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In optical imaging of solid tumors, signal contrasts derived from inherent tissue temperature differences have been employed to distinguish tumor masses from surrounding tissue. Moreover, with the advancement of active infrared imaging, dynamic thermal characteristics in response to exogenous thermal modulation (heating and cooling) have been proposed as novel measures of tumor assessment. Contrast factors such as the average rate of temperature changes and thermal recovery time constants have been investigated through an active thermal modulation imaging approach, yielding promising tumor characterization results in a xenograft mouse model. Here, to assess its clinical potential, we developed and deployed an endoscopic infrared thermal modulation imaging system, incorporating anti-reflection germanium lenses. Employing tissue cooling, we evaluated the feasibility of detecting in situ tumors in a syngeneic rectal tumor mouse model. Consequently, early-stage tumors were successfully localized and evaluated based on their heat signatures. Notably, tumors exhibited a higher rate of temperature change induced by thermal modulation compared to adjacent tissues. Through the introduction of this label-free technology, Infrared Thermal Modulation Endoscopy (ITME), our study showcased an effective method for optically delineating and assessing solid tumors. This innovative diagnostic technology holds significant promise for enhancing our ability to detect, classify, and characterize abnormal tissues. [ABSTRACT FROM AUTHOR]

Radiative cooling has been recently intensively explored for thermal management and enhancing energy efficiency. Yet, traditional materials with singular emissivity fall short in dynamic thermal management, highlighting the need for materials that can adjust their thermal radiation in real time. Active modulation methods, requiring external stimuli such as mechanical stretch, electric potential, or humidity change, offer adaptability but can increase energy use and complexity. Passive approaches, using materials' inherent thermal‐responsive properties, face manufacturing and scalability challenges. Here, a scalable yet effective passive approach is introduced for adaptive thermal modulation based on gold (Au) and liquid crystal elastomer (LCE) with a reversible response to environmental temperature changes. This modulator enables a "low thermal resistance" state through actuation‐induced microcracks that expose a high‐emissivity polymer substrate, and a "high thermal resistance" state by closing these microcracks and forming a high thermal resistance air gap between the modulator and the target object. The flexible design and fixed external dimensions of the Au‐LCE thermal modulator make it adaptable to various surface geometries. Furthermore, by adjusting the LCE's chemical composition, the modulator's transition temperature can be tailored, broadening its applications from enhancing building energy efficiency to improving clothing thermal comfort. [ABSTRACT FROM AUTHOR]

Thermotaxis, the movement in response to temperature gradients, is a widely observed phenomenon prevalent in various natural occurrences, spanning from biological processes to the migration of colloidal particles. Results from studies of thermotaxis may inspire the development of new technologies, such as sensors that mimic the navigation strategies of organisms that respond to temperature gradients. By adjusting temperature gradients through temperature modulation, microorganisms can be manipulated. Therefore, the main aim of this study is to investigate the effect of thermal modulation on biothermal convection in a layer of liquid that contains thermotactic microorganisms. In this study, we explore the impact of non-uniform, time-varying boundary conditions on the system. Our study involves an analysis of weak nonlinear stability based on the Ginzburg-Landau model, leading to the derivation of heat (Nusselt number Nu) and mass (Sherwood number Sh) transfer coefficients that are dependent on various system parameters. In-phase modulation (IPM) has a relatively weak effect on both heat transfer and mass transfer, which closely resembles the unmodulated scenario. On the contrary, in the cases of out-of-phase modulation (OPM) and lower bound modulation (LBM), significant changes in heat and mass transfer are observed. It has been determined that the Peclet number, a parameter characterizing thermotaxis, can either induce stabilization or destabilization within the system. TM instability. [ABSTRACT FROM AUTHOR]

There have been many studies on the ground state of phononic crystals, but few studies on the nature of the excited state. In this paper, we introduce the asymmetric Klein tunneling method in phononic systems, which enables selective direction and control of elastic waves by inducing polarization through an external field in an artificial barrier. Using tight-binding theory, we systematically studied phononics in a super-honeycomb structure, demonstrating the anisotropic transition properties of excited state phonons through a matrix model involving the ground state’s s-type and the first excited state’s p-type wave functions. Additionally, we exploit the thermal sensitivity of epoxy to achieve localized thermal field-induced distortion of the bottom flat band, forming a tiled Dirac cone, and thereby creating a reconfigurable polarized artificial barrier in the elastic wave system. Elastic waves propagate in these systems with topological charge conservation. Combining this with the theoretical of excited-state phonons, we demonstrate asymmetric Klein tunneling with directional selectivity in the elastic wave carriers, and systematically investigate the performance of this tunneling. Furthermore, we design a four-port elastic waveguide based on the principle of asymmetric tunneling, which achieves exceptional directional selectivity of elastic wave signals by adjusting the polarization direction of barriers at the junctions. These studies not only extend the application of Klein tunneling in elastic wave systems but also open new research avenues for the study of elastic wave devices controlled by various external fields, showing direct application potential in elastic wave signal processing.

