- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Characterisation of Timepix3 with 3D sensor
摘要： Tests were performed at the SPS facilities at CERN using a 40 GeV/c pion beam with prototype 3D-Timepix3 detectors (3D detector). A planar-Timepix3 (planar detector) was placed along the beam axis together with the 3D detectors in a telescope arrangement for comparison and reference. We demonstrate that the combination of 3D-geometry silicon sensors and Timepix3 module can reduce the effect of charge sharing and lowers the carrier drift-time, while giving the same spectroscopy performance without sacrificing the timing or any performance advantages of the Timepix3 module.
关键词： Performance of High Energy Physics Detectors,databases),Detector control systems (detector and experiment monitoring and slow-control systems,hardware,algorithms,architecture
更新于2025-09-23 15:23:52
-
(Poly)terephthalates with Efficient Blue Emission in the Solid State
摘要： We prepared dimethyl and diaryl 2,5-dialkoxyterephthalates from dimethyl 2,5-dihydroxyterephthalate in good-to-high yields via alkylation or a sequence of alkylation, hydrolysis, chlorination, and condensation. The absorption spectra of the dialkoxyterephthalates contain a small band at 332–355 nm, which could be assigned to intramolecular charge-transfer transition from the alkoxy to alkoxycarbonyl groups on the basis of theoretical calculations using density functional theory. The dialkoxyterephthalates exhibited blue fluorescence with moderate-to-excellent quantum yields not only in solution but also in the solid state, such as a poly(methyl methacrylate) (PMMA) film and a powder. The solid-state quantum yields of the diisopropoxy-substituted terephthalates were similar or considerably higher than those of the dimethoxy-substituted counterparts. Copolymerization of 2,5-diisopropoxyterephthaloyl chloride and 1,4-butanediol with or without terephthaloyl chloride gave brilliantly blue fluorescent polymers, whose quantum yields were 0.72 and 0.71 in toluene and 0.46 and 0.40 in the neat film, respectively. Furthermore, white emission was achieved when a fluorescent yellow 2,5-diaminoterephthalate was doped into the thin film of the blue fluorescent polymer at 0.4 wt %.
关键词： materials science,arenes,donor-acceptor systems,conjugation,fluorescence
更新于2025-09-23 15:23:52
-
Effect of exciton diffusion on the triplet-triplet annihilation rate in organic semiconductor host-guest systems
摘要： We study the contribution of triplet exciton diffusion to the efficiency loss resulting from F?rster-type triplet-triplet annihilation (TTA) in organic phosphorescent semiconductor host-guest systems, using kinetic Monte Carlo (KMC) simulations. Our study focusses on diffusion due to F?rster-type guest-guest transfer, but includes also a comparison with simulation results for the case of Dexter-type guest-guest transfer. The simulations are carried out for a wide range of F?rster radii, and for guest concentrations up to 100 mol%, with the purpose to support analyses of time-resolved photoluminescence experiments probing TTA. We find that the relative contribution of diffusion to the TTA-induced efficiency loss may be deduced quite accurately from a quantitative experimental measure for the shape of the time-dependent photoluminescence intensity, the so-called r ratio. For small guest concentrations and F?rster radii that are most relevant to organic light-emitting diodes (OLEDs), the diffusion contribution is in general quite small. Under these weak-diffusion conditions, the absolute diffusion contribution to the TTA-induced efficiency loss can be understood quantitatively using a capture radius formalism. The effective guest-guest diffusion coefficient that follows from the TTA simulations, using the capture radius formalism, agrees well with the diffusion coefficient that follows from direct KMC diffusion simulations. The simulations reveal that the diffusion coefficient is strongly affected by the randomness of the distribution of guest molecule locations.
