Sensitive Measurement Research Articles

Sensitivity volume as figure-of-merit for maximizing data importance in electrical impedance tomography

Objective. Electrical impedance tomography (EIT) is a noninvasive imaging method whereby electrical measurements on the periphery of a heterogeneous conductor are inverted to map its internal conductivity. The EIT method proposed here aims to improve computational speed and noise tolerance by introducing sensitivity volume as a figure-of-merit for comparing EIT measurement protocols. Approach. Each measurement is shown to correspond to a sensitivity vector in model space, such that the set of measurements, in turn, corresponds to a set of vectors that subtend a sensitivity volume in model space. A maximal sensitivity volume identifies the measurement protocol with the greatest sensitivity and greatest mutual orthogonality. A distinguishability criterion is generalized to quantify the increased noise tolerance of high sensitivity measurements. Main result. The sensitivity volume method allows the model space dimension to be minimized to match that of the data space, and the data importance to be increased within an expanded space of measurements defined by an increased number of contacts. Significance. The reduction in model space dimension is shown to increase computational efficiency, accelerating tomographic inversion by several orders of magnitude, while the enhanced sensitivity tolerates higher noise levels up to several orders of magnitude larger than standard methods.

Package-Less Liquid Phase Sensing Using Surface Acoustic Waves on Lithium Tantalate Oxide.

Surface acoustic wave (SAW) transducers propagating shear waves are compatible with sensing chemical compounds in a liquid phase. However, if the liquid surrounding the sensor possesses a higher permittivity than the piezoelectric substrate, then the interdigitated electrodes for converting the incoming electromagnetic wave to acoustic waves are susceptible to capacitive short-circuiting, leading to excessive insertion losses. By using high-permittivity lithium tantalate oxide (LTO), we demonstrate chemical sensing in water without the need for dedicated microfluidic packaging. Nevertheless, the gravimetric sensitivity of these package-less transmission Love-mode delay lines remains comparable to that of low-permittivity quartz when appropriately tuning the guiding layer of thin film to confine energy to the surface in a Love mode. We extend the transmission line gravimetric sensitivity measurement to a reflective delay line geometry for passive transducers that can be wirelessly probed. For instance, ground-penetrating radar (GPR) can be used for subsurface sensing, here targeting water pollution detection, operating in the 100-500-MHz range. This center frequency was selected as a tradeoff between penetration depth (lower frequency) and antenna size (smaller at higher frequency). Nonspecific binding of proteins detection is shown in the context of biosensing applications.

Hometronics – accessible production of graphene suspensions for health sensing applications using only household items

Nanoscience at times can seem out of reach to the developing world and the general public, with much of the equipment expensive and knowledge seemingly esoteric to nonexperts. Using only cheap, everyday household items, accessible research with real applications can be shown. Here, graphene suspensions were produced using pencil lead, tap water, kitchen appliances, soaps and coffee filters, with a children’s glue-based graphene nanocomposite for highly sensitive pulse measurements demonstrated.

Brain vital signs as a quantitative measure of cognition: Methodological implementation in a care home environment

IntroductionManaging cognitive function in care homes is a significant challenge. Individuals in care have a variety of scores across standard clinical assessments, such as the Mini-Mental Status Exam (MMSE), and many of them have scores that fall within the range associated with dementia. A recent methodological advance, brain vital sign monitoring through auditory event-related potentials, provides an objective and sensitive physiological measurement to track abnormalities, differences, or changes in cognitive function. Taking advantage of point-of-care accessibility, the current study evaluated the methodological feasibility, the assessment of whether a particular research method can be successfully implemented, of quantitatively measuring cognition of care home residents using brain vital signs. Secondarily, the current study examined the relationship between brain vital signs, specifically the cognitive processing associated N400 component, and MMSE scores in care home residents. Materials and methodsBrain vital signs used the established N100 (auditory sensation), P300 (basic attention), and N400 (cognitive processing) event-related potential (ERP) components. A total of 52 residents were enrolled, with all participants evaluated using the MMSE. Participants were assigned into homogeneous groups based on their MMSE scores, and were categorized into low (n = 14), medium (n = 17), and high (n = 13) MMSE groups. Both brain vital sign measures and underlying ERP waveforms were examined. Statistical analyses used partial least squares correlation (PLS) analyses in which both MMSE and age were included as factors, as well as jackknife approaches, to test for significant brain vital sign changes. ResultsThe current study successfully measured and analyzed standardized, quantifiable brain vital signs in a care home setting. ERP waveform data showed specific N400 changes between MMSE groups as a function of MMSE score. PLS analyses confirmed significant MMSE-related and age-related differences in the N400 amplitude (p < 0.05, corrected). Similarly, the jackknife approach emphasized the N400 latency difference between the low and high MMSE groups. Discussion and conclusionIt was possible to acquire brain vital signs measures in care home residents. Additionally, the current study evaluated brain vital signs relative to MMSE in this group. The comparison revealed significant decreasing in N400 response amplitude (cognitive processing) as a function of both MMSE score and age, as well as a slowing of N400 latency. The findings indicate that objective neurophysiological measures of impairment are detectable in care home residents across the span of MMSE scores. Direct comparison to MMSE- and age-related variables represents a critical initial step ahead of future studies that will investigate relative improvements in sensitivity, validity, reliability and related advantages of brain vital sign monitoring.

