Ms Response Research Articles

Flexible multi-modal sensors based on CNT hollow spheres/PDMS composites for human motion recognition and colloid concentration detection

Because flexible sensors with multi-modal responses are essential for applications in the complex environment of wearable products, a unique carbon nanotube (CNT) hollow-sphere scaffold is fabricated using self-assembling of microspheres and microwave irradiation to achieve flexible strain, pressure, and laser sensors. The CNT hollow-sphere scaffold comprising intertwined CNTs is featured with a sophisticated conductive network, large tensile and compressive deformability, intrinsic photothermoelectric nature, and good accommodation for polydimethylsiloxane (PDMS) matrix. Thus, the fabricated CNT hollow spheres/PDMS composite sensors showed good responses to the applied strain (a high gauge factor exceeding 55000 in the strain region of 95–107%, 27 ms response time, and over 20000 cycles durability at 40% strain), pressure (a gauge factor of 0.07–3.15 kPa−1 with a wide sensing range (up to 248 kPa pressure), and laser irradiation (0.066 s−1 at 5 s of 532 nm laser irradiation). Moreover, their uses in body movement detection, healthcare, tactile perception, and colloid concentration detection are demonstrated. It is believed that the CNT hollow spheres/PDMS composite sensors will pave the way for practical applications for future wearable electronic devices, which could recognize human motion as well as sense air quality and disease diagnosis.

Exploring Emotion Recognition Patterns Among Iranian People Using CANTAB as an Approved Neuro-Psychological Assessment.

Emotion recognition is the main component of social cognition and has various patterns in different cultures and nationalities. The present study aimed to investigate emotion recognition patterns among Iranians using the Cambridge neuro-psychological test automated battery (CANTAB) as a valid neuropsychological test. In this descriptive-analytical study, 117 males and females (Mean±SD of age 32.1±6.4) were initially assessed by computerized intelligence and progressive matrices of RAVEN-2. Furthermore, the excitement recognition subtest taken from the Cambridge neuro-psychological test automated battery (CANTAB) was performed. The correct response of participants to each of the six basic emotions as well as the recognition time was used for analysis. The maximum correct response rate was 75.83% related to happy emotion. The correct responses for sadness, surprise, disgust, anger, and fear were 70%, 68.48%, 47.84%, 42.54%, and 38.26%, respectively. Moreover, the shortest recognition time was related to disgust at 322 ms, while sadness with a mean response time of 1800 ms and fear response time at 1529 ms indicated the longest recognition time. In addition, participants recognized happiness with a mean response time of 1264 ms better than other emotions; however, post-hoc t-test analyses showed that only the correct responses for sadness and surprised emotions did not differ significantly, (t(112)=-0.59, P=0.55, d=0.05). These results suggested that different emotions have various correct responses. However, sadness and surprise did not differ. The findings of this study could be beneficial for evaluating cognitive elements, as well as cognitive abilities and inabilities among the Iranian population. Moreover, the findings could be used for investigating social cognition in this population. Emotion recognition patterns among Iranians were investigated using a valid neuropsychological test.Iranians showed higher accuracy in recognizing happiness and lower accuracy in recognizing fear.Disgust was recognized with the shortest response time, while sadness and fear had the longest recognition time.The findings highlight cultural differences in emotion recognition and can aid in evaluating cognitive abilities and social cognition in the Iranian population.The study emphasizes the importance of considering cultural factors in assessing and understanding emotion recognition. Understanding how people recognize emotions is crucial for effective communication and building social connections. However, the ability to recognize emotions can vary across cultures. This study aimed to investigate how Iranians recognize emotions using a reliable test. The researchers assessed 117 Iranian adults, both males and females, using a computer-based test. Participants were asked to identify six basic emotions (happiness, sadness, anger, disgust, fear, and surprise) displayed on a screen. The researchers measured the participants' accuracy in identifying each emotion and the time it took them to recognize it. The findings revealed that Iranians were most accurate in recognizing happiness and least accurate in recognizing fear. They were better at identifying positive emotions like happiness and surprise compared to negative emotions like disgust and anger. Participants took the least time to recognize disgust and the longest time to recognize sadness and fear. These results show that Iranians have specific patterns in recognizing emotions, which can be influenced by cultural factors. Understanding these patterns is important for assessing cognitive abilities and social cognition in the Iranian population. Moreover, these findings have broader implications. They highlight the need to consider cultural differences in emotion recognition, as it can impact communication and social interactions. The study's outcomes can be valuable for various applications. For instance, they can aid in developing tests to assess emotion recognition difficulties in individuals with conditions such as autism or schizophrenia. Furthermore, these findings can be useful for professionals, such as employees in customer service or mental health providers, who need to accurately interpret others' emotions. By shedding light on cultural variations in emotion recognition, this research contributes to our understanding of human emotions and their role in interpersonal relationships.

