Search

Nitrogen-vacancy (NV-) centers in nanodiamonds have emerged as a versatile platform for a wide range of applications, including bioimaging, photonics, and quantum sensing. However, the widespread adoption of nanodiamonds in practical applications has been hindered by the challenges associated with patterning them into high-resolution features with sufficient throughput. In this work, we overcome these limitations by introducing a direct laser-writing bubble printing technique that enables the precise fabrication of two-dimensional nanodiamond patterns. The printed nanodiamonds exhibit a high packing density and strong photoluminescence emission, as well as robust optically detected magnetic resonance (ODMR) signals. We further harness the spatially resolved ODMR of the nanodiamond patterns to demonstrate the mapping of two-dimensional temperature gradients using high frame rate widefield lock-in fluorescence imaging. This capability paves the way for integrating nanodiamond-based quantum sensors into practical devices and systems, opening new possibilities for applications involving high-resolution thermal imaging and biosensing.

The development of ultrasensitive thermometric phosphors has become an active area of research due to their appealing applications in the contactless temperature detection field. Herein, the scheelite-related compounds—CaGd 2 (WO 4) 4 : Nd3+, Yb3+ and CaGd 2 (MoO 4) 4 : Nd3+, Yb3+, which exhibit high sensing capacity—are successfully prepared and systematically characterized. The X-ray diffraction analysis reveals that CaGd 2 (WO 4) 4 : Nd3+, Yb3+ exhibits the monoclinic structure, whereas CaGd 2 (MoO 4) 4 : Nd3+, Yb3+ is in the tetragonal phase. The maximum phonon cut-off energy of CaGd 2 (WO 4) 4 : Nd3+, Yb3+ is 929 cm−1, slightly larger than that of CaGd 2 (MoO 4) 4 : Nd3+, Yb3+ (904 cm−1). Irradiated by 980 nm laser, PL spectra consist of the Nd3+: 4F j → 4I 9/2 (j = 7/2, 5/2, 3/2) and Yb3+: 2F 5/2 → 2F 7/2 emissions located in the near-infrared (NIR) range. Negative and positive thermal quenching behaviors are observed for the emissions of Nd3+ (754, 802, and 868 nm) and Yb3+ (1008 nm), respectively, attributed to the cooperative effects of the phonon-assisted energy transfer process of Yb3+ → Nd3+ and excited state absorption process of Nd3+. Moreover, the host material can affect the luminescence properties, thermal enhancement factor of the NIR anti-Stokes emission, and thermal sensing performance of the Nd3+-Yb3+ pair. Consequently, CaGd 2 (MoO 4) 4 : Nd3+, Yb3+ exhibits higher sensing sensitivity (S r-max = ∼6.00%K−1) than CaGd 2 (WO 4) 4 : Nd3+, Yb3+ (S r-max = ∼5.56%K−1). This study provides useful information for the construction of high-performance ratiometric thermometers based on the inverse thermal dependence of the NIR emissions of Nd3+ and Yb3+ ions. [ABSTRACT FROM AUTHOR]

Ratiometric thermometry is among the emerging applications in phosphor materials. Particularly, the technique of ultrafine-space thermometry has garnered significant attention in bio-imaging. Near-infrared (NIR) light, with its high tissue permeability, serves not only as an excitation source for up-conversion photoluminescence (UCPL) but also induces down-shifting photoluminescence (DSPL) at longer wavelengths. These luminescence mechanisms offer promising avenues for bio-available thermometry. In this study, we focused on highly bio-adaptable yttria-stabilized zirconia (YSZ), Zr0.85Y0.15O1.925, and prepared phosphor materials with yttrium partially substituted by ytterbium (Yb), erbium (Er), and thulium (Tm) using a hydrothermal reaction method. The synthesized YSZ:Yb–Er/Tm phosphors with different Yb3+ contents showed multi-line UCPL in the visible to NIR region due to Er3+ and Tm3+ ions under the laser irradiation at 980 nm; in particular, it showed strong UCPL at 800 nm originating from Tm3+. Furthermore, under the same excitation conditions, the phosphor exhibited not only UCPL but also DSPL due to 4I13/2 → 4I15/2 transition of Er3+ in the deeper NIR region of 1400–1700 nm. Interestingly, these DSPLs exhibit significant PL enhancement (anti-thermal quenching; anti-TQ) with increasing temperature. The thermometric properties based on the luminescence intensity ratio (LIR) of UCPL, which shows normal thermal quenching, and DSPL, which shows anti-thermal quenching, demonstrated excellent temperature sensitivity (Sr > 3% K−1 @ 283 K) and temperature resolution (δT < 0.1 K @ 283 K). This study suggests that the LIR thermometry technique using UCPL/DSPL, specifically anti-TQ/normal-TQ, can contribute to further advancements in luminescence-based temperature measurement. [ABSTRACT FROM AUTHOR]

All-optical thermometry based on laser-driven photoluminescence (PL) of germanium–vacancy (GeV−) centers in diamond is quantified in terms of a trade-off between temperature sensitivity and laser-induced heating. We show that the noise-floor sensitivity η T of the temperature readout from the GeV− PL return scales as (p Δ t) − 1 / 2 with the laser power p and detection time Δ t , allowing the temperature uncertainty to be reduced by increasing p and Δ t. This noise-floor reduction is, however, never penalty-free. Specifically, higher laser powers translate into higher temperatures of the diamond crystal. We demonstrate that the noise-floor as low as η T = 37.5 mK / Hz can be achieved with the laser power set at p = 6.30 mW. We also show that a further reduction of η T is possible at higher p. The experimental setting implemented in this study helps keep the level of heat released in a diamond crystal well below the typical level of microwave-induced heating in nitrogen-vacancy center-based thermometry, thus offering an advantageous approach for diamond-based thermometry in biological systems. [ABSTRACT FROM AUTHOR]

The Er3+/Yb3+ co‐doped tellurite glasses and glass‐ceramics (GCs) containing the Gd2Te6O15 phase were successfully fabricated via the conventional melting‐quenching technique followed by a crystallization regime. The Er3+/Yb3+ co‐doped tellurite glasses generated intense up‐conversion green (524 and 546 nm) and red (658 nm) emissions when stimulated by a 980 nm laser. The up‐conversion green emission intensity increased by 68 and 46 times with the increase of the Yb3+/Er3+ ratio, and the optimal Yb3+/Er3+ ratio was found to be 8:1. The surface crystallization process of the Gd2Te6O15 GCs was confirmed through analysis of crystallization kinetics and microscopic morphology. The up‐conversion luminescence and lifetime of Er3+ ions were enhanced by the precipitation of low‐phonon‐energy Gd2Te6O15 crystals. The GC sample crystallized at 480°C for 4 h showed the highest luminescence intensity. The optical thermometry properties of Er3+ ions at thermally coupled energy levels (2H11/2/4S3/2→4I15/2) were explored. The Gd2Te6O15 GCs co‐doped with 0.25 mol% Er2O3 and 2.0 mol% Yb2O3 exhibited an excellent temperature relative sensitivity (Sr) of 1.22% K−1 at 293 K and a great repeatability of 98.07%. These results suggest that the Er3+/Yb3+ co‐doped Gd2Te6O15 GCs show promise for optical thermometry. [ABSTRACT FROM AUTHOR]

