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Chalcopyrite selenide single crystals and epitaxial layers (CuIn1−xGaxSe2, x = 0.00, 0.08, 0.19, 1.00) were characterized by temperature‐dependent photoreflectance (PR), photoluminescence (PL), photoluminescence–excitation (PLE), and variable excitation‐energy photoluminescence (VEPL) spectroscopy. The transition energies Ea, Eb, and Ec of both CuInSe2 (CIS) and CuGaSe2 (CGS) layers sensed by PR were higher than the energies of single crystals. CuInSe2 and CuGaSe2 grown on GaAs(001) underlie compressive and tensile stresses, respectively, which lead to band‐gap broadening in CIS and band‐gap narrowing in CGS. The increase of the Ea, Eb, Ec energies of tensely stressed CuGaSe2 layers to energies higher than those of the bulk originates from the stress dependence of the non‐cubic crystal field. Band‐gap scanning of the CuGaSe2 layer with continuous‐wave Ti:sapphire‐laser confirmed the absence of correlation between band‐gap readjustment and intrinsic defects. The energy of the band‐edge exciton EFE, in the PL‐spectra, was lower than the Ea transition energy, in the PR‐spectra, which is assigned to partial quenching of ΔCF with the increase of external tensile stress by gallium‐segregation at the chalcopyrite/GaAs‐interface. The stress dependence of ΔCF is negligible in CuInSe2 and linear, with a rate of 9 meV/100 MPa, in CuGaSe2. It is revealed that the energy band‐gap of photovoltaic chalcopyrite absorbers can be tuned by simultaneous built‐in and external lattice‐tuning. [ABSTRACT FROM AUTHOR]

Tough and self‐healing hydrogels are typically sensitive to loading rates or temperatures due to the dynamic nature of noncovalent bonds. Understanding the structure evolution under varying loading conditions can provide valuable insights for developing new tough soft materials. In this study, polyampholyte (PA) hydrogel with a hierarchical structure is used as a model system. The evolution of the microscopic structure during loading is investigated under varied loading temperatures. By combining ultra‐small angle X‐ray scattering (USAXS) and Mooney–Rivlin analysis, it is elucidated that the deformation of bicontinuous hard/soft phase networks is closely correlated with the relaxation dynamics or strength of noncovalent bonds. At high loading temperatures, the gel is soft and ductile, and large affine deformation of the phase‐separated networks is observed, correlated with the fast relaxation dynamics of noncovalent bonds. At low loading temperatures, the gel is stiff, and nonaffine deformation occurs from the onset of loading due to the substantial breaking of noncovalent bonds and limited chain mobility as well as weak adaptation of phase deformation to external stretch. This work provides an in‐depth understanding of the relationship between structure and performance of tough and self‐healing hydrogels. [ABSTRACT FROM AUTHOR]

Vanadium is a typical low-activation metal and has the advantages of lower neutron irradiation activation, better mechanical properties at high temperature, and higher compatibility with the liquid lithium blanket. However, the effect of helium on the formation of irradiation defects in vanadium has not been adequately explored at low temperatures (below 723 K). Helium ion irradiations of 18 keV up to 0.54 displacement per atom were employed to study the temperature-dependent behavior of irradiation defects in vanadium at 523, 623, and 723 K. Helium bubbles were observed in vanadium under irradiations at all temperatures, but no dislocation loops were observed. With the increase of irradiation temperature, the average size of helium bubbles and swelling increased, and the density of helium bubbles decreased. It is noteworthy that the average size of helium bubbles and swelling increased significantly when the irradiation temperature increased from 623 to 723 K. In addition, pentagonal helium bubbles, helium bubbles nucleated at the grain boundary, and combinations between helium bubbles were observed. [ABSTRACT FROM AUTHOR]

In this paper, we present spectroscopic ellipsometry measurements of five selected bulk chalcogenide glasses (Ge 28 Sb 6 Se 66 , Ge 19 Sb 17 Se 64 , Ge 12 Sb 25 Se 63 , Ge 28 Sb 12 Se 60 and As 40 Se 60) for broad wavelength range (0.3–15 μm) at the temperatures from room temperature up to glass transition temperature (with reserve). Temperature dependence of bandgap energy obtained from Tauc-Lorentz oscillator together with temperature dependence of refractive index for selected wavelengths (1.55, 3.4, 7.0 and 10.6 μm) where the studied materials are transparent are presented together with thermo-optic coefficients d E g /d T and d n /d T for these wavelengths. [ABSTRACT FROM AUTHOR]

In photosynthetic reaction centers, quenching of the primary donor triplet state by energy transfer to the carotenoid molecule provides efficient suppression of generation of singlet-excited oxygen, potent chemical oxidant. This process in the Cereibacter sphaeroides reaction centers is thermoactivated, and discontinues at temperatures below 40 K. In these reaction centers, substitution of amino acid residue isoleucine at the 177 position of the L-subunit with histidine results in the sharp decrease of activation energy, so that the carotenoid triplets are populated even at 10 K. Activation energy of the T-T energy transfer was estimated as 7.5 cm–1, which is more than 10-fold lower than activation energy in the wild type reaction centers. At certain temperatures, the energy transfer in the mutant is decelerated, which is related to the increase of effective distance of the triplet-triplet transfer. To the best of our knowledge, the described mutation presents the first reaction center modification leading to the significant decrease in activation energy of the T-T energy transfer to carotenoid molecule. The I(L177)H mutant reaction centers present a considerable interest for further studies of the triplet state quenching mechanisms, and of other photophysical and photochemical processes in the reaction centers of bacterial photosynthesis. [ABSTRACT FROM AUTHOR]