Predictive performance of corneal and lid margin sensitivity for dry eye disease: An investigator-masked, prospective, prognostic accuracy study

PurposeTo evaluate the prognostic ability of non-contact esthesiometry corneal and lid margin sensitivity measurements in detecting symptoms and signs of dry eye disease, as defined by the global consensus TFOS DEWS II criteria. MethodsA total of 87 community residents (58 females; mean ± SD age, 53 ± 16 years) were recruited in an investigator-masked, prospective, prognostic accuracy study. Dry eye symptomology, tear film parameters, and ocular surface characteristics were evaluated in a single clinical session, and non-contact esthesiometry corneal and lid margin sensitivity measurements performed by an independent masked assessor. ResultsOverall, 49 (56%) participants fulfilled the TFOS DEWS II criteria for dry eye disease, while 57 (66%) exhibited clinical symptoms, and 67 (77%) had positive signs. The prognostic abilities of corneal and lid margin sensitivity measurements were significantly greater than chance for the detection dry eye signs (both p ≤ 0.03), but not for symptoms or overall disease diagnosis (all p > 0.10). The Youden-optimal prognostic cut-offs for corneal and lid margin sensitivity thresholds were both ≥0.8 mbar for the detection of clinical dry eye signs. Lid margin sensitivity demonstrated marginally higher predictive performance than corneal sensitivity (C-statistic, 0.688 versus 0.658), and was significantly correlated with tear film stability, corneal, conjunctival and lid wiper staining (all p < 0.05). ConclusionsCorneal and lid margin sensitivity demonstrated moderate prognostic utility for detecting clinical dry eye signs. Future research is warranted to investigate the utility of incorporating non-contact esthesiometry in the workup for dry eye disease and neurotrophic keratopathy.

High toughness, ultra-sensitive, and extreme environment resistant fabric temperature sensors based on supramolecular-polymer dual network ionic conductive elastomers

Liquid-free ionic conductive elastomers (ICEs) show great potential for next-gen wearable electronics, free from issues like solvent evaporation and freezing. However, crafting ICEs with both strength and temperature sensitivity remains a significant challenge. In this study, a supramolecular gel based on 1,3:2,4-bis (3,4-dimethylbenzene methylene) sorbitol (DMBS) is selected as the first network, and poly(ethylene glycol) methyl ether methacrylate (PEGMA) copolymerized with diallyl dimethyl bis (trifluoromethyl sulfonyl)imide (DADMATFSI) is added as the second network, with the addition of lithium bis(trifluoromethyl sulfonyl)imide (LiTFSI). The supramolecular-polymer dual network ion-conductive elastomer SP-DN-LiTFSI is created. The elastomer exhibits exceptional mechanical characteristics, including a maximum tensile stress of 1591.1 kPa and an impressive strain of 2361 %. Additionally, it demonstrates an extraordinarily high toughness of 33.121 MJ m−3. Moreover, this elastomer-based temperature sensor is responsive to external stimuli, such as blowing, and boasts an outstanding temperature sensing coefficient (S) of 0.114 °C−1 within the range of 30–60 °C. Remarkably, it can discern even the slightest temperature variations as low as 0.5 °C within the typical human body temperature range. This work represents an innovative integration of a dual network structure and two strategies for elastomer fabrication. It provides a novel approach for developing highly sensitive wearable temperature measurement devices that exhibit exceptional resistance to mechanical wear.

High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive Detector.

