Wide Temperature Range Research Articles

Fast and low power SiPM amplifier operating in a wide temperature range

The next generation of Ring Imaging CHerenkov detectors in high energy physics experiments may use SiPMs as photon sensing elements. This upgrade is necessary to achieve greater detector granularity and speed, however SiPMs need to be cooled down to cryogenic temperatures to detect single photons in high-radiation environments and avoid being overwhelmed by the presence of “dark signals”. It is therefore necessary to study and characterize SiPM models in dedicated campaigns, using a custom-built amplifying chain that can also operate in an extended temperature range, between 80 K and 300 K, for detector characterization purposes. The proposed amplifier configuration consists of two amplifying stages and achieves low jitter values (<10−20psRMS) thanks to the low electronic noise and the high amplifier bandwidth. The circuit achieves a signal bandwidth of 500MHz<BW<1GHz, a phase margin of approximately 45° and a power consumption of about 65−135mW. The amplifier prototype unit can be adjusted to cover the considered temperature range and still achieve low jitter values.

Wearable, eco-mimetic, and bicontinuous Ag-doped poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)/MnO2/carbon fabric for multifunctionality

Wearable and bicontinuous Ag-doped poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate)/MnO2/carbon fabric was manufactured in a facile, eco-friendly, and scalable approach. The high temperature-resistant textile performed a maximum specific capacitance of 2.97 F cm−2, and delivered 113 % retention at 80 °C compared with that at room temperature. At a cooling-heating-cooling cycle, the capacitance could recover to its initial value after 10000 charge-discharge tests at 20 mA cm−2. Density function theory proves that Ag dopants and the S-containing functional group improve the adsorption ability with Na+. The maximum energy and power density achieved 19.36 mWh cm−3 and 530.50 mW cm−3 over a wide potential window of 2 V, respectively. Moreover, the fabric could be operated at low-temperature climates by multi-offset Joule heating performance and a deicing/dewatering ability. The antimicrobial capacity against typical bacteria and fungi renders robust safety to the wearable electronics. The fabric performed shielding effectiveness of 45.95 dB at 377 μm and reliable durability after 1000 times bending cycles. The reflection-dominant shielding mechanism was further revealed by COMSOL Multiphysics software. The all-in-one fabric complies with Internet of Things design and can endure extreme environments over a wide temperature range, implying great potential for energy storage, thermal management, bacteriostasis, and electromagnetic protection.

Nonwoven fabric supported flame-retarding quasi-solid electrolyte for wider-temperature safer Li-ion battery

Energy-dense lithium-ion battery (LIB) is in high demand for advanced portable electronics as well as electric vehicle EV applications. However, the flammability of conventional carbonate-based electrolytes makes the safety of the LIB questionable. Here, we demonstrate a nonflammable, thermally stable electrolyte for LIB application in the wide temperature range of −20 °C–50 °C. Specifically, we developed a non-woven fabric-supported quasi-solid flexible polymer electrolyte with a unique liquid electrolyte combination of methyl propionate (MP), trimethyl phosphate (TMP), fluoroethylene carbonate (FEC), and Poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer. The resulting composite electrolyte is compatible with Li metal, and in a half-cell (Li||LFP) performs superior to the commercial electrolyte over the wide temperature range. A full-cell with high-loading (cathode loading 13.2 mg/cm2) LFP combined with graphite demonstrated electrochemical performance. An initial discharge capacity of 115 mAh/g at a C/10 rate and capacity retention of 57 % was observed after 100 cycles. The thermal safety of the full cell was evaluated through multimodule calorimetry, where a low heat release of 37 J/g was observed, compared to 1.5 kJ/g with commercial electrolyte. This report aims to demonstrate the great potential of using flame-retardant quasi-solid polymer electrolytes for fabricating safer LIBs.

"Bowling Collision Effect" of CoMo6 Polyoxometalate Units Enables Wide Temperature Range from -20 to 60°C and Dendrite Mitigation Li-S Batteries.

