Slow Response Speed Research Articles

Direct observation of enhanced performance in suspended ReS2 photodetectors.

Rhenium disulfide (ReS2) has emerged as a promising material for future optoelectric applications due to its extraordinary electrical, mechanical, and optoelectrical properties. However, the ReS2-based photodetectors are severely restricted by their slow response speed (>10 s). Here, we demonstrate a high-performance polarization-sensitive photodetector based on suspended ReS2. Such a transistor shows an n-type behavior with the mobility of about 14.1 cm2V-1s-1, an on/off ratio of 105, and a responsivity of 0.22 A/W. Benefitting from well-developed contact between Au and the ReS2 channel and reduced interface scattering from the Si substrate, the response time of the device can be as short as 83.5 and 325.3µs, respectively, which are three orders of magnitude faster than that reported earlier. Furthermore, the suspended ReS2 photodetector also has the capability to detect polarized light (Imax/Imin ≈ 1.4 at 532 nm) due to the robust in-plane anisotropy of the material. These findings offer an efficient approach for improving the performance of ReS2-based photodetectors.

Visual Servoing of Flying Robot Based on Fuzzy Adaptive Linear Active Disturbance Rejection Control

Visual servoing is the most common control scheme for military and civil robots. For the flying robot, a nonlinear and strongly coupled system, the traditional control methods have the problems of poor adaptive ability and sensitivity to the disturbance in the complex environment. This brief deals with the disadvantages of slow response speed and weak anti-interference ability of flying robot visual servoing by using a fuzzy adaptive linear active disturbance rejection control (FLADRC) scheme. To improve the response speed and robustness of the system, the effect of the controller parameters on the performance is analyzed and quantified into fuzzy rules, and the fuzzy adaptive method is used to adjust the parameters of the linear extended state observer in real-time. Furthermore, a high-speed and high-precision visual positioning algorithm based on YOLOv4 and efficient large-scale stereo matching (ELAS) is proposed. Finally, the performances of FLADRC, LADRC, PID, and Fuzzy-PID are compared by simulation experiments, and the effectiveness of the proposed scheme is proved.

NiO/GaN p-n junction ultraviolet photodetector and self-powered technology

<sec> Ultraviolet photodetector plays an important role in fire warning, missile tracking and dose detecting of ultraviolet sterilization and disinfection, which is closely related to human lives. With the development of integrated detection system, the requirements for the size and energy consumption of the detector are becoming more and more stringent. Traditional detector that requires an external power supply can no longer meet these requirements. Moreover, a traditional ultraviolet detector is mainly composed of first-generation semiconductors and second-generation semiconductors. These semiconductors have small band gaps and large cut-off wavelengths, and are more suitable for infrared detection. When used for implementing the ultraviolet detection, an additional layer is often required, which increases not only the volume but also the cost. </sec><sec> Gallium nitride (GaN), as a third-generation semiconductor, has a band gap of 3.4 eV and a corresponding absorption edge of 365 nm. It is a natural ultraviolet detection material. At the same time, the excellent physical and chemical properties make the devices prepared by GaN have high stability. In recent years, some studies have shown that the GaN-based ultraviolet photodetectors have excellent responsiveness, but each of these detectors usually requires an external bias and has a slow response speed. Here, we propose a high responsivity, fast response speed and self-powered ultraviolet photodetector based on NiO/GaN p-n junction. By using the magnetron sputtering, a layer of 70 nm thick p-NiO film is deposited on a high-quality n-GaN film that has been grown on a sapphire substrate by the metal-organic chemical vapor deposition. The fabricated p-n junction shows obvious rectification characteristics at ± 0.5 V. Due to the existence of the built-in electric field, the device can work without externally applied bias. Under zero bias, the detector shows a responsivity of 272.3 mA/W for 365 nm ultraviolet light while the intensity is 50 μW/cm<sup>2</sup>, and has a detectivity as high as 2.83 × 10<sup>14</sup> Jones. This indicates that the detector has a high sensitivity even for very weak light. Owing to the good crystallinity of the film, the dark current is as low as 10<sup>–10</sup> A, the switching ratio is > 10<sup>3</sup>, and the response speed reaches 31 ms. These excellent properties show the broad application prospects of the devices based on NiO/GaN p-n junctions in the field of self-powered ultraviolet detection, and thus providing new ideas for the future development of intelligent integration. </sec>