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Thermal modulation of a chaotic fire laser by using a phase-shifted fiber Bragg grating (PS-FBG) is proposed. In this chaotic laser system, a double-ring resonator model is employed, leveraging the laser self-mixing method. Specifically, one of the rings serves as the laser resonator cavity, while the other ring acts as the cavity for injecting optical feedback. A PS-FBG is setting in the laser resonant optical path to select and limit the dominant frequency of laser signals. The laser system enters chaotic state through adjusting the intensities of optical feedback self-mixing. The temperature of the PS-FBG can be changed at 26–70 °C in stepping of 0.5 °C to control the chaotic laser. According to the experimental results, the chaotic signal has a highly sensitive dynamic response to the temperature change of PS-FBG. An easy method for dynamic modulation changes of chaotic laser signal is provided, the system has great potential application value in the FBG sensing, optical storage and information transfer of chaotic laser communication.

Thermal convection in a Newtonian fluid-saturated horizontal porous medium is studied using the linear stability analysis in the present study. The porous medium is uniformly rotating about a vertical axis, and the fluid and porous matrix are out of thermal equilibrium. The horizontal boundaries are assumed to be subjected to time-periodic temperatures with heating from below. The extended Darcy law, which includes the Coriolis force and time derivative terms, is used to model the linear momentum conservation equation. A deviation in the critical Darcy-Rayleigh number is calculated as a function of governing parameters, and the impact of those is illustrated graphically to understand the effect of modulation on the onset of convection, mainly when the porous matrix and fluid are not in local thermal equilibrium. It is noted that, at low-frequency symmetric modulation, the instability can be enhanced by rotation. In contrast, in the case of asymmetric modulation, the stability can be enhanced by rotation. [ABSTRACT FROM AUTHOR]

Optical switches play key role in signal crossing and interconnection. Low-loss and compact optical switches are highly demanded in on-chip optical routing. A silica waveguide 1 × 8 thermo-optic switch based on cascaded 1 × 8 multimode interference (MMI) and 8 × 8 MMI couplers is experimentally demonstrated. Beam propagation method is adopted in the theoretical design and optimization. Standard CMOS technology fabrication is used in switch preparation. Air trenches are introduced to enhance the thermal modulation. At wavelength 1550 nm, the measured insertion loss and crosstalk of this 1 × 8 switch is less than 3.69 dB and −16.29 dB, respectively. And the extinction ratio is larger than 16.68 dB for all routing states. The rise time and fall time are 1.0 ms and 1.24 ms respectively. Compared with the 8-channel switch based on cascaded stages structure, the size reduces by 30 %. With future bandwidth improvement, this demonstrated switch has good potentials in the application of all-optical network routing. • The size of this 1 × 8 switch reduces by 30 % compared to the 8-channel switch constructed by cascaded MZIs. • Fiber-to-fiber insertion loss of less than 3.69 dB is obtained in all routing states at wavelength 1550 nm. • The extinction ratio is larger than 16.68 dB for all routing states. • The low insertion loss, low power consumption, and wide bandwidth promise the switch good potentials in WDM applications. [ABSTRACT FROM AUTHOR]

This article presents the development of an artificial olfactory bulb (OB) using an electronic nose with thermally modulated metal-oxide sensors. Inspired by animal OBs, our approach employs thermal modulation to replicate the spatial encoding patterns of glomeruli clusters and subclusters. This new approach enhances the classification capabilities of traditional electronic noses and offers new insights for biomimetic olfaction. Molecular receptive range (MRR) analysis confirms that our artificial OB effectively mimics the glomerular distribution of animal OBs. Additionally, the incorporation of a short axon cell (SAC) network, inspired by the animal olfactory system, significantly improves lifetime sparseness and qualitative ability of the artificial OB through extensive lateral inhibition, providing a theoretical framework for enhanced olfactory performance. [Display omitted] • We developed a novel artificial OB based on thermally modulated MOX sensors. • Introduced a SAC network, increasing sparsity and selectivity in the artificial OB. • In this case outperformed data analysis by traditional E-nose approach. [ABSTRACT FROM AUTHOR]

The stability of nonlinear nanofluid convection is examined using the complex matrix differential operator theory. With the help of finite amplitude analysis, nonlinear convection in a porous medium is investigated that has been saturated with nanofluid and subjected to thermal modulation. The complex Ginzburg-Landau equation (CGLE) is used to determine the finite amplitude convection in order to evaluate heat and mass transfer. The small amplitude of convection is considered to determine heat and mass transfer through the porous medium. Thermal modulation of the system is predicted to change sinusoidally over time, as shown at the boundary. Three distinct modulations IPM, OPM, and LBMOhave been investigated and found that OPM and LBMO cases are used to regulate heat and mass transfer. Further, it is found that modulation frequency (ωf varying from 2 to 70) reduces heat and mass transfer while modulation amplitude (δ1varying from 0.1 to 0.5) enhances both. [ABSTRACT FROM AUTHOR]