The temperature dependences of emission-band positions of the LED heterostructure and the phosphor of white LED lamps were determined to be linear or quasilinear with temperature coefficients K1 = –0.38 meV/K, K2 = 0.147 meV/K, and K3 = 0.27 meV/K for the bands at 2.7, 2.4, and 2.05 eV, respectively. Overheating of the heterostructure active regions during the test time was estimated using data from the spectral measurements. The estimates were compared with the results of direct temperature measurements. The temperature increased by ~20°C during the test time, which was less than the temperature increase of the electronic subsystem (~50°C), in agreement with literature data obtained for other types of LEDs. The main reason for the change in color temperature of the lamp radiation during operation was thermal quenching of luminescence in the phosphor material. [ABSTRACT FROM AUTHOR]

Although the residual stress in one‐side coating (type‐I coating) on a beam specimen can be determined by comparing the bending deformation before and after coating, the stress of a coated component without bending deformation (type‐II coating) is difficult to obtain via conventional methods, especially at high temperature. An image relative method is presented to determine variations in the curvature radius with temperatures for stress analysis at high temperature. A relationship between the residual stresses in type‐I and type‐II coatings was established so that the residual stress of type‐II coating was determined from the measured stress in type‐I coating. Thus, the core issue is to measure the temperature dependence of the bending deformation of the sample with one‐side coating. The temperature dependence of the residual stress in thermal barrier coatings on metal substrate was obtained by continuously photographing deflections of the beam specimen at temperatures ranging from 20°C to 1000°C, and the residual stress in components with symmetrical coatings in the temperature range was then determined. [ABSTRACT FROM AUTHOR]

Rheological behaviors of polymeric materials have been observed to be temperature-dependent, which demands considering temperature effects in constitutive models. In this article, a fractional rheological model is developed to describe creep and relaxation behaviors, of which linear criterion between model parameter and temperature is established. Temperature-dependent fractional orders of the model are naturally interpreted by the well-known master curve. Numerous experimental data in a limited range of temperatures are employed to certificate the applicability of the proposed models. Simulation results demonstrate that the models are equipped with a simpler formulation and high fitting accuracy compared with existing models. [ABSTRACT FROM AUTHOR]

This study examined the gel formation behavior and temperature-dependent mechanical characteristics of gel-cast alumina–agar mixtures. The shift from viscoelastic to elastic behaviors, the influence of final agar content, the reversibility of the viscoelastic–elastic transition, and the relationship between complex modulus and temperature were all investigated. The complex viscosity of the mixtures was also investigated to determine their role in ceramic shaping operations. The findings are useful for academics and practitioners in materials science and engineering, especially those who work with alumina–agar mixtures. [ABSTRACT FROM AUTHOR]

Creep is an essential aspect of the durability and longevity of concrete structures. Based on fractional-order viscoelastic theory, this study investigated a creep model for predicting the temperature-dependent creep behavior of concrete. The order of the proposed fractional-order creep model can intuitively reflect the evolution of the material characteristics between solids and fluids, which provides a quantitative way to directly reveal the influence of loading conditions on the temperature-dependent mechanical properties of concrete during creep. The effectiveness of the model was verified using the experimental data of lightweight expansive shale concrete under various temperature and stress conditions, and the comparison of the results with those of the model in the literature showed that the proposed model has good accuracy while maintaining simplicity. Further analysis of the fractional order showed that temperature, not stress level, is the key factor affecting the creep process of concrete. At the same temperature, the fractional order is almost a fixed value and increases with the increase in temperature, reflecting the gradual softening of the mechanical properties of concrete at higher temperature. Finally, a novel prediction formula containing the average fractional-order value at each temperature was established, and the creep deformation of concrete can be predicted only by changing the applied stress, which provides a simple and practical method for predicting the temperature-dependent creep behavior of concrete. [ABSTRACT FROM AUTHOR]

Summary: Bursaphelenchus xylophilus is the causative agent of pine wilt disease and is indigenous to North America. It has been introduced into Japan where the non-pathogenic close relative, B. mucronatus , is widely distributed. Both nematode species have similar life cycles with vectors of cerambycid beetles of the genus Monochamus. When interspecific hybrids are backcrossed with B. xylophilus nematodes repeatedly, a small proportion of B. mucronatus genes is infused into the B. xylophilus genome (introgression) and may lead to adaptation to locally harsh environments. Though cool temperatures had inhibited the development of pine wilt disease, B. xylophilus started expanding the range to cool-summer areas after suspending its range expansion for 10 years in Japan. To consider if the range expansion is related to the introgression hybridisation between the two Bursaphelenchus species, some traits of newly and already formed hybrid-derived populations were compared between three temperature conditions of 16, 20 and 25°C. Formation of F1 hybrids was not affected by temperature. There was no difference in the time required for hybrid formation and for population establishment at 16°C between an interspecific crossing and two intraspecific crossings of B. xylophilus. Using three hybrid-derived populations reared over multiple generations at 25°C, there was no difference in the early rate of population growth between each of two hybrid-derived populations and its parental-lineage population of B. xylophilus at 16°C. Thus, the results did not reject a hypothesis that introgression hybridisation may have enhanced the fitness components such as pathogenicity of B. xylophilus populations at cool temperatures. [ABSTRACT FROM AUTHOR]