The refractive index of seawater is one of the essential parameters in ocean observation, so it is necessary to achieve high-precision seawater refractive index measurements. In this paper, we propose a method for measuring the refractive index of seawater, based on a position-sensitive detector (PSD). A theoretical model was established to depict the correlation between laser spot displacement and refractive index change, utilizing a combination of a position-sensitive detector and laser beam deflection principles. Based on this optical measurement method, a seawater refractive index measurement system was established. To effectively enhance the sensitivity of refractive index detection, a focusing lens was incorporated into the optical path of the measuring system, and simulations were conducted to investigate the impact of focal length on refractive index sensitivity. The calibration experiment of the measuring system was performed based on the relationship between the refractive index of seawater and underwater pressure (depth). By measuring laser spot displacement at different depths, changes in displacement, with respect to both refractive index and depth, were determined. The experimental results demonstrate that the system exhibits a sensitivity of 9.93×10-9 RIU (refractive index unit), and the refractive index deviation due to stability is calculated as ±7.54×10-9 RIU. Therefore, the feasibility of this highly sensitive measurement of seawater refractive index is verified. Since the sensitivity of the refractive index measurement of this measurement system is higher than the refractive index change caused by the wake of underwater vehicles, it can also be used in various applications for underwater vehicle wake measurement, as well as seawater refractive index measurement, such as the motion state monitoring of underwater navigation targets such as AUVs and ROVs.

A nitrogen-doped hollow carbon nanospheres-based aptasensor for non-invasive salivary detection of progesterone

Developing an easy-to-use and non-invasive sensor for monitoring progesterone (P4) as a multi-functional hormone is highly demanded for point-of-care testing. In this study, an ultrasensitive electrochemical aptasensor is fabricated for monitoring P4 in human biofluids. The sensing interface was designed based on the porous nitrogen-doped hollow carbon spheres (N-HCSs). The N-HCSs covalently immobilized high-dense aptamer (Apt) sequences as the bioreceptor of P4. The electron transfer of the redox probe was hindered by incubating P4 on the aptasensor surface and forming the P4-Apt complexes. Meanwhile, the signaling was decreased under two wide linear dynamic ranges (LDRs) from 10 fM to 5.6 μM with a limit of detection (LOD) value of 3.33 fM. The aptasensor presented satisfactory selectivity in the presence of different off-target species with successful feasibility for P4 detection in some human urine and saliva samples. The aptasensor with high sensitivity, as an advantage for on-site and sensitive measurement of P4, can be considered a non-invasive tool for routine analysis of real-world clinical samples method.

A cost-effective approach to measurements of fluorophore temperature sensitivity and temperature change with reasonable accuracy

The demand for measuring fluorophore temperature sensitivity and temperature change in chemical or biological samples has spurred the search for effective methods. While infrared (IR) light-based thermal devices are popular, they are limited to surface temperature measurement. Fluorescence-based thermometry, which utilizes intensity, lifetime, polarization, and spectrum change, provides the temperature information directly from the samples and can have high temporal and spatial resolution. However, measuring fluorescence can be tricky and expensive. A cost-effective approach to achieving reasonable accuracy is highly desired. This study introduces such an approach, employing a light-emitting diode (LED) for fluorophore excitation and a laser diode (LD) for sample heating, with a phone camera recording fluorescence changes. A data processing method converts the video into digital data, processed through digital filters. Utilizing a small-volume cuvette enhances heating efficiency. This study serves as a practical guide for inexperienced individuals, including students, instructors, and researchers, facilitating entry into the field and navigating the complexities of fluorescence-based thermometry.

Measuring secondary school students’ L2 writing self‐regulated strategies in the Korean EFL context

AbstractThis study examined the evidence for the reliability and validity of the Self‐Regulatory Writing Strategy Questionnaire (SRWSQ) and its suitability for the Korean English as a foreign language (EFL) context. The results indicated that the six dimensions of self‐regulated learning (SRL) strategies (writing planning, goal‐oriented monitoring, goal‐oriented evaluation, emotional control, metacognitive judgment, and memorization strategies) were closely but independently related to each other, falling under the overarching construct of self‐regulation. However, certain items require revision to ensure a more culturally sensitive measurement of SRL strategies in the Korean EFL context. The study observed differences in the use of SRL strategies based on gender and grade level. Furthermore, the use of SRL strategies significantly influenced students’ writing achievement. The study underscores the importance of SRL writing strategies in EFL contexts and discusses implications for teachers and future research.

