Microencapsulation and controlled release have long been studied because of the high demand for practical delivery systems in the pharmaceutics and cosmetics fields. Multiphase emulsion drops have provided efficient templates for microcapsules, and various feasible methods have been developed for controlled release.[1] However, the emulsion-based approach has limitations for the in situ control of membrane permeability. Micro-origami has emerged as one of the most promising alternative approaches for producing tunable microcapsules with the potential to be applied, for example as drug carriers, [2] actuators, [3] microcontainers, [4] and microrobots.[5] Inspired by living organisms in nature such as the ice plant [6] and Venus flytrap, [7] two different micro-origami approaches have been employed to make various microstructures.[8] One approach uses solid patches connected by active hinge materials. Typical examples use various metalmetal, [9] metal-polymer, [10] and polymer-polymer [4] combinations. The patch and hinge system has enabled the capture, release, and gripping [11] of target materials, showing the feasibility of micro-origami structures. However, the microcapsule is limited to polyhedral shapes in this approach, and complete sealing of the gaps between patches requires exquisite control of the folding angles. Moreover, the delicate and complex fabrication processes make practical applications difficult. The second approach uses a bilayer structure composed of two different materials. For example, a metalpolymer bilayer can show bending/unbending when the polymeric active layer suffers significant volume change, but the metal layer remains unchanged. [12,13] Polymer materials have been employed in both layers to make biocompatible microcapsules. [14,15] However, complete sealing of the gaps in the bilayer contact regions remains an important, yet unmet, need. In addition, a simple and effective method for the fabrication of practical microcapsules has not yet been developed, and remains highly desirable. This is the main thrust of the present study.Herein, we report the use of biocompatible bilayer structures for the fabrication of tunable microcapsules based on micro-origami. Monodisperse bilayer microstructures were prepared using a facile photolithographic procedure, without employing photomask alignment. In addition, highly flexible hydrogels were selected as both active and passive layers, facilitating tight contact between patches. The bilayer structure therefore enabled in situ encapsulation, through a reversible transformation to microcapsules with a closed compartment. The resultant microcapsules showed negligible leakage of encapsulants and triggered release of the encapsulants could be achieved simply by inducing the unfolding of the hydrogel bilayer.The essential strategy of our approach relies on the anisotropic volume change of a hydrogel bilayer. As shown in Scheme 1 a, the active hydrogel layer shows significant volume expansion under external stimuli by swelling, whereas the passive h...

Bridge inspection using unmanned aerial vehicles (UAV) with high performance vision sensors has received considerable attention due to its safety and reliability. As bridges become obsolete, the number of bridges that need to be inspected increases, and they require much maintenance cost. Therefore, a bridge inspection method based on UAV with vision sensors is proposed as one of the promising strategies to maintain bridges. In this paper, a crack identification method by using a commercial UAV with a high resolution vision sensor is investigated in an aging concrete bridge. First, a point cloud-based background model is generated in the preliminary flight. Then, cracks on the structural surface are detected with the deep learning algorithm, and their thickness and length are calculated. In the deep learning method, region with convolutional neural networks (R-CNN)-based transfer learning is applied. As a result, a new network for the 384 collected crack images of 256 × 256 pixel resolution is generated from the pre-trained network. A field test is conducted to verify the proposed approach, and the experimental results proved that the UAV-based bridge inspection is effective at identifying and quantifying the cracks on the structures.

High power conversion efficiency (PCE) and long-term stability are important requirements for commercialization of organic solar cells (OSCs). In this study, we demonstrate efficient (PCE = 18.60%) and stable (t 80% lifetime > 4000 h) OSCs by developing a series of dimerized smallmolecule acceptors (DSMAs). We prepared three different DSMAs (DYT, DYV, and DYTVT) by using different linkers (i.e., thiophene, vinylene, and thiophene− vinylene− thiophene), to connect their two Y-based building blocks. We find that the crystalline properties and glass transition temperature (T g ) of DSMAs can be systematically modulated by the linker selection. A DYV-based OSC achieves the highest PCE (18.60%) among the DSMA-based OSCs owing to the appropriate backbone rigidity of DYV, leading to an optimal blend morphology and high electron mobility. Importantly, the DYVbased OSC also demonstrates excellent operational stability under 1-sun illumination, i.e., a t 80% lifetime of 4005 h.