Phosphors with multifunctional applications have attracted extensive research, especially in thermometer and anti‐counterfeiting fields. Herein, a series of Pr3+‐doped YNbO4 (YNO) phosphors with adjustable photoluminescence and red persistent luminescence (PersL) performances are developed. YNO host exhibits the blue self‐activated luminescence, and the different Pr3+ emission peaks possess various thermal stability properties due to the thermal quenching channel generated by the intervalence charge transfer state between Pr3+ and Nb5+ ions. Two kinds of fluorescence intensity ratio models with high absolute and relative sensitivities are realized to measure the temperature under dual‐wavelength excitation. Moreover, YNO:Pr3+ exhibits the red PersL with a duration of about 120 s upon ceasing the UV excitation light source. The fabricated YNO:Pr3+‐polydimethylsiloxane films display different luminescence patterns with the passage of time after turning off UV light, which can cleverly achieve dynamic conversion. These results demonstrate that YNO:Pr3+ phosphor has potential applications in dual‐wavelength excited thermometry and dynamic anti‐counterfeiting fields. [ABSTRACT FROM AUTHOR]

The high spatial resolution and contactless optical readout capabilities of luminescence thermometry offer significant advantages in numerous fields, including biomedicine, space exploration and optoelectronics. In addition, robust, reproducible, and accurate temperature measurements are essential in these areas. The ultra‐wide band gap semiconductor material Ga2O3 is a suitable host for optical sensing in harsh environments due to its high stability. In this work, the thermometric operation of Ga2O3:Cr‐based microcavities are evaluated. They are designed as follows: Ga2O3:Cr microwires are encapsulated in multilayers fabricated by atomic layer deposition (ALD), which act as both Bragg reflectors and protective layers for the thermometric sensor. Prior to the ALD encapsulation step, focused ion beam carved trenches at the microwire ends are necessary to accommodate the multilayer coating. The structural and optical properties of the devices are assessed experimentally, analytically and by simulations. The developed microthermometers can be easily calibrated using a cubic polynomial for the temperature‐dependent resonant peak position shift. A better than 0.5 °C temperature resolution and accuracy for temperatures above −80 °C is demonstrated. Additionally, the devices show robustness against excitation laser densities of at least 34 W mm−2, can operate at temperatures up to 600 °C and remain functional in liquids. [ABSTRACT FROM AUTHOR]

A multi-stimuli responsive fluorophore, named NBDNI, was developed by constructing a 1,8-naphthalimide derivative in which a rotatable electron-donating N,N-dimethylaniline group attached to its 4-position. This molecular structure endowed NBDNI with aggregate-induced emission (AIE) and twisted intramolecular charge transfer (TICT) properties, enabling remarkable fluorescence changes in response to multiple external stimuli: (i) sensitivity to polarity in various solvent systems and polymer matrix; (ii) significant fluorescence response and excellent linearity towards temperature changes in solution; (iii) distinct switch of fluorescence color upon acid and base treatments; (iv) reversible mechanochromism behavior in the solid state. Moreover, the mechanisms underlying the aforementioned stimuli-responsive phenomena have been proposed based on comprehensive systematic measurements. Furthermore, preliminary applications such as fluorescence thermometry and acid/base test paper have been demonstrated. This research will bring about new opportunities for the development of novel stimuli-responsive luminescent materials. [ABSTRACT FROM AUTHOR]

Real-time monitoring of temperature changes in substation equipment is crucial for preventing failures and ensuring a stable power supply. Currently, temperature monitoring of substation equipment primarily relies on manual infrared thermometry, which has limitations such as strong operational dependence, susceptibility to interference, and difficulty in detecting internal faults. The luminous intensity ratio (LIR) is a stable optical parameter unaffected by factors such as spectral loss and environmental influences, making it suitable for temperature detection. The multi-emission characteristics of rare-earth-doped upconversion (UC) materials are highly compatible with LIR technology, demonstrating their potential in high-precision temperature monitoring. Here we introduces a non-contact temperature monitoring method for substation equipment based on NaErF4@ NaYF4 core-shell UC materials and LIR technique. Experiments show that the method has high accuracy and sensitivity within temperature range of 25 °C to 225 °C, with a sensitivity as high as 35 x 10-3 °C-1, effectively monitoring temperature changes both inside and outside the equipment. This provides a new technical solution for temperature monitoring of substation equipment. [ABSTRACT FROM AUTHOR]

Remote thermal sensing has emerged as a temperature detection technique for tasks in which standard contact thermometers cannot be used due to environment or dimension limitations. One of such challenging tasks is the measurement of temperature in microelectronics. Here, optical thermometry using co-doped and mixed dual-center Gd2O3:Tb3+/Eu3+ samples were realized. Ratiometric approach based on monitoring emission intensities of Tb3+ (5D4–7F5) and Eu3+ (5D0–7F2) transition provided sensing in the range of 30 °C–80 °C. Dispersion system type only slightly affected relative sensitivity, accuracy and precision. The applicability of phosphors synthesized to be utilized as remote optical thermometers for microelectronics has been proved with an example on a surface mount resistor and microcontroller. [ABSTRACT FROM AUTHOR]

Numerous body locations have been utilized to obtain an accurate body temperature. While some are commonly used, their accuracy, response time, invasiveness varies greatly, and determines their potential clinical and/or research use. This review discusses human body temperature locations, their accuracy, ease of use, advantages, and drawbacks. We explain the concept of core body temperature and which of the locations achieve the best correlation to this temperature. The body locations include axilla, oral cavity, rectum, digestive and urinary tracts, skin, tympanic, nasopharynx, esophagus, and pulmonary artery. The review also discusses the latest temperature technologies, heat‐flux technology and telemetric ingestible temperature pills, and the body locations used to validate these devices. Rectal and esophageal measurements are the most frequently used. [ABSTRACT FROM AUTHOR]

Distinguishing between microscopic variances in temperature in both space and time with high precision can open up new opportunities in optical sensing. In this paper, we present a novel approach to optically measure temperature from the fluorescence of erbium:ytterbium doped tellurite glass, with fast temporal resolution at micron-scale localisation over an area with sub millimetre spatial dimensions. This confocal-based approach provides a micron-scale image of temperature variations over a 200 μ m × 200 μ m field of view at sub-1 second time intervals. We test our sensing platform by monitoring the real-time evaporation of a water droplet over a wide field of view and track it's evaporative cooling effect on the glass where we report a net temperature change of 6.97 K ± 0.03 K. This result showcases a confocal approach to thermometry to provide high temporal and spatial resolution over a microscopic field of view with the goal of providing real-time measures of temperature on the micro-scale. [ABSTRACT FROM AUTHOR]

Multiphase phosphors have garnered increased attention for their notable photothermal sensing properties. The temperature sensitivity of multiphase composites is significantly influenced by heat treatment, which impacts the interfacial diffusion of emitting centers. This study delved into the structural and optical properties of ZnAl 2 O 4 :Eu3+-ZnTiO 3 :Mn4+ composites with varying annealing temperatures. Distinct photoluminescence spectra of Eu3+ were observed in ZnAl 2 O 4 matrix, accompanied by a robust emission band corresponding to the 2E g → 4A 2g transition of Mn4+ in cubic ZnTiO 3 crystals. Notably, a sharp emission band at 714 nm emerged as the measurement temperature decreased, which is attributed to Mn4+ in hexagonal ilmenite ZnTiO 3. The emission intensity of Mn4+ in mixed phosphors decreased with increasing annealing temperature. The temperature dependence of emission peaks was investigated in two temperature regions of 80–260 K and 300–390 K for the ZnAl 2 O 4 :Eu3+-ZnTiO 3 :Mn4+ mixed phosphors with varying annealing temperatures. A second heat treatment at different temperature significantly influenced the optical properties associated with Eu3+ and Mn4+. In low temperature region, the highest temperature relative sensitivity reached 2.83% K−1 @230 K for the composites annealed at 1073 K. In high temperature region, the maximum relative sensitivity of 4.86% K−1@300 K was achieved based on the FIR of I 614 nm /I Mn 4+ in both the as-synthesized composites and those annealed at 1073 K. All the phosphors demonstrated excellent repeatability over 15 recycles. The findings suggested that ZnAl 2 O 4 :Eu3+-ZnTiO 3 :Mn4+ mixed phosphors had significant potential applications in optical thermometers. [ABSTRACT FROM AUTHOR]