Optimization of fuel cell thermal management system based on back propagation neural network

Two thermal management control strategies, namely flow following current and power mode and back propagation neural network auto-disturbance rejection method, were proposed to solve significant temperature fluctuation problems, long regulation time, and slow response speed in fuel cell thermal management system variable load. The results show that the flow following current and power control strategy can effectively weaken the coupling effect between pump and radiator fan and significantly reduce the overshoot and adjustment time of inlet and outlet cooling water temperature and temperature difference reactor. Although the control effect of the neural network and strategy is insufficient under maximum power, the overall control effect is better than that of the flow following the current control strategy.

Path Planning of Mobile Robot Based on Improved Multiobjective Genetic Algorithm

Path planning is the core technology of mobile robot decision‐making and control and is also a research hotspot in the field of artificial intelligence. Aiming at the problems of slow response speed, long planning path, unsafe factors, and a large number of turns in the conventional path planning algorithm, an improved multiobjective genetic algorithm (IMGA) is proposed to solve static global path planning in this paper. The algorithm uses a heuristic median insertion method to establish the initial population, which improves the feasibility of the initial path and generates a multiobjective fitness function based on three indicators: path length, path security, and path energy consumption, to ensure the quality of the planned path. Then, the selection, crossover, and mutation operators are designed by using the layered method, the single‐point crossover method, and the eight‐neighborhood‐domain single‐point mutation method, respectively. Finally, the delete operation is added, to further ensure the efficient operation of the mobile robot. Simulation experiments in the grid environment show that the algorithm can improve the defects of the traditional genetic algorithm (GA), such as slow convergence speed and easy to fall into local optimum. Compared with GA, the optimal path length obtained by planning is shortened by 17%.

Design and Integration of a Layered MoS2/GaN van der Waals Heterostructure for Wide Spectral Detection and Enhanced Photoresponse.

Molybdenum disulfide (MoS2) as a typical two-dimensional (2D) transition-metal dichalcogenide exhibits great potential applications for the next-generation nanoelectronics such as photodetectors. However, most MoS2-based photodetectors hold obvious disadvantages including a narrow spectral response in the visible region, poor photoresponsivity, and slow response speed. Here, for the first time, we report the design of a two-dimensional MoS2/GaN van der Waals (vdWs) heterostructure photodetector consisting of few-layer p-type MoS2 and very thin n-type GaN flakes. Thanks to the good crystal quality of the 2D-GaN flake and the built-in electric field in the interface depletion region of the MoS2/GaN p-n junction, photogenerated carriers can be rapidly separated and more excitons are collected by electrodes toward the high photoresponsivity of 328 A/W and a fast response time of 400 ms under the illumination of 532 nm light, which is seven times faster than pristine MoS2 flake. Additionally, the response spectrum of the photodetector is also broadened to the UV region with a high photoresponsivity of 27.1 A/W and a fast response time of 300 ms after integrating with the 2D-GaN flake, exhibiting an advantageous synergetic effect. These excellent performances render MoS2/GaN vdWs heterostructure photodetectors as promising and competitive candidates for next-generation optoelectronic devices.

A near-infrared fluorogenic probe with fast response for detecting sodium dithionite in living cells.