To improve the performance of Lithium-Sulfur (Li-S) batteries, the reaction catalysts of lithium polysulfides (LiPSs) reactions should have the characteristics of large surface area, efficient atomic utilization, high conductivity, small size, good stability, and strong adjustability. Herein, Anderson-type polyoxometalate ([TMMo6O24]n-, TM = Co, Ni, Fe, represented by TMMo6 POMs) are used as the modified materials for Li-S battery separator. By customizing the central metal atoms, this work gains insights into the layer-by-layer electron transfer mechanism between TMMo6 units and LiPSs, similar to the collision effect of a bowling ball. Theoretical analysis and in situ experimental characterization show that the changes of CoMo6 units with moderate binding energy and lowest Gibbs free energy result in the formation of robust polar bonds and prolonged S─S bonds after adsorption. Hence, the representative Li-S battery with CoMo6 and graphene composite modified separator has a high initial capacity of 1588.6mA h g-1 at 0.2 C, excellent cycle performance of more than 3000 cycles at 5 C, and uniform Li+ transport over 1900h. More importantly, this work has revealed the inherent contradiction between the kinetics and thermodynamics, achieving a stable cycle in the temperature range of -20 to 60°C.

Photoluminescence of dense arrays of InGaPAs/InGaAs quantum dots formed by substitution of group V elements

One drawback of self-organized quantum dots is their low optical gain. The development of new shaping methods that would allow higher gain, for example, due to a higher surface density of the QD array, remains an important task to date. In the present work, arrays of quantum dots have been formed by substituting phosphorous atoms with arsenic ones in a thin InGaP epilayer. Based on transmission electron microscopy data, the surface density was estimated to be about 1.3 × 1012 cm−2, which is one of the highest values for quantum dots on GaAs. The influence of an additional InGaAs epilayer (quantum well) on the luminescence properties of quantum dots was investigated in a wide temperature range and different optical pumping levels. It was found that placing the quantum well under the layer of quantum dots has little effect on the central emission wavelength, while quantum dots covered with the InGaAs demonstrate a strong red shift of the luminescence spectrum. A transition from a nonequilibrium to an equilibrium distribution of charge carriers over quantum-dot states, related to the lateral transport of charge carriers over quantum dot array, similar to that previously observed in In(Ga)As Stranski-Krastanow quantum dots, was revealed. This is manifested in a change in temperature dependencies of the linewidth and peak position of the photoluminescence band. For the structures under study, this transition occurs at a temperature of about 125 K. Rapid thermal annealing of the structures allows to increase the integrated photoluminescence intensity of quantum dots up to 4 times, while the maximum of the spectrum remains almost unchanged, provided that the annealing temperature does not exceed 620 °C.

Enhancing in-field performance of GdBCO coated conductors by cooperative irradiation with Ti ions and protons

Irradiation can accurately manipulate defects and adjust pinning landscapes within REBa2Cu3O7-δ (REBCO, RE: rare earths) coated conductors (CCs). This study reports a productive method to dramatically boost the in-field critical current density (Jc) for GdBCO CCs using cooperative irradiation with Ti ions and protons. Remarkably, the in-field Jc of commercial CCs can be almost doubled at a wide range of temperatures and magnetic fields. Defects of various sizes induced by cooperative irradiation are more uniform distribution through the entire GdBCO film to improve the vortex pinning characteristics, thereby enhancing the in-field performance of the GdBCO CC. This method highlights how combining different particle irradiation types can tailor defect size and distribution, optimizing pinning landscapes for commercial REBCO CCs.

