High Temperature Sensitivity Research Articles

High-sensitivity optical fiber seawater temperature and pressure sensor with a low-error demodulation method

Using a single optical microfiber (OM) sensor for multi-parameter sensing can lead to significant demodulation error due to ill-conditioned matrices and nonlinear response characteristics. To address these issues, this paper proposes a novel specially packaged optical microfiber coupler combined with a silver mirror (OMCM). OMCM is combined with a mechanically enhanced sensitivity fiber Bragg grating (FBG) to form a temperature-pressure sensor. The temperature sensitivity exceeds -1.7 nm/°C while the pressure sensitivity reaches 53.435 nm/MPa, with a depth resolution of 0.935 cm. According to the characteristics of the sensor spectrum, this paper proposes a new demodulation method, which combines machine learning methods with a traditional wavelength-tracking method to achieve low demodulation error. For temperature and pressure, the mean absolute percentage errors are 0.04% and 1.31%, respectively. This feature facilitates the detection of minute changes in shallow marine environments, lacustrine systems, and other aquatic habitats, thus making it highly suitable for applications such as underwater aquaculture and marine monitoring.

Simultaneous tri-parameter surface plasmon resonance photonic crystal fiber sensor

Abstract This study presents a photonic crystal fiber (PCF) integrated with a surface plasmon resonance (SPR) sensor that utilizes two orthogonal polarization core modes for sensing. The PCF features a thin indium tin oxide (ITO) layer on the inner channel and lower polished surface, an upper polished surface with a thin gold film, and an inner channel filled with magnetic fluid (MF) for magnetic field detection. Additionally, a temperature and refractive index sensitive material polydimethylsiloxane (PDMS) is placed on the lower polished surface, while the upper polished surface is designed for refractive index measurement. This multifunctional PCF-SPR sensor offers a compact and efficient solution for simultaneous detection of magnetic fields, temperature, and refractive index variations. The highest magnetic field sensitivity in the range of 0~12Oe is 11.1nm/Oe, the highest temperature sensitivity in the range of 20~400℃ is -0.5nm/℃, and the highest refractive index sensitivity in the range of 1.17~1.35μm is 1000nm/RIU. The designed sensor effectively mitigates the cross-sensitivity issues during concurrent measurements of the magnetic field, temperature, and refractive index simultaneously, presenting significant potential for applications in complex environment, including mineral resource exploration, geological and environmental assessments.

Engineering carbon assimilation in plants.

Carbon assimilation is a crucial part of the photosynthetic process, wherein inorganic carbon, typically in the form of CO2, is converted into organic compounds by living organisms, including plants, algae, and a subset of bacteria. Although several carbon fixation pathways have been elucidated, the Calvin-Benson-Bassham (CBB) cycle remains fundamental to carbon metabolism, playing a pivotal role in the biosynthesis of starch and sucrose in plants, algae, and cyanobacteria. However, Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), the key carboxylase enzyme of the CBB cycle, exhibits low kinetic efficiency, low substrate specificity, and high temperature sensitivity, all of which have the potential to limit flux through this pathway. Consequently, RuBisCO needs to be present at very high concentrations, which is one of the factors contributing to its status as the most prevalent protein on Earth. Numerous attempts have been made to optimize the catalytic efficiency of RuBisCO and thereby promote plant growth. Furthermore, the limitations of this process highlight the potential benefits of engineering or discovering more efficient carbon fixation mechanisms, either by improving RuBisCO itself or by introducing alternative pathways. Here, we review advances in artificial carbon assimilation engineering, including the integration of synthetic biology, genetic engineering, metabolic pathway optimization, and artificial intelligence in order to create plants capable of performing more efficient photosynthesis. We additionally provide a perspective of current challenges and potential solutions alongside a personal opinion of the most promising future directions of this emerging field.