This review article highlights the historical developments and current state of knowledge of an important neuromodulation technology: low-intensity focused ultrasound. Because compelling studies have shown that focused ultrasound can modulate neuronal activity non-invasively, especially in deep brain structures with high spatial specificity, there has been a renewed interest in attempting to understand the specific bioeffects of focused ultrasound at the cellular level. Such information is needed to facilitate the safe and effective use of focused ultrasound to treat a number of brain and nervous system disorders in humans. Unfortunately, to date, there appears to be no singular biological mechanism to account for the actions of focused ultrasound, and it is becoming increasingly clear that different types of nerve cells will respond to focused ultrasound differentially based on the complement of their ion channels, other membrane biophysical properties, and arrangement of synaptic connections. Furthermore, neurons are apparently not equally susceptible to the mechanical, thermal and cavitation-related consequences of focused ultrasound application--to complicate matters further, many studies often use distinctly different focused ultrasound stimulus parameters to achieve a reliable response in neural activity. In this review, we consider the benefits of studying more experimentally tractable invertebrate preparations, with an emphasis on the medicinal leech, where neurons can be studied as unique individual cells and be synaptically isolated from the indirect effects of focused ultrasound stimulation on mechanosensitive afferents. In the leech, we have concluded that heat is the primary effector of focused ultrasound neuromodulation, especially on motoneurons in which we observed a focused ultrasound-mediated blockade of action potentials. We discuss that the mechanical bioeffects of focused ultrasound, which are frequently described in the literature, are less reliably achieved as compared to thermal ones, and that observations ascribed to mechanical responses may be confounded by activation of synapticallycoupled sensory structures or artifacts associated with electrode resonance. Ultimately, both the mechanical and thermal components of focused ultrasound have significant potential to contribute to the sculpting of specific neural outcomes. Because focused ultrasound can generate significant modulation at a temperature <5°C, which is believed to be safe for moderate durations, we support the idea that focused ultrasound should be considered as a thermal neuromodulation technology for clinical use, especially targeting neural pathways in the peripheral nervous system. [ABSTRACT FROM AUTHOR]

This review article highlights the historical developments and current state of knowledge of an important neuromodulation technology: low-intensity focused ultrasound. Because compelling studies have shown that focused ultrasound can modulate neuronal activity non-invasively, especially in deep brain structures with high spatial specificity, there has been a renewed interest in attempting to understand the specific bioeffects of focused ultrasound at the cellular level. Such information is needed to facilitate the safe and effective use of focused ultrasound to treat a number of brain and nervous system disorders in humans. Unfortunately, to date, there appears to be no singular biological mechanism to account for the actions of focused ultrasound, and it is becoming increasingly clear that different types of nerve cells will respond to focused ultrasound differentially based on the complement of their ion channels, other membrane biophysical properties, and arrangement of synaptic connections. Furthermore, neurons are apparently not equally susceptible to the mechanical, thermal and cavitation-related consequences of focused ultrasound application—to complicate matters further, many studies often use distinctly different focused ultrasound stimulus parameters to achieve a reliable response in neural activity. In this review, we consider the benefits of studying more experimentally tractable invertebrate preparations, with an emphasis on the medicinal leech, where neurons can be studied as unique individual cells and be synaptically isolated from the indirect effects of focused ultrasound stimulation on mechanosensitive afferents. In the leech, we have concluded that heat is the primary effector of focused ultrasound neuromodulation, especially on motoneurons in which we observed a focused ultrasound-mediated blockade of action potentials. We discuss that the mechanical bioeffects of focused ultrasound, which are frequently described in the literature, are less reliably achieved as compared to thermal ones, and that observations ascribed to mechanical responses may be confounded by activation of synaptically-coupled sensory structures or artifacts associated with electrode resonance. Ultimately, both the mechanical and thermal components of focused ultrasound have significant potential to contribute to the sculpting of specific neural outcomes. Because focused ultrasound can generate significant modulation at a temperature

[Display omitted] • Verification and observation of phonons excited states. • Asymmetric Klein tunneling achieves directional selectivity. • Thermosensitive materials enable reconfigurable polarized barriers. • Topological protection and consistency of phononic behavior during transmission. • Design of a four-port elastic waveguide based on asymmetric Klein tunneling. There have been many studies on the ground state of phononic crystals, but few studies on the nature of the excited state. In this paper, we introduce the asymmetric Klein tunneling method in phononic systems, which enables selective direction and control of elastic waves by inducing polarization through an external field in an artificial barrier. Using tight-binding theory, we systematically studied phononics in a super-honeycomb structure, demonstrating the anisotropic transition properties of excited state phonons through a matrix model involving the ground state's s-type and the first excited state's p-type wave functions. Additionally, we exploit the thermal sensitivity of epoxy to achieve localized thermal field-induced distortion of the bottom flat band, forming a tiled Dirac cone, and thereby creating a reconfigurable polarized artificial barrier in the elastic wave system. Elastic waves propagate in these systems with topological charge conservation. Combining this with the theoretical of excited-state phonons, we demonstrate asymmetric Klein tunneling with directional selectivity in the elastic wave carriers, and systematically investigate the performance of this tunneling. Furthermore, we design a four-port elastic waveguide based on the principle of asymmetric tunneling, which achieves exceptional directional selectivity of elastic wave signals by adjusting the polarization direction of barriers at the junctions. These studies not only extend the application of Klein tunneling in elastic wave systems but also open new research avenues for the study of elastic wave devices controlled by various external fields, showing direct application potential in elastic wave signal processing. [ABSTRACT FROM AUTHOR]