The metrological limits of thermometry operated in nonequilibrium dynamical regimes are analyzed. We consider a finite-dimensional quantum system, employed as a quantum thermometer, in contact with a thermal bath inducing Markovian thermalization dynamics. The quantum thermometer is initialized in a generic quantum state, possibly including quantum coherence with respect to the Hamiltonian basis. We prove that the precision of the thermometer, quantified by the Quantum Fisher Information, is enhanced by the quantum coherence in its initial state. We analytically show this in the specific case of qubit thermometers for which the maximization of the Quantum Fisher Information occurs at a finite time during the transient thermalization dynamics. Such a finite-time precision enhancement can be better than the precision that is achieved asymptotically. [ABSTRACT FROM AUTHOR]

Proton resonance frequency shift (PRFS) MR thermometry is the most common method used in clinical thermal treatments because of its fast acquisition and high sensitivity to temperature. However, motion is the biggest obstacle in PRFS MR thermometry for monitoring thermal treatment in moving organs. This challenge arises because of the introduction of phase errors into the PRFS calculation through multiple methods, such as image misregistration, susceptibility changes in the magnetic field, and intraframe motion during MRI acquisition. Various approaches for motion correction have been developed for real‐time, motion‐robust, and volumetric MR thermometry. However, current technologies have inherent trade‐offs among volume coverage, processing time, and temperature accuracy. These tradeoffs should be considered and chosen according to the thermal treatment application. In hyperthermia treatment, precise temperature measurements are of increased importance rather than the requirement for exceedingly high temporal resolution. In contrast, ablation procedures require robust temporal resolution to accurately capture a rapid temperature rise. This paper presents a comprehensive review of current cutting‐edge MRI techniques for motion‐robust MR thermometry, and recommends which techniques are better suited for each thermal treatment. We expect that this study will help discern the selection of motion‐robust MR thermometry strategies and inspire the development of motion‐robust volumetric MR thermometry for practical use in clinics. [ABSTRACT FROM AUTHOR]

BACKGROUND: T2-weighted Single Shot Fast Spin Echo (SSFSE) scans at 3 Tesla (3T) are increasingly used to image fetal pathology due to their excellent tissue contrast resolution and signal-to-noise ratio (SNR). Temperature changes that may occur in response to radio frequency (RF) pulses used for these sequences at 3T have not been studied in human fetal brains. To evaluate the safety of T2-weighted SSFSE for fetal brains at 3T, magnetic resonance (MR) thermometry was used to measure relative temperature changes in a typical clinical fetal brain MR exam. METHODS: Relative temperature was estimated using sets of gradient recalled echo (GRE) images acquired before and after T2-weighted SSFSE images which lasted 27.47±8.19 minutes. Thirty-one fetuses with cardiac abnormalities, and 20 healthy controls were included in this study. Fetal brain temperature was estimated by proton resonance frequency (PRF) thermometry and compared to the estimated temperature in the gluteal muscle of the mother. Seven scans with excessive motion were excluded. Local outlier factor (LOF) was performed to remove 12 additional scans with spurious phase measurements due to motion degradation and potential field drift. Linear regression was performed to determine if temperature changes are dependent on the rate of energy deposition during the scan. RESULTS: For the 32 participants used in the analysis, 17 with cardiac abnormalities and 15 healthy controls, the average relative fetal temperate change was 0.19±0.73 ℃ higher than the mother, with no correlation between relative temperature change and the rate of images acquired during the scans (regression coefficient =-0.05, R-squared =0.05, P=0.22, F-statistic =1.60). The difference in the relative temperature changes between the fetal brain and mothers gluteal tissue in the healthy controls was on average 0.08 ℃ lower and found not to be statistically different (P=0.76) to the group with cardiac abnormalities. CONCLUSIONS: Our results indicate that the estimated relative temperature changes of the fetal brain compared to the mothers gluteal tissue from RF pulses during the course of the T2-weighted SSFSE fetal MR exam are minimal. The differences in acquired phase between these regions through the exam were found not to be statistically different. These findings support that fetal brain imaging at 3T is within FDA limits and safe.

Since dissipative processes are ubiquitous in semiconductors, characterizing how electronic and thermal energy transduce and transport at the nanoscale is vital for understanding and leveraging their fundamental properties. For example, in low-dimensional transition metal dichalcogenides (TMDCs), excess heat generation upon photoexcitation is difficult to avoid since even with modest injected exciton densities exciton-exciton annihilation still occurs. Both heat and photoexcited electronic species imprint transient changes in the optical response of a semiconductor, yet the distinct signatures of each are difficult to disentangle in typical spectra due to overlapping resonances. In response, we employ stroboscopic optical scattering microscopy (stroboSCAT) to simultaneously map both heat and exciton populations in few-layer MoS2 on relevant nanometer and picosecond length- and time scales and with 100-mK temperature sensitivity. We discern excitonic contributions to the signal from heat by combining observations close to and far from exciton resonances, characterizing the photoinduced dynamics for each. Our approach is general and can be applied to any electronic material, including thermoelectrics, where heat and electronic observables spatially interplay, and it will enable direct and quantitative discernment of different types of coexisting energy without recourse to complex models or underlying assumptions.

Background: Fever remains a common clinical indicator of disease, accounting alone for over 25% of paediatric emergency rooms consultations. Perception of this important sign is a crucial prelude and determinant of outcome in febrile children. The aim was to determine knowledge and attitudes of parents regarding fever in their children. Methods: The study is a crosssectional descriptive study carried out at the Emergency Paediatric Unit of the University of Ilorin Teaching Hospital (UITH). Fourhundred under-five children presenting with fever were recruited along with their caregivers. A semi-structured questionnaire was administered to collect information on sociodemographics, and caregiver’s knowledge and attitudes regarding fever in their wards. Results: The mean age of the caregivers was 29.5 ± 4.46 years (Range 21 – 41 years). Only 30.3% of caregivers could correctly describe what fever was. The most frequently utilised fever detection method was tactile assessment. Only 3.2% of the caregivers used a thermometer to detect fever. Social class, maternal age and religion significantly influenced the decision to use thermometers. The most common remedies caregivers would use for fever in their children were to give paracetamol (96.3%), sponging (73.2%) and a warm bath (63.8%). About 61% of caregivers had a wrong perception of the possible complications of fever. Conclusions: Caregivers in this study had a poor knowledge of fever, and parental educational and socioeconomic status impacted on their responses to fever. There is a need for education of caregivers at all contacts with the healthcare system on fever, and its management.

As the demand for computing applications capable of processing large datasets increases, there is a growing need for new in-memory computing technologies. Oxide-based resistive random-access memory (RRAM) devices are promising candidates for such applications because of their industry readiness, endurance, and switching ratio. These analog devices, however, suffer from poor linearity and asymmetry in their analog resistance change. Various reports have found that the temperature in RRAM devices increases locally by more than 1000 K during operation. Therefore, temperature control is of paramount importance for controlling their resistance. In this study, scanning thermal microscopy is used to map the temperature of Au/Ti/HfOx/Au devices at a steady power state and to measure temperature dynamics of the top electrode above the filament location during both resistive switching loops and voltage pulsing. These measurements are used to verify the thermal parameters of a multiphysics finite elements model. The model is then used to understand the impact of thermal conductivities and boundary conductances of constituent materials on resistance change during the first reset pulse in RRAM devices. It is found that the resistance change can be reduced significantly when the temperature in the titanium capping layer is reduced. We find that the greatest temperature reduction and, therefore, the lowest resistance change in the device are afforded by capping layers with increased thermal conductivities. This work links thermal properties to the resistance change in RRAM devices, providing critical insights into engineering devices with improved switching dynamics. [ABSTRACT FROM AUTHOR]