A 614 MW/cm2 AlGaN-channel Schottky barrier diode with high breakdown voltage and high temperature sensitivity

A 614 MW/cm2 AlGaN-channel Schottky barrier diode with high breakdown voltage and high temperature sensitivity

Luminescence property and energy transfer of color-tunable Bi2Mo2O9: Tb3+, Eu3+ phosphors with high temperature sensitivity

Luminescence property and energy transfer of color-tunable Bi2Mo2O9: Tb3+, Eu3+ phosphors with high temperature sensitivity

Strong near-infrared upconversion luminescence of the Er3+/Y3+ co-doped YbVO4 phosphor for multimode optical temperature measurement

This study explored the enhancement of near-infrared emissions in YbVO4: Er3+ through Y3+ ion doping under a 980 nm laser excitation. The phosphor exhibits weak green emissions at 527 nm (2H11/2 → 4I15/2) and 553 nm (4S3/2 → 4I15/2), red emissions at 654 nm (4F9/2 → 4I15/2), and a strong near-infrared emission at 803 nm (4I9/2 → 4I15/2). Optimal doping concentration of Y3+ ion in YbVO4: 0.02 Er3+ was determined to be 0.1, resulting in a 7.6-fold enhancement of near-infrared luminescence. This enhancement is attributed to defect bands facilitating energy transfer from green and red levels to the near-infrared levels. Furthermore, a multi-mode temperature sensor based on YbVO4: Er3+/Y3+ was developed, offering four distinct temperature sensing modes: TCEL of 2H11/2/4S3/2, NTCEL of 2H11/2/4F9/2 and 4S3/2/4F9/2, and single luminescence emission intensity of 4I9/2 energy level. The sensor demonstrates maximum relative sensitivities of 1.17 % K−1 at 298 K, 0.66 % K−1 at 298 K, 0.41 % K−1 at 298 K and 1.29 % K−1 at 673 K. YbVO4: Er3+/Y3+ phosphor exhibits high temperature sensitivity, showcasing significant potential for optical temperature sensing applications.

Enhanced Vernier Effect in Cascaded Fiber Loop Interferometers for Improving Temperature Sensitivity

This work presents a high-sensitivity temperature sensing system utilizing an enhanced Vernier effect implemented in cascaded fiber loop interferometers. High-sensitivity temperature sensors based on the Vernier effect have broad application prospects, but the sensitivity of traditional measurement schemes is difficult to improve further due to the limited variation in the difference between two free spectrum ranges (FSRs). Our sensing system incorporates two fiber loop interferometers and a single-mode fiber to form a Vernier spectral response, characterized by two complementary optical filter responses. As the temperature of the sensing fiber changes, one FSR decreases, and the other increases, respectively, enhancing the difference value between the two FSRs to form an enhanced Vernier effect. Experimental results demonstrate that the temperature sensitivity of a traditional Vernier effect measurement is only −298.29 kHz/°C, while our proposed enhanced Vernier effect sensing system achieves a sensitivity of 618.14 kHz/°C, which is 92 times higher than that of a two-arm optical carrier-based microwave interferometry (OCMI) sensing system and 2.07 times higher than that of a traditional Vernier effect sensing system. This approach with an enhanced Vernier effect scheme based on cascaded fiber loop interferometers can be used to design high-sensitivity sensing systems for biometrics, smart cities, and the Internet of Things.

Halometallate Ionic Liquid Dynamically Regulates Zwitterionic Hydrogels by Synergistic Multiple‐Bond Networks

AbstractImproving the compatibility between high concentration metallic ions and zwitterions to controllable construction of coordination bonds is critical and extremely challenging. Here, a facile and effective strategy to fabricate multifunctional hydrogels by randomly copolymerizing halometallate ionic liquids (ILs) and zwitterions through electron beam irradiation is reported. Introducing metal ions into ILs can balance charges and establish moderate and stable cross‐linked networks with zwitterions. The synergistic effect of coordination bonds and multiple interactions with varying strengths endows hydrogel with outstanding stretchability, compressive strength, rapid response, advanced self‐healing ability, and excellent frost resistance. The multifunctional sensor assembled from hydrogels can timely, accurately, and stably monitor human movement, write anti‐counterfeiting and remotely transmit Morse code signals. Multiple hydrogel sensors are also assembled into a flexible sensor array to track the tactile trajectory and detect spatial distribution of force. Moreover, the obtained hydrogel displays high temperature sensitivity with resistance temperature coefficient of −3.85% °C−1 at 25–40 °C, which can detect tiny temperature changes (0.1 °C). Interestingly, the processed hydrogel can effectively modulate the transmissivity through salt triggering to achieve patterning. Considering the structural designability of halometallate ILs, this work provides new insights for the development of multifunctional hydrogels.