The increasing importance of accurate battery state estimations in advanced Battery Management Systems (BMS) underscores the need for precise modelling of battery behaviour and characteristics. While equivalent circuit models are widely utilized for their low computational demands, they face challenges in maintaining precision and adaptability during dynamic conditions, posing a persistent concern for future advancements. This study focuses specifically on the battery hysteresis effect, a complicating factor in the modelling and estimation processes. Open circuit voltage (OCV) measurements and parameter identification for equivalent circuit models were conducted on prevalent Li-ion battery technologies, namely nickel-manganese–cobalt (NMC) and lithium-iron-phosphate (LFP). The experimental results indicate the hysteresis effect becomes more significant with lower temperatures. In this paper, a battery model covering the temperature influence on the hysteresis effect is proposed. The proposed model exhibits an average root mean square error of less than 13 mV. The model holds promise for application in modern battery management systems, offering an enhancement to state-of-charge estimation methodologies. [ABSTRACT FROM AUTHOR]

The present work deals with the study of the effect of temperature on the Raman spectroscopy and electrical properties of the silicon nanowires. The nanowires are fabricated through silver assisted electrochemical etching process. Prior to these studies, the fabricated nanowires are characterized through field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), and X-ray diffraction (XRD) measurements. FESEM reveals the vertical alignment of the nanowires. FETEM indicates the materials to be highly crystalline, which is also complemented by the XRD result. Raman peak is blue-shifted with a decrease of temperature suggesting lattice disturbance at low temperature. Temperature-dependent current-voltage (I-V) measurements are fitted with Cheung’s model and the characteristic parameters viz. ideality factor (n), barrier height (ϕb), and series resistance (Rs) are estimated from the fitted plots. At lower temperatures, the value of n highly deviates from the ideal value of unity and is 23.42 at 110 K. The materials are observed to obey space charge limited conduction (SCLC) to trap charge limit current (TCLC) with increasing bias at lower temperatures. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) have garnered significant attention due to their remarkable electronic and magnetic properties. In this research, we introduced multiwalled carbon nanotubes covered with tantalum (MWNTs/Ta) to systematically modulate the magnetoresistive properties of the MWNTs/Ta hybrid nanostructures. We observed distinct changes in both positive and negative magnetoresistances of MWNTs/Ta across a broad temperature range using a physical property measurement system and a four-terminal method. This study on temperature-dependent magnetoresistive behavior of the MWNTs/Ta sheds light on the fundamental properties of carbon-based materials and holds promise for practical applications in the field of spintronic devices. [ABSTRACT FROM AUTHOR]

The increasing importance of accurate battery state estimations in advanced Battery Management Systems (BMS) underscores the need for precise modelling of battery behaviour and characteristics. While equivalent circuit models are widely utilized for their low computational demands, they face challenges in maintaining precision and adaptability during dynamic conditions, posing a persistent concern for future advancements. This study focuses specifically on the battery hysteresis effect, a complicating factor in the modelling and estimation processes. Open circuit voltage (OCV) measurements and parameter identification for equivalent circuit models were conducted on prevalent Li-ion battery technologies, namely nickel-manganese–cobalt (NMC) and lithium-iron-phosphate (LFP). The experimental results indicate the hysteresis effect becomes more significant with lower temperatures. In this paper, a battery model covering the temperature influence on the hysteresis effect is proposed. The proposed model exhibits an average root mean square error of less than 13 mV. The model holds promise for application in modern battery management systems, offering an enhancement to state-of-charge estimation methodologies.

Abstract Monolayer materials typically display intriguing temperature-dependent dielectric and optical properties, which are crucial for improving the structure and functionality of associated devices. Due to its unique photoelectric capabilities, monolayer WSe2 has recently received a lot of attention in the fields of atomically thin electronics and optoelectronics. In this work, we focus on the evolution of the temperature-dependent dielectric function (ε = ε1 + i ε2) of monolayer WSe2 over energies from 0.74 to 6.40 eV and temperatures from 40 to 350 K. We analyze the second derivatives of ε with respect to energy to accurately locate the critical points (CP). The dependence of the observed CP energies on temperature is consistent with the alternative domination of the declining exciton binding energy as the temperature increases.

Highly-crystallized carbon nitride (HCCN) nanosheets exhibit significant potential for advancements in the field of photoelectric conversion. However, to fully exploit their potential, a thorough understanding of the fundamental excitonic photophysical processes is crucial. Here, the temperature-dependent excitonic photoluminescence (PL) of HCCN nanosheets and amorphous polymeric carbon nitride (PCN) is investigated using steady-state and time-resolved PL spectroscopy. The exciton binding energy of HCCN is determined to be 109.26 meV, lower than that of PCN (207.39 meV), which is attributed to the ordered stacking structure of HCCN with a weaker Coulomb interaction between electrons and holes. As the temperature increases, a noticeable reduction in PL lifetime is observed on both the HCCN and PCN, which is ascribed to the thermal activation of carrier trapping by the enhanced electron–phonon coupling effect. The thermal activation energy of HCCN is determined to be 102.9 meV, close to the value of PCN, due to their same band structures. Through wavelength-dependent PL dynamics analysis, we have identified the PL emission of HCCN as deriving from the transitions: σ *–LP, π *– π, and π *–LP, where the π *–LP transition dominants the emission because of the high excited state density of the LP state. These results demonstrate the impact of high-crystallinity on the excitonic emission of HCCN materials, thereby expanding their potential applications in the field of photoelectric conversion. [ABSTRACT FROM AUTHOR]