Developing a reliable fluorescence probe is crucial for accurately monitoring sodium dithionite (Na2S2O4, SDT) in biosystems, but the current reported azo-based ones suffers from short excitation/emission wavelengths and relative slow response speed. To address this issue, we herein present a novel near-infrared emissive fluorescence probe for SDT, namely DCM-MQ, consisting of a dicyanomethylene-benzopyran fluorogenic reporter and a 1-methylquinolinium as recognition moiety. On the basis of the specific reduction mechanism, DCM-MQ exhibited a rapid colorimetric and fluorescent recognition for SDT (less than 3s) with large Stokes shift (112nm) and high sensitivity (detection limit was 19nM). The fluorescence imaging results demonstrate that DCM-MQ is competent for monitoring SDT in living systems.

A Photoactuator Based on Stiffness-Variable Carbon Nanotube Nanocomposite Yarn.

Actuators based on carbon nanotube (CNT) yarn have attracted extensive attention due to their great properties and potential applications such as artificial muscles, sensors, intelligent robots, and so on. However, the CNT yarn actuators with one-dimensional structure were often only used to drive through electrochemical, thermal, or electrical stimulation, which limits the applications of CNT yarn actuators. In addition, the slow response speed, low output stress, uncontrollable driving deformation, and self-recovery without an external stimulus are also great challenges. Here, we propose a photoactuator with large output stress, fast response speed, large and reversible driving deformation, and good reusability based on stiffness-variable CNT nanocomposite yarn (CNT-NCY). Such a CNT-NCY photoactuator can achieve torsional and contractive actuation under irradiation of near-infrared (NIR) light; it is important that the actuation is reversible and controllable. The maximum rotation rate of the CNT-NCY photoactuator during the torsional actuation is about 45 rpm, and the contractive deformation can reach more than 9%. This CNT-NCY photoactuator can create more than 12 MPa output stress, which is 40 times higher than that of the human skeletal muscle. The driving mechanism of this CNT-NCY photoactuator has been analyzed, and its potential application has also been demonstrated.

Unlock the Flexibility of Combined Heat and Power for Frequency Response by Coordinative Control With Batteries

Owners of combined heat and power (CHP), e.g., industrial manufacturers, are motivated to provide frequency response to power grids due to clear financial benefits. Yet, the slow response speed of CHP limits its capability in providing such services. Moreover, frequent adjustments would cause a faster lifetime reduction of CHP and rapid pressure fluctuation in the gas network. To further unlock the flexibility of CHP, this article integrates a battery unit with CHP via a power electronic interface. A filter-based coordinative controller is designed for smoothing short-term fluctuations in CHP outputs. Based on the filter parameters and frequency response requirements, the minimum required capacity of the battery is identified. The results show that the proposed system enhances the capability of CHP for frequency response and mitigates the associated adverse effects on the gas network. The required capacity of the battery is economically feasible considering the benefit it brings to the CHP.

Response Speed in Executive Tasks Predicts Social Motivation and Communication in School-Aged Children With Autism Spectrum Disorder (ASD)

Abstract Date Presented 03/27/20 Our results show that a slower response speed, not accuracy, on executive function (EF) tasks is related to better social interaction in school-age children with ASD. Children with ASD reduce their response speed to maintain good accuracy. Therefore, the response speed could be a correlate of social motivation and communication for school-age children with ASD and should be included in their evaluation for better intervention planning. Primary Author and Speaker: Yen-Ting Yu Contributing Authors: Chien-Ho Lin, Ching-Lin Hsieh, Cheng-Chun Kuei-Cheng, Kuan-Lin Chen

52‐4: Late‐News‐Paper: Development of 240Hz Refresh Rate ADS Mode Gaming Product

The ADS display mode shows significant advantages of high transmittance, wide viewing angle, small color shift at large view angle, etc., and thus has been widely used in all kinds of display product such as mobile phone, tablet, notebook, monitor and television. However, ADS mode shows shortcomings of slow response speed. In this work, we made extreme optimization research and breakthroughs in improving ADS mode response speed from the aspects of LC material, cell gap, and pixel ITO slit angle. Based on the research, 27 inch FHD 240Hz refresh rate gaming product was successfully developed. It has been achieved gray to gray average response time 1.9ms with over driving as well as contrast ratio 1214:1 fulfilling static CR requirements of VESA HDR standard.

