Effect Of Temperature Modulation Research Articles

Effect of temperature modulation on the performance of top contact bottom gate organic thin film transistor

This research article investigates the influence of temperature variations on the performance parameters of Top Contact Bottom Gate (TCBG) Organic Thin Film Transistors (OTFTs). Employing the Arrhenius equation and Schottky emission model, the study explores temperature-dependent charge carrier mobility and injection mechanisms. Analyzing a wide range of parameters, the research unveils a complex interplay between temperature and OTFT behavior. The linear and saturation mobilities exhibit a decline due to enhanced carrier-phonon interactions and lattice vibrations. Transconductance and ION/IOFF ratio display a concomitant decrease at higher temperatures, indicative of the heightened susceptibility of OTFT performance to temperature fluctuations. The depreciation in subthreshold slope and threshold voltage with rising temperatures underscores the influence of temperature on trap states. The research emphasizes the importance of considering temperature’s impact during OTFT design for diverse applications, enhancing the reliability and functionality of organic electronic devices.

Combined Effect of Temperature Modulation and Rotation on the Onset of Darcy-Bénard Convection in a Porous Layer Using the Local Thermal Nonequilibrium Model

Combined Effect of Temperature Modulation and Rotation on the Onset of Darcy-Bénard Convection in a Porous Layer Using the Local Thermal Nonequilibrium Model

Selective gas detection of titania nanoparticles via impedance spectroscopy and capacitive measurement

The present paper demonstrated the impedance analysis of Au/TiO2 nanoparticles/Si–Al capacitive sensor for selective detection of volatile organic compounds (VOCs) at different frequency regimes. TiO2 nanoparticles (NP) were synthesized through the solution process and characterized by field-emission scanning electron microscopy , x-ray diffraction analysis, photoluminescence spectroscopy, and atomic force microscopy. The gas sensitivity of Au/TiO2 -NP/Si–Al was investigated, with the effect of temperature modulation (25 °C–250 °C) and dielectric variation in the vicinity of nanoparticles. Impedance spectroscopy of TiO2 -NP was carried out to obtain resonant peaks over the frequency ranging from 0.05 to 225 kHz and fitted with a complex nonlinear least-squares method. The optimum sensor response of 136%, 63%, 152%, and 174% was found at resonant frequencies of 0.38 kHz, 0.22 kHz, 0.15 kHz, and 0.1 kHz for the exposure of 2-propanol, acetone, ethanol, and methanol, respectively. The fastest response time and recovery time were found to be 32/21 s, 31.2/8 s, 32.5/9 s, and 40/26 s for acetone, 2-propanol, ethanol, and methanol, respectively. Selective detection of different VOCs at various resonant frequencies has correlated with the dielectric variation of the NPs and their associated void region under gas exposure.

Effect of Time-Dependent Sinusoidal Boundary Temperatures on the Onset Of Ferroconvection in a Porous Medium

<p>The effect of temperature modulation on the onset of Darcy ferroconvection in a horizontal porous layer heated from below is investigated. The analysis is based on the assumption that the amplitude of the temperature modulation is small enough compared with the imposed steady temperature difference. The effect of the oscillating temperature field is treated by a perturbation expansion in powers of the amplitude of the applied field. The effect of magnetic parameters, Vadasz number and temperature modulation in the cases of symmetric, asymmetric and bottom wall modulation, were discussed. The study divulges that subcritical motion exists for symmetric temperature modulation for low frequency. In the case of asymmetric and bottom wall modulation only supercritical motion exists.</p>

A study on the effect of temperature modulation on Darcy–Bénard convection using a local thermal non-equilibrium model

The criterion for the onset of Darcy–Bénard convection is analyzed when the fluid and porous medium are out of thermal equilibrium and the temperatures of the boundaries vary sinusoidally with time in either a synchronous or an asynchronous manner. A stability analysis of the linearized governing equations is performed by using the matrix differential operator theory. The shift in the critical Darcy–Rayleigh number is evaluated in terms of system parameters, and the effect of those on the shift is depicted graphically to realize the significant effect of temperature modulation on the onset, especially when the thermal non-equilibrium effects are prominent.