Opposed to piloted ignition, where a substance is ignited by an external flame or spark, the term auto-ignition describes the onset of combustion by spontaneous ignition without an external source. In this study, the influence of the size of spherical wood samples and the temperature surrounding the samples was investigated by performing ignition experiments in a muffle furnace with beech and spruce wood. On a specially constructed rig, spheres with four different diameters (8 mm, 12 mm, 18 mm, and 25 mm) were put into a preheated furnace at five isothermal temperatures (240 °C, 270 °C, 300 °C, 330 °C, and 360 °C). For every temperature, diameter, and wood species, the experiments were repeated eight times, and positions of the spheres on the rig were changed for every measurement. Temperatures inside the samples were recorded with thermocouples (TC) positioned in holes drilled to the middle of the spheres. With rising size and temperature, samples were more prone to auto-ignition in a glowing mode, due to a larger, highly reactive pyrolyzed surface and internal overheating. During heating and oxidative pyrolysis, isothermal phases were present at approximately 360 °C in the recorded temperature curves. The comparison to simultaneous thermal analysis (STA) measurements shows decomposition of hemicelluloses, and cellulose is highest around 360 °C. It is concluded that pyrolysis and disintegration of the main wood constituents use up all arising energy. Due to differences in the composition of the wood polymers, beech wood samples already ignite at lower temperatures compared to spruce wood samples with the same diameter. It can be concluded that the size is a critical factor for auto-ignition at the used temperatures. Larger samples will produce more volatile compounds during pyrolysis and have a larger pyrolyzed, porous surface area where heterogenous oxidation reactions can happen. The influence of the size is already critical at differences on the millimetre scale. [ABSTRACT FROM AUTHOR]

The current research project intends to enhance solar cells' power and conversion efficiency based on InN/p-Si utilizing the PC1D simulator. A broad direct bandgap of Indium nitride (0.65 eV) makes it suitable for various applications. The InN-based solar cells show an excellent candidate for generating a higher efficiency device, incorporating well-established silicon substrate technology. The open-source PC1D is well-known software for simulating future solar devices without the need to fabricate real devices. The simulated area was adjusted to 10 cm². The Si substrate and InN layer thicknesses were designed to be 350 µm and 1×10-3 µm, respectively. The n- and p-regions have doping concentrations of 1×1021 cm-3 and 1×1017 cm-3, respectively. This work analyses the influence of geometrical and technological aspects such as both n-p regions thickness, doping concentrations, and temperature dependency to enhance the conversion efficiency of these structures under the AM1.5G solar spectrum with intensity 0.1 W/cm2. It has been demonstrated that the growth of high-quality InN layers and p-type doping persists to be problematic. It appears challenging to find the most suitable material substrate for InN solar. To produce compatible solar cells with simple structures and cost-effective, however, extremely thin layers of n-layer material are required due to the high absorption coefficient of type III-nitrides. The results illustrate that by adjusting the optimized parameter at room temperature to the lowest temperature (200 K), the solar efficiency may increase up from 19.18% to 27.67%. [ABSTRACT FROM AUTHOR]

While the simple model of the total atmospheric carbon sink effect as a linear function of concentration has provided excellent prediction results, several problems remained to be investigated and solved. The most obvious open issue is the correct treatment of land use change emissions. It turns out that the model improves by mostly neglecting these emissions after 1950. This effectively implies that land use change emissions have been constant and small since then. The key investigation starts with the observation that the total carbon sink has a short-term component that can be explained by temperature changes. The apparent paradox, why contrary to the short-term changes no temperature-caused trend can be detected, despite the fact that several contributing processes exhibit clear temperature dependency, is analyzed and explained. The result of this analysis leads to the model extension, where the total effect of absorptions and natural emissions are a linear function of concentration and temperature. This extended model not only explains current measurements but also paleo-climate data from ice core time series. [ABSTRACT FROM AUTHOR]

In this study, the resistive switching phenomena in TiN/Ti/HfO2/Ti metal–insulator–metal stacks is investigated, mainly focusing on the analysis of set and reset transitions. The electrical measurements in a wide temperature range reveal that the switching transitions require less voltage (and thus, less energy) as temperature rises, with the reset process being much more temperature sensitive. The main conduction mechanism in both resistance states is Space-charge-limited Conduction, but the high conductivity state also shows Schottky emission, explaining its temperature dependence. Moreover, the temporal evolution of these transitions reveals clear differences between them, as their current transient response is completely different. While the set is sudden, the reset process development is clearly non-linear, closely resembling a sigmoid function. This asymmetry between switching processes is of extreme importance in the manipulation and control of the multi-level characteristics and has clear implications in the possible applications of resistive switching devices in neuromorphic computing. [ABSTRACT FROM AUTHOR]

The paper presents the noise analysis of a MEMS and ASIC readout integrated circuit (ROIC) constituting the accelerometer developed in the frame of the InnoReh project, aiming at the development of methods for monitoring patients with imbalance disorders. Several experiments were performed at different temperatures and in different configurations: ROIC alone, ROIC with emulated parasitic capacitances, MEMS and ROIC in separate packages, and MEMS and ROIC in a single package. Many noise/interference sources were considered. The results obtained experimentally were compared to the results of theoretical investigations and were within the same order of magnitude, although in practice, the observed noise was always greater than the theoretical estimation. The paper also includes an in-depth analysis to explain these differences. Moreover, it is argued that, in terms of noise, the MEMS sensing element, and not the ROIC, is the quality-limiting factor. [ABSTRACT FROM AUTHOR]