The IACOB project XII. New grid of northern standards for the spectral classification of B-type stars

With the advent of large spectroscopic surveys, automated stellar parameter determination has become commonplace. Nevertheless, spectral classification still offers a quick and useful alternative for obtaining parameter estimates for large samples of spectra of varying quality. We present a new atlas of stellar spectra covering the B-type range, with the intention of providing detailed classification criteria valid for modern spectra and improving the grid of reliable standards. This new grid will be used in future works to provide classification criteria beyond the classical classification range and addressing, in particular, the use of Gaia /RVS spectra. We analysed historical standards by means of multiple high-resolution spectra, marking out problematic cases and complementing the grid with a new set of reliable comparators. We then elaborated on a new set of classification criteria based on high-quality $R=4\,000$ spectra. Our new classification grid is much thicker than any previous set of standards, presenting a high degree of self-consistency. Although it is based entirely on morphological criteria, the grid demonstrates a much better correlation with different physical parameters. The new grid can be used to study classification criteria in other spectral ranges, providing a valuable tool for the study of B-type stars that covers a very wide range of temperatures, luminosities, and stellar masses. The very process of classification also offers valuable insights into stellar evolution.

Machine learning models coupled with ionic fragment σ-profiles to predict ammonia solubility in ionic liquids

Emitting NH3 into the atmosphere leads to significant air pollution, while NH3 itself serves as an essential component for fertilizers and refrigerants in industry. Thus, recovering and reusing NH3 is highly valuable. Ionic liquids (ILs) have shown great potential for NH3 capture, where the accurate prediction of solubility is a critical point for selecting ILs and designing a separation process. This work combined the Ionic Fragment Contribution (IFC) strategy with machine learning (ML) to develop four models (IFC-ML) to predict NH3 solubility in ILs. A dataset containing 785 solubility data points, covering 10 cations and 10 anions, was collected. From this dataset, the S1–S6 descriptors based on the IFC method were used as inputs for the ML models, together with temperature (T) and pressure (P). Among the models, the IFC-GBR model was recommended for predicting NH3 solubility in ILs due to its higher coefficient of determination (R2) of 0.9945 and lower mean squared error (MSE) of 0.0003 than the others. Additionally, in comparison with previous conductor-like screening model for real solvents (COSMO-RS) and extreme learning machine (ELM) methods, the IFC-GBR method showed a more accurate prediction of the NH3 solubility in ILs over a wider range of temperatures and pressures, providing additional chemical insights into IL-NH3 system that cations played a more important role for NH3 solubility. These results highlighted the developed IFC-GBR (gradient boosting regressor) model offered valuable insights for helping guide the process design of absorbing NH3 through IL-based technology.

Significantly improved energy storage performance of Na0.5Bi0.5TiO3–BaTiO3 ferroelectric ceramics with a wide temperature range via high-entropy doping

The emergence of high-entropy perovskite materials provides a new research idea to solve the problem of high remnant polarization and low recoverable energy storage density (Wrec) of relaxor ferroelectrics. In this study, barium-based high-entropy perovskite oxides Ba(Zr0.2Sn0.2Hf0.2Nb0.2Ti0.2)O3 (BZSHNT) were introduced into the 0.94Na0.5Bi0.5TiO3-0.06BaTiO3 (BNT-6BT) ceramic by the conventional solid state sintering method. The 0.2BZSHNT doped BNT-6BT ceramic demonstrates significantly improved Wrec of 3.57 J/cm3 and a high efficiency of 81.6 % compared to those of the BNT-6BT ceramic, which is only 0.5 J/cm3 and 60 % respectively. The doped BZSHNT refines the hysteresis loops and drastically reduces the remnant polarization, which lead to the increase of the polarization difference. The 0.8(BNT-6BT)-0.2BZSHNT ceramics show high discharge energy density, good temperature stability (25–200 °C), excellent frequency stability (10–300 Hz) and superior discharge rate (t0.9 = 83 ns) because of its increased TiO6 lattice distortion, atomic disorder, relaxation degree and band gap, as well as the disruption of the long-range ordered ferroelectric domains. Our findings make BNT-6BT doped BZSHNT based ceramics one of the most promising lead-free dielectric energy storage candidates.

