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Intelligent face masks play crucial roles in health monitoring and disease prevention, having attracted huge attention in recent years. However, most of the current intelligent face masks focus on monitoring single physical signal, which were unable to provide comprehensive information. Herein, an intelligent face mask with airflow and temperature sensing abilities, high-efficiency filtration and excellent antibacterial activity was proposed. The real-time airflow monitoring was realized by a triboelectric nanogenerator (TENG), which was composed of electrospun nanofibrous membrane and polydimethylsiloxane (PDMS) composite film. The fabricated electrospun nanofibrous membrane simultaneously played roles as tribo-positive material, filter and antibacterial membrane. The PDMS composite film prepared by co-blending and surface modification was applied as tribo-negative material. It was found that the combination of co-blending and surface modification enhanced the tribo-negative property of the PDMS film, resulting in an increment of output performance of TENG. The TENG integrated into a face mask could monitor respiratory rate and respiration intensity in real time. Additionally, the temperature sensing was achieved by a serpentine PDMS/laser-induced graphene temperature sensor. The temperature sensor exhibited a temperature coefficient of resistance of 0.316% °C−1, which could detect subtle temperature variations. Furthermore, the electrospun nanofibrous membrane exhibited excellent filtration performance and antibacterial activity. Therefore, the prepared intelligent face mask showed promising potential for healthcare applications. [ABSTRACT FROM AUTHOR]

This research investigates the integration of free-space optics (FSO) with fiber Bragg grating (FBG) sensors in self-healing ring architectures, aiming to improve reliability and signal-to-noise ratio in temperature sensing within sensor systems. The combination of FSO's wireless connectivity and FBG sensors' precision, known for their sensitivity and immunity to electromagnetic interference, is particularly advantageous in demanding environments such as aerospace and structural health monitoring. The self-healing architecture enhances system resilience, automatically compensating for failures to maintain consistent monitoring capabilities. This study emphasizes the use of intensity wavelength division multiplexing (IWDM) to manage the complexities of increasing the multiplexing number of FBG sensors. Challenges arise with the overlapping spectra of FBGs when multiplexing several sensors. To address this, a hybrid approach combining an unsupervised autoencoder (AE) with a convolutional neural network (CNN) is proposed, significantly enhancing the accuracy and efficiency of sensor signal detection. These advancements signify substantial progress in sensor technology, validating the effectiveness of the AE-CNN hybrid model in refining FBG sensor systems and underscoring its potential for robust and reliable applications in critical sectors. [ABSTRACT FROM AUTHOR]

In this paper, a temperature sensing scheme with a miniature MZI structure based on the principle of inter-mode interference is proposed. The sensing structure mainly comprises single mode–coreless–multimode–coreless–single mode fibers (SCMCSs), which have been welded together, with different core diameters. The light beam has been expanded after passing through the coreless optical fiber and is then coupled into a multimode optical fiber. Due to the light passing through the cladding and core mode of the multimode optical fiber with different optical paths, a Mach–Zehnder interferometer is formed. Moreover, due to the thermo-optic and thermal expansion effects of optical fibers, the inter-mode interference spectrum of a multimode fiber shifts when the external temperature changes. Through theoretical analysis, it is found that the change in the length of the sensing fiber during temperature detection has less of an effect on the sensitivity of the sensing structure. During the experiment, temperature changes between 20 and 100 °C are measured at sensing fiber lengths of 1.5 cm, 2.0 cm, 2.5 cm, 3.0 cm, 3.5 cm, and 4.0 cm, respectively, and the corresponding sensitivities are 65.98 pm/°C, 72.70 pm/°C, 67.75 pm/°C, 66.63 pm/°C, 74.80 pm/°C, and 72.07 pm/°C, respectively. All the corresponding correlation coefficients are above 0.9965. The experimental results indicate that in the case of a significant change in the length of the sensing fiber, the sensitivity of the sensing structure changes slightly, which is consistent with the theory that the temperature sensitivity is minimally affected by a change in the length of the sensing fiber. Therefore, the effect of the length on sensitivity in a cascade-based fiber structure is well solved. The sensing scheme has an extensive detection range, small size, good linearity, simple structure, low cost, and high sensitivity. It has a good development prospect in some detection-related application fields. [ABSTRACT FROM AUTHOR]

Respiration is one of the most important physiological processes of the human body. Continuous monitoring of respiration with wearable sensors can provide abundant information related to the health status of the respiratory system. However, the vast majority of the developed respiration sensors are constructed on nontextile substrates, resulting in dissatisfactory convenience, comfortness, and aesthetics. Additionally, special micro‐/nanomaterials are inevitably involved to construct the respiration sensors, which pose potential hazards to the human body due to the exfoliation and inhalation of these micro‐/nanomaterials. Here, humidity‐ and temperature‐sensitive electronic textiles (e‐Textiles) are presented, which are fabricated based on easily accessible and biofriendly materials (e.g., sodium chloride, glycerin, aluminum fiber, carbon fiber, and polyvinyl alcohol). Moreover, the proposed e‐Textiles use a potentiometric sensing mechanism, featuring self‐powered signal outputs and ultralow power consumption. The humidity and temperature‐sensing functionalities can also be in situ integrated into commercial masks for constructing full‐textile and all‐in‐one e‐Masks for comprehensive respiration monitoring. As demonstrations, both single‐point respiration monitoring (e.g., intensity, frequency, etc.) and 2D respiratory analysis (i.e., airflow distribution) can be realized with the e‐Masks. This work provides a facile and scalable approach to manufacture self‐powered and fully fabric respiration sensors for comprehensive respiratory analysis. [ABSTRACT FROM AUTHOR]

