Ultrasensitive, high-dynamic-range and broadband strain sensing by time-of-flight detection with femtosecond-laser frequency combs

Ultrahigh-resolution optical strain sensors provide powerful tools in various scientific and engineering fields, ranging from long-baseline interferometers to civil and aerospace industries. Here we demonstrate an ultrahigh-resolution fibre strain sensing method by directly detecting the time-of-flight (TOF) change of the optical pulse train generated from a free-running passively mode-locked laser (MLL) frequency comb. We achieved a local strain resolution of 18 p{\epsilon}/Hz1/2 and 1.9 p{\epsilon}/Hz1/2 at 1 Hz and 3 kHz, respectively, with largedynamic range of >154 dB at 3 kHz. For remote-point sensing at 1-km distance, 80 p{\epsilon}/Hz1/2 (at 1 Hz) and 2.2 p{\epsilon}/Hz1/2 (at 3 kHz) resolution is demonstrated. While attaining both ultrahigh resolution and large dynamic range, the demonstrated method can be readily extended for multiple-point sensing as well by taking advantage of the broad optical comb spectra. These advantages may allow various applications of this sensor in geophysical science, structural health monitoring, and underwater science.Comment: 20 pages, 4 figure

Imaging Fermi-level hysteresis in nanoscale bubbles of few-layer MoS2

Abstract The electrical stability and reliability of two-dimensional (2D) crystal-based devices are mainly determined by charge traps in the device defects. Although nanobubble structures as defect sources in 2D materials strongly affect the device performance, the local charge-trapping behaviors in nanobubbles are poorly understood. Here, we report a Fermi-level hysteresis imaging strategy using Kelvin probe force microscopy to study the origins of charge trapping in nanobubbles of MoS2 on SiO2. We observe that the Fermi-level hysteresis is larger in nanobubbles than in flat regions and increases with the height in a nanobubble, in agreement with our oxide trap band model. We also perform the local transfer curve measurements on the nanobubble structures of MoS2 on SiO2, which exhibit enhanced current-hysteresis windows and reliable programming/erasing operations. Our results provide fundamental knowledge on the local charge-trapping mechanism in nanobubbles, and the capability to directly image hysteresis can be powerful tool for the development of 2D material-based memory devices

Take-Over Requests after Waking in Autonomous Vehicles

Autonomous vehicles (AVs) enable drivers to devote their primary attention to non-driving-related tasks (NDRTs). Consequently, AVs must provide intelligibility services appropriate to drivers’ in-situ states and in-car activities to ensure driver safety, and accounting for the type of NDRT being performed can result in higher intelligibility. We discovered that sleeping is drivers’ most preferred NDRT, and this could also result in a critical scenario when a take-over request (TOR) occurs. In this study, we designed TOR situations where drivers are woken from sleep in a high-fidelity AV simulator with motion systems, aiming to examine how drivers react to a TOR provided with our experimental conditions. We investigated how driving performance, perceived task workload, AV acceptance, and physiological responses in a TOR vary according to two factors: (1) feedforward timings and (2) presentation modalities. The results showed that when awakened by a TOR alert delivered >10 s prior to an event, drivers were more focused on the driving context and were unlikely to be influenced by TOR modality, whereas TOR alerts delivered <5 s prior needed a visual accompaniment to quickly inform drivers of on-road situations. This study furthers understanding of how a driver’s cognitive and physical demands interact with TOR situations at the moment of waking from sleep and designs effective interventions for intelligibility services to best comply with safety and driver experience in AVs

Take-Over Requests after Waking in Autonomous Vehicles

Autonomous vehicles (AVs) enable drivers to devote their primary attention to non-driving-related tasks (NDRTs). Consequently, AVs must provide intelligibility services appropriate to drivers&rsquo; in-situ states and in-car activities to ensure driver safety, and accounting for the type of NDRT being performed can result in higher intelligibility. We discovered that sleeping is drivers&rsquo; most preferred NDRT, and this could also result in a critical scenario when a take-over request (TOR) occurs. In this study, we designed TOR situations where drivers are woken from sleep in a high-fidelity AV simulator with motion systems, aiming to examine how drivers react to a TOR provided with our experimental conditions. We investigated how driving performance, perceived task workload, AV acceptance, and physiological responses in a TOR vary according to two factors: (1) feedforward timings and (2) presentation modalities. The results showed that when awakened by a TOR alert delivered &gt;10 s prior to an event, drivers were more focused on the driving context and were unlikely to be influenced by TOR modality, whereas TOR alerts delivered &lt;5 s prior needed a visual accompaniment to quickly inform drivers of on-road situations. This study furthers understanding of how a driver&rsquo;s cognitive and physical demands interact with TOR situations at the moment of waking from sleep and designs effective interventions for intelligibility services to best comply with safety and driver experience in AVs

Non-epitheliotropic Cutaneous T-cell lymphoma in a cat: a case report

© 2022 Korean Society of Veterinary Science. All rights reserved.Cutaneous lymphoma is rare in cats. An 11-year-old spayed female Persian cat presented with crust, ulceration, and multiple nodules on the shoulder and forelimb for 2 months. Computed tomography revealed a diffuse, irregularly margined lesion in the dorsal cutis extending from cervical to thoracic vertebrae. Cytological evaluation predominantly revealed large round cells with multilobulated nuclei and basophilic cytoplasm. Histopathological examination confirmed round CD3? cells packed in the dermis. Thus, the diagnosis of non-epitheliotropic cutaneous lymphoma with a diffuse large T-cell type was made. The disease progressed rapidly for the next 2 weeks, and the owner elected humane euthanasia.N

Impact of Molecular Weight on Molecular Doping Efficiency of Conjugated Polymers and Resulting Thermoelectric Performances

The effect of molecular weight of a series of conjugated polymers (CPs) on the doping efficiency, electrical conductivity, and related thermoelectric properties of doped CPs is studied. Low (L), medium (M), and high (H) molecular weight batches of PDFD-T polymers, based on difluorobenzothia-diazole and dithienosilole moieties, are synthesized and denoted as PDFD-T(L), PDFD-T(M), and PDFD-T(H), respectively. Furthermore, to compare the effects of different donor moieties, donor units of PDFD-T(L) are structurally modified from thiophene to thienothiophene (TT) and dithienothiophene (DTT), denoted as PDFD-TT(L) and PDFD-DTT(L), respectively. After doping the CPs with FeCl3, d-PDFD-T(H) exhibits an electrical conductivity of 402.9 S cm(-1), which is significantly higher than those of d-PDFD-T(L), d-PDFD-T(M), d-PDFD-TT(L), and d-PDFD-DTT(L). The highest power factor of 101.1 mu W m(-1) K-2 is achieved through organic thermoelectric devices fabricated using PDFD-T(H). Through various characterizations, it is demonstrated that CPs with a high molecular weight tend to have a high carrier mobility while maintaining their original crystallinity and good charge trans- port pathways even after doping. Therefore, it is suggested that optimizing the molecular weight of CPs is an essential strategy for maximal power generation from their doped CP films.11Nsciescopu