The investigation of thermal modulation on double-diffusive stationary convection in the presence of an applied magnetic field and internal heating is carried out. A weakly nonlinear stability analysis has been performed using the finite-amplitude Ginzburg-Landau model. This finite amplitude of convection is obtained at the third order of the system. The study considers three different forms of temperature modulations. OPM-out of phase modulation, LBMO-lower boundary modulation, IPM-in phase modulation. The finite-amplitude is a function of amplitude δ T , frequency ω and the phase difference θ. The effects of δ T and ω on heat/mass transports have been analyzed and depicted graphically. The study shows that heat/mass transports can be controlled effectively by thermal modulation. Further, it is found that the internal Rayleigh number Ri enhances heat transfer and reduces the mass transfer in the system.

• A thermal modulated method to induce the superconducting constriction quench and recover periodically is proposed and experimentally demonstrated. • A thermo-electric–magnetic comprehensive simulation model is established to optimize the thermal modulated structure. • The fabricated samples can reach a high modulated frequency of 5 kHz, aligning well with the simulation data. • The interlayer capacitor-coupling effect can explain a phenomenon of resistance deviation from zero. To tackle the challenge posed by 1/f noise which significantly hinders the practical application of superconductor/tunnel magnetoresistance (TMR) composite magnetic sensors in low-frequency detection, this paper proposes a magnetic field thermal modulation method specifically tailored for the superconductor/TMR composite sensor. The method employs alternating joule heating via a resistance wire to induce partial quenching and recovery states conversion in the superconducting flux transformation amplifier (SFTA). Firstly, a thermo-electric–magnetic comprehensive finite element simulation model was developed to obtain the temperature and magnetic field distributions during the quenching and recovery state conversion process, and then to realize the size optimization of the thermal modulated structure. Final experimental tests conducted in the liquid nitrogen environment demonstrated a high modulation frequency of 5 kHz was achieved. Meanwhile, the interlayer capacitor-coupling effect was introduced to explain the phenomenon of resistance deviation from zero for the thermal modulated superconducting constriction under the higher modulation frequency. The breakthrough in this article holds promise for the low-frequency application of superconductor/TMR composite sensors. [ABSTRACT FROM AUTHOR]

• PCM technology saves energy, moderates temperatures, boosts solar control, and cuts consumption by 14–90%. • Windows with PCM panels reduce heat transfer up to 66%, lower solar gain. • PCMs plus nocturnal radiative cooling cuts surface temperatures over 13° Celsius. • Solar-powered desiccant AC with PCM achieves 75% average energy savings, 60–90% peak load reduction. • PCM-infused surfaces reduce energy use by 20%-66%, offering adaptive thermal regulation across various climates. Phase Change Materials (PCMs) present cutting-edge technology with substantial promise for advancing sustainable and energy-efficient cooling in buildings. These materials can absorb and release latent heat during phase transitions, facilitating thermal energy storage and temperature regulation. This comprehensive literature review explores various strategies and methods for implementing passive cooling with PCMs in buildings. The integration of PCMs enhances multiple passive cooling approaches, including solar control, ground cooling, ventilation-based heat dissipation, radiative cooling, and thermal mass-based heat modulation. The analysis delves into PCM classifications, encapsulation techniques, melting enthalpies, integration into diverse building envelopes, and performance across different climates. The findings from this comprehensive review indicated that PCM walls introduce a 2-hour delay in heat transfer and mitigate external temperature fluctuations. Windows equipped with PCM panels reduce heat transfer by 66 %. Combining PCMs with nocturnal radiative cooling leads to interior surface temperature reductions exceeding 13 °C. Natural ventilation with PCMs results in notable energy savings of up to 90 % in hot climates. The combination of free cooling and PCM thermal storage reduces charging times by 35 % while enhancing heat transfer. Simulations performed in the open literature suggested that strategic placement of PCMs in lightweight building walls reduces heat flux and overall energy consumption. Despite facing challenges related to scalability, compatibility, reliability, and recycling, PCM solutions demonstrate robust potential. When integrated thoughtfully into building design, PCMs significantly improve thermal performance and energy efficiency. Experimental validations confirm energy reductions ranging from 14 % to 90 %, underscoring the adaptability of passive cooling techniques leveraging PCM thermal storage and heat transfer capabilities across various climates. [ABSTRACT FROM AUTHOR]