Hydrogen‐bonded organic frameworks (HOFs) have shown promise in various fields; however, the construction of HOF/polymer hybrid membranes that can maintain both structural and functional integrity remains challenging. In this study, we here fabricated a new HOF (HOF‐50) with reserved polymerizable allyl group via charge‐assisted H‐bonds between the carboxylate anion and amidinium, and subsequently copolymerized the HOF with monomers to construct a covalently bonded HOF/polymer hybrid (polyHOF) membrane. The resulting polyHOF membrane not only exhibits customizable mechanical properties and extreme stability, but also shows an exceptional ratiometric luminescent temperature‐sensing function with very high sensitivity and visibility even when the lanthanide content is two orders of magnitude lower than that of the reported mixed‐lanthanide metal–organic frameworks (MOFs) and lanthanide‐doped covalent organic frameworks (COFs). This orthogonal postsynthesis copolymerization strategy may provide a general approach for preparing covalently connected HOF/polymer hybrid membranes for diverse applications. [ABSTRACT FROM AUTHOR]

Medical surgical catheters are widely used in the medical field for drug delivery or postoperative drainage. However, infections associated with local temperature rise often occur at the catheter‐tissue interface, resulting in irreversible pathological damage, cognitive behavioral abnormalities, or even an increased risk of mortality if not monitored in time. Herein, an in situ temperature‐sensing hydrogel coating on the outer surface of medical surgical catheters for real‐time infection monitoring is developed. The hydrogel coating exhibits a record temperature coefficient of resistance of 2.90% °C−1 and maintains stable in vivo. Besides, the hydrogel layer forms a mechanically compatible catheter‐tissue interface and minimizes the risk of inflammatory responses due to its tissue‐like softness (Young's modulus of 4.24 kPa). By applying it in the early detection of infections in the brain of SD rats, the individual survival rate has increased to 90% with timely intervention. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A composite fiber Fabry-Perot interferometer (FPI) -based optical fiber temperature sensor is theoretically proposed and practically demonstrated in this work, in which the composite FPI is formed by covering the end face of single-mode fiber with ultraviolet (UV) adhesive and nano-TiO 2 coating using the dip-coating method. With the superior thermo-optic characteristic of UV adhesive and the UV absorption of nano-TiO 2 , the sensitivity of the composite FPI temperature sensor can be effectively enhanced by UV irradiation. After five times of TiO 2 dip-coating processes, the composite FPI has a higher temperature sensitivity of 75.3 pm/°C (R2 = 0.9754) under 365 nm UV light, in which the measurement range is from 25 °C to 130 °C and the detection accuracy is 0.66 °C. The proposed sensor has a simple structure and preparation process, competitive sensitivity, high linearity, and satisfactory repeatability and stability, which can be an appropriate candidate to realize high-precision temperature sensing in industrial, chemical, biological, and environmental applications. [ABSTRACT FROM AUTHOR]

In this work, a plasmonic sensor based on metal–insulator–metal (MIM) waveguide for temperature sensing application is numerically investigated via finite element method (FEM). The resonant cavity filled with PDMS polymer is side-coupled to the MIM bus waveguide. The sensitivity of the proposed device is ~ − 0.44 nm/°C which can be further enhanced to − 0.63 nm/°C by embedding a period array of metallic nanoblocks in the center of the cavity. We comprehend the existence of numerous highly attractive and sensitive plasmonic sensor designs, yet a notable gap exists in the exploration of light coupling mechanisms to these nanoscale waveguides. Consequently, we introduced an attractive approach: orthogonal mode couplers designed for plasmonic chips, which leverage MIM waveguide-based sensors. The optimized transmission of the hybrid system including silicon couplers and MIM waveguide is in the range of − 1.73 dB to − 2.93 dB for a broad wavelength range of 1450–1650 nm. The skillful integration of these couplers not only distinguishes our plasmonic sensor but also positions it as a highly promising solution for an extensive array of sensing applications. [ABSTRACT FROM AUTHOR]

In this work, NaGdF4: 20%Yb, 2%Er microcrystals with varying contents of Cr3+ doping were obtained by conventional hydrothermal process. The microcrystal phase structure, morphology, upconversion luminescence mechanism, as well as temperature sensing behaviour under different treatment methods were researched. Based on the thermally coupled 2H11/2 and 4S3/2 levels of Er3+ and the dependence of fluorescence intensity ratio (FIR) on temperature, the optical temperature sensing behaviour of micrometer crystals were experimentally demonstrated. The NaGdF4: 20%Yb, 2%Er, 7%Cr microcrystals treated with high-temperature annealing show the best temperature sensing behaviour within the temperature span of 298–498 K. NaGdF4: 20%Yb, 2%Er, 7%Cr microcrystals with high temperature annealing presented the feasibility and promising properties for optical temperature sensing. The endeavour of emerging materials could lay the groundwork for future sustainable photonics engineering industrial growth. [ABSTRACT FROM AUTHOR]

Pr3+-Er3+ co-activated glass-ceramics containing Ba 3.75 Gd 0.833 Nb 10 O 30 crystalline phase were prepared as a multifunctional material. The optimum heat treatment condition was determined to be 750 °C/90 min, as this condition is most favorable for luminescence. As the Pr3+ concentration increases, the emissions of 3P 0 and 1D 2 energy levels show different trends, leading to a shift in luminescence from orange to yellow. With the introduction of Er3+, the co-doped sample achieves orange-yellow-green tunable luminescence. The 0.3%Pr3+-0.3%Er3+ co-doped sample exhibits alternating yellow-orange-green luminescence during continuous excitation in the range of 250–500 nm, which has potential applications in optical anti-counterfeiting. In the temperature interval of 298–458 K, the maximum temperature sensitivities based on the NTCLs of Pr3+ and Er3+ were 0.82 × 10−2 K−1 (S a) and 1.40 % K−1 (S r). Meanwhile, the thermal repeatability ratio is higher than 92.3 %, which proved that it is a potential temperature sensing material. In addition, the concentration quenching, energy transfer and luminescence phenomena involved were analyzed in depth and their mechanisms were explained. [ABSTRACT FROM AUTHOR]

