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Optimizing the Nonlinearity and Dissipation of a SNAIL Parametric Amplifier for Dynamic Range
摘要： We present a quantum-limited Josephson-junction-based three-wave-mixing parametric amplifier, the superconducting nonlinear asymmetric inductive element (SNAIL) parametric amplifier (SPA), which uses an array of SNAILs as the source of tunable nonlinearity. We show how to engineer the nonlinearity over multiple orders of magnitude by varying the physical design of the device. As a function of design parameters, we systematically explore two important amplifier nonidealities that limit dynamic range: the phenomena of gain compression and intermodulation distortion, whose minimization are crucial for high-fidelity multiqubit readout. Through a comparison with first-principles theory across multiple devices, we demonstrate how to optimize both the nonlinearity and the input-output port coupling of these SNAIL-based parametric amplifiers to achieve higher saturation power, without sacrificing any other desirable characteristics. The method elaborated in our work can be extended to improve all forms of parametrically induced mixing that can be employed for quantum-information applications.
关键词： gain compression,Josephson-junction,three-wave-mixing,parametric amplifier,SNAIL,dynamic range,quantum-limited,intermodulation distortion
更新于2025-09-11 14:15:04
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Search for Best Astronomical Observatory Sites in the MENA Region using Satellite Measurements
摘要： We perform a systematic search for astronomical observatory sites in the MENA (Middle-East and North Africa) region using space-based data for all the relevant factors, i.e. altitude (DEM), cloud fraction (CF), light pollution (NTL), precipitable water vapor (PWV), aerosol optical depth (AOD), relative humidity (RH), wind speed (WS), Richardson Number (RN), and diurnal temperature range (DTR). We look for the best locations overall even where altitudes are low (the threshold that we normally consider being 1,500 m) or where the combination of the afore-mentioned determining factors had previously excluded all locations in a given country. In this aim, we use the rich data that Earth-observing satellites provide, e.g. the Terra and Aqua multi-national NASA research satellites, with their MODIS (Moderate Resolution Imaging Spectroradiometer) and AIRS (Atmospheric Infrared Sounder) instruments, the Defense Meteorological Satellite Program’s Operational Linescan System (DMSP-OLS), and other products from climate diagnostics archives (e.g. MERRA). We present preliminary results on the best locations for the region.
关键词： diurnal temperature range,Richardson Number,MENA region,wind speed,precipitable water vapor,cloud fraction,relative humidity,aerosol optical depth,light pollution,astronomical observatory sites,satellite measurements
更新于2025-09-11 14:15:04
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Understanding Solid-State Solvation-Enhanced Thermally Activated Delayed Fluorescence Using a Descriptor-Tuned Screened Range-Separated Functional
摘要： An efficient computational protocol suitable for both solutions and solid films can accelerate the development of efficient thermally activated delayed fluorescence (TADF) emitters aimed at practical application in organic light-emitting diodes (OLEDs). By employing the localized orbital locator (LOL), we establish an efficient descriptor-tuning methodology for the range-separated (RS) and screened range-separated (SRS) functionals with only one single-point calculation. This scheme provides good predictions for 28 charge transfer (CT)-type TADF emitters. Moreover, in comparison to the experimental data, the scheme presents a mean absolute deviation of 0.09 eV for the absorption energies of the lowest excited singlet state (EVA(S1)) in polarizable continuum model (PCM) solution and 0.10 eV for the energy difference between the lowest excited singlet and triplet states (ΔEST) under static solid-state polarization. Importantly, our results indicate that a significantly polarized S1 is key to realizing the so-called solid-state solvation-enhanced (SSSE)-TADF, which is well captured through the screened RS functionals combined with LOL-tuning (SLOL-tuning). Compared with standard ionization potential (IP)-tuning, our scheme significantly reduces the computational cost of the prediction of singlet- and triplet-transition energies for CT molecules. It also provides a reliable approach to evaluate the practical TADF character influenced by solid-state solvation in amorphous organic thin films.
关键词： Thermally Activated Delayed Fluorescence,Optical,Solid-State Solvation-Enhanced,Plasmonics,Magnetic,Hybrid Materials,TADF,Range-Separated Functional,LOL-tuning,OLEDs
更新于2025-09-11 14:15:04
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Microstructure-Stabilized Blue Phase Liquid Crystals
摘要： We show that micron-scale two-dimensional (2D) honeycomb microwells can significantly improve the stability of blue phase liquid crystals (BPLCs). Polymeric microwells made by direct laser writing improve various features of the blue phase (BP) including a dramatic extension of stable temperature range and a large increase both in reflectivity and thermal stability of the reflective peak wavelength. These results are mainly attributed to the omnidirectional anchoring of the isotropically oriented BP molecules at the polymer walls of the top and bottom substrates. This leads to an omnidirectional stabilization of the entire BPLC system. This study not only provides a novel insight into the mechanism for the BP formation in the 2D microwell but also points to an improved route to stabilize BP using 2D microwell arrays.
关键词： honeycomb microwells,temperature range,stability,thermal stability,reflectivity,blue phase liquid crystals
更新于2025-09-11 14:15:04
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A new optical technique to monitor joint motion using position sensitive detector
摘要： BACKGROUND: Evaluation of joint movements is essential to choose an appropriate rehabilitation protocol for a patient. OBJECTIVE: The aim of this study is to suggest an alternative optical technique for measurement of joint angle which is convenient, inexpensive, and can be operated in real time. METHODS: According to the principle of the triangulation method, position sensitive detector (PSD) converts reflected light signals into distance-related voltages. Various parameters were investigated to increase detection range and resolution of joint angle measurements. RESULTS: The accuracy of the suggested optical sensor was verified by comparing with a commercial goniometer and 3D motion capture system. CONCLUSIONS: This method can be applied to monitor recovery progress for the patient in rehabilitation and sport science.