Periodic metal nanostructures-which can sustain the resonances of collective electron oscillations (known as localized surface plasmon resonances (LSPRs)) when interacting with an incident light fi eld [ 1 ] -have been used in a wide range of applications, including plasmonic sensors and novel photonic devices based on the unique properties of such nanostructures. [1][2][3][4][5][6] LSPR properties can be easily controlled by changing the geometry of the metallic nanostructures and local array environments. [2][3][4][5][6] Surface-enhanced Raman scattering (SERS)-based sensing applications based on the use of plasmonic nanostructures are a prominent research area for the detection of numerous chemical and biological molecules. [ 7 ] Enhanced Raman signals-which depend strongly on the type, size, roughness, and shape of the metal nanoparticles, the distance between them, and the excitation wavelength-have been derived from the enhancement of electromagnetic (EM) fi elds, where the enhancement was the result of the plasmonic resonance excitations. [ 6 , 8-15 ] Various studies have sought to develop suitable SERS substrates with high sensitivity and uniformity. Recently, several research groups demonstrated hybrid SERS substrates in an attempt to exploit the additional enhancement effects; these substrates contained a supporting chemical enhancement between the semiconductors (such as ZnO, TiO 2 , CuO and Si) and noble metals, and showed excellent SERS performance. [16][17][18][19][20] However, in spite of the recent advances in the design and fabrication of nanophotonic hybrid structures, a cost-effective, simple, and versatile strategy for the fabrication of uniform and tunable structures over large areas has not yet been achieved with the suitable coordination required for sensing applications. The need for such a method provided the primary motivation for the present study.Herein, we report a simple and cost-effective method for the fabrication of novel uniform hybrid plasmonic nanostructure arrays, generating lateral and vertical interparticle couplings over a large area via the use of a holographically featured porous structure as a milling mask. Recently, Caldwell et al. fabricated novel SERS substrates using sophisticated electron-beam lithography, [ 19 ] which needs a time-consuming serial fabrication procedure for nanostructures over a large-area with demanding precisions. Compared with electron-beam lithography, holographic lithography (HL) is a simple and rapid production technique for one-, two-, and three-dimensional, defect-free periodic structures over large areas using optical interference among coherent light beams. [21][22][23] However, such conventional multibeam HL techniques have some disadvantages, including the need for precise beam alignment procedures using a number A novel, highly uniform and tunable hybrid plasmonic array is created via ionmilling, catalytic wet-etching and electron-beam evaporation, using a holographically featured structure as a milling mask. A simple and low-cost pris...

Large-area, highly ordered, Ag-nanostructured arrays with various geometrical features were prepared for use as surface-enhanced Raman scattering (SERS)-active substrates by the self-assembly of inorganic particles on an SU-8 surface, followed by particle embedding and Ag vapor deposition. By adjusting the embedding time of the inorganic particles, the size of the Ag nanogap between the geometrically separated hole arrays and bowl-shaped arrays could be controlled in the range of 60 nm to 190 nm. More importantly, the SU-8 surface was covered with hexagonally ordered nanopillars, which were formed as a result of isotropic dry etching of the interstices, leading to triangular-shaped Ag plates on nanopillar arrays after Ag vapor deposition. The size and sharpness of the triangular Ag nanoplates and nanoscale roughness of the bottom surface were adjusted by controlling the etching time. The potential of the various Ag nanostructures for use as practical SERS substrates was verified by the detection of a low concentration of benzenethiol. Finite-difference time-domain (FDTD) methodology was used to demonstrate the SERS-activities of these highly controllable substrates by calculating the electric field intensity distribution on the metallic nanostructures. These substrates, with high sensitivity and simple shape-controllability, provide a practical SERS-based sensing platform.

In the previous study, a paired structured light system which incorporates lasers, cameras, and screens was proposed, and experimental tests validated the potential of a displacement measurement system for large structures. However, the estimation of relative translational and rotational displacements between two sides was based on an assumption that there is zero initial displacement and that three laser beams are always on the screens. In this paper, a calibration method is proposed to offset the initial displacement using the first captured image. The calibration matrix derived from the initial offset is used for subsequent displacement estimation. A newly designed 2-DOF manipulator for each side is visually controlled to prevent the laser beams from leaving the screen. As the manipulator actively controls the laser beams to target the center of the screen, it contains all three laser points within the bounds of the screen. To verify the feasibility of the proposed system, various simulations and experimental tests were performed. The results show that the proposed visually servoed paired structured light system solves the main problem with the former system and that it can be utilized to enlarge the estimation range of the displacement.

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Active tunable plasmonic cap arrays were fabricated on a flexible stretchable substrate using a combination of colloidal lithography, lift-up soft lithography, and subsequent electrostatic assembly of gold nanoparticles. The arrangement of the plasmonic caps could be tuned under external strain to deform the substrate in reversible. Real-time variation in the arrangement could be used to tune the optical properties and the electromagnetic field enhancement, thereby a proving a promising mechanism for optimizing the SERS sensitivity.