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An unusually large amplitude spontaneous miniature endplate potentials (gMEPPs) occur naturally at low frequency at the vertebrate neuromuscular junction. Unlike the normal miniature endplate potentials (nMEPPs), these gMEPPs have long duration and long time to peak. More strikingly, gMEPPs seem to be independent of extracellular and intracellular Ca+2. and have a greater temperature sensitivity than nMEPPs. They are potentiated by tetrodotoxin but inhibited by acetylcholine (ACh) receptor blockers indicating ACh is the neurotransmitter responsible for gMEPPs. The frequency of gMEPPs is greatly increased in muscles weakened by various drugs, toxins or disease conditions suggesting that gMEPPs may be a part of possible neurotrophic mechanism to preserve effective neuromuscular transmission when the normal function is compromised. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper proposes a nanowatt voltage reference (VR) with temperature coefficient compensation. All transistors work in the subthreshold region. The complementary‐to‐absolute‐temperature (CTAT) voltage and proportional‐to‐absolute‐temperature (PTAT) voltage are mainly generated by two NMOS transistors with different threshold voltages. At the same time, a simple temperature compensation circuit is designed to optimize the temperature coefficient at high temperatures, so that the proposed VR circuit can generate a reference voltage with a wider temperature range and a lower temperature coefficient. The proposed VR circuit is implemented using a standard 0.18‐μm CMOS process with an active area of only 0.022 mm2. The postlayout simulation results show that the proposed VR circuit generates a reference voltage of 308.21 mV at room temperature. Its temperature coefficient is 6.4 ppm/°C over a temperature range of −40°C°C–140°C, with a power consumption of 7.4 nW. The voltage line sensitivity (LS) is 0.098%/V, and the power supply ripple rejection (PSRR) is −72 dB @DC and −42 dB @10 MHz. [ABSTRACT FROM AUTHOR]

Summary: Fluorescent optical fiber temperature sensors require accurate online temperature monitoring in hazardous environments with strong electromagnetic fields, high voltages, flammability, or explosiveness. This imposes stringent requirements on the temperature coefficient stability of the bandgap reference (BGR) circuit. To address these challenges, this paper proposes a high‐order curvature compensation bandgap reference (HCC_BGR) circuit fabricated using a 0.18‐μm bipolar‐CMOS‐DMOS (BCD) process. A traditional first‐order bandgap reference (TRA_BGR) circuit is also fabricated for comparison. Experimental results demonstrate that the proposed HCC_BGR circuit generates a stable 1.22‐V reference voltage with a low‐temperature coefficient of 5.56 ppm/°C from −20°C to 85°C. Compared to the TRA_BGR circuit, the HCC_BGR reduces the temperature coefficient by 3.07 times. Furthermore, the low‐dropout regulator (LDO) using the proposed HCC_BGR exhibits excellent line sensitivity of 1.52%/V from 3.4 to 5 V. [ABSTRACT FROM AUTHOR]

Summary: A current‐mode (CM) bandgap voltage reference (BGR) with second‐order curvature compensation is presented in this paper. The proposed CM BGR offers a simple compensation structure that requires only six additional transistors compared with traditional BGR designs, making it an attractive solution for low temperature coefficient (TC) voltage references. Proportional to absolute temperature (PTAT) current digital‐to‐analog converters (DACs) are used to suppress the effect of process variation and device mismatch on TC. The compensation signal is generated using the voltage difference of two bipolar junction transistor (BJT) emitter–bases whose currents are the sum and difference of the PTAT current and the zero to absolute temperature (ZTAT) current, respectively. The proposed CM BGR is designed with 0.18‐μm BIPOLAR CMOS DMOS process. A TC is 2.41 ppm/°C over a wide temperature range of −40°C to 150°C. The linear sensitivity of the supply voltage from 1.2 to 2 V is 0.027%/V. With an active area of 0.0721 mm2, it consumes 68 μA at room temperature. The integrated output noise from 0.1 to 10 Hz is 21.9 μV. [ABSTRACT FROM AUTHOR]

With the continuous advancement of electronic technology, the application of high-voltage integrated circuits is becoming increasingly prevalent in fields such as power systems, medical devices, and industrial automation. The reference circuit within high-voltage integrated circuits must not only exhibit insensitivity to temperature variations but also maintain stability across a broad voltage supply. This paper presents a bandgap reference (BGR) source capable of operating over a wide input range. This BGR employs a high-order curvature compensation method to eliminate nonlinear voltage terms, resulting in minimal temperature drift. The circuit achieves an impressive temperature coefficient (TC) of 0.88 ppm/°C over a temperature range from −40 °C to 130 °C. To ensure stable operation within a 4–40 V range, the design incorporates a pre-regulation circuit that stabilizes the supply voltage of the BGR core at a fixed value, thereby enhancing the ability to withstand variations in power supply voltage. [ABSTRACT FROM AUTHOR]