Novel setup for detecting short-range anisotropic corrections to gravity

In this paper we argue that, even though there are strong theoretical and empirical reasons to expect a violation of spatial isotropy at short distances, contemporary setups for probing gravitational interactions at short distances have not been configured to measure such spatial anisotropies. We propose a simple modification to the state-of-the-art torsion pendulum design and numerically demonstrate that it suppresses signals due to the large spatially-isotropic component of the gravitational force while maintaining a high sensitivity to short-range spatial anisotropies. We incorporate anisotropy using both Yukawa-type and power-law-type short-distance corrections to gravity. The proposed differential torsion pendulum is shown to be capable of making sensitive measurements of small gravitational anisotropies and the resulting anisotropic torques are largely independent of the details of the underlying short-distance modification to gravity. Thus, if there is an anisotropic modification to gravity, from any theory, in any form of the modified potential, the proposed setup provides a practical means of detecting it.

Online Exercise Programs for Chronic Nonspecific Neck Pain: A Randomized Controlled Trial Reveals Comparable Effects of Global, Local, and Combined Approaches.

Specific neck exercises are recommended in the rehabilitation of chronic nonspecific neck pain (CNNP). They are unfortunately often accompanied by acute pain flare-ups. Global exercises might be a beneficial addition, as they activate endogenous analgesia without overloading painful structures. However, it is still unclear which type of exercise is most effective. This randomized controlled trial was done to evaluate the effect of an online blended program of global and specific neck exercises, compared to programs including only 1 of both types of exercise. Forty-eight patients with CNNP were randomized into 3 groups. Online questionnaires were collected at baseline, at midtreatment, immediately after treatment, and at the 3-month follow-up. Quantitative sensory testing and actigraphy were assessed at baseline and after treatment. Linear mixed-model analyses were performed to evaluate treatment effects within and between groups. Neck pain-related disability after treatment was considered the primary outcome. No time × treatment interaction effects were found. All groups improved in neck pain-related disability, pain intensity, self-reported symptoms of central sensitization, local pain sensitivity, physical activity, and pain medication use. No effects were found on quality of life, sleep quality, depression, anxiety, stress, widespread pain sensitivity, health economics, or actigraphy measurements. A higher global perceived effect was reported after performing the blended program, compared to the other groups. A blended exercise program was not superior to the stand-alone programs in reducing disability. Nevertheless, the global perceived effect of this type of exercise was higher. Future research necessitates larger sample sizes to adequately explore the optimal type of exercise for patients with CNNP. Exercise therapy should be an important part of the rehabilitation of patients with CNNP, regardless of the type of exercise.

A feasibility, randomised controlled trial of Club Connect: a group-based healthy brain ageing cognitive training program for older adults with major depression within an older people’s mental health service

BackgroundUsing the RE-AIM (reach, effectiveness, adoption, implementation, maintenance) framework, we outline steps taken to implement an evidence-based cognitive training program, Club Connect, in older adults with major depressive disorder in an Older People’s Mental Health Service in Sydney, Australia. The primary aim was to explore feasibility (or ‘reach’), tolerability (or ‘implementation’), and acceptability (or ‘adoption’). The secondary aim was to explore the most sensitive clinical outcomes and measurement tools (i.e. ‘effectiveness’) to inform a formal randomised controlled trial, and to explore the healthcare resources used (i.e. costs) to assist decision-making by health care managers and policy-makers in relation to future resource allocation.MethodsUsing a single blinded feasibility design, 40 participants (mean age: 76.13 years, SD: 7.45, range: 65–95 years) were randomised to either (a) Club Connect, a 10-week group-based multifaceted program, comprising psychoeducation and computer-based cognitive training, or (b) a waitlist control group.ResultsImplementing group-based cognitive training within a clinical setting was feasible, well tolerated and accepted by participants. Further, cognitive training, in comparison to the waiting list control, was associated with moderate to very large effect size improvements in depression, stress and inhibition (ηp2 = 0.115–0.209). We also found moderate effect size improvements on measures of daily functioning, wellbeing and cognitive flexibility. Small effect size improvements for other cognitive and psychosocial outcomes were also observed. The average cost per person participating in in the intervention was AU$607.50.ConclusionsOur findings support the feasibility of implementing group-based cognitive training into a specialised clinical (public health) setting. This trial was registered on the Australian and New Zealand Clinical Trial Registry (ACTRN12619000195156, 12/02/2019).