Au/TiO2 Nanotube/Ti Chemicapacitive Devices: An Approach for Optimal Gas Sensing

VOC sensing response of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TiO₂</i> nanotube array in capacitive mode with the effect of temperature modulation and frequency variation is presented in this paper. The optimal response of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TiO₂</i> nanotube towards acetone, 2-butanone, methanol, ethanol, and 2-propanol was obtained by identifying the resonant frequency over the frequency range of 0.05-225 kHz. The shifts in the resonant frequency upon exposure to VOCs with reference to that in air might be a simple strategy for selective detection of the VOCs. Such resonance frequency shifts have been associated with the drastic change in the dielectric ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\varepsilon _r}$</tex-math></inline-formula> ) medium under different vapor exposure at the inner and outer pore of the nanotubes. The experimental finding reveals that <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TiO₂</i> nanotube showed resonant frequency at 2.2 kHz in air which was shifted to 2.1 kHz, 1.5 kHz, 0.84 kHz, 0.52 kHz, and 0.4 kHz for the exposure of 2-butanone, acetone, 2-propanol, ethanol, and methanol, respectively. Combination of optimum temperature (125 °C) in association with resonant frequency offers a maximum sensor response of ∼180%, 225%, 406%, 556%, and 669%, towards 2-butanone, acetone, 2-propanol, ethanol, and methanol, respectively. The maximum response magnitude to methanol is possibly attributed to the high oriented polarization of the methanol molecules at relatively lower resonant frequency (0.4 kHz). An equivalent circuit model in association with complex impedance data has been analyzed to correlate the experimental findings.

Bénard-Taylor ferroconvection with time-dependent sinusoidal boundary temperatures

The combined effect of centrifugal acceleration and time-varying boundary temperatures on the onset of convective instability of a rotating magnetic fluid layer is investigated by means of the regular perturbation method. A perturbation expansion in terms of the amplitude of applied temperature field is implemented to effectively deal with the effects of temperature modulation. The criterion for the threshold is established based on the condition of stationary instability manifesting prior to oscillatory convection. The modulated critical Rayleigh number is computed in terms of Prandtl number, magnetic parameters, Taylor number and the frequency of thermal modulation. It is shown that subcritical motion exists only for symmetric excitation and the destabilizing effect of magnetic mechanism is perceived only for asymmetric and bottom wall excitations. It is also delineated that, for bottom wall modulation, rotation tends to stabilize the system at low frequencies and the opposite is true for moderate and large frequencies. Furthermore, it is established that, notwithstanding the type of thermal excitation, the modulation mechanism attenuates the influences of both magnetic stresses and rotation for moderate and large frequencies.

Effect of temperature modulation, on the gas sensing characteristics of ZnO nanostructures, for gases O2, CO and CO2

One dimensional nanostructures of ZnO grown by microwave assisted wet-chemical growth were drop casted over inter-digitated electrodes to fabricate chemi-resistive sensors. The response of this intrinsic, intentionally undoped ZnO nanomaterial, to gases O2, CO and CO2 was measured as a function of sensor operating temperature and analyte gas concentration. The sensor resistance increases upon exposure to O2 and decreases on exposure to CO and CO2. Temperature dependence data for the three gases show the maximum sensor resistance occurring in the temperature range 300 °C to 350 °C. An analysis of the sensor resistance data in temperature range 250 °C to 350 °C demonstrate that, the modulation of sensor operating temperature alone is sufficient to tailor gas sensing response of the ZnO nanomaterial. These data are important and necessary for operating the sensor in the form of an array with an appropriate pattern recognition tool.

Effect of temperature modulation on natural convection in a horizontal porous annulus

The effect of temperature modulation on natural convection in a horizontal porous annulus is investigated in this paper. The porous medium is confined between the inner and outer cylinders of the annulus which is subjected to time-dependent temperature. It is assumed that the time-dependent modulation is periodic with frequency σ and amplitude λ. The model consists of the heat equation and the equations of motion under the Darcy law. The derived problem with the stream function-temperature formulation is solved numerically using the alternating direction implicit method. It is shown that a stabilizing effect can be gained for appropriate values of the frequency σ and the amplitude λ.