The solid‐state‐modulator is a consumable‐free thermal modulator, used within the context of comprehensive two‐dimensional gas chromatography. Its consumable‐free nature is guaranteed by the presence of a thermal‐electric cooler device located between two heated chambers, everything located outside the gas chrpmatograph oven. The aim of the present research is to evaluate the solid‐state‐modulator modulation performance in relationship to different modulation capillary geometries. For this purpose, two coated modulation capillaries with the same length, but with different internal diameters (0.25 and 0.18 mm) were used. The effects of gas linear velocity, modulator temperature, and modulation period were evaluated in several applications involving standard alkanes and a sample of diesel fuel. Fundamental gas chromatography parameters (peaks widths, resolution) were measured under the different experimental conditions. Detailed information is provided on gas flow optimization, with particular emphasis on the efficiency of chromatography band reinjection onto the second‐dimension column. The results obtained from the present investigation highlight how the modulation capillary characteristics have a great impact on the overall comprehensive two‐dimensional gas chromatography separation. Specifically, considering the results herein attained, the use of a 0.18 mm ID × 0.18 μm df modulation column is advisable compared to a 0.25 mm ID × 0.25 μm df one. [ABSTRACT FROM AUTHOR]

• Hybrid GSPPs at the graphene/vacuum interface are induced by a magnetic field. • Magnetic field enhances the coupled SPh–SPPs in the reststrahlen band of NaBr. • Hybrid GSPPs and coupled SPh–SPPs play a key role in the thermal modulation. • Heat flux is modulated by the magnetic field, Fermi level and carrier mobility. • A modulation contrast as high as 4.48 is acquired at a vacuum gap of 100 nm. We propose a thermal modulation structure composed of two identical graphene-coated NaBr plates separated by a nanoscale vacuum gap (d). A static magnetic field perpendicular to the graphene sheet induces TE–TM hydrid surface plasmon polaritons between graphene and vacuum gap (called the hybrid GSPPs) and enhances the coupling of the hybrid surface plasmon polaritons in graphene to the surface phonon polaritons in the reststrahlen band of NaBr (called the coupled SPh–SPPs). The hybrid GSPPs and coupled SPh–SPPs play a key role in the thermal modulation. The heat flux is modulated by changing the static magnetic field, the Fermi level (E F) and carrier mobility (μ) in graphene. When the magnetic field varies from 0 to 30 T, the modulation contrast as high as 3.42, 3.25 and 4.48 is acquired at (d, E F , μ)=(60.64 nm, 0.2 eV, 1000 cm 2/ V · s), (100 nm, 0.21 eV, 1000 cm 2/ V · s) and (100 nm, 0.2 eV, 2500 cm 2/ V · s), respectively. The work opens new routes to magnetically modulate near-field radiative heat flux in graphene-based structures, and provides some guidance for applications in thermal management of nano/microscaled devices. [ABSTRACT FROM AUTHOR]

Abstract One of the greatest advancements in the field of gas chromatography (GC) has been the development of comprehensive two-dimensional gas chromatography (GC × GC). As the field of GC evolved from one-dimensional gas chromatography (1D-GC) to heart cutting (GC–GC), followed by the advent of GC × GC, the critical component at the center of this evolution has been the interface between the separation columns. The interface, referred to as the modulator for GC × GC, links the primary and secondary columns. This review covers the evolution of modulator systems from the founding of GC × GC in 1991 by Liu and Phillips, while focusing on the last six years. Since its inception, modulators have evolved into two distinct categories: thermal, and valve-based. The advantages and shortcomings of each category will be covered. Recent developments in the research, development, and commercialization of these various modulators is provided, with a glimpse into future modulator designs. Highlights • The past six years of GC × GC modulator advances are highlighted. • Two classes of modulators are discussed and compared: thermal and valve-based. • Valve-based modulation includes differential flow and flow diversion modulation. • Cryogen free thermal modulation is reviewed, contrasted with cryogen based systems. • Recent advances have allowed valve-based modulation periods as fast as 50 ms. [ABSTRACT FROM AUTHOR]

The present research is based on the use of a recently developed comprehensive two‐dimensional gas chromatography thermal modulator, which is defined as solid‐state modulator. The transfer device was installed on top of a single gas chromatography oven, while benchtop low‐resolution time‐of‐flight mass spectrometry was used to monitor the compounds exiting the second analytical column. The solid‐state modulator was first described by Luong et al. in 2016, and it is a moving modulator that does not require heating and cooling gases to generate comprehensive two‐dimensional gas chromatography data. The accumulation and remobilization steps occur on a trapping capillary, this being subjected to thermoelectric cooling and micathermic heating. In this study, the effects of the gas linear velocity on the modulation performance were evaluated by using two different uncoated trapping capillaries, viz., 0.8 m × 0.25 mm id and 0.8 m × 0.20 mm id. Solid‐state modulator applications were carried out on a standard solution containing n‐alkanes (C9, C10, C12), and on a sample of diesel fuel. The results indicated that the type of trapping capillary and gas velocity have a profound effect on modulation efficiency. [ABSTRACT FROM AUTHOR]