Multi-timescale robust dispatching for coordinated automatic generation control and energy storage

The increasing penetration of renewable energy into power grids is reducing the regulation capacity of automatic generation control (AGC). Thus, there is an urgent demand to coordinate AGC units with active equipment such as energy storage. Current dispatch decision-making methods often ignore the intermittent effects of renewable energy. This paper proposes a two-stage robust optimization model in which energy storage is used to compensate for the intermittency of renewable energy for the dispatch of AGC units. This model exploits the rapid adjustment capability of energy storage to compensate for the slow response speed of AGC units, improve the adjustment potential, and respond to the problems of intermittent power generation from renewable energy. A column and constraint generation algorithm is used to solve the model. In an example analysis, the proposed model was more robust than a model that did not consider energy storage at eliminating the effects of intermittency while offering clear improvements in economy and efficiency

Energy level gradient trapping based on different work functions of ZnO enhancing response and stablity for lateral photodetectors

Abstract The slow response speed and instability of the lateral photodetectors (L-PDs), often caused by the persistence of the excess minority carriers in the long channel after the termination of the illumination (called Persistent Photoconductivity effects) are the main factors that hinder the practical application of this type of device. In this research, two types of ZnO with different work functions, including ZnO nanoparticles (ZnO-NPs) doped in bulk heterojunction (BHJ) and thermal annealed ZnO nanocrystalline film (ZnO–NF), are incorporated into the L-PDs to construct an energy gradient, which could facilitate the quick transfer of the minority carriers and restrict their release into the active layer. The structure of L-PDs are optimized as quartz/ZnO–NF/PffBT4T-2OD:PC61BM:ZnO-NPs (component ratio = 5:6:1)/Au–Au electrodes. Compared with the control device, the test results show that the optimized L-PDs exhibit higher stability with much lower fall time (3.7 ms, boosted 200-fold) and gentler rise slope of dark current versus time (Kdark) (8.3 × 10−6 nA/s, reduced four orders of magnitude). Meanwhile, the very low dark current (

Research on Simulation Analysis of Valveless Hydraulic Servo System

The hydraulic transmission technology is widely used in the industrial field. With the continuous development of microelectronic technology, valveless electro-hydraulic servo technology came into being. Aiming at the problems such as slow response speed and poor displacement tracking accuracy, this paper builds a simulation model of the forward and reverse displacement of the valveless electro-hydraulic servo system, and uses AMESim and simulink software to build the hydraulic part simulation and motor part simulation of the system respectively. A fuzzy PID controller is introduced and simulation is performed with the addition of the fuzzy PID controller to improve the overall performance of the valveless electro-hydraulic servo system.

Subacute and chronic neuropsychological sequalae of acute organophosphate pesticide self-poisoning: a prospective cohort study from Sri Lanka

Context Some epidemiological evidence implicates acute organophosphate (OP) pesticide poisoning in long-term neurocognitive deficits. However, no study has prospectively followed up poisoned patients long-term from the time of intoxication. We aimed to determine whether clinically significant acute OP self-poisoning leads to subacute and chronic neurocognitive deficits, in a prospective follow up study. Methods Employing Mini Mental State Examination, Digit Span and Cambridge Neuropsychological Test Automated Battery (CANTAB), we compared multiple cognitive functions in 222 patients hospitalized with acute OP pesticide self-poisoning with a control group of 52 patients hospitalized with paracetamol overdose, at three time points: on discharge following clinical recovery, 6 weeks and 6 months post-ingestion. Intergroup comparisons at each time point were done in multiple regression models, adjusting for sex, age, education and psychiatric comorbidities. OP within-group analysis was done to determine a dose–response relationship. Results After adjusting for covariates, the OP poisoned group had significantly poorer working memory (Digit Span) and episodic memory (CANTAB Paired Associates Learning); impaired spatial planning (CANTAB Stocking of Cambridge); and slower response speed in the sustained attention task (CANTAB Rapid Visual Information Processing), in the post-discharge assessment. Only working memory and episodic memory measures were impaired in the OP group at 6 weeks, whereas no significant intergroup differences were observed at 6 months. The OP subgroup who had complete red cell acetylcholinesterase inhibition on admission had poorer episodic memory when tested post-discharge than those who had partial inhibition, but no significant subgroup differences were observed at 6 weeks or 6 months. Discussion Acute OP pesticide poisoning may cause neuropsychological impairment that outlasts the cholinergic phase on a subacute time scale; but does not cause measurable chronic neuropsychological deficits.