In this study, a solid-state reaction was employed to synthesize SrY 2 O 4 : Sm3+, SrY 2 O 4 : Eu3+ and SrY 2 O 4 : Sm3+/Eu3+ phosphors. An intriguing redshift phenomenon from charge transfer band (CTB) edge was investigated for single-band ratiometric (SBR) thermometry applications. The phosphors synthesized exhibited an orthogonal CaFe 2 O 4 structure with Pnam (62) space group. The Y3+ sites from host lattice were most likely to be replaced by Sm3+/Eu3+ ions. The sample of SrY 2 O 4 : 0.03 Sm3+/0.3Eu3+ showed a large degree of agglomeration with elongated particles, having an average size of approximately 4 μm. The energy bandgap decreased due to increased surface imperfections, resulting in enhanced defect level concentration. The dipole-dipole interaction could be used to explain energy transfer (ET) of Sm3+-Sm3+ and Sm3+-Eu3+. Furthermore, the energy transfer (ET) efficiency of Sm3+→Eu3+ in Sr 2 YO 4 reached 77.7 %. The sample exhibited a good thermal stability (90.956 %@423 K) with E a of 0.31 eV, which was an important parameter for broadening thermometry range. A thermometry strategy utilized this redshift phenomenon from CTB edge with anti-thermal quenching behavior and other peaks or bands with thermal quenching was therefore proposed. The high S r value of 1.533 % K−1@298 K provides a great potential for optical thermometry application, contributing significantly to the advancement of single band ratiometric thermometry technologies. [ABSTRACT FROM AUTHOR]

Fluorescence intensity ratio (FIR) thermometers have obtained great attention in industrial production, medical diagnosis and scientific research. However, the sensitivity has a large decline at high temperatures, which seriously limits the practical applications. Here, the Yb,Er,Tm:Sc 2 O 3 single crystal fibers were grown by laser-heated pedestal growth (LHPG) technique and its multi-mode FIR thermometry based on thermal coupled energy levels (TCLs) and non-thermal coupled energy levels (NTCLs) has been well demonstrated. The temperature measuring range of Yb,Er,Tm:Sc 2 O 3 single crystal fibers covers 298–973 K, with an increase of 2 orders of magnitude in absolute sensitivity. The relative sensitivity is higher than 0.02 % K−1 in the whole T-range of 298∼973 K, with a maximum value of 1.02 % K−1. Especially at the high temperatures of 973 K, it can still maintain 0.31 % K−1. This work proposes an innovative fluorescence intensity ratio detection strategy to achieve complementary disadvantages between TCLs and NTCLs and provides an effective method for improving detection sensitivity. [ABSTRACT FROM AUTHOR]

Aim: Agar-based phantoms are popular in high intensity focused ultrasound (HIFU) studies, with magnetic resonance imaging (MRI) preferred for guidance since it provides temperature monitoring by proton resonance frequency (PRF) shift magnetic resonance (MR) thermometry. MR thermometry monitoring depends on several factors, thus, herein, the PRF coefficient of agar phantoms was estimated. Materials and Methods: Seven phantoms were developed with varied agar (2, 4, or 6% w/v) or constant agar (6% w/v) and varied silica concentrations (2, 4, 6, or 8% w/v) to assess the effect of the concentration on the PRF coefficient. Each phantom was sonicated using varied acoustical power for a 30 s duration in both a laboratory setting and inside a 3T MRI scanner. PRF coefficients were estimated through linear trends between phase shift acquired using gradient sequences and thermocouple-based temperatures changes. Results: Linear regression (R2 = 0.9707–0.9991) demonstrated a proportional dependency of phase shift with temperature change, resulting in PRF coefficients between −0.00336 ± 0.00029 and −0.00934 ± 0.00050 ppm/°C for the various phantom recipes. Weak negative linear correlations of the PRF coefficient were observed with increased agar. With silica concentrations, the negative linear correlation was strong. For all phantoms, calibrated PRF coefficients resulted in 1.01–3.01-fold higher temperature changes compared to the values calculated using a literature PRF coefficient. Conclusions: Phantoms developed with a 6% w/v agar concentration and doped with 0%–8% w/v silica best resemble tissue PRF coefficients and should be preferred in HIFU studies. The estimated PRF coefficients can result in enhanced MR thermometry monitoring and evaluation of HIFU protocols.

Yb3+/Er3+-doped Bi2(MoO4)3−z(WO4)z phosphors were synthesized via a hydrothermal method combined with subsequent calcination. Under the excitation of a light source of 980 nm, Bi2(MoO4)3:Yb3+/Er3+ phosphors exhibited strong upconversion green light and weak red light emissions. By doping WO42− in Bi2(MoO4)3:Yb3+/Er3+ phosphors, the upconversion luminescence intensity of the phosphors significantly enhanced, which is 42 times higher than that of the undoped WO42− phosphor. With an increase in WO42− doping content, the final color coordinates of Bi2(MoO4)3−z(WO4)z:Yb3+/Er3+ phosphors were (0.2352, 0.7274), which is closer to the standard green CIE coordinates. The maximum CP of WO42−-doped phosphors is as high as 116.68%, which is 74.44% higher than that of the undoped WO42− phosphor. Based on the thermally coupled energy levels (TCLs) of Er3+ (2H11/2/4S3/2 → 4I15/2) in Bi2(MoO4)2.7(WO4)0.3:14%Yb3+,3%Er3+ phosphor, the SR value reached a maximum of 0.0081 K−1 at 323 K and the SA value reached a maximum of 0.0099 K−1 at 398 K. The obtained Bi2(MoO4)3−z(WO4)z:Yb3+/Er3+ phosphors are suitable for upconversion luminescent materials for green displays and have potential advantages in optical temperature measurement. [ABSTRACT FROM AUTHOR]

Temperature‐responsive dynamics of excited‐state population in terbium (Tb) ions may open the door for the advancement of high‐performance photothermal feedback windows. However, obtaining robust luminescence and superior transparency in Tb‐doped ceramics continues to pose a formidable challenge, leaving them far away from photonic application. Here, to fill this important gap, the demonstration of Tb doped transparent ceramics for luminescent thermometric windows is reported. Y2Zr2O7:Tb (YZO:Tb) ceramics are used as an illustrative example. After a sequence of thermal treatments, the defect centers F/F+ and defect clusters [TbY4+−O2−−TbY4+$Tb_{\mathrm{Y}}^{{{4}^ + }} - {{O}^{2 - }} - Tb_{\mathrm{Y}}^{{{4}^ + }}$] and [TbY4+−e•$Tb_{\mathrm{Y}}^{{{4}^ + }} - {{e}^ \bullet }$] in these YZO:Tb transparent ceramics are eliminated, resulting in a notable enhancement of their in‐line transmittance from 71% to 76%, making it close to the theoretical limit. Moreover, the corresponding photoluminescence increased significantly, reaching a factor of 296 times. Furthermore, a temperature feedback window is designed using the excitation intensity ratio (EIR) or single‐band luminescence intensity ratio (SBLIR) mode, which presents high sensitivity (1.04%) and high repeatability (98%). This work not only provides a paradigm in the application of the Tb doped transparent ceramics for temperature sensing windows, but also suggests a pathway to build efficient thermometers based on excited state population deployment in window systems. [ABSTRACT FROM AUTHOR]