Mortar beams incorporating carbon nanofibers (CNFs), which were synthesized in situ on Portland cement particles, were used to produce nanomodified Portland cement sensors (SmartCem sensors). SmartCem sensors exhibited an electrical response comparable to a thermistor with a temperature coefficient of resistivity of − 0.0152/ °C. The highest temperature sensing was obtained for the SmartCem sensor, which contained ~ 0.271 wt.% of CNFs. The calculated temperature sensitivity was approximately 11.76% higher in comparison with the mortar beam containing only unmodified Portland cement. SmartCem sensors were used to monitor the cement hydration in large-scale self-compacting concrete beams. The measurements were conducted after casting for 7 days. Additionally, commercially available thermocouple and humidity sensors were used as references. The results showed that changes in electrical resistivity measured by the SmartCem sensor were well aligned with the ongoing hydration processes. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The electrical characteristics and conduction mechanisms of ZrAlN thin films for their potential use as thermistor sensors were assessed. Various compositions of Zr1-xAlxN were synthesized by sputtering and studied up to 200 °C to understand their sensitivity and applicability. Among the compositions studied, the ones with x = 0.34 and x = 0.46 showed the highest sensitivities, reaching values close to 3000 K. However, the thermo-resistive properties exhibited by these compositions limited their utilization above 100 °C. Zr1-xAlxN film compositions with x higher than 0.46 showed amorphous structures and were found to be insulative. Composition with x = 0.26, within the cubic phase, showed the most promising electrical properties regarding temperature sensing in the studied range. XPS analysis of this composition confirmed the presence of Zr-N and Al-N bonds, with a Zr3+ oxidation state, which suggests the availability of a free electron contributing to the electrical conduction. Impedance measurements performed at different temperatures for this composition revealed the dominant role of the grain boundaries in the conduction mechanism, based upon electron hopping between grains, overcoming the energy barrier imposed by the grain boundaries. ZrAlN thin films demonstrate negative temperature coefficient (NTC) thermistor behavior, expanding their applications beyond protective coatings to temperature monitoring.

This study investigates an approach to temperature sensing by integrating Titanium Aluminum Nitride (TiAlN), originally engineered for wear and corrosion applications, as a temperature sensor within a multilayered thin film system. A nitride multilayer system was developed by physical vapor deposition (PVD) using a single four-target magnetron sputtering chamber; intermediate vacuum interruption steps were employed for masking procedures. The multilayer architecture design aimed to provide the sensor layer with mechanical protection and electrical shielding. Structural and electrical characterization of the TiAlN single layer revealed semiconductor behavior and stable electrical resistance up to 750 °C, with minimal signal stabilization requirements. Despite the higher Al content, the TiAlN temperature sensor exhibited a cubic crystal structure characterized by diffuse nanolayers, resulting from a two-fold rotational deposition and target configuration. A detailed examination of the multilayer system cross-section containing the TiAlN sensor was conducted using scanning transmission electron microscopy (STEM). The analysis revealed its columnar morphology with the presence of typical PVD growth defects, including voids and droplets. While the presence of these defects may impact the electrical characteristics of the sensor, the selected experimental conditions effectively maintained the structural integrity of the multilayer system despite the vacuum interruptions caused by masking procedures. Validation experiments confirmed the functionality of the multilayer system for temperature measurements up to 400 °C. The signal acquisition system addressed room temperature resistance variations and low sensitivity (thermistor coefficient ∼100 K), resulting in a measured error of approximately 6%. This study demonstrates promising results of TiAlN as a temperature sensor within a multilayered system, expanding its range of potential applications.

Improvement of luminescent thermometers requires not only the search for high-sensitivity thermometric outputs, but also availability of multiple thermometric parameters affording a combined and reliable response. We hereby detail for the first time the luminescence of Eu3+ in manganese tungstate (Eu3+:MnWO4) solids obtained by coprecipitation under ultraviolet excitation and how this material provided an optical thermometric response from 77 K to 373 K via excitation and emission spectra. Processing of up to five thermometric parameters, namely bandwidths, band positions, band shifts and luminescence intensity ratios, resulted in relative thermal sensitivities as high as 1.56% K−1 and temperature uncertainties between 0.01 and 2 K depending on the choice of the spectral parameter. In addition, we demonstrate that Eu3+:MnWO4 also act as a qualitative colorimetric thermosensor because of progressive change of emission color to greenish-yellow to bluish-green upon heating under UV excitation. Therefore, our results show that the combination of broadband tungstate emissions with the 4f-4f narrow emissions of Eu3+ is an effective approach to achieve a multiparametric luminescent thermal response via emission, excitation and visual observation, which makes Eu3+:MnWO4 a promising candidate for advanced thermometry applications.

In this paper, a photonic skin sensor based on a balloon-shaped optical fiber structure cascading a Fiber Bragg Grating (FBG) is proposed, which can simultaneously sense pressure and temperature. When the photonic skin feels pressure, the built-in polymer micro-cap is squeezed, causing a change in the radius of the balloon-shaped structure. At the same time, the capillary-enclosed FBG can be used for temperature compensation. The pressure sensitivity of the photon skin sensor can reach 6.556 nm/mN in the range of 0-0.5 mN and the temperature sensitivity can reach -0.192 nm/°C in the range of 30-50 °C. The demodulation of the dual parameter matrix shows that the error rates of pressure and temperature measurements are less than 0.5% and 2.01%, respectively. On this basis, the sensor is applied to robotic arm-assisted puncture experiment detection, and the five states of the puncture process are analyzed. Based on the backpropagation (BP) neural network for repeated training, the results show that its accuracy remains at 98.7%, indicating that the sensor has good robustness. The development of this sensor shows application potential in the field of robotic intelligent skin in the future.

Respiration is one of the most important physiological processes of the human body. Continuous monitoring of respiration with wearable sensors can provide abundant information related to the health status of the respiratory system. However, the vast majority of the developed respiration sensors are constructed on nontextile substrates, resulting in dissatisfactory convenience, comfortness, and aesthetics. Additionally, special micro‐/nanomaterials are inevitably involved to construct the respiration sensors, which pose potential hazards to the human body due to the exfoliation and inhalation of these micro‐/nanomaterials. Here, humidity‐ and temperature‐sensitive electronic textiles (e‐Textiles) are presented, which are fabricated based on easily accessible and biofriendly materials (e.g., sodium chloride, glycerin, aluminum fiber, carbon fiber, and polyvinyl alcohol). Moreover, the proposed e‐Textiles use a potentiometric sensing mechanism, featuring self‐powered signal outputs and ultralow power consumption. The humidity and temperature‐sensing functionalities can also be in situ integrated into commercial masks for constructing full‐textile and all‐in‐one e‐Masks for comprehensive respiration monitoring. As demonstrations, both single‐point respiration monitoring (e.g., intensity, frequency, etc.) and 2D respiratory analysis (i.e., airflow distribution) can be realized with the e‐Masks. This work provides a facile and scalable approach to manufacture self‐powered and fully fabric respiration sensors for comprehensive respiratory analysis.

