23 results on '"Thermal modulation"'
Search Results
2. Infrared thermal modulation endoscopy for label-free tumor detection.
- Author
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Kim, Suhyeon, Oh, Gyungseok, Kim, Young Ro, Chung, Euiheon, and Kwon, Hyuk-Sang
- Subjects
- *
INFRARED imaging , *STEREOLITHOGRAPHY , *IMAGING systems , *LABORATORY mice ,RECTUM tumors - Abstract
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]
- Published
- 2024
- Full Text
- View/download PDF
3. Autonomous Thermal Modulator Based on Gold Film‐Coated Liquid Crystal Elastsomer.
- Author
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Dong, Gaoweiang, Feng, Tianshi, Chen, Renkun, and Cai, Shengqiang
- Subjects
- *
LIQUID crystals , *HEAT radiation & absorption , *AIR resistance , *ADAPTIVE modulation , *ELECTRIC potential - Abstract
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]
- Published
- 2024
- Full Text
- View/download PDF
4. THERMAL MODULATION EFFECTS ON WEAKLY NONLINEAR BIOTHERMAL CONVECTION WITH THERMOTACTIC MICROORGANISMS IN A LIQUID LAYER.
- Author
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Kopp, M. I. and Yanovsky, V. V.
- Subjects
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NUSSELT number , *TRANSPORT equation , *PECLET number , *HEAT transfer , *NONLINEAR analysis - Abstract
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]
- Published
- 2024
- Full Text
- View/download PDF
5. Reconfigurable directional selective tunneling of p-type phonons in polarized elastic wave systems
- Author
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Guanliang Yu, Jiale Xie, Shuyang Gao, Weirong Wang, Liyan Lai, Chun Jiang, and Yigui Li
- Subjects
Elastic wave ,Polarized medium ,Asymmetric tunneling ,Thermal modulation ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
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.
- Published
- 2024
- Full Text
- View/download PDF
6. Weakly nonlinear bio-convection in a porous media under temperature modulation and internal heating
- Author
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Kiran, Palle and Manjula, S. H.
- Published
- 2024
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7. 基于 ESP32-S 的小型智能气体识别系统设计.
- Author
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刘弘禹, 李彦宽, 方晓东, and 陈志超
- Abstract
Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control 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.)
- Published
- 2023
- Full Text
- View/download PDF
8. Thermal Modulation of a Chaotic Fiber Laser by Using a Phase-Shifted Fiber Bragg Grating
- Author
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Zhanwu Xie, Wenlong Zeng, Pengfei Li, Haitao Yan, and Daofu Han
- Subjects
Chaotic fiber laser ,phase-shift fiber Bragg grating ,thermal modulation ,Applied optics. Photonics ,TA1501-1820 ,Optics. Light ,QC350-467 - Abstract
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.
- Published
- 2023
- Full Text
- View/download PDF
9. Rayleigh-Bénard Convection in the Presence of Synchronous and Asynchronous Thermal Rigid Boundary Conditions
- Author
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Kiran, Palle, Howlett, Robert J., Series Editor, Littlewood, John, Series Editor, Jain, Lakhmi C., Series Editor, Bindhu, V., editor, R. S. Tavares, João Manuel, editor, and Ţălu, Ştefan, editor
- Published
- 2022
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10. Combined Effect of Temperature Modulation and Rotation on the Onset of Darcy-Bénard Convection in a Porous Layer Using the Local Thermal Nonequilibrium Model.
- Author
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Bansal, A. and Suthar, Om P.
- Subjects
TEMPERATURE effect ,THERMAL equilibrium ,ROTATIONAL motion ,LINEAR momentum ,POROUS materials ,CORIOLIS force ,DARCY'S law ,RAYLEIGH-Benard convection ,LINEAR statistical models - Abstract
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]
- Published
- 2023
- Full Text
- View/download PDF
11. Low-loss silica waveguide 1×8 thermo-optic switch based on large-scale multimode interference couplers.
- Author
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Yue, Jianbo, Wang, Manzhuo, Zou, Jiaqi, Liu, Tingyu, Fang, Jimin, Sun, Xiaoqiang, Wu, Yuanda, and Zhang, Daming
- Subjects
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INSERTION loss (Telecommunication) , *OPTICAL switches , *SILICA , *BANDWIDTHS , *TRENCHES - Abstract
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]