This work presents a sub-nanowatt voltage reference (VR) achieving a high-power supply ripple rejection (PSRR). It utilizes a self-current biasing circuit to reduce the voltage dependency of the output voltage (VREF) to the power supply variations. For low-power operation, all transistors operate in the subthreshold region. The design's performance is verified through post-layout and Monte Carlo simulations in a standard 180 nm CMOS process. Results show that the proposed bandgap achieves an output voltage of 0.150 V with a PSRR of -81.5 dB at Vdd = 1V. Notably, it eliminates the need for an additional startup circuit and consumes only 0.72 nW at T = 27°C with Vdd = 0.5V. The proposed voltage reference exhibits a temperature coefficient (TC) of approximately 18 ppm/°C over a temperature range of -20°C to 130°C while without using a trimming circuit a reasonable (σVREF/μVREF) = 2.3% is obtained. This design's average line sensitivity (LS) is 0.072%/V (Vdd = 0.5V to 1.8V). However, the PSRR and LS values are temperature-dependent. At the high temperature of 130°C (worst-case), the PSRR and LS degrade to approximately -80.45 dB and 0.084 %/V, respectively. The output noise at the frequency of 1 KHz is obtained as 167.34 nV/√ Hz. The proposed VR occupies a small active area of 513.5 μm2. [ABSTRACT FROM AUTHOR]

Bioelectrical impedance techniques have been useful in various applications, including body composition analysis, impedance plethysmography, impedance cardiography, lung ventilation, perfusion, and tissue characterization. Electrical impedance methods have also been useful in characterizing different foods like meat, fruits, and beverages. However, the temperature of tissue samples can change their dielectric properties, affecting their impedance. This research investigated the effects of temperature on the impedance of various biological tissues over the frequency range of 10 Hz to 5 MHz. Freshly excised animal tissues (lamb, cow, chicken), fish, fruits, and plants were considered as biological samples. The samples were placed in a test cell and submerged in a water bath heated by a hot plate to vary the temperature. Impedance measurements were conducted using a bioimpedance spectrometer in 2 °C steps within the temperature range of 20 °C to 50 °C. Impedance values decreased with increased temperature across all measurement frequencies for all biological samples. Curve fitting indicated that impedance decreased linearly with temperature, with a mean correlation coefficient of 0.972 for all samples. For all biological samples under investigation, the relative impedance change ranged from −0.58% to −2.27% per °C, with a mean and standard deviation of (−1.42±0.34) %/°C. On average, animal samples exhibited a higher relative temperature coefficient of −1.56% per °C (±0.41) across the frequency range, compared to −1.31% per °C (±0.26) for fruit and vegetable samples. Additionally, the relative temperature coefficient values were generally higher at lower frequencies than at higher frequencies. The findings of this research can be valuable for studies or biomedical applications involving variable tissue temperatures.

The well-densified CaREAlO 4 (RE = Eu, Ho, Er, Yb) microwave dielectric ceramics with the K 2 NiF 4 structure are fabricated at 1360–1500 °C. Crystal structures were investigated via XRD and HRTEM, and no phase transition occurred. The ceramics exhibit low ε r of 17.9–19.3 and relatively high Q × f values of 25,110 - 48,310 GHz, and tunable τ f values ranging from −1.1 ppm/°C to +18.4 ppm/°C and then to −20.4 ppm/°C. The variations in ε r and τ f were ascribed to the mutual effects of rattling RE3+ and compressed Ca2+ characterized by bond valence theory and temperature coefficient of ion polarizability (τ αm). The Q×f values of CaREAlO 4 ceramics positively correlate with structure stability and lattice energy, the main intrinsic factors affecting Q×f. [ABSTRACT FROM AUTHOR]

Walleye (Sander vitreus) are a sexually dimorphic freshwater piscivore that have long been studied using bioenergetics modeling, yet robust estimates of metabolic rates for use in those models have been lacking. Therefore, we quantified the effects of body mass, water temperature, and sex, on standard metabolic rate (SMR). We estimated SMR across temperatures ranging 0.5–24 °C using intermittent-flow respirometry for male (n = 54) and female (n = 53) walleye raised in hatchery conditions. We found a significant interaction between sex and temperature, whereby males had lower SMR below 16 °C, but increased such that SMR was ∼16% higher than females at 22 °C. The mass-scaling coefficient, b, was similar for both sexes at a value around 1. These estimates are the first to be generated using respirometry for adult walleye and differ slightly from those being used by previous bioenergetics models, which may have underestimated the energetic costs of SMR, and did not include sex-specific estimates for metabolism. [ABSTRACT FROM AUTHOR]

The photocurrent across crystalline GaAs p-n junction induced by Nd:YAG laser radiation was investigated experimentally. It is established that the displacement current is dominant at reverse and low forward bias voltages in the case of pulsed excitation. This indicates that hot carriers do not have enough energy to overcome the p-n junction until the forward bias significantly reduces the potential barrier. At a sufficiently high forward bias, the photocurrent is determined by the diffusion of hot carriers across the p-n junction. The current–voltage (I-V) characteristics measured at different crystal lattice temperatures show that the heating of carriers by laser radiation increases with a drop in crystal lattice temperature. This study proposes a novel model for evaluating carrier temperature based on the temperature coefficient of the I-V characteristic. It is demonstrated that the heating of carriers by light diminishes the conversion efficiency of a solar cell, not only through thermalisation but also because of the conflicting interactions between the hot carrier and conventional photocurrents, which exhibit opposite polarities. These findings contribute to an understanding of hot carrier phenomena in photovoltaic devices and may prompt a revision of the intrinsic losses in solar cells. [ABSTRACT FROM AUTHOR]

In this study, we used solid-state synthesis to prepare Ba[(ZnxCo1−x)1/3(Nb0.5Ta0.5)2/3]O3 microwave ceramics for mobile communications. Compared with Ba[Zn1/3(Nb0.5Ta0.5)2/3]O3, in the prepared materials, Co2+ substitution with Zn2+ improved the Q × f value and enabled densification and sintering at a lower temperature. We used X-ray diffraction (XRD) and scanning electron microscopy (SEM) to analyze the obtained microstructure. Ba[(ZnxCo1−x)1/3(Nb0.5Ta0.5)2/3]O3 was found to have a 1:2 ordered hexagonal structure, and its Q × f value increased with the increase in sintering temperature. In this work, excellent microwave dielectric properties—τf = −0.7 ppm/°C, εr = 34.5, and Q × f = 110,000 GHz—were obtained by sintering Ba[(Zn0.3Co0.7)1/3(Nb0.5Ta0.5)2/3]O3 at 1400 °C for 5 h.

