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The design and actuation of soft robots are targeted at extreme motion control as well as high functionalization.

Cavity filter is widely used in microwave receiver front-end subsystem for the advantage of its low insertion loss, excellent band selectivity, and relative high power handle characteristics. However, the short high power microwave pulse transmission response in cavity filter is seldom studied, especially under high power microwave (HPM) electromagnetic environment. By the Particle-In-Cell/Monte Carlo Collision simulation and high power tests, the transient microwave breakdown phenomenon of an S band comb-line cavity filter are discussed. The simulation and test results show that when the input microwave pulse width is 50ns, the microwave breakdown power threshold value is about 500W. And the filter output would be nearly suppressed while the input power above 3.5kW. The simulation data of different microwave pulse widths demonstrate that the breakdown power threshold is approximately inversely proportional to the microwave pulse width in case of the pulse width is lower than 100ns.

Bioinspired superhydrophobic surfaces are an artificial functional surface that mainly extracts morphological designs from natural organisms. In both laboratory research and industry, there is a need to develop ways of giving large-area surfaces water repellence. Currently, surface modification methods are subject to many challenging requirements such as a need for chemical-free treatment or high surface roughness. Laser micro-nanofabrications are a potential way of addressing these challenges, as they involve non-contact processing and outstanding patterning ability. This review briefly discusses multiple laser patterning methods, which could be used for surface structuring toward creating superhydrophobic surfaces.

Fine-tuning the physical and chemical properties of graphene and its derivatives is crucial for developing novel multi-functional graphene-based devices. Natural bio-surfaces with rich micro-nanost...

Periodical structures induced by pulsed lasers are a unique phenomenon when pulsed lasers irradiate on some material surfaces. These periodical structures with a subwavelength-scale period hold potential in integrated-optics and biomimetic micro-nanodevices for their direct shaping by laser pulses. However, the blurred nature of the laser-induced structuring hinders its further exploration in these application scopes. In this review, the plasmon-mediated structuring targeted on various materials, both organic and inorganic, will be discussed profoundly.

Microlens arrays are crucial optical elements in micro-optics. However, their efficient fabrication is difficult. High efficiency and quality cannot be simultaneously achieved using conventional fabrication methods; therefore, we propose a novel and efficient method based on the single-pulse exposure of femtosecond lasers and etching-assisted prototyping. When developing this novel microfabrication method, we systematically reviewed several studies. Furthermore, we employed phase modulation using a spatial light modulator to realize the laser seeding-etching microfabrication method. The phase modulation enabled multi-focus exposure instead of single-focus exposure, realizing parallel fabrication in case of concave microlens arrays. Further, combined with the tuning of relative energy and the spatial arrangement of multiple foci, the morphology and optical parameters of each concave microlens can be controlled. The proposed method fundamentally changes the “point-to-point” scanning strategy adopted in conventional micro-nanofabrications via laser direct writing, which is an efficient and high-quality method for fabricating microarray structures.

There is increasing interest in tuning the optical and optoelectronic properties of semiconductor nanostructures using metal nanoparticles in their applications in light-emitting and detection devices. In this work we study the effect of a dielectric Al2O3 gap layer (i.e., spacer) on the interaction of ZnO nanowires with metal nanoparticles. The Al2O3 spacer thickness is varied in the range of 1–25 nm using atomic layer deposition (ALD) in order to tune the interaction. It is found that ~5 nm is an optimum spacer thickness common for most metals, although the enhancement ratio of the near-bandedge emission differs among the metals. Consistent results are obtained from both photoluminescence (PL) and cathodoluminescence (CL) spectroscopies, with the latter being applied to the optical properties of individual semiconductor/metal nanoheterostructures. The interaction is primarily proposed to be related to coupling of ZnO excitons with local surface plasmons of metals, although other mechanisms should not be ruled out.

Chromium-deficient Nd 0.75 Ca 0.25 Cr 1− x O 3− δ (0.02 ≤ x ≤ 0.06) oxides are synthesized and assessed as a novel ceramic interconnect for solid oxide fuel cells (SOFCs). At room temperature, all the samples present single perovskite phase after sintering at 1600 °C for 10 h in air. Cr-deficiency significantly improves the electrical conductivity of Nd 0.75 Ca 0.25 Cr 1− x O 3− δ oxides. No structural transformation occurs in the Nd 0.75 Ca 0.25 Cr 1− x O 3− δ oxides in the temperature range studied. Among all the samples, the Nd 0.75 Ca 0.25 Cr 0.98 O 3− δ sample with a relative density of 96.3% exhibits the best electrical conductivity of 39.0 and 1.6 S cm −1 at 850 °C in air and hydrogen, respectively. The thermal expansion coefficient of Nd 0.75 Ca 0.25 Cr 0.98 O 3− δ sample is 9.29 × 10 −6 K −1 in the temperature range from 30 to 1000 °C in air, which is close to that of 8 mol% yttria stabilized zirconia electrolyte (10.3 × 10 −6 K −1 ) and other cell components. The results indicate that Nd 0.75 Ca 0.25 Cr 0.98 O 3− δ is a potential interconnect material for SOFCs.