Liquid chromatography and differential mobility spectrometry—data-independent mass spectrometry for comprehensive multidimensional separations in metabolomics

The benefits of combining drift time ion mobility (DTIMS) with liquid chromatography–high-resolution mass spectrometry (HRMS) have been reported for metabolomics but the use of differential time mobility spectrometry (DMS) is less obvious due to the need for rapid scanning of the DMS cell. Drift DTIMS provides additional precursor ion selectivity and collisional cross-section information but the separation resolution between analytes remains cell- and component-dependent. With DMS, the addition of 2-propanol modifier can improve the selectivity but on cost of analyte MS response. In the present work, we investigate the liquid chromatography–mass spectrometry (LC–MS) analysis of a mix of 50 analytes, representative for urine and plasma metabolites, using scanning DMS with the single modifiers cyclohexane (Ch), toluene (Tol), acetonitrile (ACN), ethanol (EtOH), and 2-propanol (IPA), and a binary modifier mixture (cyclohexane/2-propanol) with emphasis on selectivity and signal sensitivity. 1.5% IPA in the N2 stream was found to suppress the signal of 50% of the analytes which could be partially recovered with the use of IPA to 0.05% as a Ch/IPA mixture. The potential to use the separation voltage/compensation voltage/modifier (SV/CoV/Mod) feature as an additional analyte identifier for qualitative analysis is also presented and applied to a data-independent LCxDMS-SWATH-MS workflow for the analysis of endogenous metabolites and drugs of abuse in human urine samples from traffic control.Graphical

High-performance multifunctional piezoresistive/piezoelectric pressure sensor with thermochromic function for wearable monitoring

To meet the application of the pressure sensors in various conditions, a high-performance piezoresistive/piezoelectric (IOF) sensor with a thermochromic function has been designed and fabricated in this work, which consists of a color-changing piezoelectric film (BP) and a piezoresistive layer (FPM) laminated together. Benefiting from the reaction between the color-former and the developer in a temperature-dependent co-solvent, the thermochromic function in the IOF sensor can be achieved, showing from blue at 30 °C to white at 150 °C. Moreover, by introducing Bi0.5Na0.5TiO3 (BNT) piezoelectric material, the BP piezoelectric layer can provide 80 V output voltage, 1.398 V·kPa−1 sensitivity, and 30 ms response time, respectively. Electrical conductivity is imparted to the fabric through the introduction of MXene, and the FPM piezoresistive layer displays 0.835 kPa−1 sensitivity and 73 ms response time in a wide stress range of 0–300 kPa, respectively. When the IOF sensor is attracted to the human body and KN95 masks, it has good sensitivity to measure human behavior, breath airflow, and daily speaking signals, showing a promise to use in wearable monitoring. Summarily, the studied pressure sensor integrates the advantages of piezoresistive and piezoelectric sensors and may provide a new paradigm to develop multifunctional pressure sensors for wearable monitoring with temperature visualization.