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Trichogramma chilonis (Ishii) is an important biocontrol agent that is widely used around the world to control numerous lepidopteran pests. The overuse of pesticides in agricultural systems causes lethal and sublethal effects on biocontrol agents. In ectothermic organisms, temperature influences the toxicity of insecticides. In the context of global warming, it is crucial to assess the effects of pesticides on beneficial arthropods under temperature stresses. The toxicity of bifenthrin, carbosulfan, chlorantraniliprole, dimethoate, fipronil, flubendiamide, imidacloprid, lambda-cyhalothrin and lufenuron was studied on T. chilonis at 18, 25 and 32 °C constant temperatures. The temperature coefficient was calculated as the ratio of higher LC50 values to lower LC50 values of an insecticide at different temperatures. The temperature coefficient of imidacloprid, bifenthrin and lambda-cyhalothrin was negative at 25 °C when compared to 18 °C and became positive at 32 °C, while dimethoate and lufenuron had an opposite trend. For carbosulfan and fipronil, the temperature coefficient was positive and for chlorantraniliprole and flubendiamide the coefficient was negative at all tested temperatures. Insecticides having a negative temperature coefficient become less toxic at higher temperatures; this might help reduce non-target insecticide risk to T. chilonis. The risk quotient (RQ) estimated as the ratio of field doses to the LC50 of beneficial organisms indicated that chlorantraniliprole at 25 °C and 32 °C and flubendiamide at 32 °C are harmless to T. chilonis and can be used a component of the integrated pest management (IPM) programs while the other tested insecticides should be avoided. This research can help develop successful pest management systems by reducing the adverse effects of insecticides on non-target species. [ABSTRACT FROM AUTHOR]

In this study, we used solid-state synthesis to prepare Ba[(ZnxCo1−x)1/3(Nb0.5Ta0.5)2/3]O3 microwave ceramics for mobile communications. Compared with Ba[Zn1/3(Nb0.5Ta0.5)2/3]O3, in the prepared materials, Co2+ substitution with Zn2+ improved the Q × f value and enabled densification and sintering at a lower temperature. We used X-ray diffraction (XRD) and scanning electron microscopy (SEM) to analyze the obtained microstructure. Ba[(ZnxCo1−x)1/3(Nb0.5Ta0.5)2/3]O3 was found to have a 1:2 ordered hexagonal structure, and its Q × f value increased with the increase in sintering temperature. In this work, excellent microwave dielectric properties—τf = −0.7 ppm/°C, εr = 34.5, and Q × f = 110,000 GHz—were obtained by sintering Ba[(Zn0.3Co0.7)1/3(Nb0.5Ta0.5)2/3]O3 at 1400 °C for 5 h. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate the preparation of easy-to-fabricate nanogranular strontium ferromolybdate/strontium molybdate core-shell ceramics and examine their properties, including tunnel magnetoresistance, magnetic field sensitivity, and temperature coefficient of the tunnel magnetoresistance. The tunnel magnetoresistance of nanogranular strontium ferromolybdate/strontium molybdate core-shell ceramics was modeled, yielding values suitable for magnetoresistive sensor applications. Such structures possess a narrow peak of magnetic flux sensibility located at about 80 mT. For magnetic flux measurement, single-domain granules with superparamagnetic behavior should be applied. The predicted TMR magnetic flux sensitivities for granules with superparamagnetic behavior amount to about 7.7% T−1 and 1.5% T−1 for granule sizes of 3 nm and 5 nm, respectively. A drawback of the tunnel magnetoresistance of such nanogranular core-shell ceramics is the unacceptably large value of the temperature coefficient. Acceptable values, lower than 2% K−1, are obtained only at low temperatures (less than 100 K) or large magnetic flux densities (exceeding 6 T). Therefore, a Wheatstone bridge configuration should be adopted for magnetoresistive sensor design to compensate for the effect of temperature. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, we demonstrate the preparation of easy-to-fabricate nanogranular strontium ferromolybdate/strontium molybdate core-shell ceramics and examine their properties, including tunnel magnetoresistance, magnetic field sensitivity, and temperature coefficient of the tunnel magnetoresistance. The tunnel magnetoresistance of nanogranular strontium ferromolybdate/strontium molybdate core-shell ceramics was modeled, yielding values suitable for magnetoresistive sensor applications. Such structures possess a narrow peak of magnetic flux sensibility located at about 80 mT. For magnetic flux measurement, single-domain granules with superparamagnetic behavior should be applied. The predicted TMR magnetic flux sensitivities for granules with superparamagnetic behavior amount to about 7.7% T−1 and 1.5% T−1 for granule sizes of 3 nm and 5 nm, respectively. A drawback of the tunnel magnetoresistance of such nanogranular core-shell ceramics is the unacceptably large value of the temperature coefficient. Acceptable values, lower than 2% K−1, are obtained only at low temperatures (less than 100 K) or large magnetic flux densities (exceeding 6 T). Therefore, a Wheatstone bridge configuration should be adopted for magnetoresistive sensor design to compensate for the effect of temperature.

