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- 摘要
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- 实验方案
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The Field of View, the Field of Resolution, and the Field of Contrast Sensitivity
摘要： The Field of View (FoV), the Field of Resolution, and the Field of Contrast Sensitivity describe three progressively more detailed descriptions of human spatial sensitivity at angles relative to fixation. The FoV is the range of visual angles that can be sensed by an eye. The Field of Resolution describes the highest spatial frequency that can be sensed at each angle. The Field of Contrast Sensitivity describes contrast sensitivity at each spatial frequency, at each visual angle. These three concepts can be unified with the aid of the Pyramid of Visibility, a simplified model of contrast sensitivity as a function of spatial frequency, temporal frequency, and luminance or retinal illuminance. This unified model provides simple yet powerful observations about the Field of Contrast Sensitivity. I have fit this model to a number of published measurements of peripheral contrast sensitivity. This allows us to test the validity of the model, and to estimate its parameters. Although the model is a simplification, I believe it provides an invaluable guide in a range of applications in visual technology.
关键词： Pyramid of Visibility,retinal illuminance,Field of Contrast Sensitivity,spatial frequency,luminance,Field of Resolution,Field of View,contrast sensitivity,temporal frequency
更新于2025-09-10 09:29:36
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Phase response of atom interferometers based on sequential Bragg diffractions
摘要： Large Momentum Transfer (LMT) beam splitters are implemented in atom interferometers to increase their sensitivity. However, LMT-interferometer light-pulses that modify the response function of the atom requires additional interferometer. In this paper, we develop an analytical model for the sensitivity function of the LMT-interferometers using sequential accelerating light pulses. We use the sensitivity function to calculate the acceleration sensitivity taking into account the pulse duration. In addition, the sensitivity to laser phase fluctuations is calculated, and we show that the pulse sequence can be engineered to mitigate the phase noise sensitivity.
关键词： large momentum beam splitter,atom interferometry,sensitivity function
更新于2025-09-10 09:29:36
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Gas Sensing Performances of ZnO Hierarchical Structures for Detecting Dissolved Gases in Transformer Oil: A Mini Review
摘要： Power transformer is one of the critical and expensive apparatus in high voltage power system. Hence, using highly efficient gas sensors to real-time monitor the fault characteristic gases dissolved in transformer oil is in pressing need to ensure the smooth functionalization of the power system. Till date, as a semiconductor metal oxide, zinc oxide (ZnO) is considered as the promising resistive-type gas sensing material. However, the elevated operating temperature, slow response, poor selectivity and stability limit its extensive applications in the field of dissolved gases monitoring. In this respect, rigorous efforts have been made to offset the above-mentioned shortcomings by multiple strategies. In this review, we first introduce the various ZnO hierarchical structures which possess high surface areas and less aggregation, as well as their corresponding gas sensing performances. Then, the primary parameters (sensitivity, selectivity and stability) which affect the performances of ZnO hierarchical structures based gas sensors are discussed in detail. Much more attention is particularly paid to the improvement strategies of enhancing these parameters, mainly including surface modification, additive doping and ultraviolet (UV) light activation. We finally review gas sensing mechanism of ZnO hierarchical structure based gas sensor. Such a detailed study may open up an avenue to fabricate sensor which achieve high sensitivity, good selectivity and long-term stability, making it a promising candidate for transformer oil monitor.
关键词： ZnO,sensitivity,gas sensors,hierarchical structures,stability,gas sensing mechanism,selectivity
更新于2025-09-10 09:29:36
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Tri-core photonic crystal fiber based refractive index dual sensor for salinity and temperature detection
摘要： This article discusses the tri-core photonic crystal microstructure fiber for the process of simultaneous sensing for salinity and temperature of water substances. This kind of microstructure is preferred in many sensing application to scale the detection process in micrometer range. In this novel sensor, the sensitivity is calculated through coupling mechanism by tracking wavelength shift of various concentrations of salinity and temperature using finite element method. The sensible samples are in liquid and are infiltrated into the framed hollow cavity. Based on the coupling principle between silica substrate and the analyte material, the sense of the salt as well as temperature is obtained. Finally, it is noted that sensitivity of the salt level in water as 5404.9 nm/RIU for x polarization direction and 5674 nm/RIU for y polarization direction have been calculated with the temperature sensitivity of 4 nm/(cid:1)C in the same water substances.