Compact Viscosity Sensors for Downhole Enhanced Oil Recovery Polymer Fluid Degradation Monitoring

Summary There are currently no technologies available to measure polymer solution viscosities at realistic downhole conditions in a well during enhanced oil recovery (EOR). In this paper, custom-made probes using quartz tuning fork (QTF) resonators are demonstrated for measurements of viscosity of polymer fluids in the laboratory. The electromechanical response of the resonators was calibrated in simple Newtonian fluids and in non-Newtonian polymer fluids at different concentrations. The responses were then used to measure field-collected samples of polymer injection fluids. In the polymer fluids, the measured viscosity values by tuning forks were lower than those measured by the conventional rheometer at 6.8 s−1, closer to the solvent viscosity values. However, the predicted rheometer viscosity vs. QTF-measured viscosity showed a distinct exponential correlation (R2=0.9997), allowing for an empirical calibration between the two viscometers for fluids having the same solvent and polymer compositions. The QTF sensors produced acceptable viscosity measurements of polymer fluids within the required polymer concentration ranges used in the field and predicted field sample viscosities with less than 1–2 cp (or 10–20%) error from the rheometer data. Results were validated based on separate independent tests where the devices were used to measure the viscosity of Newtonian fluids and non-Newtonian polymer fluids in a series of consecutive dip tests, simulating more realistic usage. These devices can be used to measure either the “relative” viscosity changes from a polymer solution prior and post-injection or to measure a “calibrated” viscosity via empirical exponential correlation. The compact QTF sensors developed in this study can be easily integrated into portable systems for laboratory or wellsite deployment as well as logging tools for downhole deployment. This work also demonstrates the ability of these QTF devices to make sensitive viscosity measurements at high-frequencies, opening opportunities for their use in high-frequency rheology studies of EOR fluids.

High enrichment and sensitive measurement of oxytetracycline in tea drinks by thermosensitive magnetic molecular imprinting based magnetic solid phase extraction coupled with boron doped carbon dots

As a typical kind of new pollutants, there are still some challenges in the rapid detection of antibiotics. In this work, a sensitive fluorescent probe based on boron-doped carbon dots (B-CDs) in combination with thermo-responsive magnetic molecularly imprinted polymers (T-MMIPs) was constructed for the detection of oxytetracycline (OTC) in tea drinks. T-MMIPs were designed, fabricated and employed to enrich OTC at trace level from tea drinks, and B-CDs were utilized as the fluorescent probe to detect the concentration of OTC. The proposed method exhibited good linear relationship with OTC concentration from 0.2 to 60 μg L−1 and the limit of detection was 0.1 μg L−1. The established method has been successfully validated with tea beverages. Present work was the first attempt application of T-MMIPs in combination with CDs in detection of OTC, and demonstrated that the proposed method endowed the detection of OTC with high selectivity, sensitivity, reliability and wide application prospect, meanwhile offered a new strategy for the method establishment of rapid and sensitive detection of trace antibiotics in food and other matrices.

Development of low-radon ultra-pure water for the Jiangmen Underground Neutrino Observatory

The Jiangmen Underground Neutrino Observatory (JUNO) is a state-of-the-art liquid scintillator-based neutrino physics experiment under construction in South China. To reduce the background from external radioactivities, a water Cherenkov detector composed of 35 kton ultra-pure water and 2,400 20-inch photomultiplier tubes is developed. Even after specialized treatment, ultra-pure water still contains trace levels of radioactive elements that can contribute to the detector background. Among which 222Rn is particularly significant. To address this, an online radon removal system based on the JUNO prototype has been developed. By integrating micro-bubble generators to enhance degasser’s radon removal efficiency, the radon concentration in water can be reduced to 1 mBq/m3 level, meeting the stringent requirements of JUNO. Additionally, a highly sensitive online radon concentration measurement system capable of detecting concentrations ∼1 mBq/m3 has been developed to monitor the radon concentration in water. In this paper, the details regarding both systems will be presented.

Highly sensitive fiber force sensor based on cascaded Fabry-Perot cavities and Vernier effect

In this article, we introduce a new concept for an in-line optical fiber force sensor probe, which is based on two cascaded Fabry-Perot (F-P) cavities to generate the Vernier effect and enhance sensitivity. Due to the significantly low Young’s modulus of UV-cured adhesive within the sensing cavity, extremely high force sensitivity is obtained. In our initial sample, we achieved an impressive force sensitivity of −61,301 nm/N. To improve that, the optical path difference between the two cavities is further reduced, exhibiting a remarkable increased force sensitivity of −140,813 nm/N. As an application, we conducted an experiment using this highly sensitive force sensor probe to measure the evaporation rate of ethanol, a common solvent, which is 7.79 × 10−5 g/s at room temperature. The proposed sensor features advantages of high sensitivity, simple structure, ease of fabrication, compactness, which is an ideal fiber sensor probe for sensitive force measurement.