With the continuous advancement of electronic technology, the application of high-voltage integrated circuits is becoming increasingly prevalent in fields such as power systems, medical devices, and industrial automation. The reference circuit within high-voltage integrated circuits must not only exhibit insensitivity to temperature variations but also maintain stability across a broad voltage supply. This paper presents a bandgap reference (BGR) source capable of operating over a wide input range. This BGR employs a high-order curvature compensation method to eliminate nonlinear voltage terms, resulting in minimal temperature drift. The circuit achieves an impressive temperature coefficient (TC) of 0.88 ppm/°C over a temperature range from −40 °C to 130 °C. To ensure stable operation within a 4–40 V range, the design incorporates a pre-regulation circuit that stabilizes the supply voltage of the BGR core at a fixed value, thereby enhancing the ability to withstand variations in power supply voltage.

Recent NMR studies of the exchangeable protons of GAGs in aqueous solution, including those of the amide, sulfamate, and hydroxyl moieties, have demonstrated potential for the detection of intramolecular hydrogen bonds providing insights into secondary structure preferences. GAG amide protons are observable by NMR over wide pH and temperature ranges; however, specific solution conditions are required to reduce the exchange rate of the sulfamate and hydroxyl protons and allow their detection by NMR. Building on the vast body of knowledge on detection of hydrogen bonds in peptides and proteins, a variety of methods can be used to identify hydrogen bonds in GAGs including temperature coefficient measurements, evaluation of chemical shift differences between oligo- and monosaccharides, and relative exchange rates measured through line shape analysis and EXSY spectra. Emerging strategies to allow direct detection of hydrogen bonds through heteronuclear couplings offer promise for the future. Molecular dynamic simulations are important in this effort both to predict and confirm hydrogen bond donors and acceptors.

The photocurrent across crystalline GaAs p-n junction induced by Nd:YAG laser radiation was investigated experimentally. It is established that the displacement current is dominant at reverse and low forward bias voltages in the case of pulsed excitation. This indicates that hot carriers do not have enough energy to overcome the p-n junction until the forward bias significantly reduces the potential barrier. At a sufficiently high forward bias, the photocurrent is determined by the diffusion of hot carriers across the p-n junction. The current–voltage (I-V) characteristics measured at different crystal lattice temperatures show that the heating of carriers by laser radiation increases with a drop in crystal lattice temperature. This study proposes a novel model for evaluating carrier temperature based on the temperature coefficient of the I-V characteristic. It is demonstrated that the heating of carriers by light diminishes the conversion efficiency of a solar cell, not only through thermalisation but also because of the conflicting interactions between the hot carrier and conventional photocurrents, which exhibit opposite polarities. These findings contribute to an understanding of hot carrier phenomena in photovoltaic devices and may prompt a revision of the intrinsic losses in solar cells.

Abstract Background Spodoptera littoralis Boisad. (Lepidoptera: Noctuidae) is an important pest causing significant losses to agricultural crops worldwide. Management practices for this insect pest rely on insecticides applications throughout the entire season over wide ranging temperature. However, studies involving the development of resistance in S. littoralis against these insecticides at different temperatures are limited. Methods Using leaf-dipping bioassay technique, the effect of temperature (range, 15–30 °C) on the toxicity of spinosad, lambda-cyhalothrin and methomyl, and resistance development was evaluated in larvae S. littoralis. Results Spinosad, lambda-cyhalothrin and methomyl exhibited increased toxicity with increasing temperature from 15 to 30 °C. The results indicated a successive decrease in insecticide resistance at the temperatures of 15, 20, 25 and 30 °C from 1st to 12th generations of S. littoralis to spinosad, lambda-cyhalothrin and methomyl. Conclusions This study suggests that spinosad, lambda-cyhalothrin, and methomyl can be included in the management of S. littoralis.

This paper presents a resistor-less high-order curvature compensation bandgap voltage reference. A high-order curvature compensation is based on generating successive VGS voltages with different temperature characteristics, which are used to cancel thermal nonlinearity the first- and higher-order terms of the transistor voltage VEB. At the same time, a piecewise-linear curvature compensation circuit is used to broaden the temperature range of the whole circuit and achieve low-temperature coefficient. The proposed bandgap reference was designed using standard CSMC 0.18-μm CMOS technology. Simulation results indicate that the proposed bandgap reference achieves the best temperature coefficient of 2.37 ppm/°C from − 40 to 125 °C with a supply voltage of 5 V. The BGR output is about 1.1881 V and a − 60.7-dB PSRR at 10 kHz while only consuming 200 μW. [ABSTRACT FROM AUTHOR]

In the analog and mixed-signal integrated circuits, voltage references that are independent of various factors such as temperature drift, noise, supply voltage, etc., and efficient in terms of power as well as area, are highly in demand to improve the efficiency of the overall circuits. Voltage references are one of those circuits that have applications in both high-power systems and low-power system-on-chip (SoC) designs for wireless connectivity like the internet of the things (IoT) or the internet of the medical things (IoMT). They are responsible for providing a stable bias or reference voltage. Thus, voltage reference influences directly or indirectly the performance of these systems. A comparative study between the techniques used in bandgap voltage references and CMOS voltage references, in terms of performance parameters such as line sensitivity, output noise, PSRR, temperature coefficient, etc., is presented in this paper so that we can choose the voltage references as per the applications and environment. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