The onset of magnetoelectroconvection in a dielectric fluid-saturated horizontal porous layer in the presence of uniform electric field and the magnetic field is investigated for various time periodic temperature modulations. The dielectric constant is assumed to be a linear function of temperature. The modified Darcy equation is used to describe the flow in a porous medium, and the resulting eigenvalue problem is solved using a regular perturbation method with small amplitude approximation. It is observed that the correction Rayleigh number decreases as the Hartmann number increases in the cases of symmetric modulation and only lower wall temperature modulation while it increases in the case of asymmetric modulation. Whereas, correction Rayleigh number increases as the electric Rayleigh number, Darcy number, and Prandtl number increase irrespective of the type of modulation. It is found that the combined effects of electric field and the magnetic field is more favorable to suppress convection significantly than in the presence of electric field alone. This result is useful in synthesizing smart and strong materials needed for much aeronautical, automobile, and biomedical engineering applications to minimize the weight and maximize the strength to achieve the sufficient dynamic advantages. [ABSTRACT FROM AUTHOR]

The volatile composition of honeybush ( Cyclopia ) species was studied by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOF-MS). Headspace-solid phase micro-extraction (HS-SPME) was used to extract the volatile compounds from tea infusions prepared from the three species C. genistoides , C. maculata and C. subternata . A total of 287 compounds were identified, 101 of which were confirmed using reference standards, while the remainder were tentatively identified using mass spectral and retention index (RI) data. The identification power of TOF-MS enabled the tentative identification of 147 compounds for the first time in honeybush tea. The majority of the compounds identified were common to all three Cyclopia species, although there were differences in their relative abundances, and some compounds were unique to each of the species. In C. genistoides , C. maculata and C . subternata 265, 257 and 238 compounds were identified, respectively. Noteworthy was the tentative identification of cinnamaldehyde in particular C. maculata samples, which points to the likely contribution of this compound to their distinct sensory profiles. This study emphasises the complexity of honeybush tea volatile composition and confirms the power of GC × GC combined with TOF-MS for the analysis of such complex samples. [ABSTRACT FROM AUTHOR]

• Thermally reconfigurable implementation of the Klein tunneling simulation. • Strategy of pre-raising the barrier to improve the response speed of the modulation. • Extending the scope of Klein tunneling using quasiparticle models. The field of signal processing is focused on increasing the modulation rate over a wide frequency range. In this paper, we introduce a new strategy for accelerating modulation, specifically in the case of thermal modulation. Klein tunneling is a counterintuitive effect in quantum systems, which allows a quasiparticle to pass through a barrier perfectly under certain conditions. First, we construct quasiparticles that satisfy Klein tunneling conditions by pre-etching and covering epoxy films on a patterned substrate. Then, by using the temperature sensitivity of the epoxy, we produced an artificial barrier through thermal modulation. By elevating the barrier to the Kleinian tunneling threshold in the middle of the elastic wave path using the sandwich structure, the path was instantly interrupted when the barrier was raised beyond this point, allowing for on/off switching of the path in a short temperature interval using this strategy. Furthermore, we expanded the understanding of elastic wave tunneling through the quasiparticle model and simulated Klein tunneling in a structure devoid of Dirac points, as found in graphene. These studies do not rely on the band structure of the degenerate state for simulation purposes, demonstrating the potential for immediate applications and providing new avenues for future research. [ABSTRACT FROM AUTHOR]

A new signal processing technique has been developed for resistive metal oxide (MOX) gas sensors to enable high-bandwidth measurements and enhanced selectivity at PPM levels (

We have proposed the mathematical formulations of quantum Zeno and anti-Zeno effects at non-zero temperature on vibrational population transfer and dissociation of a diatomic system. The proposed formulation has been tested for diatomic systems HBr+and HI using time-dependent Fourier grid Hamiltonian method. The effect of temperature on the dynamics is incorporated through the population distribution at different vibrational states following Boltzmann distribution formula. It has been found that with increase in temperature Zeno effect increases and anti-Zeno effect decreases in case of survival probability on ground vibrational state. In case of dissociation, with increase in temperature Zeno effect increases while anti-Zeno effect remains almost same. [ABSTRACT FROM PUBLISHER]

The applicability of comprehensive two-dimensional gas chromatography (GC×GC) using a single-stage thermal modulator was explored for the analysis of honeybush tea ( Cyclopia spp.) volatile compounds. Headspace solid phase micro-extraction (HS-SPME) was used in combination with GC×GC separation on a non-polar × polar column set with flame ionisation (FID) detection for the analysis of fermented Cyclopia maculata, Cyclopia subternata and Cyclopia genistoides tea infusions of a single harvest season. Method optimisation entailed evaluation of the effects of several experimental parameters on the performance of the modulator, the choice of columns in both dimensions, as well as the HS-SPME extraction fibre. Eighty-four volatile compounds were identified by co-injection of reference standards. Principal component analysis (PCA) showed clear differentiation between the species based on their volatile profiles. Due to the highly reproducible separations obtained using the single-stage thermal modulator, multivariate data analysis was simplified. The results demonstrate both the complexity of honeybush volatile profiles and the potential of GC×GC separation in combination with suitable data analysis techniques for the investigation of the relationship between sensory properties and volatile composition of these products. The developed method therefore offers a fast and inexpensive methodology for the profiling of honeybush tea volatiles. [ABSTRACT FROM AUTHOR]