High-sensitive and linear temperature sensor based on liquid-filled photonic crystal fiber

High-sensitive and linear temperature sensor based on liquid-filled photonic crystal fiber

Elucidation of Ubiquitin-Related Functions via an Ubiquitin Overexpression Approach.

To identify new ubiquitin-related functions using yeast, we searched for mutants conferring a temperature-sensitivity phenotype that could be rescued through ubiquitin overexpression. Screening of mutants using this overexpression strategy identified SPC2, which encodes a subunit of the endoplasmic reticulum (ER) signal peptidase complex (SPC). Ubiquitin overexpression rescued a high-temperature sensitivity of spc2 deletion mutant, suggesting that ubiquitin could compensate for Spc2 loss-of-function at high temperatures. The double mutant of Spc2 and Hrd1, an ER E3 ubiquitin ligase, showed a synergistic growth defect at higher temperatures. A weak genetic interaction was also observed between spc2Δ and cdc48-3 mutation. The results suggest a close functional relationship between SPC and the ubiquitin-proteasome system in yeast and further provide proof-of-principle for this ubiquitin overexpression approach to identify novel ubiquitin-related genes and associated cellular processes.

Advances in surface coating and performance enhancement of ammonium perchlorate

Abstract Ammonium perchlorate (AP), which has the advantages of high oxygen content, good thermal and chemical stability, and no solid residue after thermal decomposition, is considered to be the most widely used oxidiser for solid propellant applications. However, the high mechanical sensitivity, moisture absorption, and thermal decomposition temperature of AP seriously affect the performance of the solid propellant. In this paper, we systematically review the research progress of the improvement of desensitization, anti-hygroscopicity, and thermal decomposition performance by surface coating of AP. At the same time, the surface coating methods are focusing on electrospray technology, reduced pressure distillation, ultrasonic synthesis, liquid phase deposition, supercritical fluid, intermittent spray coating, and electrostatic self-assembly coating method. Among above, intermittent spray coating and liquid phase deposition method are the preferred surface coating method due to their uniformity of coating, ease of adhesion and good performance enhancement. It is expected that the research on surface coating and performance enhancement of AP can greatly promote the innovation and development of AP in the field of high burning rate solid propellant.

Microsphere-Augmented PDMS integration in tapered FBG small-scale sensors for enhanced temperature sensitivity

This work presents a novel high-sensitivity temperature sensor based on a fiber Bragg grating inscribed on a tapered optical fiber which terminates in a microsphere, all embedded within a PDMS-filled silica capillary. The fabricated microsphere at the taper’s end enhances PDMS traction, improving strain transfer between the polymer and the fiber during temperature changes. Different waist diameters for the tapered fiber were considered for the design of the sensor. The sensor’s response was analyzed over a temperature range of 20 °C to 90 °C for taper waist diameters ranging from 60 μm to 20 μm. Experimental results demonstrate a wavelength temperature sensitivity of 47.19 pm °C⁻1 for a 60 μm waist diameter and 221.2 pm °C⁻1 for a 20 μm waist diameter, achieving up to 22 times the sensitivity of a bare FBG. The experimental results were supported by finite element analysis simulations, which showed a clear correlation between the enhanced sensitivity and the increase in axial strain applied by the PDMS on the embedded fiber. This enhancement in sensitivity was demonstrated by housing the fiber in a capillary, integrating the microsphere at the end of the fiber, and diminishing the fiber taper’s diameter. Moreover, unlike traditional techniques aimed at enhancing the thermal sensitivity of fiber Bragg gratings, the sensor developed through this innovative approach exhibits enhanced performance regarding both dimensions and sensitivity.