Large area electrochromic displays with ultrafast response speed and high contrast using solution-processable and patternable honeycomb-like polyaniline nanostructures

Electrochromic displays have attained considerable attention attributed to the low energy consumption and open-circuit memory effects. However, the low optical contrast and slow response speed have limited their application fields. To overcome these deficiencies, we focus on the preparation of solution-processable nanostructured electrochromic materials with high contrast and fast response speed. Here, the solution-processable honeycomb-like polyaniline (H-PANI) nanostructure networks were prepared by the combination of chemical oxidative polymerization and template method for the first time. The H-PANI nanostructured film shows improved electrochromic properties owing to large interface area and short diffusion length. And the all-solid-state electrochromic device (ECD-HP) was fabricated by employing spray-coated H-PANI as coloring electrode and spray-coated commercial PEDOT:PSS as counter electrode. The ECD-HP shows high optical contrast (71.6% at 600 nm), ultrafast response speed (447 ms for coloring and 650 ms for bleaching), high coloration efficiency (560.6 cm2/C) and remarkable cycling stability (sustaining 96% of its initial optical contrast after cycling 1000 cycles). Furthermore, the large-area patterned electrochromic displays based on H-PANI film were successfully assembled by spray-coating method using masks to form patterns. These demonstrate solution-processable H-PANI could have widely applications in large area patternable electrochromic smart windows and displays.

S61. COMPUTATIONAL MODELLING OF VISUAL MOTION PERCEPTION AND ITS ASSOCIATION WITH SCHIZOTYPAL TRAITS

BackgroundPsychotic symptoms might be explained by disturbances of information processing due to errors of inference during neural coding, and hierarchical models could advance our understanding of how impaired functioning at different levels of the processing hierarchy are associated with psychotic symptoms. However, in order to examine to what extent such alterations are temporary or stable, the psychometric reliability and validity of the measurements need to be established. Individual differences in visual perception were measured by responses to uncertain stimuli presented during a probabilistic associative learning task. Our novel contributions are the measurement of cross-modal (visual and acoustic) associative learning and the assessment of the psychometric properties of indicators derived from a perceptual decision task: we evaluate its internal consistency, test-retest reliability and external validity as shown by associations with schizotypal traits.MethodsParticipants (32 healthy individuals, 13 men, age (SD) = 27.4 (9.4)) performed a perceptual decision task twice with one week delay. They were asked to indicate the direction of perceived motion of disambiguous and ambiguous visual stimuli (640 trials), which were preceded by visual and acoustic cues that were probabilistically associated with the motion direction and were congruent (both predict the same motion) or incongruent (cues predict different motion). Schizotypal traits were measured with the short version of the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE) questionnaire, which showed good internal consistency and test-retest reliability (Cronbach’s alpha: 0.71 – 0.83 for subscales, test-retest correlation for Cognitive Disorganization: r = 0.84, and Unusual Experiences: r = 0.79).ResultsWe found a significant difference in response reaction times between stimuli with high and low probability (t = -2.037; p = 0.044). Acoustic cues predicted the decision significantly higher in case of ambiguous stimuli in both sessions (1. t=4.19, p<0.001; 2: t=3.46, p=0.002). Congruency of visual and acoustic cue pairs had no significant effect on response times for ambiguous stimuli. Reaction times and bias towards reliance on auditory cues during perceptual decision making under uncertainty showed stability over the two sessions (test-retest rho’s ranging from 0.56 – 0.72). Cognitive Disorganization scores showed weak negative correlation with response time under uncertainty (session 1: r= -0.24, session 2: r= -0.28), Unusual Experiences scores showed weak negative correlation with the bias towards reliance on auditory cues (session1: r= -0.21, session 2: r= -0.19). We did not find relationship between general response speed and any O-LIFE subscale scores.DiscussionThe results show some intraindividual stability of individual differences in perceptual decision making as measured by our paradigm. Participants with higher schiztypal scores tend to have slower response speed under uncertainty and greater bias towards reliance on auditory cues in a small healthy sample which implies it might be useful to measure these variables in clinical population and evaluate the effectiveness of therapeutic interventions or illness progression in follow-up studies.The presented preliminary results derived from descriptive statistics of the behavioral data. Our research group is currently working on fitting a trial-by-trial hierarchical computational model - which includes the representation of uncertainty - to find more detailed individual differences, e.g. the time course of parameter changes while learning in a visual perception task.

