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Light(Science & Applications) 2024年第5期13卷 941-956页

作者： Shunda Qiao Ying He Haiyue Sun Pietro Patimisco Angelo Sampaolo Vincenzo Spagnolo Yufei Ma National Key Laboratory of Laser Spatial Information Harbin Institute of TechnologyHarbinChina PolySense Lab Dipartimento Interateneo di FisicaUniversity and Politecnico of BariVia AmendolaBariItaly

Photoacoustic spectroscopy(PAS)as a highly sensitive and selective trace gas detection technique has extremely broad application in many ***,the laser sources currently used in PAS limit the sensing *** to diode laser and quantum cascade laser,the solid-state laser has the merits of high optical power,excellent beam quality,and wide tuning *** we present a long-wave,high-power,wide-tunable,singlelongitudinal-mode solid-state laser used as light source in a PAS sensor for trace gas *** self-built solid-state laser had an emission wavelength of~2μm with Tm:YAP crystal as the gain material,with an excellent wavelength and optical power stability as well as a high beam *** wide wavelength tuning range of 9.44 nm covers the absorption spectra of water and ammonia,with a maximum optical power of~130 mW,allowing dual gas detection with a single laser *** solid-state laser was used as light source in three different photoacoustic detection techniques:standard PAS with microphone,and external-and intra-cavity quartz-enhanced photoacoustic spectroscopy(QEPAS),proving that solid-state laser is an attractive excitation source in photoacoustic spectroscopy.

关键词： power tunable tuning

Incoherent non-Hermitian skin effect in photonic quantum walks

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Light(Science & Applications) 2024年第5期13卷 885-893页

作者： Stefano Longhi dipartimento di Fisica Politecnico di MilanoPiazza L.da Vinci 32I-20133 MilanoItaly IFISC(UIB-CSIC) Instituto de Fisica Interdisciplinar y Sistemas ComplejosE-07122 Palma de MallorcaSpain

The non-Hermitian skin effect describes the concentration of an extensive number of eigenstates near the boundaries of certain dissipative *** phenomenon has raised a huge interest in different areas of physics,including photonics,deeply expanding our understanding of non-Hermitian systems and opening up new avenues in both fundamental and applied aspects of topological *** skin effect has been associated to a nontrivial pointgap spectral topology and has been experimentally demonstrated in a variety of synthetic matter systems,including photonic *** most of physical models exhibiting the non-Hermitian skin effect full or partial wave coherence is generally *** we push the concept of skin effect into the fully incoherent regime and show that rather generally(but not universally)the non-Hermitian skin effect persists under dephasing *** results are illustrated by considering incoherent light dynamics in non-Hermitian photonic quantum walks.

关键词： dynamics. quantum effect

A quantitative analysis of the US materials flow methodology and comparison to the EU methodology for MSW statistics

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Waste Disposal and Sustainable Energy 2024年第1期6卷 85-94页

作者： Demetra Tsiamis Fabio Poretti Stefano Consonni Marco J.Castaldi Earth Engineering Center Department of Chemical EngineeringThe City College of New YorkNew YorkNYUSA dipartimento Di Energetica Politecnico Di MilanoPiazza Leonardo da Vinci 3220133MilanItaly

The European Union(EU)and the United States(US)determine municipal solid waste(MSW)statistics *** EU applies a site-specific methodology that directly measures waste whereas the US employs a materials flow methodology that estimates MSW statistics indirectly based on production and recovery data from *** study dissects the materials flow methodology and presents quantitative materials flow Sankey diagrams for the primary MSW materials to highlight data gaps that can be addressed to improve the methodology’s *** industry plastics data were applied to the materials flow methodology,and the results were within 10%of the plastics statistics reported by the US Environmental Protection Agency(US EPA).Drawbacks to the methodologies include EU measurement inaccuracies due to double-counting and not accounting for residual waste in the *** latter may partially explain why landfilling tonnages reported by the US EPA were approximately 60%less than the tonnages reported by the Waste to Energy Research and Technology Council(WTERT)in its national MSW survey that applied the EU methodology in the *** the EU,there is no US national policy that requires states to measure and report state-level waste data to the US *** improvements in US MSW statistics rely heavily on the implementation of national policies to homogenize the measurement and collection of waste data from states.