TOPAZ-Ⅱ space nuclear reactor power supply adopts thermionic static thermoelectric conversion mode, the output power of the system is 5 kW, and its service life can reach 3 years. It is one of the most advanced space nuclear power supply systems that can be rapidly engineered at present. However, the temperature coefficient of moderator in TOPAZ-Ⅱ reactor is a large positive value, which leads to the positive temperature coefficient of the whole reactor, which puts forward high requirements on the reliability of the reactivity control system, so it is necessary to study its mechanism in detail. A three-dimensional accurate MCNP model of TOPAZ-Ⅱ reactor core was established, and the causes of the positive temperature effect of moderator in TOPAZ-Ⅱ reactor were analyzed in detail from three aspects: The change of neutron spectrum, the change of neutron equilibrium relationship and the change of neutron cycle factors. It is found that the positive temperature effect of moderator is the result of the joint action of three factors. First of all, TOPAZ-Ⅱ adopts zirconium hydride solid moderator. Secondly, unlike TRIGA, TOPAZ-Ⅱ adopts the heterogeneous arrangement of rod-shaped fuel inserted in moderator matrix. Finally, TOPAZ-Ⅱ uses highly enriched uranium with 235U enriched to 96%, and the fuel pellets are thick. Under the synergistic effect of these three factors, the thermal neutron utilization factor of fuel increases obviously after the temperature of moderator increases, which leads to the positive temperature effect. From the point of reducing the heterogeneity in the reactor core, a verification example was established, and it verifies the correctness of the analysis. On this basis, a method to reduce the positive temperature effect of moderator was found, which provides a guiding direction for the optimization design of thermionic reactors in the future.

Moisture ingress into PV module in the presence of ultraviolet radiation, high temperature, and other environmental stressors can affect the optical integrity of the PV module. Optical degradation can take the form of delamination, discolouration of encapsulant, metal grids corrosion, and trapped moisture or chemical species. This can influence the photon absorption and current transport properties in the PV module bulk, which can affect the module operating temperature. In the present work, the relationship between optical degradation and temperature sensitivity of 20-year-old multicrystalline silicon field-aged PV modules have been investigated. The selected PV modules were characterized using visual inspection, current-voltage (I–V) characterization, temperature coefficients profiling, current resistivity profiling, infrared (IR) thermal, ultraviolet fluorescence (UV–F), and electroluminescence (EL) imaging. PV modules affected by optical degradation show weak fluorescence and luminescence signal intensities. The average difference in cell temperature (ΔT) between the warmest and coldest cell for the PV modules investigated was found to be around 10 ± 2 °C and the average power degradation rate was approximately 0.8% per year. The underlying factor for the observed degradation is attributed to the degradation in the temperature coefficients of open circuit voltage (βVoc) and maximum power point voltage (βVmpp). The average temperature coefficient of efficiency (βηm) of the modules was found to be around −0.5%/°C. Finally, a temperature dependent resistivity method for extracting temperature coefficients from IR thermal data of PV modules has been proposed.

Automotive drive shaft is an indispensable key component of the transmission system, and the use of composite drive shafts has shown great promise. The epoxy matrix of the shaft is susceptible to the effects of temperature in comparison to carbon fiber. To investigate the influence of the environmental temperature on the fatigue life of a carbon fiber‐reinforced plastic drive shaft, a temperature‐based property curve and performance fraction model for the shaft are established. The temperature coefficient is calculated and introduced by combining the collected temperature data with the property fraction function. A generalized S‐N surface of the composite drive shaft is proposed based on experimental data. The fatigue life under collected and processed random loads of the carbon fiber‐reinforced plastic drive shaft is predicted by modified Miner's law. The effect of mean, amplitude of load and ambient temperature on fatigue life are taken into account. Highlights: Drive shaft load spectrum was acquired and preprocessed.Model of the carbon fiber‐reinforced plastic (CFRP) drive shaft was built for torsion strength with temperature.The temperature coefficient was calculated via temperature distribution and the model.Fatigue life of CFRP drive shaft was predicted by combining improved S‐N surfaces. [ABSTRACT FROM AUTHOR]

Solar Photovoltaic (PV) panels are extensively employed for the purpose of converting renewable energy, namely solar energy, into electrical energy. A significant portion of the solar radiation collected by Photovoltaic (PV) panels is transformed into thermal energy, resulting in the heating of PV cells and a consequent reduction in PV efficiency. The increase in the temperature of Photovoltaic (PV) panels leads to a decrease in their conversion efficiency. The data indicate that an increase of one degree Celsius in PV temperature can lead to a reduction in efficiency of up to 0.65%. This phenomenon has garnered significant scholarly interest in the realm of reducing and managing Photovoltaic (PV) temperature. One of the ways that has been explored is the use of Phase Change Material (PCM), which has the ability to effectively regulate the temperature of Photovoltaic (PV) systems due to its latent heat storing capabilities. Additionally, integrating Phase Change Material (PCM) in Photovoltaic (PV) systems not only helps in temperature regulation but also contributes to extending the lifespan of PV panels by mitigating thermal stress. As the demand for sustainable energy solutions continues to grow, optimizing the efficiency and durability of solar technologies remains a crucial focus for researchers and industry professionals alike. [ABSTRACT FROM AUTHOR]

