Anisotropic thermal conductivity tensor measurements using beam-offset frequency domain thermoreflectance (BO-FDTR) for materials lacking in-plane symmetry

Many materials have anisotropic thermal conductivity, with diverse applications such as transistors, thermoelectrics, and laser gain media. Yet measuring the thermal conductivity tensor of such materials remains a challenge, particularly for materials lacking in-plane symmetry (i.e., transversely anisotropic materials). This paper demonstrates thermal conductivity tensor measurements for transversely anisotropic materials, by extending beam-offset frequency-domain thermoreflectance (BO-FDTR) methods which had previously been limited to transversely isotropic materials. Extensive sensitivity analysis is used to determine an appropriate range of heating frequencies and beam offsets to extract various tensor elements. The new technique is demonstrated on a model transversely anisotropic material, x-cut quartz ( {\alpha}-SiO2), by combining beam offset measurements from different sample orientations to reconstruct the full in-plane thermal conductivity tensor. The technique is also validated by measurements on two transversely isotropic materials, sapphire and highly oriented pyrolytic graphite (HOPG). The anisotropic measurements demonstrated very good self-consistency in correctly identifying isotropic directions when present, with residual anisotropy errors below 4% for sapphire and 2% for HOPG and quartz. Finally, a computational case study (simulated experiment) shows how the arbitrary in-plane thermal conductivity tensor of a fictitious material with high in-plane anisotropy can in principle be obtained from only a single sample orientation, rather than multiple orientations like the experiments on x-cut quartz

Single-photon transport in a whispering-gallery mode microresonator directionally coupled with a two-level quantum emitter

We investigate the single-photon transport problem in the system of a Whispering-Gallery mode microresonator directionally coupled with a two-level quantum emitter (QE). This QE-microresonator coupling system can usually be studied by cavity quantum electrodynamics and the single-photon transport methods. However, we find that if we treat a two-level QE as a single-photon phase-amplitude modulator, we can also deal with such systems using the transfer matrix method. Further, in theory, we prove that these three methods are equivalent. The corresponding relations of respective parameters among these approaches are precisely deduced. Our work can be extended to a multiple-resonator system interacting with two-level QEs in a chiral way. Therefore, the transfer matrix method may provide a convenient and intuitive form for exploring more complex chiral QE-resonator interaction systems

Structure–Activity Relationship between the Superhydrophilic Nanowire Structure and the Oil Dewetting Property

Materials require specific surface structures to achieve the best performance, but achieving an optimal structural design requires a systematic study of how structure affects performance. In this work, we comprehensively and systematically investigated the structure–activity relationship between the nanowire structure and the oil dewetting self-cleaning performance. It is easy for an oil droplet to enter this structure, but it is difficult for it to escape from the gaps between the structures even under the action of water. So, the oil dewetting ability is greatly reduced, showing that this “easy to enter and difficult to exit” mode is very disadvantageous for oil desorption. Moreover, if the structure is dissolved during the test, the oil dewetting ability will be restored. The desorption effect is affected by structural parameters and reaction conditions, which further verifies the negative effect of this structure. In contrast, copper(II) oxide nanowires completely lose their self-cleaning ability due to the enhancement of hydrophobicity and oleophilicity, and the larger-diameter copper(II) oxalate nanorods exhibit a “difficult to enter and difficult to exit” mode, leading to the partial recovery of the oil dewetting performance. This study helps us deeply understand the influence of the surface microstructure on the oil dewetting performance and lay a solid foundation for further appropriate structural design

Structure–Activity Relationship between the Superhydrophilic Nanowire Structure and the Oil Dewetting Property

Materials require specific surface structures to achieve the best performance, but achieving an optimal structural design requires a systematic study of how structure affects performance. In this work, we comprehensively and systematically investigated the structure–activity relationship between the nanowire structure and the oil dewetting self-cleaning performance. It is easy for an oil droplet to enter this structure, but it is difficult for it to escape from the gaps between the structures even under the action of water. So, the oil dewetting ability is greatly reduced, showing that this “easy to enter and difficult to exit” mode is very disadvantageous for oil desorption. Moreover, if the structure is dissolved during the test, the oil dewetting ability will be restored. The desorption effect is affected by structural parameters and reaction conditions, which further verifies the negative effect of this structure. In contrast, copper(II) oxide nanowires completely lose their self-cleaning ability due to the enhancement of hydrophobicity and oleophilicity, and the larger-diameter copper(II) oxalate nanorods exhibit a “difficult to enter and difficult to exit” mode, leading to the partial recovery of the oil dewetting performance. This study helps us deeply understand the influence of the surface microstructure on the oil dewetting performance and lay a solid foundation for further appropriate structural design

Structure–Activity Relationship between the Superhydrophilic Nanowire Structure and the Oil Dewetting Property