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The temperature dependence of vegetable hardening due to preheating was found to be similar for Japanese radishes, carrots and potatoes. The hardening phenomenon occurred slightly at 50–55 °C and markedly at 60–70 °C, especially at 65 °C, and decreased at 80 °C. However, temperature dependence of the cell membrane damage that triggered hardening was different across the vegetables, as revealed by the measurements of eluted potassium ions and electrical properties. The highest heat sensitivity of the cell membrane was observed in carrots while the lowest was in potatoes. The maximum hardening at 65 °C was confirmed by a complete loss of cell membrane integrity, followed by adequate leakage of intracellular potassium ions, resulting in high PME activity despite the effect of heat inactivation. A sample size of 1 cm cubic used this study was beneficial for distinguishing the effect of different temperatures, because the inner temperature quickly matched the preheating temperature. [ABSTRACT FROM AUTHOR]

An effective procedure to explore the thermal response of living skin tissue exposed on severe thermal circumstance is proposed in this paper. The triple-layered inner structure with variable blood perfusion is employed to construct the governing equations via the dual-phase-lag model of bio-heat transfer. An analytical procedure, based on the Laplace transform and its limit theorem, is then introduced to the solution, in which a linearization technique is prior to disperse the non-linear terms included in these governing equations. The thermal response of the skin tissue with its boundary subjected to a pulse heat flux is solved and verified. A detailed parametric study has been carried out to evaluate the effect of the temperature dependency, phase lags, and material distribution on thermal response and associated thermal damage. [ABSTRACT FROM AUTHOR]

Based on the numerical results on the non‐linear correlation between volume of plastic zone and global loading level represented by stress intensity factor, the dependence of cleavage fracture toughness of ferritic steels on specimen size and temperature is evaluated based on an empirical statistical model. The statistical correlation is supported by two sets of toughness data measured from different sized compact tension specimens at different temperatures. To further improve the accuracy of the statistical model, future work is identified to quantify the variation of volume of plastic deformation zone with loading level and measure the average volume for each microcrack at different temperature. Highlights: A non‐Weibull statistical model of cleavage toughness is proposed.Dependence of cleavage toughness on temperature and specimen size is studied.The model is validated by two sets of cleavage toughness data.Two research topics are identified for model improvement. [ABSTRACT FROM AUTHOR]

This paper investigates the temperature-dependent effects of gamma-ray irradiation on β-Ga2O3 vertical Schottky barrier diodes (SBDs) under a 100 V reverse bias condition at a total dose of 1 Mrad(Si). As the irradiation dose increased, the radiation damage became more severe. The total ionizing dose (TID) degradation behavior and mechanisms were evaluated through DC, capacitance–voltage (C-V), and low-frequency noise (LFN) measurements by varying irradiation, and the test results indicated that TID effects introduced interface defects and altered the carrier concentration within the material. The impact of TID effects was more pronounced at lower temperatures compared to higher temperatures. Additionally, the annealing effect in the high-temperature experimental conditions ameliorated the growth of interface trap defects caused by irradiation. These results suggest that compared to low-temperature testing, the device exhibits higher TID tolerance after high-temperature exposure, providing valuable insights for in-depth radiation reliability studies on subsequent related devices. [ABSTRACT FROM AUTHOR]

In the dynamic landscape of display technologies, the advent of Micro‐LEDs has sparked a revolutionary shift, promising unparalleled advancements in visual display capabilities. This study immerses itself in the realm of GaN‐based MicroLED devices, specifically delving into the nuanced effects of varying current density and temperature on the spectra of MicroLEDs with gallium nitride substrates. Through a meticulous comparative analysis, we unravel the optical distinctions between MicroLEDs utilizing gallium nitride and sapphire substrates. Additionally, our exploration extends to the examination of the diverse luminous intensity decay rates experienced by these devices under different substrate temperatures. The findings illuminate the pronounced optical advantages bestowed by gallium nitride substrates in GaN‐based MicroLEDs, providing pivotal insights for the ongoing refinement and enhancement of these cutting‐edge display technologies. [ABSTRACT FROM AUTHOR]

Δ3-carene is a prominent monoterpene in the atmosphere, contributing significantly to secondary organic aerosol (SOA) formation. However, knowledge about Δ3-carene oxidation pathways, particularly regarding its ability to form highly oxygenated organic molecules (HOM), is still limited. In this study, we present HOM measurements during Δ3-carene ozonolysis under various conditions in two simulation chambers. We identified numerous HOM (monomers: C7-10H10-18O6-14, dimers: C17-20H24-34O6-18) using a chemical ionization mass spectrometer (CIMS). Δ3-carene ozonolysis yielded higher HOM concentrations than a-pinene, with a distinct distribution, indicating differences in formation pathways. All HOM signals decreased considerably at lower temperatures, reducing the estimated molar HOM yield from ~3 % at 20 °C to ~0.5 % at 0 °C. Interestingly, temperature change altered the HOM distribution, increasing the observed dimer-to-monomer ratios from roughly 0.8 at 20 °C to 1.5 at 0 °C. HOM monomers with 6 or 7 O-atoms condensed more efficiently onto particles at colder temperatures, while monomers with nine or more O-atoms and all dimers condensed irreversibly even at 20 °C. Using the gas and particle-phase chemistry kinetic multilayer model ADCHAM, we were also able to reproduce the experimentally observed HOM composition, yields and temperature dependence. [ABSTRACT FROM AUTHOR]