3D printing constitutes a technological advancement, revolutionizing contemporary industry by enabling manufacturers to fabricate intricate, customized components efficiently and precisely from digital blueprints. Moreover, the fusion of 3D printing with cutting‐edge materials has given rise to compelling elements boasting a diverse range of applications. For this reason, this work describes the incorporation of a luminescent material, NaYF4, doped with Yb3+ and Er3+, embedded in resin for 3D printing to create motorized luminescent gears. The fabricated luminescent gears take advantage of the intensity ratio between the Er3+ emissions at 525 nm (2H11/2 → 4I15/2) and 550 nm (4S3/2 → 4I15/2), which are thermally coupled, to detect the slight temperature variations that gears undergo through friction. This technique can be complementary to thermovision, proving especially valuable for monitoring temperature in elements where measurement with thermographic cameras or direct contact thermometers is hampered. The findings demonstrate that optical measurements provide enhanced (statistical) precision in temperature readings compared to thermovision, with δT = 0.07 K for luminescence thermometry as opposed to δT = 0.3 K for the thermal camera. This work can inspire new research directions using 3D printing and materials with exciting properties, fostering innovative solutions in contemporary industrial technologies. [ABSTRACT FROM AUTHOR]

The SC‐YAG:Tb@YAG:Pr‐SCF composite epitaxial structure consisting of a 1 mm thick single crystal substrate of YAG:Tb garnet and a thin (9 µm) single crystalline film of YAG:Pr garnet is fabricated, and its luminescent properties are examined toward luminescence thermometry. The possibility to efficiently excite, individually or simultaneously, the Tb3+ and Pr3+ dopants by their intense allowed 4f→5d transitions is executed to reach relative thermal sensitivity higher than 1% K−1 over the range of temperatures as wide as 100–625 K and above 0.5% K−1 over 13–650 K. The obtained results demonstrate that using intra‐ and inter‐configurational emission transitions of Pr3+ and other lanthanides makes it possible to design wide‐range luminescence thermometers with high sensitivity spanning the entire operating limits. [ABSTRACT FROM AUTHOR]

Near-white emission phosphors of the Bi3+/Sm3+ co-doped double-perovskite Ca 2 YTaO 6 were successfully prepared via a simple solid-state reaction. The crystal structures and lattice parameters as functions of doping ion type and its content were analyzed. Note that all the prepared samples have the monoclinic structure with the space group of P 21/n (14). Their lattice parameters were enlarged with the increment of doping ion content since the Y3+ ion with the smaller radius was substituted by the Bi3+ and Sm3+ ions. The photoluminescence (PL) properties of single Bi3+-doped and Bi3+/Sm3+ co-doped Ca 2 YTaO 6 phosphors were fully investigated in terms of PL emission spectrum, emission intensity, energy transfer mechanism, chromaticity coordinate, decay curve, thermal stability, and internal quantum yield. Interestingly, the Ca 2 YTaO 6 :0.015Bi3+/0.07Sm3+ phosphor exhibited a high quantum yield (70.71%). Furthermore, the relative sensitivity based on the dual-emission centers (Bi3+ and Sm3+) was also analyzed. It is demonstrated that high-efficiency near-white Ca 2 YTaO 6 :Bi3+/Sm3+ phosphor with good sensing properties is expected to be a candidate in the field of optical thermometry. [ABSTRACT FROM AUTHOR]

Rare earth doped luminescent sensing materials as non-contact thermometers have attracted extensive research interests due to their wide applications in areas like military, medical care, aerospace, etc. How to expand the working temperature range and improve the sensitivity has become the focus. In this work, we synthesized a series of apatite-structured luminescent temperature sensors M 2 La 7.9 Ce 0.1 (SiO 4) 6 O 2 (M = Ca, Sr, Ba) via isomorphic substitution. By monitoring the differential changes of emission intensities from Ce3+ at the 7-coordinate and 9-coordinate site respectively when temperature varies, the real-time temperature can be determined. These materials were proven to possess the maximum absolute sensitivity up to 0.825 × 10−3 K−1, 2.63 × 10−3 K−1 and 4.33 × 10−3 K−1, respectively. Meanwhile interesting regular patterns were observed for their temperature sensitivities with the substitution of Ca, Sr and Ba. Furthermore, through studying the temperature sensitivity of Ba 2 La 8 (SiO 4) 6 O 2 : x Ce3+ samples with different concentrations, it was found that when the Ce3+ content was at the optimal doping concentration of 0.7, the absolute sensitivity of the sample reached 14.64 × 10−3 K−1 at 573 K. This finding has opened up a new avenue for designing fluorescent temperature sensors. Synopsis: In this work, Ce3+ were doped into a series of phosphor-structured matrices containing two cationic sites (7-coordinated Ce1 and 9-coordinated Ce2 sites) via the solid-state high-temperature method. Due to the different temperature dependencies of luminescence intensities between the two Ce3+ sites, their intensity ratio could be used for temperature calibration. [Display omitted] [ABSTRACT FROM AUTHOR]

The accuracy and efficacy of laser ablation procedures depend on the accurate placement of the laser applicator within the diseased tissue, monitoring the real-time temperature during the ablation procedure, and mapping the extent of the ablated region. Ultrasound (US) imaging has been widely used to guide ablation procedures. While US imaging offers significant advantages for guiding ablation procedures, its limitations include low imaging contrast, angular dependency, and limited ability to monitor the temperature. Photoacoustic (PA) imaging is a relatively new imaging modality that inherits the advantages of US imaging and offers enhanced capabilities for laser-guided ablations, such as accurate, angle-independent tracking of ablation catheters, the potential for quantitative thermometry, and monitoring thermal lesion formation. This work provides an overview of ultrasound-guided procedures and how different US-related artifacts limit their utility, followed by introducing PA as complementary to US as a solution to address the existing limitations and improve ablation outcomes. Furthermore, we highlight the integration of PA-driven features into existing US-guided laser ablation systems, along with their limitations and future outlooks. Integrated US/PA-guided laser ablation procedures can lead to safer and more precise treatment outcomes. [ABSTRACT FROM AUTHOR]

Measuring temperature inside chemical reactors is crucial to ensuring process control and safety. However, conventional methods face a number of limitations, such as the invasiveness and the restricted dynamic range. This paper presents a novel approach using ultrasound transducers to enable accurate temperature measurements. Our experiments, conducted within a temperature range of 28.8 to 83.8 °C, reveal a minimal temperature accuracy of 98.6% within the critical zone spanning between 70.5 and 75 °C, and an accuracy of over 99% outside this critical zone. The experiments focused on a homogeneous environment of distilled water within a stainless-steel tank. This approach will be extended in a future research in order to diversify the experimental media and non-uniform environments, while promising broader applications in chemical process monitoring and control. [ABSTRACT FROM AUTHOR]

Taupō volcanic zone, the site of the 26 ka Oruanui supereruption, produced ~70 km3 of new rhyolites since 11 ka, culminating in 50 km3 Taupō eruption 1.8 ka. Major phenocrysts decrease from 4 to 1 vol%, and Oruanui and post-Oruanui ignimbrites all have identical high-δ18Omelt values of 7.39 ± 0.1‰ and lack low-δ18O values despite overlapping calderas. The Δ'17O values are −0.07‰, lower than the mantle and indicate source contamination of high-δ18O, low-Δ'17O metasediments, and limited interaction with high-Δ'17O hydrothermally altered crust. Previously published U-Th-Pb zircon ages demonstrate their diversity spanning 104–105 years for each unit. Zircon crystal size distribution shows a decrease in abundance and the mean size, and some units lack small (<~10 um) zircons suggesting that zircons were both growing and dissolving in the coexisting magma generation areas. Isotope thermometry indicates heating of the system from ~812 ± 35°C to 874 ± 36°C past zircon saturation in 1.8 ka eruption. We advocate that a deep vertically continuous and laterally discontinuous silicic magma system at the base of the Taupō rift, rather than a shallow batholith or an evolving mush, drives volcanism at Taupō. To explain the post-Oruanui magma production, rift-base silicic magma origin and moderate (~2 km3/1000 years) rhyodacitic magma flux from a growing and heating liquid magma body creates a sufficient solution for the most recent magmatism. [ABSTRACT FROM AUTHOR]