This research presents the design and implementation of a chipless Radio Frequency Identification (RFID) multi-sensor tag on a flexible laminate. Along with the tag's primary function of data encoding for object identification purposes, the tag also incorporates moisture and temperature sensing functionalities within a compact size measuring a mere 15 × 16 mm2. The tag structure comprises of a total 29 resonators, with each resonator corresponding to one bit in the microwave response. The initial design utilized the bendable Rogers RT/duroid®5880 within a frequency band of 5.48–28.87 GHz. To conduct a comprehensive comparative analysis, the tag design is optimized for two distinct substrates including Kapton®HN and PET. The optimization process involves exploring the utilization of both silver nanoparticle-based ink and Aluminum as radiators. The sensing feature was incorporated by deploying a thin film of Kapton®HN over the longest slot of the tag which acts as a moisture sensor. Temperature sensing feature was achieved by combining Stanyl® polyamide, a temperature dependent polymer, with Rogers RT/duroid®5880 which served as a fused substrate. The tag showcases a high code density of 12.08 bits/cm2 enabling it to efficiently label 229 unique items. Its unique features include flexibility, miniaturized design, printability, cost-effectiveness and multi sensing property.

Rare earth ion-doped upconversion luminescent materials have found extensive utility in anti-counterfeiting applications. However, in practice, single-mode photoluminescence falls short of addressing increasingly intricate demands of contemporary anti-counterfeiting measures. This work presents successfully synthesized dual-mode excited SrBi4Ti4O15 upconversion phosphor doped with Yb3+/Er3+, designed to emit two distinctive colors, green and red under excitation at either 980 or 1550 nm. Introduction of the multi-color emission significantly enhances the security of anti-counterfeiting strategies in a variety of modes. A comprehensive investigation is conducted into potential upconversion mechanisms driven by different excitation sources, examining both 980 and 1550 nm wavelengths. Anti-counterfeiting properties are evaluated for synthesized phosphor by gauging the luminous intensity ratio between red and green light. Research findings unequivocally point to the immense potential of SrBi4Ti4O15 upconversion phosphor doped with Yb3+/Er3+ for robust multimode anti-counterfeiting applications, representing a promising development in this field. [ABSTRACT FROM AUTHOR]

Flexible and stretchable electronic yarn containing electronic components (i.e., hybrid electronic yarn) are essential for manufacturing smart textile garments or fabrics. Due to their low stretchability and easy interconnection fracture, previously reported hybrid electronic sensing yarns have poor mechanical durability and washability. In order to address this issue, a stretchable hybrid electronic yarn for body temperature monitoring was designed and prepared using a spandex filament as the core yarn and a thin enameled copper wire connected with a thermal resistor as the wrapping fiber. The temperature sensing performance of different hybrid electronic yarn samples was evaluated using the following three types of interconnection methods: conductive adhesive bonding, melt soldering, and hot pressure bonding. The optimal interconnection method with good sensing performance was determined. Furthermore, in order to improve the mechanical durability of the hybrid electronic yarn made using the optimal interconnection method, the interconnection area was encapsulated with polymers, and the effect of polymer materials and structures on the temperature-sensing properties was evaluated. The results show that traditional wrapping combined with hot pressing interconnection followed by tube encapsulating technology is beneficial for achieving high stretchability and good temperature-sensing performance of hybrid electronic yarn. [ABSTRACT FROM AUTHOR]

In this paper, a novel microstrip resonator technique for temperature sensing is proposed, designed, and implemented using a hybrid planar microstrip line and photonic band gap (PBG) structure. To implement the PBG structure of the microstrip line, a microfluidic channel with periodic form is introduced into the substrate and filled with water. The operation principle of the sensor is based on a frequency shift due to the variation in the center of the band gap, which in turn changes with the variation of the permittivity of water, which relates to the temperature. The different empirical expressions describing the complex permittivity with the resonant frequency were carried out. The proposed sensor is simple in design and low cost, which may be applied in different applications at the industrial. [ABSTRACT FROM AUTHOR]

Near‐infrared (NIR) II region (1000–1700 nm) lighting sources possess special potential for temperature sensing and quantitative composition analysis. However, it is a challenge to tune the luminescence toward such long wavelength NIR‐II emission. Herein, Cr4+ ions occupation is designed and verified in olivine‐type CaYGaO4 as [CrO4] tetrahedron by site occupancy confinement. Under 620 nm red light excitation, the phosphors display broadband NIR‐II emission centered at 1330 nm with a full width at half maximum (FWHM) of 233 nm, resulting from spin‐allowed 3T2 to 3A2 transition of Cr4+ ions in Td symmetry. The optical thermometry application is demonstrated by decoding the spectral shift and decay times varying with temperature, and the maximum relative sensitivities are 5.82% and 0.78% K−1, respectively. Furthermore, a flexible film containing CaYGaO4:Cr4+ is fabricated to implement the non‐invasive detections of fillet temperature and NH3 concentration in ammonia. This work represents a step toward developing next‐generation NIR‐II luminescence materials and widens non‐invasive detection applications. [ABSTRACT FROM AUTHOR]