关键词： Materials flow methodology Site-specific methodology United States European Union Municipal solid waste Discrepancy

Observing the collapse of super-Bloch oscillations in strong-driving photonic temporal lattices

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Advanced Photonics 2024年第4期6卷 14-24页

作者： Xinyuan Hu Shulin Wang Chengzhi Qin Chenyu Liu Lange Zhao Yinglan Li Han Ye Weiwei Liu Stefano Longhi Peixiang Lu Bing Wang Huazhong University of Science and Technology School of Physics Wuhan National Laboratory for Optoelectronics Wuhan Institute of Technology Hubei Key Laboratory of Optical Information and Pattern Recognition politecnico di Milano Dipartimento di Fisica IFISC (UIB-CSIC) Instituto de Fisica Interdisciplinary Sistemas Complejos

Super-Bloch oscillations(SBOs) are amplified versions of direct current(dc)-driving Bloch oscillations realized under the detuned dc-and alternating current(ac)-driving electric fields. A unique feature of SBOs is the coherent oscillation inhibition via the ac-driving renormalization effect, which is dubbed as the collapse of SBOs. However, previous experimental studies on SBOs have only been limited to the weak ac-driving regime, and the collapse of SBOs has not been observed. Here, by harnessing a synthetic temporal lattice in fiber-loop systems, we push the ac-field into a strong-driving regime and observe the collapse of SBOs, which manifests as the oscillation-trajectory localization at specific ac-driving amplitudes and oscillation-direction flip by crossing collapse points. By adopting arbitrary-wave ac-driving fields, we also realize generalized SBOs with engineered collapse conditions. Finally, we exploit the oscillation-direction flip features to design tunable temporal beam routers and splitters. We initiate and demonstrate the collapse of SBOs, which may feature applications in coherent wave localization control for optical communications and signal processing.

关键词： Electric fields Optical modulators Phase modulation Bessel functions Optical coherence Polarization Pulse signals Solids Physical coherence Signal processing

Effectiveness of Sodium Silicate on the Corrosion Protection of AA7075-T6 Aluminium Alloy in Sodium Chloride Solution

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Materials Sciences and Applications 2024年第4期15卷 53-65页

作者： Francesco Rosalbino Giorgio Scavino Graziano Ubertalli dipartimento di Scienza Applicata e Tecnologia (DISAT) Politecnico di Torino Torino Italy

The influence of sodium silicate on the corrosion behaviour of aluminium alloy 7075-T6 in 0.1 M sodium chloride solution was studied by open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) techniques. Scanning electron microscopy (SEM) was used to characterize the AA7075-T6 surface. Silicate can significantly reduce corrosion deterioration and the inhibition efficiency increases with the concentration of Na2SiO3. The corrosion inhibition mechanism involves the formation of a protective film over the alloy surface by adsorption of aluminosilicate anions from solution, as has also been suggested by others in literature.

关键词： Aluminium Alloy 7075-T6 Silicate Sodium Chloride Electrochemical Impedance Spectroscopy (EIS) Scanning Electron Microscopy (SEM)

Complementary memtransistors for neuromorphic computing: How, what and why

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Journal of Semiconductors 2024年第6期45卷 64-80页

作者： Qi Chen Yue Zhou Weiwei Xiong Zirui Chen Yasai Wang Xiangshui Miao Yuhui He School of Integrated Circuits Huazhong University of Science and TechnologyWuhan 430074China Department of Electrical and Computer Engineering University of CaliforniaSan DiegoUSA dipartimento di Elettronica e Informazione and *** Politecnico di MilanoMilanoItaly Department of Applied Physics Hong Kong Polytechnic UniversityHong KongChina

Memtransistors in which the source-drain channel conductance can be nonvolatilely manipulated through the gate signals have emerged as promising components for implementing neuromorphic *** the other side,it is known that the complementary metal-oxide-semiconductor(CMOS)field effect transistors have played the fundamental role in the modern integrated circuit ***,will complementary memtransistors(CMT)also play such a role in the future neuromorphic circuits and chips?In this review,various types of materials and physical mechanisms for constructing CMT(how)are inspected with their merits and need-to-address challenges *** the unique properties(what)and poten-tial applications of CMT in different learning algorithms/scenarios of spiking neural networks(why)are reviewed,including super-vised rule,reinforcement one,dynamic vision with in-sensor computing,*** exploiting the complementary structure-related novel functions,significant reduction of hardware consuming,enhancement of energy/efficiency ratio and other advan-tages have been gained,illustrating the alluring prospect of design technology co-optimization(DTCO)of CMT towards neuro-morphic computing.

关键词： complementary memtransistor neuromorphic computing reward-modulated spike timing-dependent plasticity remote supervise method in-sensor computing

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Quartz-enhanced multiheterodyne resonant photoacoustic spectroscopy

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Light(Science & Applications) 2024年第4期13卷 696-705页

作者： Jiapeng Wang Hongpeng Wu Angelo Sampaolo Pietro Patimisco Vincenzo Spagnolo Suotang Jia Lei Dong State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Laser SpectroscopyShanxi UniversityTaiyuan 030006China. Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China. PolySense Lab Dipartimento Interateneo di FisicaUniversity and Politecnico of BariCNR-IFNVia Amendola 17370126 BariItaly