Stepwise solid phase extraction integrated with chemical derivatization for all-in-one injection LC-MS/MS analysis of metabolome and lipidome

The metabolome and lipidome are critical components in illustrating biological processes and pathological mechanisms. Generally, two or more independent methods are required to analyze the two compound panels due to their distinct chemical properties and polarity differences. Here, a novel strategy integrating stepwise solid-phase extraction (SPE) and dansyl chemical derivatization was proposed for all-in-one injection LC-MS/MS analysis of serum metabolome and lipidome. In this workflow, a stepwise elution procedure was firstly optimized to separate the metabolome and lipidome fractions using an Ostro plate. Dansyl chemical derivatization was then applied to label amine/phenol, carboxyl, and carbonyl-containing sub-metabolomes. Our results demonstrated that the dansyl labeling could significantly improve chromatographic separation, enhance the MS response, and overcome the matrix effect of co-eluting lipids. Ultimately, an all-in-one injection LC-MS/MS method measuring 256 lipids (covering 20 subclasses) and 212 metabolites (including amino acids, bile acids, fatty acids, acylcarnitines, indole derivatives, ketones and aldehydes, nucleic acid metabolism, polyamines, etc.) was established. This method was applied to investigate the metabolic changes in cisplatin-induced nephrotoxicity in rats and the results were compared with previous untargeted metabolomics. The presented strategy could predominantly improve the analytical coverage and throughput and can be of great use in discovering reliable potential biomarkers in various applications.

A stationary phase with a positively charged surface allows for minimizing formic acid concentration in the mobile phase, enhancing electrospray ionization in LC-MS proteomic experiments.

The default choice of mobile phase acidifier for bottom-up LC-MS proteomic analyses is 0.10% formic acid because of its decent acidity, decent ion pairing ability, and low suppression of electrospray ionization. In recent years, state-of-the-art columns have been designed specifically to provide efficient separation even when using an MS-friendly mobile phase of low ionic strength. Despite this, no attempts have been made to improve the sensitivity of the MS-based analytical methods by reducing the amount of formic acid in the mobile phase. In this study, we evaluated the effect of reduced formic acid concentration in the mobile phase on the chromatographic behavior and MS response of peptides when separated using columns packed with a C18 stationary phase with a positively charged surface. Using 0.01% formic acid in the mobile phase maintained excellent chromatographic performance and increased MS signal response compared to the standard of 0.10%. The enhanced MS response translated to about 50% improved peptide identifications depending on the complexity and amount of sample injected. The increased retention of peptides at a reduced formic acid concentration was directly proportional to the number of acidic residues in the peptide sequence. The study was carried out by covering a spectrum of protein samples with varied complexity using analytical flow, micro-, and nanoflow regimes to expand the applicability in routine practice.

Self-Stabilized 50 Gb/s Silicon Photonic Microring Modulator Using a Power-Independent and Calibration-Free Control Loop

This paper demonstrates the possibility of automatically stabilizing the working condition of an integrated Silicon Photonics microring modulator with a novel dithering-based control scheme. The proposed feedback strategy leverages a real-time acquisition of the modulator non-linear transfer function (TF) and operates by setting the target locking point to the zero of the TF second derivative, i.e. where the ring slope is maximum. This results in a control algorithm that is both power-independent and calibration-free. The paper shows that the operating point identified in this way has a negligible difference with respect to the optimum working condition of minimum Transmitter Penalty normally targeted and that the employed dithering signal does not affect the modulation quality. The control performances, made possible by an FPGA-based platform ensuring a 30 ms response time, are assessed in a 50 Gbit/s routing scenario, demonstrating effective compensation of wavelength and thermal variations and successful transmission even in demanding environments.