Background: Spodoptera littoralis Boisad. (Lepidoptera: Noctuidae) is an important pest causing significant losses to agricultural crops worldwide. Management practices for this insect pest rely on insecticides applications throughout the entire season over wide ranging temperature. However, studies involving the development of resistance in S. littoralis against these insecticides at different temperatures are limited. Methods: Using leaf-dipping bioassay technique, the effect of temperature (range, 15–30 °C) on the toxicity of spinosad, lambda-cyhalothrin and methomyl, and resistance development was evaluated in larvae S. littoralis. Results: Spinosad, lambda-cyhalothrin and methomyl exhibited increased toxicity with increasing temperature from 15 to 30 °C. The results indicated a successive decrease in insecticide resistance at the temperatures of 15, 20, 25 and 30 °C from 1st to 12th generations of S. littoralis to spinosad, lambda-cyhalothrin and methomyl. Conclusions: This study suggests that spinosad, lambda-cyhalothrin, and methomyl can be included in the management of S. littoralis. Highlights: Toxicity due to lambda-cyhalothrin, methomyl and spinosad exposure increases with increasing temperature. Temperature influences the resistance of S. littoralis to lambda-cyhalothrin, methomyl and spinosad. Temperature should be integrated into the assessment of both toxicity and insecticide resistance. [ABSTRACT FROM AUTHOR]

The Fluoride salt–cooled High-temperature Reactor (FHR) is a Generation IV reactor concept that can operate under near atmospheric pressure circumstances and further enhance inherent safety. In this study, an FHR core design with 165 MW of thermal output [MW(thermal)] is proposed. The reactor core employs tristructural-isotropic (TRISO) particle fuel within prismatic graphite blocks as the basic fuel form, FLiBe [lithium-beryllium fluoride (2 7LiF-BeF2)] as the primary coolant, and a three-batch fuel cycle scheme. Sensitivity analyses on various parameters were performed to optimize the cycle length and neutronic parameters. The fuel cycle of this core design was evaluated in detail from four aspects: cycle length, power peaking factor (PPF), discharge burnup, and temperature coefficient. It was found that a larger fuel channel pitch would have a relatively harder neutron spectrum and yield a relatively longer cycle length, lower PPF, and better fuel temperature coefficient and moderator temperature coefficient (MTC). In addition, burnable poison (BP) (Er2O3) can effectively reduce PPF, hold down the multiplication factor, and more importantly it can improve the MTC. The preliminary design of control blades is also presented in this paper. Furthermore, on the basis of the proposed 165-MW(thermal) core, we propose a novel core design that incorporates "fuel inside radial moderator (FIRM)" assemblies, movable moderator, and movable BP. This new design can extend the fuel cycle length by approximately 45 days for an 18-month fuel cycle. In addition, improvements were also found in PPF, discharge burnup, and temperature coefficients. [ABSTRACT FROM AUTHOR]

A novel low temperature coefficient voltage referece without resistors is presented in this brief, which is compatible with standard TSMC 0.18 µm CMOS technology. Threshold voltage (Vth) and proportional to absolute temperature voltage (VPTAT) form the basic linear temperature components. By weighting the sum of the two through asymmetric differential operational amplifier, the nonlinearity in the voltage reference is cancled and the precision of the output voltage is improved. The Vth is achieved by resistorless circuit and the VPTAT is achieved by asymmetric differential operational amplifier. The experimental results show that in the temperature range of -55 ℃ to 125 ℃, the voltage reference is 1.23 V with a temperature coefficient of 4.5 ppm/℃, and the power supply rejection ratio is lower than -93 dB while without filtering capacitor.

This paper presents a fully MOSFET DC voltage limiter with low current consumption. In the proposed voltage reference structure to reduce power consumption, transistors are biased in the sub-threshold region. To generate complementary to absolute temperature (CTAT) voltage in the voltage reference circuit, only a PMOS transistor is used, in which its drain, gate, and source terminals are connected together and acts as a diode that reduces the layout area occupation. To further reduce power consumption, a part of the rectifier output voltage is compared with the reference voltage by the sampling circuit. Also, four stage inverters are used as buffers to provide the I-V limiting characteristic closer to the ideal situation. The use of series pass-gate transistors in the first inverter also reduces power consumption as much as possible. The results of post-layout simulation based on 0.18μm CMOS technology depict that the suggested voltage reference circuit has a reference voltage equivalent to 0.579V with a TC of 37.2ppm/℃ in the temperature range of -50°C to 50°C. LR and PSRR attained 0.008%/V and 45dB, respectively. The output voltage and current consumption of the limiter circuit are 2V and 32.13nA, respectively. The total layout area of the proposed limiter is 3249µm2.