Electronic textiles (e-textiles) build upon existing technologies to develop truly smart textiles: garments that sense, react, and adapt. Thermoregulatory e-textiles are an area of significant interest across the field. Designing e-textiles that satisfy electrical performance and simple construction is a significant challenge. To address these issues, a simple dip-coating and in-situ polymerization method was used to develop the first example of a thermoregulatory e-textile using green synthesized silver nanoparticles (AgNP) and polypyrrole (Ppy), based on the method previously reported (Naysmith, A.; Mian, N.S.; Rana, S. Development of conductive textile fabric using Plackett–Burman optimized green synthesized silver nanoparticles and in situ polymerized polypyrrole. Green Chemistry Letters and Reviews2023,16 (1)). This methodology was optimized using a Taguchi statistical design determining the optimal AgNP-Ppy synthesis method to obtain high performance Joule heating e-textiles, novel within the field of e-textiles. Reactant concentration and reaction time had the largest effects on the electrical resistance of subsequent e-textiles. The result is the first example of an e-textile heater based on green synthesized AgNPs. The e-textile demonstrated exceptional Joule heating (120°C), low electrical resistance (37 Ω), resistive temperature sensing behavior (negative TCR = −0.0046), and increased thermal conductivity (19.55 l (Wm−1 K−1)); the strain sensing behavior (gauge factor = −0.07). This work extends knowledge of the development and challenges within e-textile technologies as the field creates the next generation of textiles. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Xinyang Normal University Natural Science Edition is the property of Journal of Xinyang Normal University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding how cells sense temperature is a fundamental question in biology and is pivotal for the evolution of life. In numerous organisms, temperature is not only sensed but also generated due to cellular processes. Consequently, the mechanisms governing temperature sensation in various organisms have been experimentally elucidated. Extending upon others' proposals and demonstration of protein- and nucleic acid-based thermosensors, and utilizing a colonial India 'punkah-wallahs' analogy, I present my rationale for the necessity of temperature sensing in every organelle in a cell. Finally, I propose temperature-sensing riboceptors (ribonucleic acid receptors) to integrate all the RNA molecules (mRNA, non-coding RNA, and so forth) capable of sensing temperature and triggering a signaling event, which I call as thermocrine signaling. This approach could enable the identification of riboceptors in every cell of almost every organism, not only for temperature but also for other classes of ligands, including gaseous solutes, and water. [ABSTRACT FROM AUTHOR]

Optical temperature sensing based on fluorescence intensity ratio (FIR) technology has become a potential temperature measurement method due to its fast response, non-invasive and high accuracy. In order to improve the efficiency of development, a multi-strategy combination method was used to study the multi-mode temperature sensing performance of optical temperature sensing materials. Bi3+ doped, Sm3+ doped materials and K 3 YSi 2 O 7 :Bi3+,Sm3+ materials have been successfully prepared and multi-mode temperature sensing models have been established. According to FIR sources, the strategies used are classified according to Bi3+ occupying two sites, energy level thermal coupling of Sm3+ and Bi3+-Sm3+ dual center. The relative sensitivity of the material is up to 0.705% K−1, which adds a new member to the high-performance optical temperature sensing materials family. More importantly, the multi-strategy combination method based on one system opens up an effective way for the rapid development of inorganic optical temperature sensing materials. [ABSTRACT FROM AUTHOR]

Background: Symmetric sigmoidal models with four parameters based on an idealized S/Z-shaped curve are commonly used to analyze the optical parameters of thermochromic materials. However, our experimental findings show that this approach leads to systematic errors involving the incorrect estimation of the transition temperature or the possibility of a virtual indication of the hysteresis nature of a reversible thermochromic change. For this reason, we sought to find a five-parameter model that would appropriately avoid this problem. Methods: Two commercial thermochromic pigments were used for the test and applied to a textile substrate at different concentrations. The optical properties were measured using reflectance spectrophotometry and then converted to Kubelka–Munk function values and colorimetric coordinates. The following statistics were used to assess the quality of the selected sigmoidal models: coefficient of determination, R2; adjusted coefficient of determination, AR2; root mean square error, RMSE; and Akaike Information Criterion, AIC. Results: The four-parameter models were compared with each other and with the five-parameter models using nested F-tests based on residual variance to obtain a statistical measure of superior performance. For all thermochromic color change data examined, the five-parameter models resulted in significantly better fitting. It could be shown that the five-parameter model showed significantly higher accuracy and precision in determining the transition temperature, like non-sigmoidal quantification methods. Conclusions: We concluded that the asymmetric five-parameter model is a valuable extension of the symmetric model in the investigation of thermochromic color changes, providing better parameter estimates and a new approach to investigating the mechanisms contributing to the asymmetry of the thermochromic curve. [ABSTRACT FROM AUTHOR]

Temperature measuring is a daily procedure carried out worldwide in practically all environments of human activity, but it takes particular relevance in industrial, scientific, medical, and food processing and production areas. The characteristics and performance of the temperature sensors required for such a large universe of applications have opened the opportunity for a comprehensive range of technologies and architectures capable of fulfilling the sensitivity, resolution, dynamic range, and response time demanded. In this work, a highly sensitive fiber optic temperature sensor based on a double-cavity Fabry-Perot interferometer (DCFPI) is proposed and demonstrated. Taking advantage of the Vernier effect, we demonstrate that it is possible to improve the temperature sensitivity exhibited by the polymer-capped fiber Fabry-Perot interferometer (PCFPI) up to 39.8 nm/°C. The DCFPI is sturdy, reconfigured, and simple to fabricate, consisting of a semi-spherical polymer cap added to the surface of the ferrule of a commercial single-mode fiber connector (SMF FC/PC) placed in front of a mirror at a proper distance. The length of the air cavity (Lair) was adjusted to equal the thickness of the polymer cap (Lpol) plus a distance δ to generate the most convenient Vernier effect spectrum. The DCFPI was packaged in a machined, movable mount that allows the adjustment of the air cavity length easily but also protects the polymer cap and simplifies the manipulation of the sensor head. [ABSTRACT FROM AUTHOR]

Aiming at the problem of poor control accuracy in the existing automatic temperature control system, an automatic temperature sensing and control system based on STM single chip microcomputer was designed. The system framework was divided into four layers: temperature perception layer, information communication layer, control adjustment layer and human-computer interaction layer. The STM32 L4 microcomputer was used as the hardware core of the system, and the temperature information perceived by the temperature sensor was transmitted to the controller through the ZigBee wireless communication network. In the control process, the fuzzy neural network control program was run to obtain the temperature control amount and generate the control instruction, and the instruction set was transmitted to the on-site temperature adjustment equipment to realize the automatic temperature adjustment. The experimental results show that compared with PID control, fuzzy control and fuzzy PID control methods, the overshoot between the temperature control system based on STM32 L4 single-chip microcomputer and the expected temperature is relatively small, and the temperature control is closer to the expected value. [ABSTRACT FROM AUTHOR]