Shooter biases and stereotypes among police and civilians

The present research assesses potential correlates of discriminatory police behavior, comparing police and civilian participants in a first person shooter task (FPST) as well as on various self-report measures of intergroup contact, intergroup attitudes, and ideological beliefs in three preregistered studies. Study 1 (N = 330), using a FPST with a short response window (630 ms), did not observe shooter biases in reaction times, error rates and signal detection parameters in neither police nor civilian participants. Study 2a (N = 290), using a longer response window (850 ms), observed a shooter bias in reaction times, error rates, and response criterion in both civilian and police participants. These shooter biases were largely driven by faster reactions, fewer errors, and more liberal shoot decisions for armed Arab (vs. White) targets. Study 2b (N = 191; 850 ms response window) closely replicated shooter biases in reaction times, error rates, and response criterion in a sample of civilian online participants. Across studies, we observed similar results in the shooter task for police and civilian samples. Furthermore, both police and civilian participants expressed anti-Muslim and anti-Arab attitudes across a variety of self-report measures. However, compared to civilians, police participants reported higher levels of anti-Muslim attitudes on some measures as well as higher levels of social dominance orientation, which might pose additional risk factors for discriminatory behavior. Lastly, while we observed reliable individual differences in self-reported intergroup attitudes, ideologies, and intergroup contact, none of these characteristics correlated with shooter biases.

Targeted isolation and identification of bioactive pyrrolidine alkaloids from Codonopsis pilosula using characteristic fragmentation-assisted mass spectral networking

Codonopsis pilosula (CP), a well-known food medicine homology plant, is commonly used in many countries. In our preliminary study, a series of pyrrolidine alkaloids with high MS responses were detected as characteristic absorbed constituents in rat plasma after oral administration of CP extract. However, their structures were unclear due to the presence of various isomers and the lack of reference standards. In the present study, an MS-guided targeted isolation of pyrrolidine alkaloids of CP extract was performed by ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF MS). For data analysis under fast data directed acquisition mode (Fast-DDA), an effective approach named characteristic fragmentation-assisted mass spectral networking was successfully applied to discover new pyrrolidine alkaloids with high MS response in CP extract. As a result, seven new pyrrolizidine alkaloids [codonopyrrolidiums C-I (3-9)], together with two known ones (1 and 2), were isolated and identified by NMR spectral analysis. Among them, codonopyrrolidium B (1), codonopyrrolidium D (4) and codonopyrrolidium E (5) were evaluated for lipid-lowering activity, and they could improve high fructose-induced lipid accumulation in HepG2 cells. In addition, the characteristic MS/MS fragmentation patterns of these pyrrolizidine alkaloids were investigated, and 17 pyrrolidine alkaloids were identified. This approach could accelerate novel natural products discovery and characterize a class of natural products with MS/MS fragmentation patterns from similar chemical scaffolds. The research also provides a chemical basis for revealingin vivo effective substances in CP.

Rapid LC–MS assay for targeted metabolite quantification by serial injection into isocratic gradients

Liquid chromatography mass spectrometry (LC–MS) has emerged as a mainstream strategy for metabolomics analyses. One advantage of LC–MS is that it can serve both as a biomarker discovery tool and as a platform for clinical diagnostics. Consequently, it offers an exciting opportunity to potentially transition research studies into real-world clinical tools. One important distinction between research versus diagnostics-based applications of LC–MS is throughput. Clinical LC–MS must enable quantitative analyses of target molecules in hundreds or thousands of samples each day. Currently, the throughput of these clinical applications is limited by the chromatographic gradient lengths, which—when analyzing complex metabolomics samples—are difficult to conduct in under ~ 3 min per sample without introducing serious quantitative analysis problems. To address this shortcoming, we developed sequential quantification using isotope dilution (SQUID), an analytical strategy that combines serial sample injections into a continuous isocratic mobile phase to maximize throughput. SQUID uses internal isotope-labelled standards to correct for changes in LC–MS response factors over time. We show that SQUID can detect microbial polyamines in human urine specimens (lower limit of quantification; LLOQ = 106 nM) with less than 0.019 normalized root mean square error. Moreover, we show that samples can be analyzed in as little as 57 s. We propose SQUID as a new, high-throughput LC–MS tool for quantifying small sets of target biomarkers across large cohorts.Graphical