A series of Er3+ ions doped Sr9Y2W4O24 (SYW) phosphors have been synthesised using solid‐state reaction technique. For optical thermometry and solid state lighting applications, the crystal structure, morphological, and luminescence features of the SYW : Er3+ phosphors were explored. X‐ray diffraction (XRD) reveal that synthesized phosphors having single phase with a tetragonal crystal structure and I41/a space group. Scanning electron microscopy (SEM) was used to examine the morphological behaviour and presence of composition elements. The optical bandgap of the phosphor was evaluated using UV‐Vis diffuse reflection spectra (DRS). The photoluminescence (PL) emission spectra were captured under 380 nm excitation, and the peak with the maximum intensity was identified at 563 nm ascribed to transition 4S3/2→4I15/2, that emits green color in visible region. The temperature dependent PL (TD‐PL) spectra show that SYW phosphor is substantially more thermally stable, having thermal activation energy of about 0.247 eV. Additionally, the fluorescence intensity ratio (FIR) was used to study the optical sensing characteristics of the thermal quenching transitions (2H11/2, 4S3/2) with maximum relative sensitivity (SR) and an absolute sensitivity (SA) being 1.33 % K−1and 0.307 % K−1, respectively. All of the aforementioned findings demonstrate that SYW : Er3+ ions doped phosphors have potential for optical thermometry and other photonic devices. [ABSTRACT FROM AUTHOR]

In this work, we report on the synthesis and investigation of new hybrid multifunctional iron oxide nanoparticles (IONPs) coated by coumarin-bound copolymer, which combine magneto- or photothermal heating with luminescent thermometry. A series of amphiphilic block copolymers, including Coum-C11-PPhOx27-PMOx59 and Coum-C11-PButOx8-PMOx42 bearing luminescent and photodimerizable coumarin moiety, as well as coumarin-free PPhOx27-PMOx57, were evaluated for their utility as luminescent thermometers and for encapsulating spherical 26 nm IONPs. The obtained IONP@Coum-C11-PPhOx27-PMOx59 nano-objects are perfectly dispersible in water and able to provide macroscopic heating remotely triggered by an alternating current magnetic field (AMF) with a specific absorption rate (SAR) value of 240 W.g−1 or laser irradiation with a photothermal conversion efficiency of η = 68%. On the other hand, they exhibit temperature-dependent emission of coumarin offering the function of luminescent thermometer, which operates in the visible region between 20 °C and 60 °C in water displaying a maximal relative thermal sensitivity (Sr) of 1.53%·°C−1 at 60 °C. [ABSTRACT FROM AUTHOR]

Accurate on-chip temperature sensing is critical for the optimal performance of modern complementary metal-oxide-semiconductor (CMOS) integrated circuits (ICs), to understand and monitor localized heating around the chip during operation. The development of quantum computers has stimulated much interest in ICs operating at deep cryogenic temperatures (typically 0.01–4 K), in which the reduced thermal conductivity of silicon and silicon oxide and the limited cooling power budgets make local on-chip temperature sensing even more important. Here, we report four different methods for on-chip temperature measurements native to CMOS industrial fabrication processes. These include secondary and primary thermometry methods and cover conventional thermometry structures used at room temperature as well as methods exploiting phenomena that emerge at cryogenic temperatures, such as superconductivity and Coulomb blockade. We benchmark the sensitivity of the methods as a function of temperature and use them to measure local excess temperature produced by on-chip heating elements. Our results demonstrate thermometry methods that may be readily integrated in CMOS chips with operation from the millikelvin range to room temperature. [ABSTRACT FROM AUTHOR]

Due to the incorrect speciation of iron during thermometry modelling, Coulthard et al. (2024) produced an incorrect olivine‐liquid equilibrium diagram, which failed to identify multiple potential equilibrium olivine‐melt pairs. With the new pairs identified here, the temperatures inferred from olivine‐groundmass pairs move closer in temperature space to those inferred from olivine‐glass pairs. Additionally, it is recognised that the most significant difference between these thermometry data is due to differences in inferred melt water mass fraction. If a mean value of water is used for all thermometry, the mean temperatures calculated for olivine‐glass and olivine‐groundmass pairs converge to within 10 °C of one another. This indicates that groundmass compositions inferred via the defocused beam analysis of a polyphase groundmass may reproduce enough information to confidently perform olivine‐melt thermometry despite the glass and groundmass data representing significantly different compositions in multivariate space. [ABSTRACT FROM AUTHOR]

Polyphase groundmasses (micro‐scale minerals with or without glass) are generated from silicate liquids during the cooling of natural lavas often alongside larger minerals formed long before eruption. Many researchers have posited that compositions gleaned from the analysis of groundmasses closely approximate the compositions of the melts they were derived from, and these have been used frequently to model pre‐eruptive magma conditions. However, it is difficult to confidently identify and sample these groundmasses once they are formed. Using a sample of lava that exhibits a wide degree of textural variation (ranging from holocrystalline to hypohyaline) we show that compositions of groundmasses sampled using defocused electron beams are significantly different from glass compositions in terms of mean composition and covariance. Despite this, several groundmass compositions qualify as 'in equilibrium' with matrix/rim olivine. When processed using available thermometers, however, modelled equilibrium temperatures are significantly higher than those produced using glass data, on average. Because of this, we prescribe caution in using polyphase groundmass data generated using defocused beam analysis even as a rudimentary approach. [ABSTRACT FROM AUTHOR]

The Sm3+-doped Y 2 MgTiO 6 phosphor was successfully synthesized by high-temperature solid-phase method. X-ray diffraction, photoelectron spectroscopy and scanning electron microscopy characterized the phase, electronic structure and morphology. Meanwhile, the luminescence properties were analyzed, and the results showed that the Y 2 MgTiO 6 :Sm3+ phosphors emit vibrant orange light when excited at 407 nm, with emission peaks at 565 nm, 603 nm, and 649 nm. The luminescence efficiency of the sample reaches 79.71% of the initial intensity at 423 K. The temperature sensing properties of Y 2 MgTiO 6 :Sm3+ phosphors were investigated between different wavelength bands based on the fluorescence intensity ratio (FIR) technique, where FIR (I 565 /I 649) had the maximum relative sensitivity of 0.26% K−1 at 298K. The quantum yield of the sample was 59.88%, with calculated Correlated Color Temperature of 1646 K. The research results suggest that Y 2 MgTiO 6 :Sm3+ phosphors have potential applications in optical temperature sensing and w-LEDs devices. [ABSTRACT FROM AUTHOR]

In this work, we present a compact, bifunctional chip-based sensor setup that measures the temperature and electrical conductivity of water samples, including specimens from rivers and channels, aquaculture, and the Atlantic Ocean. For conductivity measurements, we utilize the impedance amplitude recorded via interdigitated electrode structures at a single triggering frequency. The results are well in line with data obtained using a calibrated reference instrument. The new setup holds for conductivity values spanning almost two orders of magnitude (river versus ocean water) without the need for equivalent circuit modelling. Temperature measurements were performed in four-point geometry with an on-chip platinum RTD (resistance temperature detector) in the temperature range between 2 °C and 40 °C, showing no hysteresis effects between warming and cooling cycles. Although the meander was not shielded against the liquid, the temperature calibration provided equivalent results to low conductive Milli-Q and highly conductive ocean water. The sensor is therefore suitable for inline and online monitoring purposes in recirculating aquaculture systems. [ABSTRACT FROM AUTHOR]