Materials require specific surface structures to achieve the best performance, but achieving an optimal structural design requires a systematic study of how structure affects performance. In this work, we comprehensively and systematically investigated the structure–activity relationship between the nanowire structure and the oil dewetting self-cleaning performance. It is easy for an oil droplet to enter this structure, but it is difficult for it to escape from the gaps between the structures even under the action of water. So, the oil dewetting ability is greatly reduced, showing that this “easy to enter and difficult to exit” mode is very disadvantageous for oil desorption. Moreover, if the structure is dissolved during the test, the oil dewetting ability will be restored. The desorption effect is affected by structural parameters and reaction conditions, which further verifies the negative effect of this structure. In contrast, copper(II) oxide nanowires completely lose their self-cleaning ability due to the enhancement of hydrophobicity and oleophilicity, and the larger-diameter copper(II) oxalate nanorods exhibit a “difficult to enter and difficult to exit” mode, leading to the partial recovery of the oil dewetting performance. This study helps us deeply understand the influence of the surface microstructure on the oil dewetting performance and lay a solid foundation for further appropriate structural design

Structure–Activity Relationship between the Superhydrophilic Nanowire Structure and the Oil Dewetting Property

Materials require specific surface structures to achieve the best performance, but achieving an optimal structural design requires a systematic study of how structure affects performance. In this work, we comprehensively and systematically investigated the structure–activity relationship between the nanowire structure and the oil dewetting self-cleaning performance. It is easy for an oil droplet to enter this structure, but it is difficult for it to escape from the gaps between the structures even under the action of water. So, the oil dewetting ability is greatly reduced, showing that this “easy to enter and difficult to exit” mode is very disadvantageous for oil desorption. Moreover, if the structure is dissolved during the test, the oil dewetting ability will be restored. The desorption effect is affected by structural parameters and reaction conditions, which further verifies the negative effect of this structure. In contrast, copper(II) oxide nanowires completely lose their self-cleaning ability due to the enhancement of hydrophobicity and oleophilicity, and the larger-diameter copper(II) oxalate nanorods exhibit a “difficult to enter and difficult to exit” mode, leading to the partial recovery of the oil dewetting performance. This study helps us deeply understand the influence of the surface microstructure on the oil dewetting performance and lay a solid foundation for further appropriate structural design

Structure–Activity Relationship between the Superhydrophilic Nanowire Structure and the Oil Dewetting Property

Materials require specific surface structures to achieve the best performance, but achieving an optimal structural design requires a systematic study of how structure affects performance. In this work, we comprehensively and systematically investigated the structure–activity relationship between the nanowire structure and the oil dewetting self-cleaning performance. It is easy for an oil droplet to enter this structure, but it is difficult for it to escape from the gaps between the structures even under the action of water. So, the oil dewetting ability is greatly reduced, showing that this “easy to enter and difficult to exit” mode is very disadvantageous for oil desorption. Moreover, if the structure is dissolved during the test, the oil dewetting ability will be restored. The desorption effect is affected by structural parameters and reaction conditions, which further verifies the negative effect of this structure. In contrast, copper(II) oxide nanowires completely lose their self-cleaning ability due to the enhancement of hydrophobicity and oleophilicity, and the larger-diameter copper(II) oxalate nanorods exhibit a “difficult to enter and difficult to exit” mode, leading to the partial recovery of the oil dewetting performance. This study helps us deeply understand the influence of the surface microstructure on the oil dewetting performance and lay a solid foundation for further appropriate structural design

Additional file 1 of The effect of ECD program on the caregiver’s parenting knowledge, attitudes, and practices: based on a cluster-randomized controlled trial in economically vulnerable areas of China

Supplementary Material

Laser-Induced Graphene Electrodes on Poly(ether–ether–ketone)/PDMS Composite Films for Flexible Strain and Humidity Sensors

Laser-induced graphene prepared on polymer substrates with a high modulus is a widely applied method to fabricate varied flexible electronics; however, the resulting relatively poor stretchability considerably limits its applicability. In this paper, an elastic composite consisting of poly(ether–ether–ketone) powder and poly(dimethylsiloxane) (PDMS) is reported to fabricate stretchable electrodes using direct laser-induced graphitization without transferring. The liquid composites before curing can be cast into various shapes for different applications. To balance the conductivity and stretchability of stretchable electrodes, we optimized the composite mass ratios and laser parameters and performed a series of morphological and performance characterizations on the composites; furthermore, we analyzed the elemental composition and functional groups of the laser-induced products. With the proper encapsulating method, strain sensors were prepared, exhibiting high sensitivity (a gauge factor of 78) and a stable resistance response over 50% operating range with the ability to monitor both fine pulse beats and larger strains such as human joint movement. Furthermore, a humidity sensor composited with laser-patterned interdigital electrode and graphene oxide on the elastic composite substrate had characteristics of high sensitivity (14.18 pF/%RH) and fast recovery time (9 s), which could be used for breathing monitoring and noncontact sensing. In conclusion, laser-induced graphene prepared in one step on a stretchable composite film of polymers with a high modulus and low modulus is a promising method to fabricate wearable electronics

Switchable Nanostructures Triggered by Noyori-Type Organometallics

Janus particles (JPs) self-assembled by a typical small organic gemini surfactant in water were reported by us. After the addition of a small amount Noyori-type organometallics to an organic solvent, these gourd-shaped JPs became new nanostructures, such as nanotubes (NTs), nanoribbons (NRs), and new types of JPs. Significant changes in specific rotation occurred on the solution-like samples, triggered by chiral organometallics in 20 μL of ethyl acetate. Almost all of these organometallics-triggered nanostructures can be conveniently detached and reversed within 5 min due to the easy-phase separation of ethyl acetate from the emulsion and the chemical-selective unstable binding between the organometallics and carbonate group on the surfactant