Multifunctional MOF: Cold/hot adapted sustainable oxidase-like MOF nanozyme with ratiometric and color tonality for nitrite ions detection

Integrating multiple functionalities into a single entity is highly important, especially when a broad spectrum of application is required. In the present work, we synthesized a novel manganese-based MOF (denoted as UoZ-6) that functions as a cold/hot-adapted and recyclable oxidase nanozyme (Km 0.085 mM) further developed for ratiometric-based colorimetric and color tonality visual-mode detection of nitrite in water and food. Nitrite ions promote the diazotization process of the oxTMB product, resulting in a decay in the absorbance signal at 652 nm and the emergence of a new signal at 461 nm. The dual-absorbance ratiometric platform for nitrite ion detection functions effectively across a wide temperature range (0 °C to 100 °C), offering a linear detection range of 5–45 μM with a detection limit of 0.15 μM using visual-mode. This approach is sensitive, reliable, and selective, making it effective for detecting nitrite ions in processed meat and water.

Analysis of amplitude and dissipation factor of AT-cut quartz crystal resonators over a wide temperature range

Analysis of amplitude and dissipation factor of AT-cut quartz crystal resonators over a wide temperature range

Characterization of In-Field Critical Currents in REBCO Tapes Over Wide Temperature Range by Pulsed Current Source With Supercapacitor

Characterization of In-Field Critical Currents in REBCO Tapes Over Wide Temperature Range by Pulsed Current Source With Supercapacitor

Enhancement of persistent luminescence and mechanoluminescence in Pr3+ doped CaAl2Si2O8: Mn for multifunctional applications at wide temperature range

The orange-red phosphor, which combines persistent luminescence and mechanoluminescence, holds significant importance in advanced bioimaging and optical anti-counterfeiting. However, there are relatively few reports on this type of material currently. In this study, doping CaAl2Si2O8: Mn2+ phosphor with Pr3+ ions significantly increases the material's defect density. Under X-ray/UV excitation, the sample displays exceptional orange-red persistent luminescence and superior mechanoluminescence. More importantly, the samples exhibit the above properties in all temperature regions (including low temperature, room temperature (RT) and high temperature). Additionally, the material demonstrates excellent tissue penetration capabilities and dual-mode luminescence (persistent luminescence and mechanoluminescence), highlighting its potential for bioimaging and optical anti-counterfeiting applications.

Polymorphic Localized Heterostructure Design for High-Performance Amorphous/Nanocrystalline Composite Film.

Analogous to linear dielectric, amorphous perovskite dielectrics characterized of high breakdown strength and low remanent polarization possess in-depth application in the sea, land, and air fields. Amorphous engineering is a common approach to balance the inverse relationship between polarization and breakdown strength in dielectric ceramic capacitor, however, the low polarization is the major barrier limiting the improvement of energy storage density. To address this concern, the polymorphic localized heterostructure confirmed by high-resolution transmission electron microscope (HR-TEM) and HADDF images is constructed in BaTiO3-Bi(Ni0.5Zr0.5)O3 amorphous/nanocrystalline composite film with SiO2 addition (BT-BNZ-xS, x = 3, 5, 7, 10 mol%). The stability of nanocrystalline region achieved by Si-rich transition region and the enhancive ultra-short-range ordering in the amorphous region synergistically result in large breakdown strength and nonhysteretic polarized response. This polymorphic localized heterostructure optimizes the thermal stability in a wide temperature range and contributes ultrahigh energy storage density of 149.9 J cm-3 with markedly enhanced efficiency of 79.0%. This study provides a universal strategy to design the polarization behavior in other amorphous perovskite-based dielectrics.

The dielectric response of a novel low-loss oxyfluoride Li0.5NaY9(SiO4)6O2F0.5 ceramic from Gigahertz band to Terahertz band

The exploration of dielectric ceramics with excellent dielectric responses at Gigahertz band and Terahertz band is becoming urgent for the upcoming 6th generation wireless communication. In this work, we propose a new approach to design novel dielectric ceramics by using the density functional theory. According to the analysis of Electron Localization Functions (ELF), Density of States (DOS) and crystal bond lengths, it indicates that the strategy of co-doping with lithium and fluorine will contribute to a much more stable crystal structure of Li0.5NaY9(SiO4)6O2F0.5 as compared to that of NaY9(SiO4)6O2. Furthermore, we report the innovative synthesis of a Li0.5NaY9(SiO4)6O2F0.5 oxyfluoride ceramic, a solid solution with a wide sintering temperature range, along with an in-depth analysis of its crystal structure, dielectric responses at both Gigahertz band and Terahertz band, which shows the promising application of Li0.5NaY9(SiO4)6O2F0.5 in the 6G wireless communication.