Thermal properties are essentially decided by atomic geometry and thus stress is the most direct way for manipulating. In this paper, we investigate stress modulation of thermal conductivity of graphene by molecular dynamics simulations and discuss the underlying microscopic mechanism. It is found that thermal conductivity of flexural-free graphene increases with compression and decreases with strain, while thermal conductivity of flexural-included graphene decreases with both compression and strain. Such difference in thermal behavior originates from the changes in the anharmonicity of the interatomic potential, where the wrinkle scattering is responsible for the thermal conductivity diminishment in flexural-included graphene under strain. By comparing the results obtained from the Tersoff and AIREBO potentials, it is revealed that the degree of the symmetry of interatomic potential determines the thermal conductivity variation of graphene. Our results indicate that the symmetry of interatomic potential should be taken into careful consideration in constructing the lattice model of graphene. [ABSTRACT FROM AUTHOR]

A new signal processing technique has been developed for resistive metal oxide (MOX) gas sensors to enable high-bandwidth measurements and enhanced selectivity at PPM levels (2, WO3, NiO) to be extracted using a fast Fourier transform. Signal processing is performed in real-time using a low-cost microcontroller integrated into a sensor module. The approach enables the remove of baseline drift and is resilient to environmental temperature changes. Bench-top experimental results are presented for 50 to 200 ppm of ethanol and CO, which demonstrate our sensor system can be used within a mobile robot.

Acting like thermal resistances, ferroelectric domain walls can be manipulated to realize dynamic modulation of thermal conductivity (k), which is essential for developing novel phononic circuits. Despite the interest, little attention has been paid to achieving room-temperature thermal modulation in bulk materials due to challenges in obtaining a high thermal conductivity switching ratio (k high /k low ), particularly in commercially viable materials. Here, room-temperature thermal modulation in 2.5 mm-thick Pb(Mg 1/3 Nb 2/3 )O 3 -xPbTiO 3 (PMN-xPT) single crystals is demonstrated. With the use of advanced poling conditions, assisted by the systematic study on composition and orientation dependence of PMN-xPT, a range of thermal conductivity switching ratios with a maximum of ≈1.27 is observed. Simultaneous measurements of piezoelectric coefficient (d 33 ) to characterize the poling state, domain wall density using polarized light microscopy (PLM), and birefringence change using quantitative PLM reveal that compared to the unpoled state, the domain wall density at intermediate poling states (0< d 33 33,max ) is lower due to the enlargement in domain size. At optimized poling conditions (d 33,max ), the domain sizes show increased inhomogeneity that leads to enhancement in the domain wall density. This work highlights the potential of commercially available PMN-xPT single crystals among other relaxor-ferroelectrics for achieving temperature control in solid-state devices., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

This article demonstrates the feasibility of an alternative strategy for producing temperature sensitive molecularly imprinted microspheres (MIMs) for solid-phase dispersion extraction of malachite green, crystal violet and their leuko metabolites. Thermo-sensitive MIMs can change their structure following temperature stimulation. This allows capture and release of target molecules to be controlled by temperature. The fabrication technique provides surface molecular imprinting in acetonitrile using vinyl modified silica microspheres as solid supports, methacrylic acid and N-isopropyl acrylamide as the functional monomers, ethyleneglycol dimethacrylate as the cross-linker, and malachite green as the template. After elution of the template, the MIMs can be used for fairly group-selective solid phase dispersion extraction of malachite green, crystal violet, leucomalachite green, and leucocrystal violet from homogenized fish samples at a certain temperature. Following centrifugal separation of the microspheres, the analytes were eluted with a 95:5 mixture of acetonitrile and formic acid, and then quantified by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) with isotope internal calibration. The detection limits for malachite green, crystal violet and their metabolites typically are 30 ng·kg. Positive samples were identified by UHPLC-MS/MS in the positive ionization mode with multiple reaction monitoring. The method was applied to the determination of the dyes and the respective leuko dyes in fish samples, and accuracy and precision were validated by comparative analysis of the samples by using aluminum neutral columns. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) is a noninvasive and effective approach for cancer treatment. The main bottlenecks of clinical PDT are poor selectivity of photosensitizer and inadequate oxygen supply resulting in serious side effects and low therapeutic efficiency. Herein, a thermal-modulated reactive oxygen species (ROS) strategy using activatable human serum albumin-chlorin e6 nanoassemblies (HSA-Ce6 NAs) for promoting PDT against cancer is developed. Through intermolecular disulfide bond crosslinking and hydrophobic interaction, Ce6 photosensitizer is effectively loaded into the HSA NAs, and the obtained HSA-Ce6 NAs exhibit excellent reduction response, as well as enhanced tumor accumulation and retention. By the precision control of the overall body temperature instead of local tumor temperature increasing from 37 °C to 43 °C, the photosensitization reaction rate of HSA-Ce6 NAs increases 20%, and the oxygen saturation of tumor tissue raise 52%, significantly enhancing the generation of ROS for promoting PDT. Meanwhile, the intrinsic fluorescence and photoacoustic properties, and the chelating characteristic of porphyrin ring can endow the HSA-Ce6 NAs with fluorescence, photoacoustic and magnetic resonance triple-modal imaging functions. Upon irradiation of low-energy near-infrared laser, the tumors are completely suppressed without tumor recurrence and therapy-induced side effects. The robust thermal-modulated ROS strategy combined with albumin-based activatable nanophotosensitizer is highly potential for multi-modal imaging-guided PDT and clinical translation. [ABSTRACT FROM AUTHOR]