关键词： OLEDs,photoluminescence,kinetic Monte Carlo simulations,Dexter transfer,organic semiconductors,triplet-triplet annihilation,exciton diffusion,host-guest systems,F?rster transfer
更新于2025-09-23 15:23:52
-
Projector-based renormalization approach to electron-hole-photon systems in their nonequilibrium steady state
摘要： We present an extended version of the projector-based renormalization method that can be used to address not only equilibrium but also nonequilibrium situations in coupled fermion-boson systems. The theory is applied to interacting electrons, holes, and photons in a semiconductor microcavity, where the loss of cavity photons into vacuum is of particular importance. The method incorporates correlation and fluctuation processes beyond mean-field theory in a wide parameter range of detuning, Coulomb interaction, light-matter coupling, and damping, even in the case when the number of quasiparticle excitations is large. This enables the description of exciton and polariton formation and their possible condensation through spontaneous phase symmetry breaking by analyzing the ground-state, steady-state, and spectral properties of a rather generic electron-hole-photon Hamiltonian, which also includes the coupling to two fermionic baths and a free-space photon reservoir. Thereby, the steady-state behavior of the system is obtained by evaluating expectation values in the long-time limit by means of the Mori-Zwanzig projection technique. Tracking and tracing different order parameters, the fully renormalized single-particle spectra and the steady-state luminescence, we demonstrate the Bose-Einstein condensation of excitons and polaritons and its smooth transition when the excitation density is increased.
关键词： exciton condensation,nonequilibrium steady state,semiconductor microcavity,projector-based renormalization method,electron-hole-photon systems,Bose-Einstein condensation,polariton condensation
更新于2025-09-23 15:23:52
-
[IEEE 2017 4th International Conference on Opto-Electronics and Applied Optics (Optronix) - Kolkata (2017.11.2-2017.11.3)] 2017 4th International Conference on Opto-Electronics and Applied Optics (Optronix) - A noble approach to light the path trail using swarm technology
摘要： Swarm intelligence (Intro SI) is the collective behaviour of decentralized, self-organized systems, natural or artificial. It is many minds working together. It is the first step in allowing people to pool their knowledge and insights into a single elevated intelligence. The objective is to light on a path trail by the leading robot, so that the rest of the robots could follow the trail to work as a unified system, thereby reducing time and manpower.
关键词： adaptive path exploration,swarm intelligence,Robot sensing systems,cognitive map generation,neighbouring robots,path trail information
更新于2025-09-23 15:23:52
-
[IEEE 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) - Bologna, Italy (2018.9.9-2018.9.12)] 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) - Improved LAS Detector for MIMO Systems with Imperfect Channel State Information
摘要： The performance of coherent symbol detection in multiple-input multiple-output (MIMO) systems is tightly related to the channel knowledge at the receiver side. For MIMO detection, achieving near-optimal performance with a low computational complexity has been a topic of several recent researches. In this paper, we propose a robust detector for uncoded MIMO systems with imperfect CSI (ICSI). The proposed detector is based on the likelihood ascent search (LAS) algorithm which achieves near maximum likelihood (ML) performance with a reduced complexity. To take into account the channel estimation error, we propose to use a modified likelihood metric function. Moreover, to enhance the system performance, we suggest to perform the channel estimation and the data detection in an iterative manner. Simulation results show that the proposed scheme outperforms the conventional LAS detector.
关键词： LAS detector,MIMO systems,robust detection,iterative detection,imperfect CSI
更新于2025-09-23 15:23:52
-
[IEEE 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Waikoloa Village, HI, USA (2018.6.10-2018.6.15)] 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Commercial Test of Anti-Reflective Coating on First Solar Cadmium Telluride PV Modules
摘要： Anti-reflective coatings (ARC) are commonly applied to photovoltaic (PV) modules in the solar industry to increase power and energy output. In addition to characterization of initial module power and angle of incidence modifier (IAM), it is important to verify that the expected gain is observed in commercial system operation. This analysis shows the increased performance of ARC First Solar CdTe PV modules compared to non-ARC equivalent modules in a commercial test in New South Wales, Australia. PPI analysis indicates a sustained ARC performance gain over time, suggesting good ARC durability. Detailed actual-expected analysis shows both array types performing at or above expected levels after almost 2 years in the field. ARC arrays show slightly greater benefit than predicted compared to non-ARC arrays.