Влияние режимов работы на отклик сенсоров аммиака на основе пленок диоксида олова

The effect of temperature modulation on the response of ammonia sensors based on tin dioxide films was studied. Samples were obtained by RF-magnetron sputtering of a SnO2: Sb target on sapphire substrates with pre-deposited Pt-electrodes and a heater. Varying the duration of the heating cycle and lowering the temperature in the cooling cycle can increase the response by one to two orders of magnitude. The results are explained by a change in the density of chemically adsorbed oxygen on the surface of the SnO2: Sb film depending on the temperature mode.

Field- and temperature-modulated spin diode effect in a GMR nanowire with dipolar coupling

The magnetization dynamics of single Co/Cu/Co spin valves, embedded in electrodeposited nanowires of 30 nm avarage diameter, was observed using the spin-diode effect. The electrically-detected magnetic resonances were compared when using modulation of either the magnetic field or a laser irradiation. The effect of temperature modulation was accounted for by introducing the temperature dependence of the saturation magnetization and anisotropy, as well as thermal spin-transfer torque (TSTT). The predictions of the model are compared with experimental data. Two forms of modulation give rise to qualitative differences in the spectra that are accounted for by the model only if both temperature-modulated magnetization and TSTT are introduced in the model. On the contrary, the temperature modulation of the magnetic anisotropy has a smaller contribution.

Effect of temperature modulations on TEMPO-mediated regioselective oxidation of unprotected carbohydrates and nucleosides

Regioselective oxidation of unprotected and partially protected oligosaccharides is a much sought-after goal. Herein, we report a notable improvement in the efficiency of TEMPO-catalyzed oxidation by modulating the temperature of the reaction. Mono-, di-, and tri-saccharides are oxidized regioselectively in yields of 75 to 92%. The present method is simple to implement and is also applicable for selective oxidations of other mono- and poly-hydroxy compounds including unprotected and partially protected nucleosides.

The Linear and Non-linear Study of Effects of Temperature Modulation on Double Diffusive Convection in Oldroyd-B Liquids

The problem aims to find the effects of temperature modulation in viscoelastic fluids, namely Oldroyd-B liquids, subjected to double diffusive convection. Both linear as well as a non-linear study has been carried out. A regular perturbation technique has been employed to determine the correction Rayleigh number. The results show that the Lewis number and strain retardation parameter induces stability to the system whereas stress relaxation parameter destabilizes the system for synchronous modulation. Truncated Fourier series represents the non-linear analysis. Nusselt number and Sherwood number are used to quantify the heat and mass transfer respectively. Strain retardation parameter and the Lewis number decrease the heat and mass transfer for synchronous modulation while stress relaxation parameter increases them. The opposite results are obtained for asynchronous and lower wall modulations. Modulation is shown mostly to give rise to super-critical motion.

Study of Effects of Temperature Modulation on Double Diffusive Convection in Oldroyd-B Liquids

Study of Effects of Temperature Modulation on Double Diffusive Convection in Oldroyd-B Liquids

Sex Differences in Behavioral Outcomes Following Temperature Modulation During Induced Neonatal Hypoxic Ischemic Injury in Rats

Neonatal hypoxia ischemia (HI; reduced oxygen and/or blood flow to the brain) can cause various degrees of tissue damage, as well as subsequent cognitive/behavioral deficits such as motor, learning/memory, and auditory impairments. These outcomes frequently result from cardiovascular and/or respiratory events observed in premature infants. Data suggests that there is a sex difference in HI outcome, with males being more adversely affected relative to comparably injured females. Brain/body temperature may play a role in modulating the severity of an HI insult, with hypothermia during an insult yielding more favorable anatomical and behavioral outcomes. The current study utilized a postnatal day (P) 7 rodent model of HI injury to assess the effect of temperature modulation during injury in each sex. We hypothesized that female P7 rats would benefit more from lowered body temperatures as compared to male P7 rats. We assessed all subjects on rota-rod, auditory discrimination, and spatial/non-spatial maze tasks. Our results revealed a significant benefit of temperature reduction in HI females as measured by most of the employed behavioral tasks. However, HI males benefitted from temperature reduction as measured on auditory and non-spatial tasks. Our data suggest that temperature reduction protects both sexes from the deleterious effects of HI injury, but task and sex specific patterns of relative efficacy are seen.