Acoustics Reveals Short‐Term Air Temperature Fluctuations Near Mars' Surface

AbstractAcoustics is new on Mars: it allows the characterization of turbulence at smaller scales than previously possible within the lowest part of the Planetary Boundary Layer. Sound speed measurements, by the SuperCam instrument and its microphone onboard the NASA Perseverance rover, allow the retrieval of atmospheric temperatures at 0.77 m above the ground, at 3 Hz, with a ∼10 ms response time that is 20–100 times shorter than for typical thermocouple sensors used on Mars. Here we report on the first measurements of the sound speed‐derived temperature and its fluctuations near the surface. Data highlight large and rapid fluctuations up to ±7 K/s, whose amplitude over such a timescale has never been reported, nor predicted by atmospheric models. These fluctuations follow the daytime pattern of the turbulence and highlight occasional high amplitude events that are likely due to the conjunction of low thermal inertia and strong winds.

Fabrication of Rb2TeI6 thin films for stable, lead-free perovskite photodetector via dry-processed approach

In the vacancy-ordered double perovskite group, rubidium tellurium iodide is a rarely studied material. In this paper, we report the fabrication of Rb2TeI6 thin film via a dry-processed approach. The process includes the chemical vapor deposition of the RbI film, followed by a thermal annealing treatment in TeI4 vapor. The film has a tetragonal structure with good morphology, high absorption coefficient (>105 cm−1 in the 280–620 nm wavelength range), and good stability in ambient air. A photodetector is fabricated by growing a 300 nm-thick Rb2TeI6 film on indium-doped tin oxide electrodes. The Rb2TeI6-based photodetector has 0.87 pA dark current at 5 V bias. Under 450 nm illumination, it shows 1.4 mA/W photoresponsivity, approximately 1010 J photodetectivity, and 16.4 ms/19.2 ms response times with an excellent operational stability. This study not only presents an effective technique for fabricating the Rb2TeI6 perovskite thin film, but also shows its potential for photodetector application.

Transient Response Characteristics Analysis of High-Power Piezoelectric Transducers.

Highlights What are the main findings? Derive the characteristics of transient equations under different excitations, and conclude the time constant is the key to the stability of the transducers.Applying a vector reduction method to analyze a series RLC transient matching scheme, which can change the electromechanical damping and improve the transient response time of the system. What is the implication of the main finding? A matching scheme combined with full-bridge inverter, transformer and series LC, is adopted to improve the transient response characteristic, which can provide suitable electrical damping without causing energy losses. To improve suitability in applications with high dynamic performance requirements, the transient response characteristics of high-power piezoelectric transducers should be studied quantitatively. This paper proposes the vector reduction method to solve the complex transient equations and obtains a transient matching scheme clarifying the mechanism of electrical matching resistance on electromechanical damping. A matching scheme with a combination of full-bridge inverter, transformer and series LC circuit is designed and validated, which can provide suitable electrical damping without causing energy losses. Consequently, the experiment verifies the transient properties of the proposed scheme. For a typical piezoelectric cutting transducer with 100.8 ms response time, our scheme is verified to have high dynamic performance within frequency response time of 5.5 ms and vibration response time of 15.0 ms.

Stimulus-Evoked Activity Modulation of In Vitro Engineered Cortical and Hippocampal Networks.

The delivery of electrical stimuli is crucial to shape the electrophysiological activity of neuronal populations and to appreciate the response of the different brain circuits involved. In the present work, we used dissociated cortical and hippocampal networks coupled to Micro-Electrode Arrays (MEAs) to investigate the features of their evoked response when a low-frequency (0.2 Hz) electrical stimulation protocol is delivered. In particular, cortical and hippocampal neurons were topologically organized to recreate interconnected sub-populations with a polydimethylsiloxane (PDMS) mask, which guaranteed the segregation of the cell bodies and the connections among the sub-regions through microchannels. We found that cortical assemblies were more reactive than hippocampal ones. Despite both configurations exhibiting a fast (<35 ms) response, this did not uniformly distribute over the MEA in the hippocampal networks. Moreover, the propagation of the stimuli-evoked activity within the networks showed a late (35–500 ms) response only in the cortical assemblies. The achieved results suggest the importance of the neuronal target when electrical stimulation experiments are performed. Not all neuronal types display the same response, and in light of transferring stimulation protocols to in vivo applications, it becomes fundamental to design realistic in vitro brain-on-a-chip devices to investigate the dynamical properties of complex neuronal circuits.