Few‐Layer Organic Crystalline van der Waals Heterojunctions for Ultrafast UV Phototransistors

AbstractOrganic UV photodetectors using a transistor architecture can yield higher photoresponsivity than diode‐based devices because of the presence of a gate electrode. However, a long‐term issue of these phototransistor devices is the slow response speed, which hinders their practical applications. Here, organic UV phototransistors are constructed using few‐layer organic crystalline van der Waals (vdW) heterojunctions as the photoactive layers. The thickness of the photoactive layers is even less than the exciton diffusion length, thus removing the exciton‐diffusion bottleneck and giving rise to the confinement of charge separation and recombination within the adjacent molecular layers across the heterojunction interface. Hence, the phototransistor devices can exhibit a remarkably enhanced response speed (rise and decay times as short as only ≈4 and 6 ms, respectively). The layer‐dependent photoresponse characteristics are also observed, reinforcing the great importance of few‐layer organic heterostructures in phototransistor devices. This work not only provides a promising avenue toward fast response optoelectronic devices but also presents an in‐depth understanding on the microscopic nature of photogenerated charge carriers at the precision of molecular layers.

The Room Temperature Gas Sensor Based on Polyaniline/SrGe4O9 Nanocomposites for Ppt-Level NH3 Detection

Introduction It is an urgent requirement to development of ammonia sensors with low detection limits for environmental monitoring and disease detection [1]. In recent years, much effort has been devoted to developing high performance gas sensors with low detection limit and room temperature detection. However, the development of gas sensors with ppt-level detection limit still faces enormous challenges.PANI-based material has a good selective NH3 response at room temperature. However, the applications of PANI-based sensors have been limited by their slow response speed and high detection limit [2]. To address such limitations, Sensors based on the PANI-based nanocomposite materials have been demonstrated to be effective method for low detection limit to NH3 at room temperature. SrGe4O9 is one of the wide-bandgap metal oxide semiconductors and have the best sensing performance to NH3 among alkaline earth metal germanate. In addition, the morphology of SrGe4O9 can be regulated by various synthetic means. Hence, a flexible NH3 sensor based on PANI/SrGe4O9 nanocomposites thin film was proposed for ultra-low level NH3 detection. Method SrGe4O9 nanowires were synthesized by a facile one-step hydrothermal synthesis, particular steps are described as fellows: 4mmol Sr(CH3COO)2 and 16mmol CeO2 dispersed in 60mL deionized water, then transferred to a 100 mL Teflon-lined stainless autoclave. The solution was stirred for 40 min and heated at 180℃ for 24h, the reaction product washed 3 times alternately with deionized water and dried at 50 ° C for 24 h. To fabricate the PANI-SrGe4O9 flexible gas sensor, the interdigital electrode was first soaked in PDDA solution (1%) and PSS solution (2 mg/ml, PH≈1, adjusted by HCl). After that, the thin sensor was fabricated by in-situ self-assembly method at ~10℃. Specifically ,100 μL Aniline (C6H5NH2) and 5 mg SrGe4O9 nanowires was dissolved in 20ml HCl (2 M). Subsequently, 10 ml APS ((NH4)2S2O8) was gradually added to the mixture within 120 s. The flexible interdigital electrode was immersed into the mixture when the color of solution turn to pale blue. After 15 min the substrate with PANI-SrGe4O9 nanocomposite thin film was removed and washed with HCl (2 M). Finally, the sensor was dried at room temperature for