Study of heat transport in a temperature-dependent viscous liquid under temperature modulation

The effect of time-periodic temperature modulation on thermal instability in a temperature dependent viscous fluid layer has been investigated by performing a weakly nonlinear stability analysis. The amplitude of temperature modulation is considered to be very small, and the disturbances are expanded in terms of power series of amplitude of convection. The Ginzburg–Landau equation for the stationary mode of convection is obtained and consequently the effect of temperature modulation on heat transport has been investigated. Effect of various parameters has been explained graphically. It has been found that, an increment in the values of thermo-rheological parameter and Prandtl number is to enhance the heat transport in the system. Further, temperature modulation can be used to control the heat transport effectively as external mechanism to the system.

Reversing the Resistance Phenotype of the Biomphalaria glabrata Snail Host Schistosoma mansoni Infection by Temperature Modulation

Biomphalaria glabrata snails that display either resistant or susceptible phenotypes to the parasitic trematode, Schistosoma mansoni provide an invaluable resource towards elucidating the molecular basis of the snail-host/schistosome relationship. Previously, we showed that induction of stress genes either after heat-shock or parasite infection was a major feature distinguishing juvenile susceptible snails from their resistant counterparts. In order to examine this apparent association between heat stress and snail susceptibility, we investigated the effect of temperature modulation in the resistant snail stock, BS-90. Here, we show that, incubated for up to 4 hrs at 32°C prior to infection, these resistant snails became susceptible to infection, i.e. shedding cercariae at 5 weeks post exposure (PE) while unstressed resistant snails, as expected, remained resistant. This suggests that susceptibility to infection by this resistant snail phenotype is temperature-sensitive (ts). Additionally, resistant snails treated with the Hsp 90 specific inhibitor, geldanamycin (GA) after heat stress, were no longer susceptible to infection, retaining their resistant phenotype. Consistently, susceptible snail phenotypes treated with 100 mM GA before parasite exposure also remained uninfected. These results provide direct evidence for the induction of stress genes (heat shock proteins; Hsp 70, Hsp 90 and the reverse transcriptase [RT] domain of the nimbus non-LTR retrotransposon) in B. glabrata susceptibility to S. mansoni infection and characterize the resistant BS-90 snails as a temperature-sensitive phenotype. This study of reversing snail susceptibility phenotypes to S. mansoni provides an opportunity to directly track molecular pathway(s) that underlie the B. glabrata snail's ability to either sustain or destroy the S. mansoni parasite.

Effect of temperature modulation during temperature gradient solution growth of [formula omitted]- FeSi2

We have grown β- FeSi2 single crystals by the temperature modulated TGSG method using Ga solvent and Fe0.98Co0.02Si2 solute to observe the solution growth process. Growth striations corresponded to the temperature modulation cycles were clearly observed in the β- FeSi2 crystals grown using Fe0.98Co0.02Si2 solute, whereas they were not observed in the crystals grown using FeSi2 solute. SEM-EDX measurements revealed the striation was caused by the fluctuation of Co impurity. From the observation of striations, we found that the growth mechanism of β- FeSi2 would be explained by the constant growth rate model and also the growth rates along 〈011〉 and 〈010〉 directions were larger than that of 〈001〉 direction.

Combined Effect of Temperature Modulation and Magnetic Field on the Onset of Convection in an Electrically Conducting-Fluid-Saturated Porous Medium

The effect of temperature modulation on the onset of thermal convection in an electrically conducting fluid-saturated-porous medium, heated from below, has been studied using linear stability analysis. The amplitudes of temperature modulation at the lower and upper surfaces are considered to be very small. The porous medium is confined between two horizontal walls and subjected to a vertical magnetic field; flow in porous medium is characterized by Brinkman–Darcy model. Considering only infinitesimal disturbances, and using perturbation procedure, the combined effect of temperature modulation and vertical magnetic field on thermal instability has been studied. The correction in the critical Rayleigh number is calculated as a function of frequency of modulation, Darcy number, Darcy Chandrasekhar number, magnetic Prandtl number, and the nondimensional group number χ. The influence of the magnetic field is found to be stabilizing. Furthermore, it is also found that the onset of convection can be advanced or delayed by proper tuning of the frequency of modulation. The results of the present model have been compared with that of Darcy model.

Effect of Temperature Modulation on the onset of Darcy Convection in a Rotating Porous Medium

Effect of Temperature Modulation on the onset of Darcy Convection in a Rotating Porous Medium