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The fall armyworm (FAW) Spodoptera frugiperda is an important invasive pest in Africa and Asia. It is a polyphagous pest with at least 353 recorded host plant species, including corn. Chemical control of this pest is unsuccessful because of a developed resistance and harmful effects on the environment. Entomopathogenic fungi are potential biological control agents for FAW. In this study, the native strain of Metarhizium rileyi (KNU-Ye-1), collected from a cornfield at Yeongcheon, Korea, was identified by morphological and molecular characterization. The susceptibility of the fourth-instar larvae of FAW to the native strain M. rileyi was examined in the laboratory. The results showed that the Korean strain of M. rileyi (KNU-Ye-1) was highly virulent to FAW larvae, causing 89% mortality 7 days posttreatment. Therefore, M. rileyi (KNU-Ye-1) identified in this study is highly valuable for the biological control of FAW in the field.

Although several molecular diagnostic techniques are available for the identification of the apple-feeding pests Grapholita molesta Busck and Grapholita dimorpha Komai, these pests are severely affecting apple orchards in Korea. These two pests may be misidentified or the available molecular diagnostic techniques may not facilitate the simultaneous identification of the morphological features of both species. In this study, we developed a multiplex assay for these two species using the polymerase chain reaction – restriction fragment length polymorphism (PCR-RFLP) method. Sixty-two specimens were collected from apples presumed infested with moth larvae and from pheromone traps from 2013 to 2014. Both species were identified morphologically, and a partial region of the cytochrome b gene was sequenced to design primers for PCR-RFLP. Digestion profiles of G. molesta and G. dimorpha, using the Sau3A1 restriction enzyme, were characterized using three DNA fragments each for G. molesta (363 bp, 91 bp and 31 bp) and G. dimorpha (220 bp, 234 bp and 31 bp). The RFLP assay developed for both species in this study was more efficient and accurate than other currently used diagnostic assays and would be helpful to identify field-collected specimens for pest control research.

Since the surface plasmon polariton (SPP) has received a great deal of attention because of its capability of guiding light within the subwavelength scale, finding methods for arbitrary SPP field generation has been a significant issue in the area of integrated optics. To achieve such a goal, it will be necessary to generate a plasmonic complex field. In this paper, we propose a novel method for generating a plasmonic complex field propagating with arbitrary curvatures by using double-lined distributed nanoslits. As a unit cell, two facing nanoslits are used for tuning both the amplitude and the phase of excited SPPs as a function of their tilted angles. For verification of the proposed design rule, the authors experimentally demonstrate some plasmonic caustic curves and Airy plasmons.

Metal nanostructures have been created in a film format to develop unique plasmonic properties. Here, well-defined metal nanostructures are designed on the surface of microspheres to provide plasmonic microgranules. As conventional techniques are inadequate for nanofabrication on spherical surfaces, photocurable emulsion drops with a regular array of silica particles are employed at the interface to create periodic nanostructures. The silica particles, originating from the dispersed phase, fully cover the interface by forming a non-close-packed hexagonal array after drop generation, and slowly protrude to the continuous phase during aging while their interparticle separation decreases. Therefore, hexagonal arrays of spherical dimples with controlled geometry and separation are created on the surface of microspheres by photocuring the drops and removing the particles. Directional deposition of either aluminum or gold results in a continuous film with a hexagonal array of holes on the outermost surface and isolated curved disks in dimples, which renders the hemisphere of microspheres plasmonically colored. The resonant wavelength is controlled by adjusting the aging time, metal thickness, and size of silica particles, providing various plasmonic colors. This granular format of the plasmonic Janus microspheres will open a new avenue of optical applications including active color pixels, optical barcodes, and microsensors.

Author(s): Choi, J; Hua, M; Lee, SY; Jo, W; Lo, CY; Kim, SH; Kim, HT; He, X | Abstract: Structural colors of 2D gratings are iridescent, color-tunable, and never fade, which renders them appealing for anti-counterfeiting applications. However, for advanced security, it still remains a challenge to completely hide the encrypted color patterns and reveal them on demand. In this work, a water-responsive photonic grating consisting of a micropillar array and a hydrogel overcoat with a similar refractive index, termed “hydrocipher”, is presented. The joint effect of stimuli-reversible refractive-index (mis)match and reconfigurable grating-based diffraction coloration enables a complete encryption of the structural color and rapid decryption. The photonic structure shows a strong iridescence due to the angle-dependent diffraction when the hydrogel overcoat is swollen from water. Upon drying, the micropillars bend and the refractive index contrast disappears, which dramatically lessens the diffraction intensity and renders the surface highly transparent. The dehydrated-to-hydrated state transition can occur within 1 s, enabling fast decryption. The color switching is highly reversible over a prolonged hydration/dehydration cycle, and the dehydrated hydrogel layer protects the delicate micropillar array from external mechanical stress. The creative combination of hydrogel material and the 2D grating structure offers a new and simple strategy for realizing reversible, durable, and fast-response cryptography with potentially broad impact on the anti-counterfeiting technology market.

For the miniaturization of optical devices, surface plasmon polaritons (SPPs) have been widely utilized due to their outstanding confinement and field-enhancement characteristics. Analyzing a spectrum of optical signals and splitting certain regions of the spectrum range within a submicrometer-scale structure are demanded for optical integrated systems. In this paper, a novel type of dichroic surface plasmon launcher that can switch the launching direction according to incident polarization states is demonstrated. Compared to the previously reported plasmonic dichroic splitters, the proposed schemes do not use any asymmetric geometry for directional launching. Hence, the direction of guided SPPs can be interchanged according to the polarization state. Such characteristics will be helpful to design switchable plasmonic devices that can be applied to active plasmonic integrated circuits.

This study was supported by the CEFV (Center for Environmentally Friendly Vehicle) of Eco-STAR project from MOE (Ministry of Environment, Republic of Korea). Special thanks are also indebted to Dr. Q. S. Khan who gave a hand in the preparation of this experiment.

Recently, the trend in architectural forms has been towards larger and taller buildings. Building materials are, therefore, also becoming larger and heavier. Typical construction machineries are not adequate for handling such materials, and most construction works are still managed by a human operator. Construction processes are, therefore, fraught with a number of problems, including frequent accidents, high construction cost, and heterogeneous construction quality depending on the experience of the workers. Automation has been introduced at various sites to address these construction problems. In this paper, the process of a curtain-wall installation in a skyscraper is analyzed, and the prototype of a construction robot for curtain-wall installation (CRCWI) is proposed. Use of the proposed CRCWI can reduce the need for manpower and the construction period and cost, and can assure safety in the curtain-wall construction site. The performance of the proposed CRCWI was verified with a real application test in a skyscraper construction site. © 2006 Wiley Periodicals, Inc.