Large Nonhysteretic Volume Magnetostriction in a Strong and Ductile High-Entropy Alloy.

Rapid development of smart technologies poses a big challenge for magnetostrictive materials, which should not only permit isotropic and hysteresis-free actuation (i.e., nonhysteretic volume change) in magnetic fields, but also have high strength and high ductility. Unfortunately, the magnetostriction from self-assembly of ferromagnetic domains is volume-conserving; the volume magnetostriction from field-induced first-order phase transition has large intrinsic hysteresis; and most prototype magnetostrictive materials are intrinsically brittle. Here, a magnetic high-entropy alloy (HEA) Fe35Co35Al10Cr10Ni10 is reported that can rectify these challenges, exhibiting an unprecedented combination of large nonhysteretic volume magnetostriction, high tensile strength and large elongation strain, over a wide working temperature range from room temperature down to 100 K. Its exceptional properties stem from a dual-phase microstructure, where the face-centered cubic (FCC) matrix phase with nanoscale compositional and structural fluctuations can enable a magnetic-field-induced transition from low-spin small-volume state to high-spin large-volume state, and the ordered body-centered cubic (BCC) B2 phase contributes to mechanical strengthening. The present findings may provide insights into designing unconventional and technologically important magnetostrictive materials.

Temperature dependent electrical resistance and mesoscopic electronic transport mechanisms on aerographite and single-walled carbon nanotube aerogel

We investigate temperature dependent electrical resistance properties of aerographite and single-walled carbon nanotube (SWCNT) aerogel in the temperature range of 2–300 K by employing the four-probe method with magnetic field effects (in the range 0–9 T, in steps of 2 T). The current–voltage (I–V) curves were taken for several temperatures varying from 5 to 300 K, and the electrical resistance values of aerographite and SWCNT aerogel were decreased from 7.30 Ω (5 K, 0 T) to 4.88 Ω (300 K, 0 T) and 22.56 Ω (5 K, 0 T) to 0.99 Ω (300 K, 0 T) with temperature increases, respectively. Experimental results show that the electrical resistance falls exponentially as the temperature increases. Such temperature dependence of R(T) points to a form of tunneling conduction or hopping. Two mesoscopic mechanisms for electronic transport, fluctuation-induced tunneling conduction (FITC) and variable range hopping (VRH), are employed to explicate possible electrical conduction mechanisms occurring in aerographite and SWCNT aerogel, respectively. These mainly result in disorder-induced symmetry-breaking, which are modified by their structural symmetries and electronic band structures, both play important roles in temperature dependent electrical resistance properties of aerographite and SWCNT aerogel. Characteristic parameters (T0, T1, and R0) have been estimated using the morphology and the uncertainty principle for aerographite and the percolation theory for SWCNT aerogel. While the FITC mechanism captures a wide temperature range of data for aerographite, the VRH model provides an explanation for SWCNT aerogel. This study provides groundwork for further development of carbon aerogel systems with high conductivity in large-scale preparation.

Simulation of the impact of an ultrasonic drill as a composition of a robotic platform for investigation of soil on celestial bodies