one day. For comparison, pure PANI thin film was also fabricated by the same method. Results and Conclusions In this work, a flexible and ultra-highly sensitive NH3 sensor based on polyaniline/SrGe4O9 nanowires nanocomposites was successfully fabricated via a combined route of facile hydrothermal method and in situ chemical oxidation polymerization method to load the gas sensing material on flexible polyimide (PI) substrate. XRD pattern revealed that polyaniline and SrGe4O9 phases coexisted in the as-prepared nanocomposites. Morphology results indicated polyaniline nanoparticles anchored on the SrGe4O9 nanowires with an average diameter of 100 nm and a length of 2–5 mm. In addition, The NH3 sensing properties of the as-fabricated sensors were evaluated at room temperature (∼25℃) and results indicated that the PANI/SrGe4O9 sensor exhibited higher response value of 344% to 50 ppm NH3, which was greatly superior to the pure PANI. Furthermore, the present sensor also showed fast response speed (37.3s), satisfactory long-term stability, good bending resistance and excellent selectivity towards 50 ppm NH3 at room temperature. The response of the PANI/SrGe4O9 sensor increased with the increasing relative humidity, which can further expand the practical application of the PANI/SrGe4O9 sensor. What's more, the sensor demonstrated an ultra-low detection limit of 50 ppt NH3 at room temperature in 60%RH, which was reported for the first time. Such dramatically enhanced gas-sensing properties of PANI/SrGe4O9 nanofilm might be owing to the synergism effects, the formation of p-n heterojunction at the interface between the n-type SrGe4O9 and p-type PANI, and high surface area of PANI/SrGe4O9 nanocomposite. This research offers new strategies for developing supersensitive gas NH3 sensor and the PANI/SrGe4O9 sensor points its promising applications in ultrasensitive environmental detection and human disease detection.

Hand-Held and Wrist-Worn Field-Based PVT Devices vs. the Standardized Laptop PVT.

BACKGROUND: Given the challenges of collecting reliable Psychomotor Vigilance Task (PVT) data in the field, this study compared a 3-min PVT on a hand-held device and wrist-worn device vs. a standardized laptop.METHODS: The experiment utilized a randomized, repeated-measures design. Subjects (N = 36) performed the PVT on a touch-screen, hand-held device (HHD), a wrist-worn device (WWD), and a standardized laptop (L). Sleep was assessed using wrist-worn actigraphy.RESULTS: Compared to the L, the HHD was slower on average (∼50% longer reaction times; ∼34% slower response speeds; ∼600% more lapses in attention combined with false starts) and introduced a proportional bias that decreased the range of response speeds by 60%. Compared to the L, the WWD with the backlight on was faster on average (reaction time: ∼6%; response speed: ∼13%), but equivalent in lapses combined with false starts, and introduced a proportional bias that increased the range of responses by 60%.DISCUSSION: Compared to the L PVT, using a hand-held, touch screen interface to collect PVT data may introduce a large constant bias and a proportional bias that decreases the range of response speed. However, performance on the WWD closely mirrors performance on the L PVT and the proportional bias tends to be in favor of detecting individuals with slower responses. Researchers should avoid comparing PVT metrics between different device types. Reliability of PVT data from a WWD or HHD may be degraded when used in an operational setting with unpredictable environmental movement (such as a surface maritime setting).Matsangas P, Shattuck NL. Hand-held and wrist-worn field-based PVT devices vs. the standardized laptop PVT. Aerosp Med Hum Perform. 2020; 91(5):409-415.