关键词： photonic crystal fiber,finite element method,sensitivity and coupling mechanism
更新于2025-09-10 09:29:36
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Synthesis, photophysical, viscosity and DFT study of solid state fluorescent molecular rotors
摘要： Four novel Fluorescent Molecular Rotors (FMR) (1, 2, 3, 4) comprising carbazole, triphenylamine, phenothiazine, diethylaniline as donating groups and cyanoformyl vinylene as an accepting group are synthesized and characterized by NMR. They show emission in the solid state in the range of 581–651 nm. The viscosity sensitivity of emission was investigated 3.1–3.4 fold increase in emission intensity was observed in a mixture of polar protic ethanol and polyethyleneglycol 400 mixture. The experimental results are well in correlation with those of Density Functional Theory (DFT) computations. Compounds show higher values of dipole moment, linear polarizability values ranging from 49 to 59 × 10^?24 e.s.u., first order hyperpolarizability ranging from 77 to 250 × 10^-30 e.s.u. and second order hyperpolarizability ranging between 105–695 × 10^-30 e.s.u. suggest that the compounds show good Nonlinear Optical (NLO) property. The two photon absorption cross sections are found in the range 50–150 GM, which is further elucidated using Mulliken Hush analysis for analyzing effective charge transfer in the present compounds.
关键词： Photophysical study,Diethyl aniline,Triphenylamine,Carbazole,Viscosity sensitivity
更新于2025-09-10 09:29:36
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[IEEE 2018 2nd IEEE Advanced Information Management, Communicates, Electronic and Automation Control Conference (IMCEC) - Xi'an (2018.5.25-2018.5.27)] 2018 2nd IEEE Advanced Information Management,Communicates,Electronic and Automation Control Conference (IMCEC) - Measurement Method for RFID Tags Group Sensitivity Based on Reading Distance
摘要： Sensitivity is an important factor in the application of RFID tag, and it has attracted widespread attention. Firstly, the definition of sensitivity is introduced, and a new test method is proposed, which calculates the sensitivity by measuring reading distance. Secondly, the reading distance is measured by a semi-physical verification system. Thirdly, the single-tag sensitivity is tested and verified. The results have a strong agreement with the verification results. Finally, the RFID tags group sensitivity is tested. The experimental results show that this testing method is an effective method to test the tag sensitivity. The presented method has good characteristics in terms of usage and accuracy. Therefore, the research of this paper is very useful for testing of single-tag sensitivity, especially the RFID tags group sensitivity.
关键词： sensitivity,RFID tags group,dynamic testing,RFID
更新于2025-09-10 09:29:36
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Enhanced H2S sensing performance of cobalt doped free-standing TiO2 nanotube array film and theoretical simulation based on density functional theory
摘要： A cobalt doped free-standing TiO2 nanotube (Co-doped TiNT) array film was firstly synthesized by a one-step anodization followed by immersion method. The characterization analysis results of TiNT with the field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS) proved that the doped cobalt ions had entered into the lattice of TiO2. Subsequently, the Co-doped TiNT gas sensors with different concentration of cobalt ions were developed for testing the gas-sensing properties for H2S. Compared with the undoped one, by 0.1 M Co-doping operation, working under the temperature of 300 °C, the Co-doped TiNT gas sensor was demonstrated the following superiorities: the response time and recovery time were 14 s and 4 s, which were shortened by 36.4% and 33.3%, respectively. Moreover, the Co-doped TiNT gas sensor with superior selectivity, stability and repeatability, reached the response value at 199.16 for 50 ppm H2S, which was improved by 7.6 times. Finally, based on the density functional theory (DFT), the calculated band gap of the Co-doped TiO2 decreased from 2.285 eV to 1.418 eV with a 38% decline. The mechanism simulation explained the obtained promotions in the gas sensing properties of the Co-doped TiNT gas sensor.