A novel Bi3+,Eu3+ co-doped Ca3Zr2SiGa2O12 phosphors for high-sensitive temperature measurement

High-sensitive optical thermometers have garnered significant attention due to rapid technological advances. Here, novel Bi3+,Eu3+ co-doped Ca3Zr2SiGa2O12 (CZSG) phosphors with high temperature sensitivity were synthesized. Extensive researches of structure, photoluminescence and mechanism of energy transfer from Bi3+ to Eu3+ in CZSG:Bi3+,Eu3+ were carried out. Under excitation of 291 nm light, a broadband at 310–400 nm from Bi3+ ions as well as peaks at 580–710 nm from Eu3+ ions are both observed in CZSG:Bi3+,Eu3+. Fluorescence intensity (FI) of Bi3+ and fluorescence intensity ratio (FIR) of Bi3+ and Eu3+ were used to design dual-mode optical thermometer. The maximal relative sensitivities (SR) are 2.98 %K−1 @ 573 K (FI) and 1.88 %K−1 @ 303 K (FIR), respectively. Noticeably, when two modes are combined, the minimal SR of CZSG:Bi3+,Eu3+ is higher than 1.04 %K−1 over the whole temperature range (303–573 K). Above results indicate the potential application of CZSG:Bi3+,Eu3+ sample in optical thermometers.

High-sensitivity ocean temperature sensor usinga reflective optical microfiber coupler andmachine learning methods.

This paper proposes a novel seawater temperature sensor, to the best of our knowledge, that utilizes an optical microfiber coupler combined with a reflective silver mirror (OMCM). The sensor's sensitivity and durability are enhanced by encapsulating it in polydimethylsiloxane (PDMS). Additionally, a specially designed metal casing prevents the OMCM from responding to pressure, thus avoiding the challenge of multi-parameter demodulation and increasing its adaptability to harsh environments. The paper analyzes the advantages of the new sensor structure and evaluates its performance in terms of temperature sensitivity and compressive strength through experiments. Finally, the paper employs machine learning demodulation methods. Compared with traditional demodulation methods, the particle swarm optimization support vector regression (PSO-SVR) algorithm demonstrates a substantial reduction in the demodulation error. Specifically, the mean absolute percentage error (MAPE) relative to the full scale drops from 2.16% to 0.157%. This paper provides an effective solution for high-precision monitoring of the ocean environmental temperature.

Highly Sensitive Solid Ratiometric Luminescent Thermometer Based on N,C-Chelating Four-Coordinate Organoboron Compounds.

Realizing ratiometric thermometers using single-component organic solid-state luminophores is attractive but challenging. Here, we synthesized a series of N,C-chelated tetra-coordinated organoboron compounds and characterized their structures. Among them, sample BN2Br can be used as a luminescent thermometer and exhibits a high temperature sensitivity (3.67% K-1), a wide response range of 120-280 K, and good reversibility, which is mainly due to the temperature-dependent intermolecular stacking effect in the solid state. The proposed ratiometric thermometry protocol may provide new insights for developing photonic thermometers.

Comparative investigation of the effect of rare earth elements (Y, Sm and La) in NiO-based NTC thermistors with high temperature sensitivity

Negative temperature coefficient (NTC) thermistors with high temperature sensitivity have significance to the high-accuracy applications for temperature measurement and control. While, a NTC thermistor with high temperature sensitivity is typically accompanied by high room temperature resistivity (ρ25), and vice versa. To develop NTC thermistors with high temperature sensitivity and low ρ25, NiO-based ceramics modified with rare earth (RE) elements (Y, Sm and La) were prepared using the traditional solid-phase reaction method. The microstructure, morphology and electrical properties of these ceramics were thoroughly investigated. All ceramics doped with different concentrations of RE ions exhibited the main phase of rock-salt NiO structure and demonstrated typical NTC characteristics. Depending on the RE ion content, the prepared ceramics presented adjustable properties, low ρ25 and NTC material constant B higher than 5200 K can be received. The differences in conduction behavior and temperature sensitive characteristics affected by the RE ions were comparatively investigated, considering both grain effect and grain boundary effect.

