： Dielectric functions,Fourier transform infrared spectroscopy,Transmission,Reflectivity,Ellipsometry,Epilayers
更新于2025-09-16 10:30:52
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Route from single-pulse to multi-pulse states in a mid-infrared soliton fiber laser
摘要： State-of-the-art ultrafast mid-IR ?ber lasers deliver optical solitons with durations of several hundred femtoseconds. The Er- or Ho-doped ?uoride gain ?bers generally used in these lasers have strong anomalous dispersion at ～3 μm, which generally forces them to operate in the soliton regime. Here we report that a pulse-energy clamping e?ect, caused by the buildup of intracavity nonlinearities, limits the shortest obtainable pulse durations in these mid-infrared soliton ?ber lasers. Excessive intra-cavity energy results in soliton instability, collapse and fragmentation into a variety of stable multi-pulse states, including phase-locked soliton molecules and harmonically mode-locked states. We report that the spectral evolution of the mid-IR laser pulses can be recorded between roundtrips through stretching their second-harmonic signal in a 25-km-length of single-mode ?ber. Using a modi?ed dispersive Fourier transform set-up, we were able to perform for the ?rst time spectro-temporal measurements of mid-IR laser pulses both in the pulsed state and during pulse collapse and fragmentation. The results provide insight into the complex nonlinear dynamics of mid-IR soliton ?ber lasers and open up new opportunities for obtaining a variety of stable multi-pulse mode-locked states at mid-IR wavelengths.
关键词： dispersive Fourier transform,soliton instability,multi-pulse states,pulse-energy clamping,mid-IR soliton ?ber lasers
更新于2025-09-16 10:30:52
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Fundamentals and Applications of Fourier Transform Mass Spectrometry || Fourier transform ion cyclotron resonance mass spectrometry and laser: A versatile tool
摘要： The coupling of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with laser combines the attributes of laser mass spectrometry with the analytical capabilities of a mass spectrometer having high resolution, high mass measurement accuracy, long ion-observation times, and exceptional ion isolation capabilities required for ion-molecule reaction or ion fragmentation studies [1–3]. The laser may be used for different purposes in mass spectrometry. The most standard one is to generate ions from the surface of the laser-irradiated sample. Two regimes have to be considered in respect with the laser fluence (energy deposit per surface unit in J/cm2) or the laser power density also named irradiance (power density deposit per surface unit in W/cm2). At low laser fluence, laser desorption/ionization (LDI) may take place. When the laser fluence increases, the regime of laser–matter interaction is modified and laser ablation (LA) occurs. In both cases, the ionization phenomenon and the transfer of the atoms or molecules to the gas phase are the direct result of the laser matter interaction. LDI and LA are well suited to the analysis of a wide range of organic, inorganic and also biological compounds. For complex matrices, it is important to note that information may be obtained on both organic and inorganic species. This is of first importance for the study of environmental or composite samples for example, in which organics, inorganics and/or polymers are intimately associated.
关键词： laser,Fourier transform ion cyclotron resonance mass spectrometry,laser desorption/ionization,organic compounds,mass spectrometry imaging,inorganic compounds,laser ablation
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Post Equalization Scheme Based on Deep Neural Network for a Probabilistic Shaping 128 QAM DFT-S OFDM Signal in Underwater Visible Light Communication System
摘要： We have presented a post equalization scheme based on Deep Neural Network (DNN) for DFT-S OFDM modulation using (PS) technique in underwater visible light communication (VLC) system. By this method, we successfully demonstrated a data rate of 1.74Gbit/s PS128QAM DFT-S OFDM modulation over 1.2meter underwater optical transmission with bit error rate (BER) below 7% FEC threshold of 3.8×10-3. Compared to the typical PS128QAM DFT-S OFDM modulation without DNN, the proposed method would lead to an improvement of system capacity of 5.4% by increasing the data rate by 90 Mbps. The experimental results validate that the proposed DNN-based post equalization scheme for odd order QAM PS technique can be a promising solution for future high speed underwater VLC system.
关键词： Probabilistic Shaping (PS),odd order QAM,Deep Neural Network (DNN),Underwater VLC,Discrete Fourier Transform-Spread (DFT-S) OFDM
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Machine Learning Scheme for Geometrically-shaped Constellation Classification utilizing Support Vector Machine in Multi-access Internet of Vehicle Lighting
摘要： In this paper, we propose a multi-access Internet of Vehicles (IoV) scheme based on multi-band DFTS-OFDM VLC system. The experimental results show that with the bandwidth of 62.5MHz, the dynamic range was enhanced 1.6 dBm employing SVM in hexagonal constellation Geometrically-shaped (GS) 16QAM and the overall capacity is 250Mbps.
关键词： discrete Fourier transform spread (DFT-S),Geometrically-shaped,optical orthogonal frequency division multiplexing (OFDM),Visible light communication,Internet of Vehicles,Support vector machine
更新于2025-09-16 10:30:52