关键词： Cobalt ion doping,H2S gas sensor,Highly sensitivity,TiO2 nanotube array film,Density functional theory
更新于2025-09-10 09:29:36
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Calibration of the Pyranometer Sensitivity Using the Integrating Sphere
摘要： The pyranometer for observing the solar radiation reaching the surface of the earth is manufactured by various companies around the world. The sensitivity of the pyranometer at the observatory is required to be properly controlled based on the reference value of the World Radiometric Center (WRC) and the observatory environment; otherwise, the observational data may be subject to a large error. Since the sensitivity of the pyranometer can be calibrated in an indoor or outdoor calibration, this study used a CSTM-USS-4000C Integrating Sphere by Labsphere Inc. (USA) to calibrate the sensitivity of CMP22 pyranometer by Kipp&Zonen Inc. (Netherlands). Consequently, the factory sensitivity of CMP22 was corrected from 8.68 μV·(Wm?2)?1 to 8.98 μV·(Wm?2)?1, and the result from the outdoor calibration according to the observatory environment was 8.90 μV·(Wm?2)?1. After the indoor calibration of the pyranometer sensitivity, the root mean square error (RMSE) of the observational data at the observatory on a clear day without clouds (July 13, 2017) was 7.11 Wm?2 in comparison to the reference pyranometer. After the outdoor calibration of the pyranometer sensitivity based on these results, the RMSE of the observational data was 1.74 Wm?2 on the same day. Periodic inspections are required because the decrease of sensitivity over time is inevitable in the pyranometer data produced at the observatory. The initial sensitivity after indoor calibration (8.98 μV·(Wm?2)?1) is important, and the sensitivity after outdoor calibration (8.90 μV·(Wm?2)?1) can be compared to the data at the Baseline Surface Radiation Network (BSRN) or can be used for various studies and daily applications.
关键词： Sensitivity,Pyranometer,Solar radiation,Indoor?outdoor calibration,Integrating sphere
更新于2025-09-10 09:29:36
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[IEEE 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Espoo, Finland (2018.8.27-2018.9.1)] 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Investigation of metasurface eigenmode impact on receive sensitivity enhancement of MRI machine
摘要： Magnetic resonance image quality directly depends on the signal-to-noise ratio provided by the receive coil. It was recently shown that wire metasurface can enhance the signal-to-noise ratio of the commercial scanner due to the spatial redistribution of the radiofrequency electromagnetic field through the resonant excitation of a wire metasurface eigenmode. In this work, we experimentally investigate the impact of this eigenmode on receive sensitivity enhancement of the 1.5 T birdcage coil. We proof that due to the certain spatial profile of the metasurface eigenmode, signal-to-noise ratio enhancement directly depends on the position and dimensions of the studied object on the metasurface.
关键词： metasurface,receive sensitivity,MRI,signal-to-noise ratio,eigenmode
更新于2025-09-10 09:29:36
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A Bifunctional Luminescent Coordination Polymer as Recyclable Sensor for Detecting TNP and Fe3+ with High Selectivity and Sensitivity
摘要： A thermo-stable three dimensional network [Cd2(BPDPE)2(1,2-H2bdc)2]n (1) (1,2-H2bdc = 1,2-benzenedicarboxylic acid, BPDPE = 4,4′-bis(pyridyl)diphenyl ether) with blue fluorescence was successfully synthesized and characterized. Complex 1 is a two-dimensional layer constructed by BPDPE connecting [Cd(1,2-bdc)]n one-dimensional chains, then a three-dimensional network is finally formed via π···π interactions. Importantly, Complex 1 presents an excellent fluorescent MOF sensor for highly sensitive and selective detecting TNP, the Ksv is up to 1.03×105 M-1. Further more, complex 1 can be quickly regenerated by simple washing, exhibiting good recyclability for detecting TNP. In addition, complex 1 shows higher sensitive fluorescent sensor for detecting Fe3+ cation than other metal ions. the Ksv is calculated to be 1.84×105 M-1. Furthermore, the quenching mechanisms of complex 1 as bifunctional sensor were studied as well.
关键词： Nitro aromatic explosives,Selectivity and sensitivity,Fluorescence sensing,Metal ions,Coordination polymer
更新于2025-09-10 09:29:36