Phonons play a pivotal role in the lattice dynamics and thermal transport properties of AlN epilayers. Revealing the phonon anharmonicity and epilayer-substrate interactions is the most fundamental step to develop high-performance AlN-based optoelectronic devices. We systematically report the temperature-dependent behavior of phonons in AlN epilayers grown on sapphire substrates in the temperature range of 4 – 870 K. The nonlinear frequency redshifts (softening) of the two main phonon modes, E 2 (high) and A 1 (LO), are fitted by our proposed formula with robust generalizability. Strikingly, the weakly anomalous phonon behavior of AlN epilayers and bulk AlN was observed below 100 K, which may be attributed to the negative thermal expansion of AlN crystals. More pronounced phonon softening due to substrate induced strain effect was observed in AlN epilayers than in bulk AlN. This stronger temperature dependence in AlN epilayers can be used as a non-invasive thermal probe to determine the local temperature variation of AlN-based devices. Combined with first-principles calculations, the frequency redshift and linewidth broadening of E 2 (high) and A 1 (LO) modes are further quantified by a physical model involving thermal expansion, phonon anharmonic effects, and substrate effects. Our findings shed insight into phonon-phonon interactions in AlN and provide an indicator for its extreme device applications. This process can also be fundamentally applicable to other emerging epitaxial films and 2D materials. Additionally, the biaxial stress coefficient and pure temperature coefficient of the E 2 (high) mode determined by the contribution of substrate-induced strain effects to the phonon frequency shift are −6.63 ± 0.27 cm−1/GPa and −0.0217 cm−1/K, respectively. These coefficients provide critical information for accurately assessing the impact of temperature and stress on device reliability. [ABSTRACT FROM AUTHOR]

Recently, the significant improvements in the surface and contact passivation of silicon (Si) solar cells as well as their bulk quality have shifted their operating point to higher injections. Hence, they are less dependent on wafer doping. This shift opens an opportunity of using high‐resistivity wafers for practical photovoltaic applications, introducing a promising approach to push the cell efficiency towards the intrinsic limit and to improve the module reliability by increasing the cell breakdown voltage. Therefore, insights into the performance of Si solar cells using high‐resistivity wafers at various operating temperatures are of significant interest. In this study, we investigate the temperature‐ and illumination‐dependent performance of Si heterojunction (SHJ) solar cells using a wide range of wafer resistivities (between 3 and 1000 Ω⋅cm). Although a reduction in the passivation quality of the passivating contacts is observed at elevated temperature, the impact on the temperature coefficient of the open‐circuit voltage (TCVoc)—the dominant contributor to the temperature coefficient (TC) of the cell efficiency—is very limited. Their TCVoc are still dominated by the temperature dependence of the effective intrinsic carrier concentration. Furthermore, we also find that the investigated cells are more sensitive to temperature variation at lower illumination intensities. It is noteworthy that the efficiency of the cells fabricated using high‐resistivity wafers is comparable to that of the reference cells at any given temperature, highlighting the potential of using high‐resistivity wafers for solar cells. [ABSTRACT FROM AUTHOR]

ISFH is following a distinct cell development roadmap, which comprises—as a short‐term concept—the combination of an n‐type doped electron‐collecting poly‐Si on oxide (POLO) junction with an Al‐alloyed p+ junction for hole collection. This combination can be integrated either in front‐ and back‐contacted back junction cells (POLO‐BJ) or in interdigitated back‐contacted cells (POLO‐IBC). Here, we present recent progress with these two cell concepts. We report on a certified M2‐sized 22.9% efficient POLO‐BJ cell with a temperature coefficient TCη of only −(0.3 ± 0.02) %rel/K and a certified 23.7% (4 cm2 d.a.) efficient POLO‐IBC cell. We discuss various specific conceptual aspects of this technology and present a simulation‐based sensitivity analysis for quantities related to the quality of the hole‐collecting alloyed Al‐p+ junction which are subject to continuous improvement and thus hard to predict exactly. We report that the measured pseudo fill factor values decrease more due to metallization than would be expected from recombination in the metallized regions with an ideality factor of one only. The gap to pseudo fill factor values that are theoretically achievable at the respective open‐circuit voltages is 1.1%abs (Ga‐doped wafer) for POLO‐IBC and 1.4%abs (B‐doped wafer) to 2%abs (Ga‐doped wafer) for POLO‐BJ. With an embedded blocking layer for Ag crystallites in the poly‐Si, we present a concept to reduce this gap. [ABSTRACT FROM AUTHOR]

This paper presents a sub-microwatt sub-bandgap voltage and current reference that can generate proportional-to-absolute-temperature (PTAT) and complementary-to-absolute-temperature (CTAT) currents concurrently. The voltage reference is derived from the process-insensitive silicon bandgap voltage of a bipolar junction transistor, whereas the current reference is made by combining PTAT and CTAT currents. Line regulation is improved by incorporating cascode devices without an operational amplifier (opamp). Fabricated in a standard 0.18-µm CMOS process, the proposed bandgap reference occupies an active area of 0.4 mm2. The current and voltage reference ( I REF and V REF ) are measured as 170 mV and 21 nA, respectively, while the start-up settling response is measured as 20 ms at room temperature. The average temperature coefficient of I REF and V REF is 79.8 ppm/°C and 87.93 ppm/°C across the temperature range from − 40 to 120 °C, respectively. The power consumption is 134 nW at the minimum supply voltage of 1.2 V. The power supply ripple rejection of V REF is measured as − 10 dB at 100 kHz without any filtering capacitor, when the 1.6 V input line voltage is distorted by a 300-mVp-p ripple. The measured line sensitivity of the voltage and current reference is 0.142%/V and 0.757%/V, respectively. [ABSTRACT FROM AUTHOR]