关键词： CdTe thin film photovoltaics,solar power generation,performance analysis,photovoltaic systems,PV anti-reflective coatings,solar energy
更新于2025-09-23 15:23:52
-
[ACM Press the 2018 ACM Symposium - Warsaw, Poland (2018.06.14-2018.06.17)] Proceedings of the 2018 ACM Symposium on Eye Tracking Research & Applications - ETRA '18 - A gaze-contingent intention decoding engine for human augmentation
摘要： Humans process high volumes of visual information to perform everyday tasks. In a reaching task, the brain estimates the distance and position of the object of interest, to reach for it. Having a grasp intention in mind, human eye-movements produce specific relevant patterns. Our Gaze-Contingent Intention Decoding Engine uses eye-movement data and gaze-point position to indicate the hidden intention. We detect the object of interest using deep convolution neural networks and estimate its position in a physical space using 3D gaze vectors. Then we trigger the possible actions from an action grammar database to perform an assistive movement of the robotic arm, improving action performance in physically disabled people. This document is a short report to accompany the Gaze-contingent Intention Decoding Engine demonstrator, providing details of the setup used and results obtained.
关键词： Eye hand interaction,Gaze-contingent systems,Assistive robotics,Eye-movements
更新于2025-09-23 15:23:52
-
Glint Removal Assessment to Estimate the Remote Sensing Reflectance in Inland Waters with Widely Differing Optical Properties
摘要： The quality control of remote sensing reflectance (Rrs) is a challenging task in remote sensing applications, mainly in the retrieval of accurate in situ measurements carried out in optically complex aquatic systems. One of the main challenges is related to glint effect into the in situ measurements. Our study evaluates four different methods to reduce the glint effect from the Rrs spectra collected in cascade reservoirs with widely differing optical properties. The first (i) method adopts a constant coefficient for skylight correction (ρ) for any geometry viewing of in situ measurements and wind speed lower than 5 m·s?1; (ii) the second uses a look-up-table with variable ρ values accordingly to viewing geometry acquisition and wind speed; (iii) the third method is based on hyperspectral optimization to produce a spectral glint correction, and (iv) computes ρ as a function of wind speed. The glint effect corrected Rrs spectra were assessed using HydroLight simulations. The results showed that using the glint correction with spectral ρ achieved the lowest errors, however, in a Colored Dissolved Organic Matter (CDOM) dominated environment with no remarkable chlorophyll-a concentrations, the best method was the second. Besides, the results with spectral glint correction reduced almost 30% of errors.
关键词： remote sensing accuracy,inland waters,optically complex systems
更新于2025-09-23 15:23:52
-
SCExAO/CHARIS Near-IR High-contrast Imaging and Integral Field Spectroscopy of the HIP 79977 Debris Disk
摘要： We present new, near-infrared (1.1–2.4 μm) high-contrast imaging of the bright debris disk surrounding HIP 79977 with the Subaru Coronagraphic Extreme Adaptive Optics system (SCExAO) coupled with the CHARIS integral field spectrograph. SCExAO/CHARIS resolves the disk down to smaller angular separations of (0.11; r ～ 14 au) and at a higher significance than previously achieved at the same wavelengths. The disk exhibits a marginally significant east–west brightness asymmetry in H band that requires confirmation. Geometrical modeling suggests a nearly edge-on disk viewed at a position angle of ～114°.6 east of north. The disk is best-fit by scattered-light models assuming strongly forward-scattering grains (g ～ 0.5–0.65) confined to a torus with a peak density at r0 ～ 53–75 au. We find that a shallow outer density power law of αout = ?1 to ?3 and flare index of β = 1 are preferred. Other disk parameters (e.g., inner density power law and vertical scale height) are more poorly constrained. The disk has a slightly blue intrinsic color and its profile is broadly consistent with predictions from birth ring models applied to other debris disks. While HIP 79977?s disk appears to be more strongly forward-scattering than most resolved disks surrounding 5–30 Myr old stars, this difference may be due to observational biases favoring forward-scattering models for inclined disks versus lower inclination, ostensibly neutral-scattering disks like HR 4796A’s. Deeper, higher signal-to-noise SCExAO/CHARIS data can better constrain the disk’s dust composition.
关键词： stars: individual (HIP 79977),circumstellar matter,techniques: high angular resolution,planetary systems
更新于2025-09-23 15:23:52