Elastomeric foams are composite materials comprising of a polymeric elastomer and interconnected gas‐filled pores, endowing them with exceptional compliance and the ability to undergo large, reversible deformations along with substantial volume change. These foams find extensive utility in contexts demanding compliance and compressibility, such as impact protection and cushioning, spanning a diverse range of applications. Changing temperature can dramatically alter foam stiffness, strength and deformation characteristics specifically around the material's glassy‐rubbery transition temperature (Tg$$ {T}_g $$). With the aim of informing new constitutive model developments for elastomeric foams, we conducted a comprehensive series of large deformation, homogeneous compression and tension tests across strain rates from 10−2 s−1 to 100 s−1 and ambient temperatures ranging from −10°C to 50°C covering an even range around the material's Tg$$ {T}_g $$ of 20°C. To achieve precise control of ambient temperatures during mechanical testing, we constructed a custom‐designed environmental chamber for controlling the ambient temperature from −10°C to 50°C with a variation of less than 1°C. The obtained digital image correlation based stress‐strain data shows significant tension‐compression asymmetry as well as significant dependence on strain rate and ambient temperature, especially above and below the glass transition temperature. We provide full access to these data sets for the future development of rate‐ and temperature‐dependent constitutive models. [ABSTRACT FROM AUTHOR]

Upconversion (UC) nanomaterials are of interest to researchers because of their excellent photostability, effective quantum efficiency and optical temperature dependence. However, most UC nanomaterials are thermally quenched, which causes optical nanothermometers to be susceptible to their own thermal effects, reducing the accuracy of temperature measurements. In this paper, NaYF4:Yb3+/Ho3+/Tm3+/Gd3+ nanorods with UC luminescence and resistance to thermal quenching are prepared through a simple hydrothermal method. The UC luminescence intensity of NaYF4:Yb3+/Ho3+/Tm3+/Gd3+ nanorods is adjusted by doping with Tm3+ ions. The luminescence intensity at each location shows different temperature dependence as the temperature increases. When the temperature reaches 573 K, the integrated luminescence intensity is three times that at 293 K. At the same time, the intensity at all temperature points in the range of 293–573 K is greater than the intensity at 293 K, which shows that the nanorods have excellent resistance to thermal quenching. In addition, the relative sensitivity (Sr) of LIR(I696/I476), LIR(I696/I541), LIR(I696/I646), LIR(I696/I802), and LIR(I541/I476) is investigated based on the luminescence intensity ratio (LIR) technique. The Sr of LIR(I696/I802) is found to have larger values in the low-temperature range, while Sr of LIR(I696/I476) has larger values in the high-temperature range. The use of LIR(I696/I802) and LIR(I696/I476) in separate temperature bands allows Sr to reach 0.93–1.67 %K−1 in the range of 293–573 K, confirming that the nanorods have high Sr over a wide temperature interval. This study indicates that the NaYF4:Yb3+/Ho3+/Tm3+/Gd3+ nanorods are promising candidates for optical thermometers with high sensitivity, wide temperature range, and resistance to thermal quenching. [ABSTRACT FROM AUTHOR]

Herein, the authors investigate the temperature‐dependent properties of delayed luminescence in an as‐grown nitrogen‐containing chemical vapor deposition synthetic diamond gemstone when excited above its bandgap. At room temperature, this gemstone exhibits delayed luminescence from nitrogen‐vacancy centers at 575 nm. However, at 77 K, the first recorded instance of a long‐lived delayed blue luminescence centered at ≈465 nm, accompanied by spectral peaks at 419, 455, and 499 nm is reported. By analyzing spectral and temporal data at different temperatures, it can be speculated on potential photophysical transitions. This discovery documents the initial observation of this delayed luminescence emission, contributing to the collective understanding of synthetic diamonds. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) (PVDF) is predominantly characterized by alternating CH2 and CF2 units in a polymer backbone, originating from the head-to-tail addition of monomers or regular propagation. Due, to a small extent, to inverse monomer addition, so-called defect structures occur which influence the macroscopic properties of PVDF significantly. The amount of defect structures in the material is determined by the polymerization conditions. Here, the temperature dependence of the fraction of defect structures in PVDF obtained from polymerizations between 45 and 90 °C is reported. We utilized 19F-NMR spectroscopy to determine the fraction of defect structures as a function of temperature. To derive kinetic data, the polymerization of VDF is considered a quasi-copolymerization described by the Terminal Model involving four different propagation reactions. Based on the experimentally determined temperature-dependent fractions of defect structures, the known overall propagation rate coefficient, and taking into account the self-healing behavior of the macroradical, the Arrhenius parameters of the individual propagation rate coefficients were determined using the Monte Carlo methods. [ABSTRACT FROM AUTHOR]

Radar observation is an effective way to understand subsurface structures in terms of the dielectric constant, whose controlling factors include chemical composition, packing density, and water/ice content. Recently, laboratory measurements have shown that the dielectric constant of lunar regolith simulants also depends on the temperature, which has never been evaluated from remote sensing data. In this study, we estimated the dielectric constant from the Miniature Radio Frequency (Mini-RF) data on a lunar crater floor in the north polar region at two different local times (i.e., different surface temperatures). We calculated the dielectric constant using the inversion method and obtained the bolometric surface temperature from the Diviner Lunar Radiometer Experiment (Diviner) data. The histograms of the estimated dielectric constant values are different between the two local times. This could be interpreted as a result of the temperature dependence of the dielectric constant, while further evaluation of the influence of topography on the incidence angle and small surface roughness is needed. Nevertheless, our result suggests that the temperature dependence of the dielectric constant should be considered when interpreting S-band radar observations of the Moon and other celestial bodies with large surface temperature differences. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) utilize the synergetic effect of triboelectrification and electrostatic induction to guide electrons through an external circuit, enabling low‐frequency mechanical and biomechanical energy harvesting and self‐powered sensing. Integrating 2D material with a high specific surface area into flexible ferroelectric polymers such as polyvinylidene difluoride (PVDF) has proven to be an efficient strategy to improve the performance of TENG devices. Scalable fabrication of graphene‐integrated PVDF nanocomposite fiber using thermal drawing process is demonstrated for the first time in this study. The open‐circuit voltage and short‐circuit current show 1.41 times and 1.48 times improvement with the integration of 5% graphene in the PVDF fibers, respectively. The TENG fabric shows a maximum power output of 32.14 µW at a matching load of 7 MΩ and a power density of 53.57 mW m−2. The fibers exhibit excellent stability in harsh environmental conditions such as alkaline medium, high/low temperature, multi‐washing cycle, and long‐time usage. [ABSTRACT FROM AUTHOR]