关键词： position sensitive detector,Human joint angle,range of motion,optical goniometer,rehabilitation
更新于2025-09-10 09:29:36
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All-optical Multi-Octave Microwave Phase Shifter
摘要： In wideband multi-octave phase-shifting photonic links, second-order distortions (SDs) overlap with fundamental signals and cannot be filtered out. In this paper, we propose an all-optical microwave phase shifter, which suppresses the SDs and supports the amplitude tuning of the fundamental signals. The proposed all-optical phase shifter is based on polarization modulation and differential detection. Thanks to the all-optical techniques, maximum operating frequency of the proposed phase shifter is not limited by electronic bottlenecks. By using polarization modulation, the phase and amplitude of the output fundamental signals are tuned by simply manipulating the polarization states of the optical signals. By using differential detection, SDs components with same frequencies cancel out each other. Simulation results show that phase shift of 360° and power adjustable extent over 21.41 dB for the output fundamental signals are achieved. The direct current (DC) and the SDs components are well suppressed after differential detection. The typical spurious free dynamic range (SFDR) is significant improved by 21.79 dB from 77.78 dB·Hz1/2 to 99.57 dB·Hz2/3.
关键词： differential detection,polarization modulation,spurious free dynamic range,second-order distortions,Phase shift
更新于2025-09-10 09:29:36
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Determination of hydrological roughness by means of close range remote sensing
摘要： The objective of the presented work was to develop a method to acquire Manning’s n by creating very high-resolution surface models with structure-from-motion methods. As hydraulic roughness is an essential parameter for physically based erosion models, a practical measuring technique is valuable during field work. Data acquisition took place during several field experiments in the Lainbach valley, southern Germany, and on agricultural sites in Saxony, eastern Germany, and in central Brazil. Rill and interrill conditions were simulated by flow experiments. In order to validate our findings stream velocity was measured with colour tracers. Grain sizes were derived by measuring distances from a best fit line to the reconstructed soil surface. Several diameters from D50 to D90 were tested with D90 showing best correlation between tracer experiments and photogrammetrically acquired data. Several roughness parameters were tested (standard deviation, random roughness, Garbrecht’s n and D90). Best agreement in between the grain size and the hydraulic roughness was achieved with a non-linear sigmoid function and D90 rather than with the Garbrecht equation or statistical parameters.
关键词： soil erosion models,hydrological roughness,close range remote sensing,Manning’s n,structure-from-motion
更新于2025-09-10 09:29:36
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[IEEE 2017 XVII Workshop on Information Processing and Control (RPIC) - Mar del Plata (2017.9.20-2017.9.22)] 2017 XVII Workshop on Information Processing and Control (RPIC) - Feasibility and analysis of a system of two in tandem interferometers for optical coherence tomography
摘要： A signal obtained from a combined system of two interferometers of low coherence in the frequency domain is presented and analyzed. This system allows to expand the range of measurement offered by the conventional optical tomography system of a single interferometer with a spectrometer as a detector.
关键词： dynamics range,large depth,optics tomograpfy,FD-OCT,Interferometry
更新于2025-09-10 09:29:36
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On the possibility of the electron-beam welding of quartz glasses by a forevacuum plasma electron source
摘要： The article demonstrates a principle possibility of the electron-beam welding of high-temperature quartz glasses by a plasma electron source operating in the forevacuum range of pressure of 10-50 Pa. We studied the dependence of the composition of the gas atmosphere in the vacuum chamber on the heating temperature of the weld seam. It is shown that the optimal temperature of the weld seam for melting and minimum mass entrainment from the molten pool is 1300 to 1400 0C. We determined the welding regime for cylindrical tubes and rods that provides high seam strength, reaching 90-95% of the original strength of quartz glass.
关键词： forevacuum range of pressure,electron-beam welding,plasma electron source,quartz glass
更新于2025-09-10 09:29:36
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Microwave Photonic Link With Improved Dynamic Range Through π phase Shift of the Optical Carrier Band
摘要： A microwave photonic link (MPL) with an improved spurious-free dynamic range (SFDR) by introducing a π phase shift to the spectral complements in the optical carrier band (OCB) is proposed and experimentally demonstrated. The fundamental concept to improve the SFDR is to suppress the third-order intermodulation distortion (IMD3) terms while retaining a high gain for the fundamental terms, which is achieved by introducing a π phase shift to the OCB with the joint use of an electrical 90? hybrid coupler and a dual-parallel Mach-Zehnder modulator (DP-MZM). When detecting the optical signal from the DP-MZM at a photodetector (PD), the IMD3 components originated from the beating between different optical sidebands can be fully cancelled, while the gain for the fundamental terms remains reasonably high. Therefore, the SFDR of the MPL is significantly increased. The proposed MPL is experimentally demonstrated. An SFDR of 108.1 dB?Hz2/3 or 120.4 dB?Hz2/3 for a noise floor of -146.9 or -163.9 dBm/Hz is achieved, which is 14 dB or 15 dB higher than that of a conventional intensity-modulation direct-detection (IMDD) MPL.
关键词： parallel intensity modulators,third-order intermodulation,microwave photonic link (MPL),Spurious-free dynamic range (SFDR)
更新于2025-09-10 09:29:36