Comprehensive two-dimensional gas chromatography (GC × GC) with a temperature-programmed microfabricated thermal modulator (μTM) is demonstrated. The 0.78 cm 2 , 2-stage μTM chip with integrated heaters and a PDMS coated microchannel was placed in thermal contact with a solid-state thermoelectric cooler and mounted on top of a bench scale GC. It was fluidically coupled through heated interconnects to an upstream first–dimension ( 1 D) PDMS-coated capillary column and a downstream uncoated capillary or second-dimension ( 2 D) PEG-coated capillary. A mixture of n -alkanes C 6 –C 10 was separated isothermally and the full-width-at-half-maximum ( fwhm ) values of the modulated peaks were assessed as a function of the computer-controlled minimum and maximum stage temperatures of μTM, T min and T max , respectively. With T min and T max fixed at −25 and 100 °C, respectively, modulated peaks of C 6 and C 7 had fwhm values <53 ms while the modulated peaks of C 10 had a fwhm value of 1.3 s, due to inefficient re-mobilization. With T min and T max fixed at 0 and 210 °C, respectively, the fwhm value for the modulated C 10 peaks decreased to 67 ms, but C 6 and C 7 exhibited massive breakthrough. By programming T min from −25 to 0 °C and T max from 100 to 220 °C, the C 6 and C 7 peaks had fwhm values ≤ 50 ms, and the fwhm for C 10 peaks remained < 95 ms. Using the latter conditions for the GC × GC separation of a sample of unleaded gasoline yielded resolution similar to that reported with a commercial thermal modulator. Replacing the PDMS phase in the μTM with a trigonal-tricationic room temperature ionic liquid eliminated the bleed observed with the PDMS, but also reduced the capacity for several test compounds. Regardless, the demonstrated capability to independently temperature program this low resource μTM enhances its versatility and its promise for use in bench-scale GC × GC systems. [ABSTRACT FROM AUTHOR]

The stability of a porous medium saturated with a nanofluid with thermal conductivity and viscosity dependent on the nanoparticle volume fraction is examined in the case of a time-dependent wall temperature. The regular perturbation method based on the small amplitude of modulation is employed to compute the critical Rayleigh number and the corresponding wave number. The stability of the system characterized by a correction Rayleigh number is calculated as a function of the concentration Rayleigh number, porosity, Lewis number, heat capacity ratio, Vadász number, viscosity variation parameter, conductivity variation parameter and frequency of modulation. It is found that the low frequency symmetric thermal modulation is destabilizing while moderate and high frequency symmetric modulation is always stabilizing. The nanofluid is found to have more stabilizing effect when compared to regular fluid. The asymmetric modulation and lower wall temperature modulation is stabilizing for all frequencies. [ABSTRACT FROM AUTHOR]

Osmotic energy conversion (OEC) is attractive for salinity-gradient power utilization. Nevertheless, the OEC still faces a challenge of relatively low power density owing to the limited ionic mass transfer. In this paper, we present designed interfacial nanostructures (DINS) to enhance ion selective transport in nanopores. The maximum osmotic power under 50-fold salt concentration ratio is ameliorated by 180.6%, when DINS are applied in nanopore region. When DINS are partially applied at low salt concentration side rather than high salt concentration side, the maximum osmotic power under 50-fold salt concentration ratio is enhanced by 139.1%. Once the temperature of aqueous solution at low salt concentration side with high original electric double layer thickness is raised up, the maximum osmotic power under 50-fold salt concentration ratio is consolidated by 19.8%. Therefore, a principle "Strengthening the electric double layer with high original thickness adjacent to low salt concentration reservoir" is constructed for enhancing OEC performance. Besides, when temperature difference between two reservoirs with artificial seawater and freshwater is varied from 35 °C to −35 °C, the experimental osmotic power density is consolidated from 3.09 W/m2 to 4.78 W/m2 by 54.7%. The current work offers a principle to improve OEC performance with DINS under thermal modulation. • Designed interfacial nanostructures (DINS) are used to improve ion selectivity. • Thermal modulation of osmotic energy conversion (OEC) is analyzed. • Electric double layer with high original thickness need to be consolidated. • A scientific principle for using DINS with thermal modulation is constructed. [ABSTRACT FROM AUTHOR]