As is known, grain boundary (GB) energy determines the mobility of GBs and their population in metals. In this work, we study the energy of GBs in the (100) crystallographic plane and in the temperature range from 100 to 700 K. The study is carried out using both the molecular dynamic (MD) method and machine learning approach to approximate the MD data in order to obtain functional dependence in the form of a feed-forward neural network (FCNN). We consider the tilt and twist grain boundaries in the range of misorientation angles from 0 to 90°. Also, we calculate the average and minimum energy over the ensemble of GB states, since there are many stable and metastable structures with different energies even at a fixed grain misorientation. The minimum energies decrease with increasing temperature, which is consistent with the results of other studies. The scatter of GB energies in the temperature range from 100 to 700 K is obtained on the basis of MD simulation data. The obtained energy spread is in reasonable agreement with the data from other works on the values of GB energy in pure aluminum. The predictive ability of the trained FCNN as well as its ability to interpolate between the energy and temperature points from MD data are both demonstrated. [ABSTRACT FROM AUTHOR]

The elasticity matrix and the coefficients of thermal expansion (CTEs) of 8-harness satin-woven (8HS) carbon-fiber-reinforced carbon matrix (C/C) composites at high temperatures were obtained by the asymptotic homogenization method (AHM) and finite element method (FEM). By analyzing the microstructure of the 8HS C/C composites, a representative volume element (RVE) model considering a braided structure was established. The effects of the temperature and component volume fraction on the elasticity matrix and CTEs of the composites were investigated. The sensitivity of model parameters, including the size of RVE model and mesh sensitivity, were studied. The optimal calculation model was employed. In addition, the effects of the 4HS methods and 8HS methods on the elastic constants of the composites were compared. The temperature and variation in the carbon fiber volume fraction were found to have a significant impact on the elasticity matrix and CTEs of composite materials. At the same volume fraction of carbon fibers, some elastic coefficients of the 4HS composite material were slightly lower than those of 8HS composite material. This research affords a computational strategy for the accurate prediction of the themo-mechanical properties of satin-woven C/C composites. [ABSTRACT FROM AUTHOR]

Lead halide perovskite nanocrystals (NCs) have emerged as next‐generation semiconductors capable of unifying superior photoemission properties, facile and inexpensive preparation, compositional and structural versatility. Among them, CsPbBr3 is a model system in theoretical and experimental studies owing to its intrinsic chemical stability. Nonetheless, knowledge of the precise magnitude and the size‐ and temperature‐dependent lattice and structural distortions is lacking, and the static/dynamic nature of disorder in NCs remains an open question. Herein, robust reciprocal space X‐ray total scattering analysis is applied and accurate lattice distortions, PbBr bond distances, and PbBrPb angles versus NCs size are extracted. The lattice anisotropy increases upon expansion on downsizing while, upon contraction on cooling, the lattice distortion behaves differently at intermediate (9 nm) and ultrasmall (5 nm) sizes and from the bulk. Bond distances (stretched by ≈1%) do not show any size dependence, whereas equatorial and axial angles denote more symmetric octahedral arrangements in the smallest sizes, where they differ by ≈2° compared to ≈8° in the bulk. Anomalously high atomic displacement parameters of axial bromine ions persisting down to cryogenic temperatures suggest statically disordered octahedral tilts. These results provide insights having important implications on size‐dependent emission properties and the exciton fine structure. [ABSTRACT FROM AUTHOR]

Zirconia toughened alumina (ZTA) has a wide range of applications in high temperature. Though some routes were reported to enhance the mechanical properties at room temperature, the preparation of ZTA with improved high temperature properties was still unknown. In this work, cordierite/ZTA pre‐stressed ceramics (marked as Cor‐ZTA30) have been fabricated successfully by using prestressed coating reinforcement method. The relationships among the temperature, residual stress and the flexural strength of Cor‐ZTA30 have been established based on experimental data. Due to the compressive stresses exists in the surface layer of Cor‐ZTA30 hinder the crack extension, the flexural strength of Cor‐ZTA30 was greatly enhanced at the temperatures below 1000°C. In addition, the difference in flexural strength between coated and uncoated ZTA ceramics decreased with increasing temperature until 1000°C. It indicated that the residual stress vanished entirely as the temperature above 1000°C, which resulted in the same flexural strength for ZTA and Cor‐ZTA30. Therefore, strengthening ZTA ceramics by prestressing is available under the temperatures below 1000°C. [ABSTRACT FROM AUTHOR]