Sensitive Electrochemical Biosensor Using Gold and Manganese (IV) Oxide Nanomaterials on Multiwalled Carbon Nanotubes for the Determination of Homocysteine With a Portable Potentiostat

Serum homocysteine (Hcy) is considered to be a reliable biomarker of cardiovascular, cerebrovascular and neurological diseases. Therefore, rapid, specific and sensitive measurement of homocysteine is crucial for prevention and diagnosis. Electrochemical methods, which benefit from simplicity, low-cost and quick response, have been widely utilized in the determination of targeted biomolecules. In this work, based upon a portable mini-potentiostat, a homocysteine electrochemical biosensor has been successfully developed combined with the modification of gold and manganese (IV) nanomaterials on multiwalled carbon nanotubes (MWCNTs) (denoted as Au@MnO2/MWCNTs) on screen-printed electrodes (SPEs). Due to the excellent electrochemical activity and catalytic capability of Au@MnO2/MWCNTs, the proposed electrochemical biosensor exhibited wide-linear range (5–125 μmol L−1), high sensitivity (0.01110 μA (μmol L−1)−1) and low detection limit (0.6173 μmol L−1) for homocysteine, requiring only 400 s to complete detection. It was effectively applied in the determination of serum homocysteine, and the results were consistent with those of an automated clinical chemistry analyzer. Furthermore, the simple and portable electrochemical device offers a promising manner for on-site analysis and home health monitoring.

Accelerometry as a tool for measuring the effects of transcranial magnetic stimulation

ObjectiveWe predicted that accelerometry would be a viable alternative to electromyography (EMG) for assessing fundamental Transcranial Magnetic Stimulation (TMS) measurements (e.g. Resting Motor Threshold (RMT), recruitment curves, latencies). New Method21 participants were tested. TMS evoked responses were recorded with EMG on the First Dorsal Interosseus muscle and an accelerometer on the index fingertip. TMS was used to determine the (EMG-defined) RMT, then delivered at a range of intensities allowing determination of both the accelerometry-defined RMT and measurement of recruitment curves. ResultsRMT assessed by EMG was significantly lower than for accelerometry (t(19)=-3.84, p<.001, mean±SD EMG = 41.1±5.28% MSO (maximum stimulator output), Jerk = 44.55±5.82% MSO), though RMTs calculated for each technique were highly correlated (r(18)=.72, p<.001). EMG/Accelerometery recruitment curves were strongly correlated (r(14)=.98, p<.001), and Bayesian model comparison indicated they were equivalent (BF01>9). Latencies measured with EMG were lower and more consistent than those identified using accelerometry (χ2(1)=80.38, p<.001, mean±SD EMG=27.01±4.58 ms, Jerk=48.4±15.33 ms). Comparison with existing methodsEMG is used as standard by research groups that study motor control and neurophysiology, but accelerometry has not yet been considered as a potential tool to assess measurements such as the overall magnitude and latency of the evoked response. ConclusionsWhile EMG provides more sensitive and reliable measurements of RMT and latency, accelerometry provides a reliable alternative to measure of the overall magnitude of TMS evoked responses.

Comparative study on fluorescence intensity ratio and chromatic coordinate temperature measurement using CsPbBr3-Eu3+ co-doped glass

We have fabricated CsPbBr3-Eu3+ co-doped glass for optical temperature measurement. Photoluminescence (PL) spectra, PL excitation (PLE) spectra and PL decay have been measured. The CsPbBr3 and Eu3+ show distinguishable PL spectra and different temperature dependences. Fluorescence intensity ratio (FIR) and chromatic coordinate temperature measurements are investigated. Absolute sensitivity (Sa), relative sensitivity (Sr) and temperature measurement accuracy (UT) are analyzed. For the FIR method, the Sa and Sr are better in comparison with other temperature sensing materials. The chromatic coordinate is calculated by using PL spectra. Comparing with FIR method, the chromatic coordinate method has smaller Sa and Sr, but better UT due to small uncertainty Ur(x). In addition, the chromatic coordinate method has linear temperature dependence, good compatibility and universality. Both FIR mode and chromatic coordinate mode have excellent temperature cycle characteristics..