Dual-Channel High-Sensitivity Temperature and Magnetic Field Sensor Based on Mach–Zehnder Interference and Surface Plasmon Resonance

Dual-Channel High-Sensitivity Temperature and Magnetic Field Sensor Based on Mach–Zehnder Interference and Surface Plasmon Resonance

Plasmon-enhanced NIR-II photoluminescence of rare-earth oxide nanoprobes for high-sensitivity optical temperature sensing.

With ongoing advancements in photothermal therapy, achieving efficient tumor cell eradication while minimizing damage to healthy tissues necessitates a highly effective and non-invasive real-time temperature monitoring technique for human tissues. Herein, we report a near-infrared (NIR)-II optical temperature sensing nanoprobe featuring rare-earth-doped gadolinium oxide nanocrystals (RENCs) attached to the dumbbell mesoporous silica-coated gold nanorods (AuNRs). The composite nanoprobe presents an intense absorption in the NIR region, and NIR-II photoluminescence (PL) increases by 97.2 to 102-fold compared to pure RENCs upon 980 nm irradiation. The localized electric field generated through surface plasmon resonance effects of AuNRs demonstrated a dumbbell-shaped distribution that aligns with the structure of nanoprobes, maximizing the PL enhancement of RENCs. Moreover, the NIR-II emissions are changed with the rising temperature, with an exceptional relative sensitivity of 7.25% K-1 at 338 K based on PL lifetime, indicating the nanoprobe is highly potential for optical temperature sensing.

Flexible Thermoelectric BiSbTe/Carbon Paper/BiSbTe Sandwiches for Bimode Temperature‐Pressure Sensors

AbstractBimode temperature‐pressure sensors hold significant promise in personal health monitoring, wearables and robotic signal detection. Traditional bimode sensors typically combine two independent sensors, leading to fabrication complexity. This study develops a bimode temperature‐pressure sensor by using a facile electrodeposition method to create sandwiched BiSbTe/Carbon Paper/BiSbTe thin films and stacking them to a vertical structure. It demonstrates high sensitivity for temperature sensing, capable of detecting temperature difference as low as 1 K, and a rapid response time of 0.92 s due to a vertical structure. Utilizing its thermoelectric mechanism, the sensor achieves self‐powered sensing for finger touch and respiration states. Furthermore, its island‐like contact surface ensures high sensitivity with an extremely fast response time of 0.17 s, by rapidly changing contact resistance under pressure, allowing it to detect various human behaviors, including body movements and micro‐expressions. Beyond its sensing capabilities, the film excels in flexibility, electromagnetic interference shielding, and stability, presenting significant potential for integration into self‐powered electronic skin systems for health monitoring, wearables, artificial intelligence, and other electronic skin applications.

Upconversion luminescence and thermosensitive properties of NaGd(PO3)4:Yb3+/Er3+

High-sensitivity optical temperature measurement has attracted extensive attention in both fundamental studies and practical applications. In this study, a series of upconversion (UC) luminescence phosphors composed of NaGd(PO3)4 (NGP) doped with 20 at% Yb3+ and various concentrations of Er3+ (0.5 at% as the optimal concentration) was synthesized by high-temperature solid-state method. And their crystal structure and the distribution of lanthanide dopants were analyzed using X-ray diffraction with Rietveld refinement verifies. Under 980 nm laser excitation, the obtained phosphors show the characteristic Er3+ upconversion green and red emission bands through two-photon processes. The fluorescence intensity ratio (FIR) based on the thermal coupled states demonstrates the thermal sensing ability in a wide temperature range of 200–573 K. The thermal sensitivity is relatively high with the maximum absolute thermal sensitivity Sa of 0.53 % K−1 (523 K) and the maximum relative thermal sensitivity Sr of 2.60 % K−1. The phosphor NGP:Yb/Er also exhibits high repeatability as the thermal sensors reach 97 %. These findings postulate the potential of NGP:Yb/Er as a promising candidate in optical thermal sensing applications.