Efficient fall detection in four directions based on smart insoles and RDAE-LSTM model

Efficient fall detection is significant for the elderly, persons with motor symptoms, and people who perform risky actions, with four types of falling postures. However, most studies focused on distinguishing fall or not, although the fall direction information is crucial to turn on the corresponding part of the airbag or quickly assess the damage level. To accurately, rapidly, and reliably recognize different directional falls (forward, backward, left, and right) during daily life, this study proposes a novel fall detection methodology based on a pair of commercial lightweight smart insoles and a long short-term memory (LSTM) framework with a trained referencing denoising autoencoder (RDAE). Compared with traditional autoencoders, the referencing sub-path, i.e., RDAE, is additionally attached to achieve the automatic feature extraction. A pair of wireless in-shoe insoles (OpenGo, Moticon GmbH), each side equipped with 13 plantar pressure sensors and a tri-axial accelerometer, was employed to capture comprehensive spatial-temporal gait parameters. Hence an effective response to a fall, together with the estimation of the corresponding direction, can be accomplished, where the accuracy and response time are two primary concerns. The proposed RDAE-LSTM network provides a reliable testing result in classification, with 98.6% accuracy and 8.7 ms response time for determining fall directions, demonstrating a more convincing performance than other algorithms. The proposed methodology is an unobtrusive choice for users whose daily life is not affected by the fall detection device. The RDAE-LSTM model was proven to accurately and quickly recognize falls in four directions for the unbalanced fall detection dataset.

Control of an ultrasonic haptic interface for button simulation

This work presents the control of a piezoelectric interface that combines two vibration modes of a plate to render the haptic feeling of a button click. By principle, the two vibration modes create an elliptical motion of particles of a beam that can induce a lateral force to the fingerpulp. In this device, the synchronization of the modes’ vibrations is essential, and can be obtained with a closed loop control. In the paper, we present the control in the (d,q) frame, because it can ensure the dynamic performances to achieve a compelling haptic feedback, yet being robust besides the external disturbances produced by the user’s finger. The proposed method could achieve a 2 ms response time, and the haptic feedback was perceived by 100% of users in a psychophysical study.

An efficient and sensitive method on the identification of unsaturated fatty acids in biosamples: Total lipid extract from bovine liver as a case study

Unsaturated fatty acids (UFAs) are fatty acids with one or more carbon-carbon double bonds (C=C). They are building blocks of structurally complex lipids. According to the position of C=C bond in the UFAs, there are multiple isomers with different physiological activities. Therefore, an accurate understanding of UFAs is essential. Combining Paternò-Büchi (PB) reaction with tandem mass spectrometry (MS/MS) analysis has been successfully used to identify unsaturated lipids in bio-samples. However, there are still some challenges, such as low reactive rate and low MS response of PB products. In this study, 3-pyridinecarboxaldehyde (3-PYA) was selected as an efficient PB reagent for the first time. According to the nitrogen rule, introduction of nitrogen did not only make the target MS and MS/MS ions to be easily identified but also increase the ionization efficiency significantly. The developed method in this study demonstrated greater efficiency and sensitivity for the identification of UFAs in total lipid extracts from bovine liver compared with other commonly used PB reagents.