A chirped long-period grating inscribed in a planer optical waveguide sensor is demonstrated. The distribution of electric field within the structure has been obtained using boundary condition for the electric field equations at different dielectric boundaries. The transmission spectrum of the proposed sensor is obtained by transfer-matrix method. Further, the sensitivity for ambient refractive index and temperature has been analysed by observing the shift in resonance wavelengths. The presence of two dips in the transmission spectrum effectively doubles the sensitivity in comparison to the single resonance structure. We have achieved refractive index sensitivity of 5600 nm/RIU and temperature sensitivity of 0.8 nm/ °C, respectively. [ABSTRACT FROM AUTHOR]

The combined effects of temperature (from −80 °C to +80 °C) and 100 kV X-ray exposure (up to 108 kGy(SiO2)) on the physical properties of Brillouin scattering and losses in three differently doped silica-based optical fibers, with varying dopant type and concentration (4 wt%(Ge), 10 wt%(Ge) and 1 wt%(F)), are experimentally studied in this work. The dependencies of Brillouin Frequency Shifts (BFS), Radiation-Induced Attenuation (RIA) levels, Brillouin gain attenuation, Brillouin frequency temperature (CT) and strain (Cε) sensitivity coefficients are studied under X-rays in a wide temperature range [−80 °C; +80 °C]. Brillouin sensing capabilities are investigated using a Brillouin Optical Time Domain Analyzer (BOTDA), and several properties are reported: (i) similar behavior of the Brillouin gain amplitude decrease with the increase in the RIA; (ii) the F-doped and heavily Ge-doped fibers do not exhibit a temperature dependence under radiation for their responses in Brillouin gain losses. Increasing Ge dopant concentration also reduces the irradiation temperature effect on RIA. In addition, Radiation-Induced Brillouin Frequency Shift (RI-BFS) manifests a slightly different behavior for lower temperatures than RIA, presenting an opportunity for a comprehensive understanding of RI-BFS origins. Related temperature and strain sensors are designed for harsh environments over an extended irradiation temperature range, which is useful for a wide range of applications. [ABSTRACT FROM AUTHOR]

Remote and noncontact surface temperature measurements are frequently required yet challenging to execute. One the most promising options consists in using rare earth or transition metal doped materials as optical (luminescence) temperature sensors. In this paper, a series of novel Tb3+/Mn4+ co-doped SrLaMgNbO 6 (SLMN) phosphors have been synthesized and thoroughly investigated for their structural, luminescence spectroscopic and decay kinetics properties as well as for temperature sensing performance. X-ray powder diffraction (XRD) analysis has shown that the prepared sample presents a double perovskite structure. Upon the UV excitation, emission spectra of SLMN:Tb3+, Mn4+ exhibit green and red emission bands for Tb3+ and Mn4+ dopants, respectively. Temperature-dependent photoluminescence (TD-PL) studies revealed sever thermal quenching of Mn4+ emission while that of Tb3+ was moderate providing well pronounced difference in fluorescence intensity ratios (FIR) of the ions. The maximum relative sensitivity (Sr) was found to be 3.27% K−1 and 1.92% K−1 for Mn4+ and Tb3+, respectively. This implies that SLMN: Tb3+, Mn4+ phosphor is a viable candidate material for a dual-mode optical temperature detection. [ABSTRACT FROM AUTHOR]

Converting mechanical energy into photon emission provides a promising route for intelligent sensing, self‐powered lighting, and distributed energy harvesting, which is of great significance for finding a feasible solution to the current sensing technical bottleneck and energy crisis. As the basis for understanding the conversion mechanism and realizing high‐frequency mechanical energy utilization, elucidating the dynamic process of intensity variation in the mechano‐to‐photon conversion remains a great challenge. Herein, a time‐domain characterization scheme that enables to unravel the intrinsic decay of mechanoluminescence (ML) with lifetimes from milliseconds down to tens of microseconds is constructed. It is demonstrated that ML decay characterization is an important tool to reveal the dynamics of charge migration in ML materials. The ML decay in a typical self‐reproducible ML material ZnS:Mn2+ shows temperature dependence and stress fluctuation resistance, which opens up a new reliable approach for self‐powered and remote temperature sensing. Finally, benefiting from the shortest ML lifetime recorded to date, an ultrafast‐response stress sensor that enables to detect individual pulses of ultrasonic waves with ML sensing technology is developed. [ABSTRACT FROM AUTHOR]

Upconversion nanoparticles have emerged as promising materials for non-contact temperature sensors due to their unique detection capabilities and low interference, so it is valuable to explore simple and effective approaches to enhance the temperature measurement sensitivity. In this study, we employed a special sol-gel method to prepare NaGd(MoO 4) 2 powder by calcining the precursor mixture, and the fluorescence properties as well as thermal sensitivity were investigated. Analysis based on XRD, SEM and energy transfer modes revealed that the enhancement in temperature sensitivity resulted from the increased distance between the sensitizer and activator ions as well as changes in crystallinity, compared with normal sol-gel method. By optimizing the doping of rare earth ions, the highest sensitivity reached 3.34 %K−1. Additionally, fluorescence spectra analysis of NaGd(MoO 4) 2 samples synthesized via different methods demonstrated that energy transfer between the sensitizer and activator ions can be achieved through high-temperature calcination. Moreover, LiGd(MoO 4) 2 samples prepared using the unique sol-gel method exhibited similar enhancements in temperature sensitivity as NaGd(MoO 4) 2 powder. These findings imply that the samples prepared through the unique sol-gel synthesis method exhibit significant potential in terms of their fluorescence and temperature detection capabilities. [Display omitted] • NaGd(MoO 4) 2 :Er3+-Yb3+ sample was prepared by a special sol-gel method which were calcined after precursor mixing. • The method of calcining after precursor mixing increases the distance between ions and affects crystallinity. • The mixing ratio of the Er3+-Yb3+ doped precursor can be adjusted to achieve higher upconversion. • The temperature sensitivity of the special sol-gel sample prepared in the manuscript is higher, reaching 3.34 %K−1. • Er3+/Yb3+ doped LiGd(MoO 4) 2 prepared by the special sol-gel method also showed similar enhancement in temperature sensitivity. [ABSTRACT FROM AUTHOR]