Purpose: A hybrid principal component analysis and projection onto dipole fields (PCA-PDF) MR thermometry motion compensation algorithm was optimized with atlas image augmentation and validated. Methods: Experiments were conducted on a 3T Philips MRI and Profound V1 Sonalleve high intensity focused ultrasound (high intensity focused ultrasound system. An MR-compatible robot was configured to induce motion on custom gelatin phantoms. Trials with periodic and sporadic motion were introduced on phantoms while hyperthermia was administered. The PCA-PDF algorithm was augmented with a predictive atlas to better compensate for larger sporadic motion. Results: During periodic motion, the temperature SD in the thermometry was improved from 1.1 ± 0.1 to 0.5 ± 0.1°C with both the original and augmented PCA-PDF application. For large sporadic motion, the augmented atlas improved the motion compensation from the original PCA-PDF correction from 8.8 ± 0.5 to 0.7 ± 0.1°C. Conclusion: The PCA-PDF algorithm improved temperature accuracy to <1°C during periodic motion, butwas not able to adequately address sporadicmotion. By augmenting the PCA-PDF algorithm, temperature SD during large sporadic motion was also reduced to <1°C, greatly improving the original PCA-PDF algorithm. [ABSTRACT FROM AUTHOR]

Metabasites are important constituents of deep crustal sections and are the favored rock type for studying lower crustal amphibolite to granulite transitions. However, metapelites may develop a larger number of temperature-sensitive mineral assemblages and are particular useful when extreme ultrahigh temperature (UHT) conditions are envisaged. A recent calibration of the Ti-in-amphibole thermometer by Liao et al. (2021) was supposed to make thermometry on metabasites quick and easy to apply. However, their calibration is based on experiments which were not originally designed to investigate in detail the temperature dependence of Ti in amphibole. In addition, a possible effect of aTiO2 and/or pressure on the Ti content of amphibole was not fully taken into account. This resulted in a calibration uncertainty of ± 70 °C (2σ), much higher than that of other single-mineral thermometers. In this study we firstly test the newly calibrated Ti-in-amphibole thermometer across the mid to lower crustal section of the Ivrea–Verbano Zone (IVZ; NW Italy) and compare the performance of different thermometric techniques across the sequence. Ti-in-amphibole thermometry records increasing peak temperatures from amphibolite (600–700 °C), transition (750–800 °C) and granulite (850–950 °C) zones. Titanium content of amphibole may be modified by retrograde fluid influx returning temperatures c. 200–300 °C lower than in non-altered domains. The comparison reveals that Zr-in-rutile thermometer in pelitic granulites seems to be more prone to post-peak resetting than the Ti-in-amphibole thermometry in nearby mafic rocks. This behavior is also confirmed by amphibole analyses from other UHT localities, where the performance of Ti-in-amphibole thermometry is comparable with that of Al-in-orthopyroxene in pelitic granulites. However, Ti-in-amphibole temperatures are underestimated in rutile-bearing samples and this limitation is not solely restricted to rocks containing high H2O contents as previously thought. Derived constraints on the diffusivity of Ti through amphibole demonstrate the robustness of the Ti-in-amphibole thermometer to later thermal disturbances. However, ad-hoc experiments are still necessary to improve the accuracy and precision of calibration and to extend its applicability. This advance will make mafic granulites routine targets for studies devoted to understanding the regional extent of UHT metamorphism. [ABSTRACT FROM AUTHOR]

Tectonic mélanges, characterized by conditions reflective of modern subduction fault zones, preserve mineral veins formed through mass transfer, a mechanism influencing the slip behavior of subduction megathrusts. In this study, we apply secondary ion mass spectrometry quartz‐calcite oxygen isotope thermometry and clumped isotope thermometry to examine the temperatures of vein formations in six mélange units in the Cretaceous Shimanto belt and one mélange in the Kodiak accretionary prism. Calcite in the veins exhibits δ13CPDB values ranging from −17.2‰ to −6.8‰, indicative of a carbon source mixing with sedimentary carbonate and organic matter. δ18OSMOW values of calcite range from +11.1‰ to +17.2‰; quartz yields δ18OSMOW values of +14.9‰ to +21.7‰. Oxygen isotopic signatures in minerals reveal that most vein‐forming fluids are significantly affected by rock buffering, while some retain isotopic compositions of seawater and meteoric water. Temperature estimates, derived from both thermometers, fall within the range of 100–250°C. Notably, vein temperatures remain constant across diverse vein types and mélange units with distinct maximum temperatures. The combined temperature records and fluid isotopic compositions imply vein formations at shallower depths linked to the incorporation of seawater, meteoric water, and fluid released from early dehydration reactions. At greater depths, vein formations are associated with fluid released from clay dehydration and long‐distance fluid flow. Reduced vein formations between 250 and 350°C may correlate with a shift to fluid‐unsaturated conditions resulting from clay hydration reactions. Our study highlights potential mechanical and hydraulic variations within the thermal conditions of 100–350°C along the plate boundary driven by fluid‐mineral interactions. Plain Language Summary: Temperature influences the processes responsible for triggering earthquakes at subduction zones. This inference is supported by the observed concentration of seismic activities within a specific temperature range along the plate interface. To investigate the topic, we examine a distinctive rock type known as tectonic mélanges, which has undergone subduction in the past and has since been exposed. These mélanges contain mineral veins formed through the movement of materials; a factor that has shown correlation with the occurrence of earthquakes at subduction zones. To determine the temperatures at which the mechanism operates, leading to the formation of the veins, we employ two methodologies: quartz‐calcite oxygen isotope thermometry and clumped isotope thermometry. Our findings indicate that, regardless of the geographical locations or the types of veins, they formed within a temperature range of 100–250°C. This consistency implies the existence of a consistent depth range within subduction zones, where fluids are predominantly present, facilitating material movement and consequently, the development of these mineral veins. Key Points: Quartz‐calcite veins in ancient accretionary prisms record temperatures of 100–250°C, implying a fluid‐rich zone along plate interfacesFluid isotopic compositions suggest rock‐buffered fluids as major vein‐forming fluids derived from the dehydration of host rocksReduced vein formation, along with clay hydration at 250–350°C, may cause a shift in hydrogeology and mechanics of subduction fault zones [ABSTRACT FROM AUTHOR]

Real-time temperature monitoring with high accuracy and spatiotemporal resolution is critical for many biological applications, including disease diagnosis, drug delivery, and biomedical research. However, traditional methods for measuring temperature in biological systems present difficulties for a variety of reasons, such as slow response time, limited spatial resolution, low amplitude, and susceptibility to electromagnetic interference. Most importantly, in many cases, the thermal mass of temperature probes limits the accuracy and speed of measurement significantly. Here, we show that photonic microring resonators (MRRs) can be used for sensitive, precise, and high spatiotemporal resolution measurement of temperature in the biological milieu. The high refractive index of Si MRR and negligible thermal mass enable sensitive, ultrafast, and accurate temperature transients. By using a double resonator circuit, we demonstrate that MRR sensors can measure temperature with a 1 mm spatial resolution. We then show that MRR yields more accurate results than fiber optic probes for measuring temperature transients. Finally, we demonstrate the localized temperature measurement capability of MRRs in mouse brain tissue heated by superparamagnetic nanoparticles in an alternating magnetic field. This compact, lab-on-chip photonic temperature sensing platform holds great promise for continuous monitoring of temperature in critical biological and biomedical applications. [ABSTRACT FROM AUTHOR]