The extension of dual-comb spectroscopy(DCS)to all wavelengths of light along with its ability to provide ultralarge dynamic range and ultra-high spectral resolution,renders it extremely useful for a diverse array of applications in physics,chemistry,atmospheric science,space science,as well as medical *** this work,we report on an innovative technique of quartz-enhanced multiheterodyne resonant photoacoustic spectroscopy(QEMR-PAS),in which the beat frequency response from a dual comb is frequency down-converted into the audio frequency *** this way,gas molecules act as an optical-acoustic converter through the photoacoustic effect,generating heterodyne sound *** conventional DCS,where the light wave is detected by a wavelengthdependent photoreceiver,QEMR-PAS employs a quartz tuning fork(QTF)as a high-Q sound transducer and works in conjunction with a phase-sensitive detector to extract the resonant sound component from the multiple heterodyne acoustic tones,resulting in a straightforward and low-cost hardware *** novel QEMRPAS technique enables wavelength-independent DCS detection for gas sensing,providing an unprecedented dynamic range of 63 dB,a remarkable spectral resolution of 43 MHz(or~0.3 pm),and a prominent noise equivalent absorption of 5.99×10^(-6)cm^(-1)·Hz-1/2.

关键词： Quartz hardware resonant

Repeat-pass space-surface bistatic SAR tomography:accurate imaging and first experiment

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Science China(Information Sciences) 2024年第09期67卷 245-262页

作者： Zhiyang CHEN Yuanhao LI Cheng HU Shenglei WANG Xinpeng CHEN Mihai DATCU Andrea Virgilio MONTI-GUARNIERI Radar Technology Research Institute School of Information and Electronics Beijing Institute of Technology Beijing Key Laboratory of Embedded Real-Time Information Processing Technology Beijing Institute of Technology Advanced Technology Research Institute Beijing Institute of Technology CEOSpace Tech University Politehnica of Bucharest dipartimento di Elettronica Informazione e Bioingegneria Politecnico di Milano

Space-surface bistatic synthetic aperture radar(SS-BiSAR) offers an additional observation angle for monostatic spaceborne SAR, making it a promising technology for high-accuracy deformation retrieval technology in local regions. Repeat-pass SS-BiSAR tomography can accurately estimate the surfaces of buildings and steep areas, effectively removing terrain phases during deformation retrieving. However, inaccuracies in the orbital ephemeris can lead to image geometry distortion, reducing image pair coherence,introducing interferometric phase errors, and consequently deteriorating tomographic precision. This paper precisely models the image geometry distortion and interferometric phase error caused by repeat-pass ephemeris error. We propose an ephemeris correction method based on the chirp-Z transform to address these issues. Furthermore, we introduce an accurate tomography model to improve 3D reconstruction *** first SS-BiSAR tomography experiment, conducted using the Chinese Lutan-1 satellite, demonstrates that the correlation coefficient is improved by 0.16 after ephemeris error correction. Moreover, the density and precision of the tomographic point cloud are improved by 13.7% and 12.1%, respectively.

关键词： space-surface SAR tomography orbit error image distortion Lutan-1

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Stochastic Maximum Principle for Optimal Advertising Models with Delay and Non-Convex Control Spaces

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Advances in Pure Mathematics 2024年第6期14卷 442-450页

作者： Giuseppina Guatteri Federica Masiero dipartimento di Matematica Politecnico di Milano via Bonardi Milano Italia dipartimento di Matematica e Applicazioni Universit di Milano-Bicocca via Cozzi Milano Italia

In this paper we study optimal advertising problems that model the introduction of a new product into the market in the presence of carryover effects of the advertisement and with memory effects in the level of goodwill. In particular, we let the dynamics of the product goodwill to depend on the past, and also on past advertising efforts. We treat the problem by means of the stochastic Pontryagin maximum principle, that here is considered for a class of problems where in the state equation either the state or the control depend on the past. Moreover the control acts on the martingale term and the space of controls U can be chosen to be non-convex but now the space of controls U can be chosen to be non-convex. The maximum principle is thus formulated using a first-order adjoint Backward Stochastic Differential Equations (BSDEs), which can be explicitly computed due to the specific characteristics of the model, and a second-order adjoint relation.

关键词： Stochastic Optimal Control Delay Equations Advertisement Models Stochastic Maximum Principle

Finite Sample Properties of Virtual Reference Feedback Tuning Control

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Journal of Systems Science & Complexity 2018年第3期31卷 664-676页

作者： WANG Jianhong dipartimento di Elettronica Informazione Politecnico di Milano

In this paper, finite sample properties of virtual reference feedback tuning control are considered, by using the theory of finite sample properties from system identification. To design a controller in closed loop system structure, the idea of virtual reference feedback tuning is proposed to avoid the identification process corresponding to the plant model. After constructing one identification cost without any knowledge of plant model, the author derives one bound on the difference between the expected identification cost and its sample identification cost under the condition that the number of data points is finite. Also the correlation between the plant input and external noise is considered in the derivation of this bound. Furthermore, the author continues to derive one probability bound to quantify this difference by using some probability inequalities and control theory.

关键词： Asymptotic theory finite sample properties, virtual reference feedback control.

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