The behavior of multilevel atomic ensembles (e.g., alkali-metal atoms) can be influenced significantly by the intensity of a driving field (or controlling/coupling field). The phase coherence between two transition pathways driven by a probe light and a driving field can lead to the effect known as electromagnetically induced transparency (EIT). In EIT, the probe light can pass through a three-level alkali-metal atomic vapor without absorption or reflection when two coherent resonances (transition pathways driven by the driving and probe fields) are present and the linewidths of the transparency windows are sufficiently narrow. The optical characteristics of atomic systems can also be affected by the Doppler broadening of the absorption profile in a spectroscope. Our analysis indicates that both broadenings (related to the transitions excited by the driving and probe fields) can be expanded, leading to an increase in the transmittance and reflectance broadenings when a coupling field with adaptive strength is applied; the corresponding temperature would, thus, be implemented and readable. We show that the most suitable preparation for temperature sensing via an EIT vapor is to provide 80 times the spontaneous decay rate (SDR) of the excited atomic levels. This configuration results in reflectance and transmittance values that range between zero and one and cover a temperature range of 0 K to 600 K. As an example, we demonstrate the integration of specialized coating technologies with EIT ensembles for temperature sensing in the range of dozens of kelvins at and above room temperature. A key advantage of this temperature-sensing system is its ability to use adaptive resonant visible light as the probe field. This novel approach may find applications in providing unprecedented levels of precision and control in temperature sensing for coating processes and in the design of other photonic or optical devices. It can also be used to determine the temperature-dependent behavior of the specific heat of alkali-metal solids and gases (including the latent heats of vaporization or sublimation of alkali-metal solids) through the reflection and transmission spectra of the vaporized EIT atomic vapors. [ABSTRACT FROM AUTHOR]

Corannulene‐derived materials have been extensively explored in energy storage and solar cells, however, are rarely documented as emitters in light‐emitting sensors and organic light‐emitting diodes (OLEDs), due to low exciton utilization. Here, we report a family of multi‐donor and acceptor (multi‐D‐A) motifs, TCzPhCor, TDMACPhCor, and TPXZPhCor, using corannulene as the acceptor and carbazole (Cz), 9,10‐dihydro‐9,10‐dimethylacridine (DMAC), and phenoxazine (PXZ) as the donor, respectively. By decorating corannulene with different donors, multiple phosphorescence is realized. Theoretical and photophysical investigations reveal that TCzPhCor shows room‐temperature phosphorescence (RTP) from the lowest‐lying T1; however, for TDMACPhCor, dual RTP originating from a higher‐lying T1 (T1H) and a lower‐lying T1 (T1L) can be observed, while for TPXZPhCor, T1H‐dominated RTP occurs resulting from a stabilized high‐energy T1 geometry. Benefiting from the high‐temperature sensitivity of TPXZPhCor, high color‐resolution temperature sensing is achieved. Besides, due to degenerate S1 and T1H states of TPXZPhCor, the first corannulene‐based solution‐processed afterglow OLEDs is investigated. The afterglow OLED with TPXZPhCor shows a maximum external quantum efficiency (EQEmax) and a luminance (Lmax) of 3.3 % and 5167 cd m−2, respectively, which is one of the most efficient afterglow RTP OLEDs reported to date. [ABSTRACT FROM AUTHOR]

Some organic dyes and photosensitizers with strong visible absorption can behave as photo‐responsive oxidase mimics. However, the relationship between the photo‐oxidase activity and molecular structure remains unclear to date. In this work, a new type of photosensitizer with the characteristics of molecular rotors, namely DPPy, served as the molecular scaffold for further investigation. To adjust the photocatalytic oxidation ability, DAPy and CBPy were designed and synthesized based on the enhancement and diminishment of the intramolecular charge transfer (ICT) process, respectively. Kinetic studies revealed that DAPy and CBPy both exhibited highly efficient photo‐activated oxidase‐like activity with 3,3′,5,5′‐tetramethylbenzidine (TMB) as the substrate, which were in good accordance with their molecular engineering to promote either type I or type II reactive oxygen species (ROS) generation. Impressively a colorimetric method based on the visible light induced oxidase‐like activity of molecular rotors was developed to determine the environmental temperature for the first time. Both DAPy and CBPy showed distinct sensitivities toward temperature as compared with several molecular rotors based on the typical fluorimetric detection. This work provides a new strategy for the application of molecular rotors to overcome the non‐emissive challenge in temperature sensing. [ABSTRACT FROM AUTHOR]

Cr3+‐activated near‐infrared (NIR) phosphors are one of the most influential candidates for the new generation of intelligent NIR phosphor‐converted light‐emitting diode (pc‐LED) light sources. For spectral analysis, the broader the spectrum, the more useful information it contains. Herein, ultra‐broadband Cr‐activated Sc2O3 nanophosphors, which exhibit NIR ultra‐broadband from 650 to 1600 nm, are developed by the sol–gel method. This ultra‐broadband emission originates from the presence of Cr3+ and Cr4+, two luminescent centers confirmed by diffuse reflection spectra, electron paramagnetic resonance, time‐resolved photoluminescence spectra, and temperature‐dependent emission spectra. The nanophosphor exhibits excellent temperature‐sensing performance with SA = 4.102% K−1 and SR = 1.855% K−1. Co‐doping Yb3+ into Sc2O3 nanophosphors builds the Cr3+‐Yb3+‐Cr4+ model to bridge the spectral gap located at 1000 nm, forming a continuous NIR ultra‐broadband spectrum ranging from 650 to 1600 nm for the first time. Moreover, the introduction of Yb3+ improves the thermal stability of nanophosphors from 29.49% to 50.65% at 150 °C. The NIR transmission spectra of water, ethanol, and peanut oil demonstrate that Sc2O3:Cr3+‐Yb3+‐Cr4+ NIR nanophosphors favor potential applications in spectral analysis. The construction of a Cr3+‐Yb3+‐Cr4+ spectral bridge for realizing NIR ultra‐broadband phosphors based on cheap blue LEDs provides novel and effective insights. [ABSTRACT FROM AUTHOR]