Rare-earth (RE) doped aluminum nitride (AlN) holds great promise for integrated optoelectronic devices. Here, the Ho and Yb co-doped AlN (AlN:Ho3+/Yb3+) submicron towers were prepared by a direct nitridation route. XRD, Raman, XPS and EDS studies showed successful doping of Ho and Yb ions into AlN. SEM images show that the submicron towers have an interesting layered structure by layer-by-layer stacking of hexagonal AlN nanosheets. Under excitation at 980 nm, AlN:Ho3+/Yb3+ submicron towers exhibit up-conversion (UC) luminescence at 540, 550, 659, and 762 nm, which are due to Ho3+/Yb3+ system from 5F 4 , 5S 2 →5I 8 , 5F 5 →5I 8 , and 5F 4 , 5S 2 →5I 7 respectively. Based on the intensity ratio and decay lifetime of UC luminescence, the optical temperature sensing characteristics are investigated from 298 K to 548 K. The maximum relative sensitivities associated with the intensity ratio of I 540, 550 and I 659 and decay lifetime of 659 nm are as high as 2.73% K−1 and 0.43% K−1, respectively. This work broadens the optoelectronic properties of RE doped AlN. [ABSTRACT FROM AUTHOR]

Germanate tellurite glasses doped with Eu3+ and Tb3+ were synthesized by the conventional melt-quenching method. There is no indication of the energy transfer between dopant ions in this host, but the co-dopants exhibit excellent color purity of 100% for Eu3+ and 80% for Tb3+. The co-doped glass exhibits yellow luminescence. The quantum yield of the Eu3+ emission is equal to 23% under 395 nm excitation. The thermal quenching of Eu3+ and Tb3+ luminescence occurs at different temperature ranges, which enables the thermal sensing properties of the material. The relative fluorescence intensity ratio (FIR) sensitivity of 0.16% K−1 was recorded in the wide range of temperatures spanning from −193 °C up to 0 °C. The temperature dependence of the decay times was also studied. The lifetime-based temperature sensitivity was determined to be 0.95% K−1 at 250 °C for Tb3+5D3 level emission and 0.3% K−1 at 225 °C for Eu3+5D1 level emission. [ABSTRACT FROM AUTHOR]

Multifunctional materials with optical temperature sensing and anti-counterfeiting properties have vast application prospects in our daily life, but the development of them still faces huge challenges. Herein, a novel SrY 2 O 4 :Bi3+,Er3+ phosphor with multicolor luminescence was synthesized triumphantly. Stimulated by different ultraviolet (UV) lights, the sample exhibits blue or green emissions, while emits yellow up-conversion luminescence under 980 nm laser irradiation. Interestingly, abnormal thermal quenching and thermal stimulation enhanced persistent luminescence are realized in SrY 2 O 4 :Bi3+,Er3+. Benefiting from the distinct responses of Bi3+ and Er3+ luminescence to temperature, thermochromism is verified when excited by UV or 980 nm light. Furthermore, the color shift from yellow-green to dark yellow is seen as the 980 nm laser power density reduces or the distance between laser source and the sample increases. Based on the luxuriant luminescence properties, multimode optical temperature sensing and dynamic anti-counterfeiting are constructed. All findings indicate that the multicolor emissive SrY 2 O 4 :Bi3+,Er3+ material offers a fresh outline for the exploitation of multiple optical thermometry and anti-counterfeiting. [ABSTRACT FROM AUTHOR]

A fast and simple method for the synthesis of solid solutions based on erbium-doped yttrium oxide (Y1–xErx)2O3 was developed. The crystal structures of the samples were determined by x-ray diffraction methods. The compounds exhibited greenish-yellow upconversion emission upon IR laser excitation (980 nm). An increase in the erbium concentration in (Y1–xErx)2O3 caused a color change and a growth in the intensity of the upconversion luminescence. The maximum upconversion luminescence intensity was observed for the oxide with x = 0.05. A two-photon excitation mechanism was determined based on the dependence of the emission line intensities associated with 2H11/2/4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions on the pumping power. The absolute and relative sensitivities were calculated from the temperature dependences of the ratio of emission lines corresponding to transitions from thermally coupled excited 2H11/2 and 4S3/2 levels and showed the promise of the oxides as materials for noncontact temperature sensing. [ABSTRACT FROM AUTHOR]

Background: Percutaneous microwave ablation (pMWA) is a minimally invasive procedure that uses a microwave antenna placed at the tip of a needle to induce lethal tissue heating. It can treat cancer and other diseases with lower morbidity than conventional surgery, but one major limitation is the lack of control over the heating region around the ablation needle. Superparamagnetic iron oxide nanoparticles have the potential to enhance and control pMWA heating due to their ability to absorb microwave energy and their ease of local delivery. Purpose: The purpose of this study is to experimentally quantify the capabilities of FDA‐approved superparamagnetic iron oxide Feraheme nanoparticles (FHNPs) to enhance and control pMWA heating. This study aims to determine the effectiveness of locally injected FHNPs in increasing the maximum temperature during pMWA and to investigate the ability of FHNPs to create a controlled ablation zone around the pMWA needle. Methods: PMWA was performed using a clinical ablation system at 915 MHz in ex‐vivo porcine liver tissues. Prior to ablation, 50 uL 5 mg/mL FHNP injections were made on one side of the pMWA needle via a 23‐gauge needle. Local temperatures at the FHNP injection site were directly compared to equidistant control sites without FHNP. First, temperatures were compared using directly inserted thermocouples. Next, temperatures were measured non‐invasively using magnetic resonance thermometry (MRT), which enabled comprehensive four‐dimensional (volumetric and temporal) assessment of heating effects relative to nanoparticle distribution, which was quantified using dual‐echo ultrashort echo time (UTE) subtraction MR imaging. Maximum heating within FHNP‐exposed tissues versus control tissues were compared at multiple pMWA energy delivery settings. The ability to generate a controlled asymmetric ablation zone using multiple FHNP injections was also tested. Finally, intra‐procedural MRT‐derived heat maps were correlated with gold standard gross pathology using Dice similarity analysis. Results: Maximum temperatures at the FHNP injection site were significantly higher than control (without FHNP) sites when measured using direct thermocouples (93.1 ± 6.0°C vs. 57.2 ± 8.1°C, p = 0.002) and using non‐invasive MRT (115.6 ± 13.4°C vs. 49.0 ± 10.6°C, p = 0.02). Temperature difference between FHNP‐exposed and control sites correlated with total energy deposition: 66.6 ± 17.6°C, 58.1 ± 8.5°C, and 20.8 ± 9.2°C at high (17.5 ± 2.2 kJ), medium (13.6 ± 1.8 kJ), and low (8.8 ± 1.1 kJ) energies, respectively (all pairwise p < 0.05). Each FHNP injection resulted in a nanoparticle distribution within 0.9 ± 0.2 cm radially of the injection site and a local lethal heating zone confined to within 1.1 ± 0.4 cm radially of the injection epicenter. Multiple injections enabled a controllable, asymmetric ablation zone to be generated around the ablation needle, with maximal ablation radius on the FHNP injection side of 1.6 ± 0.2 cm compared to 0.7 ± 0.2 cm on the non‐FHNP side (p = 0.02). MRT intra‐procedural predicted ablation zone correlated strongly with post procedure gold‐standard gross pathology assessment (Dice similarity 0.9). Conclusions: Locally injected FHNPs significantly enhanced pMWA heating in liver tissues, and were able to control the ablation zone shape around a pMWA needle. MRI and MRT allowed volumetric real‐time visualization of both FHNP distribution and FHNP‐enhanced pMWA heating that was useful for intra‐procedural monitoring. This work strongly supports further development of a FHNP‐enhanced pMWA paradigm; as all individual components of this approach are approved for patient use, there is low barrier for clinical translation. [ABSTRACT FROM AUTHOR]

Based on numerical modeling of thermohydrodynamic processes in the wellbore under conditions of oil degassing, the possibility of estimating the coefficient of gas solubility in oil and the well flow rate is investigated based on an analysis of temperature distribution along the wellbore. It is shown that degassing of oil in the wellbore or in a bed leads to the formation of temperature cooling anomalies, which can be used to solve certain oilfield problems. The results obtained can be used in planning field-geophysical studies and interpreting the results of temperature studies of wells during the production of live crude. [ABSTRACT FROM AUTHOR]