Integrative analyses of widely targeted metabolomic profiling and derivatization-based LC-MS/MS reveals metabolic changes of Zingiberis Rhizoma and its processed products

Zingiberis Rhizoma (ZR) has nutritional value and application potentiality, while Zingiberis Rhizoma Praeparatum (ZRP) and Carbonised Ginger (CG) are two main processed products of ZR based on different methods. Here, we performed a widely targeted metabolomics method with Sequential Windowed Acquisition of all Theoretical fragment ions (SWATH) mode to analyze differential metabolites in ZR, ZRP and CG. Additionally, the chemical derivatization was applied to characterize different submetabolomes and improve the separation effect and MS response of metabolites. In total, 369 metabolites were identified and divided into 14 categories, 104 of which were differential metabolites. Our results suggest that carbohydrates, nucleotides, organic acids, vitamins, lipids, indoles, alkaloids, and terpenes contributed to a downward trend after processing, but the maximum content of flavanones, phenylpropanes and polyphenols appeared in ZRP, and that of alcohols appeared in CG. These findings serve as promising perspectives for developing functional food in ZR, ZRP and CG.

TPU/CNTs flexible strain sensor with auxetic structure via a novel hybrid manufacturing process of fused deposition modeling 3D printing and ultrasonic cavitation-enabled treatment

The broad technological concept as so-called "hybrid additive manufacturing" is introduced into the fabrication of flexible strain sensing structure, employing the combination process of fused deposition modeling (FDM) 3D printing technique and ultrasonic cavitation-enabled treatment. We customize the FDM settings to print auxetic structures with a negative Poisson's ratio (NPR), using the flexible thermoplastic polyurethane (TPU) material. Then, we employ the ultrasonic cavitation-enabled treatment conducted towards the flexible auxetic structure immersing in carbon nanotubes (CNTs) liquid, aiming to embed the CNTs into the surface layer of the auxetic structures. It is equivalent to two additive manufacturing steps, proving effective in designing and fabricating flexible strain sensors. Instead of 3D printing after the hybridization of the TPU matrix material, this manufacturing procedure can ensure that the intrinsic excellent mechanical properties of TPU are not weakened due to the internally mixed conductive materials but able to exhibit usable sensing performances. The Poisson's ratio of the sensor structure is - 0.8. The sensor achieves over 300% strain. The sensitivity within the initial strain range is 2.661. The reliability of signal acquisition during the cyclic deformations is proved. Its response-recovery duration under 5% strain at 500 mm/min deformation rate is 130 ms(response)− 250 ms(recovery). It gives accurate feedback to external stimuli at different frequencies. It can maintain stable output signals during 3000 cycles of stretching. It also can sense 1% minor-strain stimuli. The strain sensing behavior of the fabricated flexible sensor with the auxetic structure is detailed. The CNTs are combined tightly with the TPU surface layer to form a conductive network with variable resistance during recoverable deformation of the auxetic structure. The macro and micro-mechanisms of sensing are dissected, considering the tunneling effect of discontinuous CNTs. The hybrid additive manufacturing process is verified to be feasible, credible, and low-cost for easy fabrication of flexible strain sensors with complex geometry configurations.

Nomex paper-based double-sided laser-induced graphene for multifunctional human-machine interfaces

Motivated by the inevitable trend of the Internet of Everything, human-machine interaction technology has gradually been permeated into people's daily life. Receptive devices that capture human behaviors and responsive devices that provide machine feedback are key components of human-machine interface. While it is a great challenge to integrate receptive and responsive devices in a well-organized way due to the limitations of material properties and device structures. In this work, we investigate the formation of laser-induced graphene on Nomex paper and propose an efficient interactive strategy based on its piezoresistive and thermoacoustic effects. Functional integration of receiving instructions (pressure-sensing capability) and providing feedback (sound-emitting capability) can be achieved by simply assembling three layers of Nomex paper that have been laser-customized on both sides. The integrated device not only has a sensitive response (∼12 relative current change and ∼50 ms response time) to the pressure similar to a gentle finger press (∼10 kPa), but also can emit a high-quality sound signal with larger sound pressure levels (∼70 dB at 1 W/cm2 power density). Furthermore, two proof-of-concept demonstrations, a press-to-audio pad and a command-responding thermo-earphone, are presented to substantiate the feasibility in information exchange activities.