The article discusses the theoretical issues of developing an ultrasonic drill for drilling soil on celestial bodies as part of a robotic platform and formulates the tasks of its control. The specifics of using the drill require a wide temperature range during operation, low energy consumption, an efficient operating cycle and the requirement to ensure the preservation of the structure and composition of the soil when exposed to the tool. One of the promising areas of development is devices with vibration decoupling from the ground by ultrasound due to the transformation of ultrasonic vibrations into repeated impacts of sound frequency using a specially introduced “free” body between the ultrasonic and impact parts of the drill (bit). This allows continuous drilling regardless of the condition of the impact bit, including jamming. The purpose of the work is to select the most effective drill design and compile a mathematical model that provides simulation modeling. Materials and methods. Technical solutions of both domestic and foreign authors were considered, and a prototype was selected. Theoretical works were analyzed and it was found that the materials presented in them do not contain detailed mathematical models necessary for simulation modeling at the stage of design and optimization of the structure. In the theoretical part of the article, mathematical models are proposed, obtained on the basis of equivalent parameters found from a distributed description of the drill design elements. Methods of mathematical physics, classical mechanics and similarity theory were used. The results are that two alternative mathematical models are developed. One of the models has a continuous description with a significantly nonlinear rigidity of the “wall” upon impact, while the impact motion is considered as a type of self-oscillation. The second model is based on the theory of impact. Conclusion. A parametric study was carried out and the dependences of the oscillation frequency of a free body on the size of the impact gap, body mass and amplitude of oscillations of the concentrator, etc. were obtained. The considered models can be used for simulation modeling when developing a drill design. The tasks of controlling a robotic drilling platform are formulated from the position of ensuring the operability of the drill when drilling various soils.

Wide-temperature-range pressure sensing by an aramid nanofibers/reduced graphene oxide flakes composite aerogel

Aerogel-based conductive materials have emerged as a major candidate for piezoresistive pressure sensors due to their excellent mechanical and electrical performance besides light-weighted and low-cost characteristics, showing great potential for applications in electronic skins, biomedicine, robot controlling and intelligent recognition. However, it remains a grand challenge for these piezoresistive sensors to achieve a high sensitivity across a wide working temperature range. Herein, we report a highly flexible and ultra-light composite aerogel consisting of aramid nanofibers (ANFs) and reduced graphene oxide flakes (rGOFs) for application as a high-performance pressure sensing material in a wide temperature range. By controlling the orientations of pores in the composite framework, the aerogel promotes pressure transfer by aligning its conductive channels. As a result, the ANFs/rGOFs aerogel-based piezoresistive sensor exhibits a high sensitivity of up to 7.10 kPa−1, an excellent stability over 12,000 cycles, and an ultra-wide working temperature range from −196 to 200 °C. It is anticipated that the ANFs/rGOFs composite aerogel can be used as reliable sensing materials in extreme environments.

Highly Concentrated Asymmetric KTFSI for Aqueous Potassium Ion Batteries

AbstractPotassium imide salt (KCTFSI), featuring cyano (C≡N) and trifluoromethanesulfonyl (TFSI) branches, is reported for the first time as a promising electrolyte for aqueous potassium‐ion batteries (KIBs). In contrast to the limited solubility of symmetric KTFSI (1.5m), asymmetric KCTFSI achieves a high saturation concentration of 32.2m within a “water‐in‐salt” region. Experimental and theoretical studies reveal that the remarkable enhancement of solubility is associated with the asymmetry of CTFSI anions and likely the preferential formation of contact‐ion pairs through C≡N coordination. The 32.2m KCTFSI solution not only extends the electrochemical stability window (3.80 V on Al) but also maintains a liquid state at low temperatures (−15 °C) for an extended period, in sharp contrast to the immediate solidification of potassium bis(fluorosulfonyl)imide (KFSI, 30m) and potassium trifluoromethanesulfonate (KOTF, 22m) solutions. Thanks to its wide voltage window and supercooling behavior, KCTFSI demonstrates excellent compatibility with perylene‐3,4,9,10‐tetracarboxylic diimide (PTCDI) anode and KVPO4F (or K2Fe[Fe(CN)6]·2H2O) cathode over a wide temperature range. For instance, full cells of PTCDI/KCTFSI/KVPO4F exhibit reasonable cyclability with an average discharge voltage of 1.7 V over 300 charge/discharge cycles at −15 °C. it is anticipated that this work will inspire new designs of hybrid electrolytes based on CTFSI to advance the realization of viable aqueous KIBs.