The self-sensing ability of materials, in particular carbon fiber polymer composites (SSCFPC), is a must-have requirement when designing a structural monitoring network for remote assessment of structural serviceability. This work presents a study using an Artificial Deep Neural Network (ADNN) wherein is evaluated the electrical resistance (R) output of specimens subjected to an unchanged deformation state of 2.86% strain for prolonged periods of time. Six ADNN architectures are evaluated with varying numbers of neurons on pre-defined hidden layers, sharing the same four data inputs and one output. The dataset is based on 3276 data points collected during the experimental campaign of an innovative electrode design embedded in SSCFPC specimens. The effect of the number of iterations and the architecture of the neural network is investigated in proposed ADNN models. Simple moving average, and moving Standard Deviation, σ M , are determined and plotted in terms of z -score to assist in performance evaluation of proposed ADNN models. The optimal ADNN architecture is found among six proposed architectures and for each of the four SSCFPC mixtures. Results show the proposed model architectures are able to predict values of R with greater accuracy than traditional regression mathematical methods when traditional statistical coefficients are used. However, when analyzing data in a time-series manner, results show further research is needed to achieve optimal accuracy results. The analysis presented focused on the structural monitoring network infrastructure and hardware electronics compatibility for further development of this type of SSCFPC as a self-sensing composite material with ability of automatic calibration and suitable for real-time data acquisition and artificial intelligence modeling. [ABSTRACT FROM AUTHOR]

Because the conventional Temperature Drift Error (TDE) estimation model for Capacitive MEMS Gyros (CMGs) has inadequate Temperature Correlated Quantities (TCQs) and inaccurate parameter identification to improve their bias stability, its novel model based on thermal stress deformation analysis is presented. Firstly, the TDE of the CMG is traced precisely by analyzing its structural deformation under thermal stress, and more key decisive TCQs are explored, including ambient temperature variation ∆T and its square ∆T2, as well its square root ∆T1/2; then, a novel TDE estimation model is established. Secondly, a Radial Basis Function Neural Network (RBFNN) is applied to identify its parameter accurately, which eliminates local optimums of the conventional model based on a Back-Propagation Neural Network (BPNN) to improve bias stability. By analyzing heat conduction between CMGs and the thermal chamber with heat flux analysis, proper temperature control intervals and reasonable temperature control periods are obtained to form a TDE precise test method to avoid time-consuming and expensive experiments. The novel model is implemented with an adequate TCQ and RBFNN, and the Mean Square Deviation (MSD) is introduced to evaluate its performance. Finally, the conventional model and novel model are compared with bias stability. Compared with the conventional model, the novel one improves CMG's bias stability by 15% evenly. It estimates TDE more precisely to decouple Si-based materials' temperature dependence effectively, and CMG's environmental adaptability is enhanced to widen its application under complex conditions. [ABSTRACT FROM AUTHOR]

It was found that in the region of the percolation threshold, depending on the dominance of one or another conduction mechanism, the temperature dependence of the specific volume resistivity ρ(T) of the polymer composite based on a matrix of ethylene vinyl acetate is significantly transformed. With an increase in the CB content, there is a decrease by several orders of magnitude in the maximum value of the relative resistivity ρ(T)max/ρ20 in its temperature dependence. Peroxide crosslinking of matrix macromolecules leads to a change in the nature of the temperature dependence of resistivity. [ABSTRACT FROM AUTHOR]

Context: The solvation of metal ions is crucial to understanding relevant properties in physics, chemistry, or biology. Therefore, we present solvation enthalpies and solvation free energies of the ferrous ion in water and ammonia. Our results agree well with the experimental reports for the hydration free energy and hydration enthalpy. We obtained - 1888.7 kJ mol - 1 for the hydration free energy and - 1900.7 kJ mol - 1 for the hydration enthalpy of ferrous ion in water at room temperature. At ambient temperature, we obtained - 2065.7 kJ mol - 1 as the F e 2 + ammoniation free energy and - 2124.2 kJ mol - 1 for the ammoniation enthalpy. In addition, the free energy of solvation is deeply affected when the temperature increases. This pattern can be attributed to the rise of entropy when the temperature rises. Besides, the temperature does not affect the ammoniation enthalpies and the hydration enthalpy of the F e 2 + ion. Method: All the geometry optimizations are performed at the MP2 methods associated with the 6-31++g(d,p) basis set of Pople. solvated phase structures of F e 2 + ion in water or in ammonia are performed using the PCM model. The G a u s s i a n 16 program suite was used to perform all the calculations. The program TEMPO was also used to evaluate the temperature sensitivity of the different obtained geometries. [ABSTRACT FROM AUTHOR]

The article summarizes the results of experimental studies of the temperature dependence of the thermophysical properties and thermodynamic functions of lead babbitt BLa (PbSb15Sn10) with lanthanum additives. The heat capacity of lead babbitt was determined in the "cooling" mode according to the known heat capacity of a reference sample of C2C lead. For this purpose, by processing the cooling curves of lead babbitt samples and reference, equations were obtained that describe their cooling rates. Further, on the basis of the experimentally found cooling rates of the reference and alloy samples, knowing their masses, polynomials for the temperature dependence of the heat capacity of the alloys and the standard were established, which are described by a four-term equation. Using integrals of specific heat capacity, the temperature dependence of changes in enthalpy, entropy, and Gibbs energy is determined. The data obtained show that, with increasing temperature, the heat capacity, heat transfer coefficient, enthalpy, and entropy of babbitt BLa (PbSb15Sn10) increase, and the Gibbs energy decreases. At the same time, lanthanum additives from 0.01 to 1.0 wt % increase the heat capacity, enthalpy, and entropy of babbitt BLa (PbSb15Sn10), while the value of the Gibbs energy decreases. [ABSTRACT FROM AUTHOR]