- Published
- 2024
- Full Text
- View/download PDF
12. Development and analysis of an artificial olfactory bulb.
- Author
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Li, Hantao, Covington, James A., Tian, Fengchun, Wu, Zhiyuan, Liu, Yue, and Hu, Li
- Subjects
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ELECTRONIC noses , *OLFACTORY bulb , *ZOOGEOGRAPHY , *SMELL , *DATA analysis - Abstract
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]
- Published
- 2024
- Full Text
- View/download PDF
13. Time-Periodic Thermal Boundary Effects on Porous Media Saturated with Nanofluids: Cgle Model for Oscillatory Mode.
- Author
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Kiran, Palle and Manjula, Sivaraj H.
- Subjects
POROUS materials ,NANOFLUIDS ,MASS transfer ,DIFFERENTIAL operators ,OPERATOR theory ,HEAT transfer - Abstract
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 (ω
f varying from 2 to 70) reduces heat and mass transfer while modulation amplitude (δ1 varying from 0.1 to 0.5) enhances both. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
14. A review of the bioeffects of low-intensity focused ultrasound and the benefits of a cellular approach.
- Author
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Collins, Morgan N. and Mesce, Karen A.
- Subjects
PERIPHERAL nervous system ,ACTION potentials ,NEURONS ,ION channels ,BRAIN anatomy ,BIOLOGICAL neural networks - Abstract
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]
- Published
- 2022
- Full Text
- View/download PDF
15. A review of the bioeffects of low-intensity focused ultrasound and the benefits of a cellular approach
- Author
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Morgan N. Collins and Karen A. Mesce
- Subjects
low-intensity focused ultrasound ,non-invasive brain stimulation ,neuromodulation ,transcranial focused ultrasound ,leech ,thermal modulation ,Physiology ,QP1-981 - Abstract
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
- Published
- 2022
- Full Text
- View/download PDF
16. Reconfigurable directional selective tunneling of p-type phonons in polarized elastic wave systems.
- Author
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Yu, Guanliang, Xie, Jiale, Gao, Shuyang, Wang, Weirong, Lai, Liyan, Jiang, Chun, and Li, Yigui
- Subjects
- *
ELASTIC waves , *PHONONIC crystals , *EXCITED states , *PHONONS , *SIGNAL processing - Abstract
[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]
- Published
- 2024
- Full Text
- View/download PDF
17. Study on the high-frequency conversion characteristics of quench and recovery states under thermal modulation of a superconducting flux transformation amplifier.
- Author
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Li, Guilong, Ding, Qiaochu, Zhang, Shiyi, Du, Qingfa, Pan, Mengchun, Li, Peisen, Peng, Junping, Qiu, Weicheng, Hu, Jiafei, and Hu, Yueguo
- Subjects
- *
TUNNEL magnetoresistance , *PINK noise , *MAGNETIC sensors , *FINITE element method , *MAGNETIC fields - Abstract
• 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]
- Published
- 2024
- Full Text
- View/download PDF
18. Advancing sustainable building through passive cooling with phase change materials, a comprehensive literature review.
- Author
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Ghamari, Mehrdad, See, Chan Hwang, Hughes, David, Mallick, Tapas, Reddy, K Srinivas, Patchigolla, Kumar, and Sundaram, Senthilarasu
- Subjects
- *
HEAT storage , *PHASE transitions , *CLEAN energy , *PHASE change materials , *HEAT flux - Abstract
• 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]
- Published
- 2024
- Full Text
- View/download PDF
19. Klein-tunneling Increases the signal modulation rate of elastic wave systems.
- Author
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Yu, Guanliang, Xia, Jie, Lai, Liyan, Peng, Tongrui, Zhu, Houyao, Jiang, Chun, and Li, Yigui
- Subjects
- *
QUANTUM tunneling , *QUANTUM tunneling composites , *ELASTIC waves , *SANDWICH construction (Materials) , *ACOUSTIC surface waves , *RANDOM noise theory , *PHONONIC crystals , *AERODYNAMIC heating - Abstract
• 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]