In recent years, lanthanide doped materials have been extensively studied in the field of fluorescence temperature sensing due to their abundant emission levels and sensitive thermal response. Temperature sensing based on fluorescence intensity ratio (FIR) of upconversion nanoparticles has the advantages of fast temperature response, non-aggressiveness, and high spatial resolution. However, the most reported FIR sensing has limited sensitivity, probably due to the use of thermal coupling levels. Herein, we report a novel FIR temperature measurement based on non-thermal coupling levels of NaGdF 4 :Yb3+/Er3+@NaGdF 4 @NaGdF 4 :Yb3+/Tm3+ core-shell-shell nanostructure, which has high sensitivity and robustness simultaneously. The relative sensitivity based on I 801 / I 654 and I 801 / I 841 of Tm3+ to Er3+ can reach up to 4.56 (303 K) and 3.82% K−1 (313 K), respectively. Between them, FIR of I 801 / I 841 is independent of excitation power and time. These results show the great potential of FIR based on non-thermal coupling levels in high-sensitive and robust temperature sensors. [ABSTRACT FROM AUTHOR]

Recent developments in textiles have led to the manufacturing of a variety of fabrics. These developments include spacer fabrics, embroidered fabrics, embedded sensors in fabrics, ECG vests, etc. Electronic components are also being knit within fabrics. The study used a configuration of thermocouples, based on the Seebeck effect, knitted into the main structure using a variety of yarn filaments. The knitted fabric was tested against temperature variation to examine how it affects the impedance of the knitted thermocouples. The testing procedure produced promising results, as it showed that certain combinations of knitting materials may result in positive and negative temperature coefficients of the fabric. The combination of the tested materials provides a guide to developing similar structures for thermoelectric sensor applications. [ABSTRACT FROM AUTHOR]

Most thermometers suffer from thermal quenching resulting in low signal to noise ratio at elevated temperature. To overcome thermal quenching, we fabricated a negative thermal expansion (NTE) thermometer based on Sc 2 Mo 3 O 12 :Nd3+/Yb3+/Er3+ phosphor. Under 808 nm excitation, the upconversion (UC) emissions of Er3+ ions show the thermal enhancement and its 524 nm emission increases 10-fold as the temperature increased from 310 to 670 K. Furthermore, the temperature sensing behaviors are investigated. It is found fluorescence intensity ratio (FIR) of 524–559 nm is linear with temperature over a wide range of 310–790 K. The maximum relative sensitivity is 0.84% K−1 at 310 K. These results indicate such phosphor not only achieves a high sensitivity, but also exhibits excellent performances at high temperature due to its thermal enhancement. [ABSTRACT FROM AUTHOR]

In this paper, a temperature sensor based on fluorescence intensity ratio (FIR) technique is prepared by the dual curing method. The pumping threshold is only 0.1 mW for the application of real-time thermal monitoring on small transformers. This not only greatly reduces the thermal effects accumulated by laser irradiation but also contributes to the integration and portability of the light source. Based on the FIR, the temperature information could be demodulated through tracking the fluorescence spectral changes. The basic temperature sensing characteristics of this sensor were evaluated, which showed that the maximum stability deviation and reproducibility error were within ±1.1 K and ±0.8 K, respectively. Notably, it has a maximum measurement error of only 0.61 K when applied to the temperature monitoring of transformers. And a fast time response of 2.1 s was exhibited in the cyclic exhalation experiment. This proposed sensor is suitable for mass production due to its resistance to electromagnetic interference, low pumping power, fast time response, excellent stability and reproducibility. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Hyperbranched polysiloxanes have attracted increasing interest due to their unique fluorescence properties. However, the relatively short emission wavelength and low fluorescence lifetime are still the main obstacles to their broader application. In this study, we first synthesized a β‐diketone contained hyperbranched polysiloxane with excitation‐dependent multicolor emission. Further through the coordination of HBPSi‐NMDEA with Eu3+ ion, a hybrid luminescent material was prepared. It exhibited not only aggregation‐induced red emission at 613 nm, but also a long fluorescence lifetime of 681.45 μs. Particularly, it showed highly sensitive reversible fluorescence response to temperature variation, thus displaying the potential to be used in fluorescence temperature detection. [ABSTRACT FROM AUTHOR]

Here, we document a D-type double open-loop channel floor plasmon resonance (SPR) photonic crystal fiber (PCF) for temperature sensing. The grooves are designed on the polished surfaces of the pinnacle and backside of the PCF and covered with a gold (Au) film, and stomata are distributed around the PCF core in a progressive, periodic arrangement. Two air holes between the Au membrane and the PCF core are designed to shape a leakage window, which no longer solely averts the outward diffusion of Y-polarized (Y-POL) core mode energy, but also sets off its coupling with the Au movie from the leakage window. This SPR-PCF sensor uses the temperature-sensitive property of Polydimethylsiloxane (PDMS) to reap the motive of temperature sensing. Our lookup effects point out that these SPR-PCF sensors have a temperature sensitivity of up to 3757 pm/°C when the temperature varies from 5 °C to 45 °C. In addition, the maximum refractive index sensitivity (RIS) of the SPR-PCF sensor is as excessive as 4847 nm/RIU. These proposed SPR-PCF temperature sensors have an easy nanostructure and proper sensing performance, which now not solely improve the overall sensing performance of small-diameter fiber optic temperature sensors, but also have vast application prospects in geo-logical exploration, biological monitoring, and meteorological prediction due to their remarkable RIS and exclusive nanostructure. [ABSTRACT FROM AUTHOR]