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The temperature–size rule (TSR) has been consistently observed in numerous studies, showing that ectotherms reared at higher temperatures experience accelerated growth during the juvenile stage and ultimately reach smaller sizes and younger ages at maturity. One explanation for this response is that it occurs when the effect of temperature on mortality, including predation, outweighs its effect on food intake and metabolism. While several studies have found that the latter effect is close to the expected result based on the Q10 = 2 assumption, confirmation of this hypothesis requires evidence that the effect of temperature on mortality exceeds the Q10 = 2 threshold. To test this hypothesis, we conducted experiments with two fish species: rudd and Malabar danio. We examined the capture rate, which serves as a proxy for mortality, as well as the standard metabolic rate (SMR) and several parameters characterising the mobility of the fish and their planktonic prey (Daphnia) at different temperatures. The results strongly supported our hypothesis, as the capture rate increased significantly more than expected based on the Q10 = 2 assumption, especially for the danio. This substantial effect cannot be attributed solely to the thermal sensitivity of the SMR, as the Q10 for the SMR was only around 2. The most likely explanation seems to be a much more pronounced increase in the fish’s mobility and resulting reaction field volume compared to its planktonic prey at elevated temperatures. This increased mobility leads to an improved attack rate by the fish, which exceeds the prediction made by the Q10 = 2 assumption. This mechanism may explain not only the TSR pattern in zooplankton, but also their reduced mean body size and density at population and community levels at elevated temperatures, and may hypothetically be observed at other predator–prey interfaces.

This work presents an examination and unification of fragmented data on spin polarization in half-metallic, ferrimagnetic oxides. It also includes well understood ferromagnetic metals for comparison. The temperature and disorder dependencies of the spin polarization are evaluated. Both the temperature dependence of the tunnel magnetoresistance and, for the very first time, its temperature coefficient are calculated based on the simplified Julliére model. The tunnel magnetoresistance in the magnetic tunnel junctions deteriorates due to the temperature dependence of the spin polarization the lower the Curie temperature is. As a result, magnetic tunnel junctions—consisting of ferromagnetic oxides with a Curie temperature not far above room temperature—are not promising for room temperature applications. Additionally, ferrimagnetic oxides possessing a Curie temperature below 650 K are not suitable for room temperature applications because of an unacceptable temperature coefficient exceeding −2%.

Low dissipation factor (tanδ) and excellent temperature stability of high dielectric permittivity are obtained in Ti1-x(Co1/3Ta2/3)xO2 ceramics, which were prepared using a mixed oxide method. The unit cell of the rutile TiO2 structure expanded due to relatively larger ionic radii of the co–dopants. The dopants homogeneously appeared in the microstructure of the TiO2 ceramics. Highly dense sintered–ceramics without second phase exhibit low tanδ of 0.015–0.043 with very high dielectric permittivities of 7.0–9.1 × 104 at 1 kHz. Notably, the temperature coefficient in the range of ±15 % was obtained in the temperature range of −60–200 °C. The electrically heterogeneous microstructure was studied using impedance spectroscopy. The contributions of extrinsic and intrinsic factors were separated by the dielectric relaxations in low and high–frequency ranges, respectively. The dielectric relaxations were well fitted using a modified Cole-Cole model. A low–frequency relaxation was well described based on the Maxwell-Wagner relaxation model. A high permittivity was originated from the intrinsic (i.e., defect dipoles) and extrinsic (internal barrier layer capacitor, IBLC) effects. A low tanδ was primarily caused by the IBLC effect associated with a high resistance of the insulating part and defect dipoles.

This paper presents an ultra-low-power voltage reference designed in 180 nm CMOS technology. To achieve near-zero line sensitivity, a two-transistor (2-T) voltage reference is biased with a current source to cancel the drain-induced barrier-lowering (DIBL) effect of the 2-T core, thus improving the line sensitivity. This compensation circuit achieves a Monte-Carlo-simulated line sensitivity of 0.035 %/V in a supply range of 0.6 to 1.8 V, while generating a reference voltage of 307.8 mV, with 21.4 pW power consumption. The simulated power supply rejection ratio (PSRR) is −54 dB at 100 Hz. It also achieves a temperature coefficient of 24.8 ppm/°C in a temperature range of −20 to 80 °C, with a projected area of 0.003 mm2. [ABSTRACT FROM AUTHOR]

As energy yields of photovoltaic modules are highly related to local climate and ambient conditions, it is necessary to assess the energy-yield performance of PV modules under various operating conditions. This work compares commercial crystalline silicon (c-Si) based PV modules (including mono c-Si Al BSF, mono c-Si PERC, multi-crystalline (mc-Si) Al BSF, and n-type c-Si solar cells) sampled from 27 PV module manufacturers located in the Asia-Pacific region between 2016 and 2022. Several test items were compared including: (i) light-induced degradation (LID), (ii) irradiance-temperature-efficiency (GTE) matrix, (iii) angular response and (iv) temperature coefficients, which are correspondingly performed according to IEC 61215-1, -1-1, -2 and IEC 61853-1, -2. The coefficient of variation (CoV) was calculated to express the module-to-module differences within similar technology types. Benefiting from the technological innovation of c-Si based PV modules, emerging PV modules feature better performance in some extreme ambient conditions, such as low irradiance, high ambient temperature, and high ratio of diffuse irradiance. The analysis of CoV indicates that the difference of irradiance-dependent and thermal behavior between modules within the same technology may exceed the differences between different technologies. Using synthetic hourly meteorological data of 5 sites from MeteoNorm in PVsyst, the annual specific yield of four technology groups of PV modules were simulated and compared. Overall, it is shown that the maximum differences as large as 7.34% in terms of PV module's specific yield are expected within same PV technology, which exceeds the maximum difference of 2.16% obtained for specific yields of different PV technologies. [ABSTRACT FROM AUTHOR]