- Published
- 2023
- Full Text
- View/download PDF
20. Ferroelectric Domain Wall Engineering Enables Thermal Modulation in PMN-PT Single Crystals.
- Author
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Negi A, Kim HP, Hua Z, Timofeeva A, Zhang X, Zhu Y, Peters K, Kumah D, Jiang X, and Liu J
- Abstract
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 /klow ), particularly in commercially viable materials. Here, room-temperature thermal modulation in 2.5 mm-thick Pb(Mg1/3 Nb2/3 )O3 -xPbTiO3 (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 (d33 ) 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< d33 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.)- Published
- 2023
- Full Text
- View/download PDF
21. Salinity-gradient power harvesting using osmotic energy conversion with designed interfacial nanostructures under thermal modulation.
- Author
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Ren, Qinlong, Cui, Qiongyao, Chen, Kelei, Xie, Jingyao, and Wang, Pengfei
- Subjects
- *
ENERGY conversion , *ELECTRIC double layer , *ELECTRO-osmosis , *OSMOTIC pressure , *SALTWATER solutions , *ARTIFICIAL seawater , *NANOSTRUCTURES , *ENERGY harvesting - Abstract
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]
- Published
- 2022
- Full Text
- View/download PDF
22. Cold-Starting All-Solid-State Batteries from Room Temperature by Thermally Modulated Current Collector in Sub-Minute.
- Author
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Ye Y, Huang W, Xu R, Xiao X, Zhang W, Chen H, Wan J, Liu F, Lee HK, Xu J, Zhang Z, Peng Y, Wang H, Gao X, Wu Y, Zhou G, and Cui Y
- Abstract
All-solid-state batteries (ASSBs) show great potential as high-energy and high-power energy-storage devices but their attainable energy/power density at room temperature is severely reduced because of the sluggish kinetics of lithium-ion transport. Here a thermally modulated current collector (TMCC) is reported, which can rapidly cold-start ASSBs from room temperature to operating temperatures (70-90 °C) in less than 1 min, and simultaneously enhance the transient peak power density by 15-fold compared to one without heating. This TMCC is prepared by integrating a uniform, ultrathin (≈200 nm) nickel layer as a thermal modulator within an ultralight polymer-based current collector. By isolating the thermal modulator from the ion/electron pathway of ASSBs, it can provide fast, stable heat control yet does not interfere with regular battery operation. Moreover, this ultrathin (13.2 µm) TMCC effectively shortens the heat-transfer pathway, minimizes heat losses, and mitigates the formation of local hot spots. The simulated heating energy consumption can be as low as ≈3.94% of the total battery energy. This TMCC design with good tunability opens new frontiers toward smart energy-storage devices in the future from the current collector perspective., (© 2022 Wiley-VCH GmbH.)
- Published
- 2022
- Full Text
- View/download PDF
23. Elaborate manipulation on CNT intertube heat transport by using a polymer knob.
- Author
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Qiu, Lin, Li, Fengcheng, Zhu, Ning, Feng, Yanhui, Zhang, Xinxin, and Zhang, Xiaohua
- Subjects
- *
HEAT conduction , *POLYMERS , *DENSITY of states , *THERMAL conductivity , *PHONONS , *CARBON nanotubes - Abstract
• Across-tube heat conduction is doubled by placing PE chains in the grooves of CNTs. • Elaborately arranging the spatial position of PE plays a role of thermal switch knob. • Heat conduction boost is accompanied by VDOS redshift due to flattening deformation [Display omitted] The interface engineering between carbon nanotubes (CNTs) is a key to enhance the thermal conductivity of CNT assembled materials to match the trend of microelectronics miniaturization. In this study, according to the experimental finding of polymer-promoted CNT intertube heat transport, we reveal that there is a strong dependence of heat conductance on the orientation of polymer chain, corresponding to an effect of thermal switch knob. When the soft long-chain polyethylene molecular chains are placed in the grooves on both sides of two parallel CNTs at θ = 30 –60 ∘ , flattening deformation will occur at the CNT contacts, and multi-point enhancement of vibrational density of states in 2.5–12 THz frequency range and a redshift of 3 THz for the frequencies are observed. These two phenomena point to a strong enhancement of the phonon coupling at the CNT contact, which is verified by 120% boost of the interfacial thermal conductance for the across-tube thermal transport. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
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