Chromium-deficient Nd 0.75 Sr 0.25 Cr 1− δ O 3 (0.02 ≤ δ ≤ 0.06) solid solutions were prepared using a conventional solid-state reaction. The effects of chromium-deficiency content on sintering, transport properties and thermal expansion of the solid solutions were investigated. The results showed that all the solid solutions present single phase orthorhombic perovskite structure at room temperature. The cell volume and the electrical conductivity of Nd 0.75 Sr 0.25 Cr 1− δ O 3 solid solutions decrease with the increase of Cr vacancy content. The Nd 0.75 Sr 0.25 Cr 0.98 O 3 sample exhibits the best properties. The relative density is 95.5%, and the electrical conductivity and thermal expansion coefficient (TEC) reach 18.8 S cm −1 at 850 °C and 9.62 × 10 −6 K −1 in the temperature range of 30–1000 °C in air, respectively. Compared with Nd 0.75 Sr 0.25 CrO 3 , TEC of the Nd 0.75 Sr 0.25 Cr 0.98 O 3 sample is more compatible with that of yttria stabilized zirconia (10.3 × 10 −6 K −1 ). Sintering, electrical and thermal expansion properties all indicate that Nd 0.75 Sr 0.25 Cr 0.98 O 3 can be a promising candidate for interconnect material application in solid oxide fuel cells.

Nd1−xCaxCrO3 (0≤x≤0.25) solid solutions are synthesized using a two-step calcination solid-state reaction method and can potentially be used as interconnect applications in solid oxide fuel cells (SOFCs). The lattice parameters and unit cell volume decrease with an increase of the Ca2+ dopant concentration at the A-site. On the other hand, the relative density, electrical conductivity, and thermal expansion coefficient (TEC) increase with an increase of Ca2+ contents. Calcium doping significantly depresses the chromium vaporization of NdCrO3, thus accelerating the sintering and densification of the oxides. Nd1−xCaxCrO3 with x=0.25 shows the best electrical conductivity of 28.8 and 1.1 S/cm at 850°C in air and hydrogen, respectively, with a high relative density of 98.0% and a good TEC of 9.19 × 10−6 K−1 in the temperature range from 30° to 1000°C in air. This indicates that Nd0.75Ca0.25CrO3 is a promising candidate as an interconnect material for application in SOFCs.

Strontium doped NdCrO 3 solid solutions (0.05 ≤ x ≤ 0.25) were synthesized using a solid-state reaction. The effects of Sr doping on the structures, electrical and thermal expansion properties of the solid solutions were studied. The results show that all the solid solutions prepared possess a single phase orthorhombic perovskite structure at room temperature. With the increase of Sr content in Nd site, the cell volume of Nd 1− x Sr x CrO 3 solid solutions decreases gradually. The sinterability of the solid solutions is remarkably improved compared with pure NdCrO 3 . The relative densities of the samples are all higher than 96%, among which Nd 0.75 Sr 0.25 CrO 3 sample presents the highest value of 97.8%. Both the electrical conductivity and the thermal expansion coefficient (TEC) of Nd 1− x Sr x CrO 3 increase with the increase of Sr content. Sample Nd 0.75 Sr 0.25 CrO 3 exhibits the highest electrical conductivity of 1.73 × 10 3 S m −1 at 850 °C in air. And it also attains the highest TEC of 9.45 × 10 −6 K −1 over temperature range from 30 to 1000 °C, which is basically compatible with that of yttria stabilized zirconia (10.3 × 10 −6 K −1 ). Nd 0.75 Sr 0.25 CrO 3 may be considered as a promising interconnect material for solid oxide fuel cells according to the electrical and thermal expansion behaviors.

Biomimetic hierarchical structures are an important branch among bio-inspired materials. These structures are responsible for rich physical and chemical phenomena. In this paper, we briefly reviewed facile methods to fabricate large-area biomimetic hierarchical structures via laser processing. One is based on femtosecond laser direct writing, and the other is based on two-beam interference lithography. In details, the first method is laser ablation on ZnS thin films via femtosecond direct writing combined with a phase mask. The second method is a multi-exposure lithography by two-beam interference on a photoresist with varied exposure angles to acquire structural hierarchies with periodicity. Owing to the outstanding patterning ability of the two laser-processing approaches, a diversity of large-area hierarchical structures can be obtained and show rich biomimetic functions such as superhydrophobicity.

Atomic layer deposition (ALD) provides a tool for conformal coating on high aspect-ratio nanostructures with excellent uniformity. It has become a technique for both template-directed nanofabrications and engineering of surface properties. This Feature Article highlights the application of ALD in selected fields including photonics, SERS and energy materials. Specifically, the topics include fabrication of plasmonic nanostructures for the SERS applications, fabrication of 3-D nanoarchitectured photoanodes for solar energy conversions (dye-sensitized solar cells and photoelectrochemical cells), and coating of electrodes to enhance the cyclic stability and thus device life span of batteries. Dielectric coating for tailoring optical properties of semiconductor nanostructures is also discussed as exemplified by ZnO nanowires. Future direction of ALD in these applications is discussed at the end.

When two metallic surfaces supporting plasmonic excitation are brought into close proximity of each other, a nanogap (of width on the subwavelength scale) will form, which boosts greatly the local optical field. Based on this idea, we fabricated two types of three-dimensional plasmonic substrates with such nanogaps, taking advantage of both atomic layer deposition (ALD) and the capillary effect. Owing to the counteraction of the gap-reducing and capillary, nanogaps with different widths and profiles have been formed on the scaffold of aligned ZnO nanorods and shown to induce large field enhancement with enhancement factor up to 2.64 × 10(6) for surface-enhanced Raman scattering (SERS).