3,123 research outputs found
Controlled sub-nanometer tuning of photonic crystal resonator by carbonaceous nano-dots
No full textWe propose and demonstrate a scheme that enables spectral tuning of a photonic crystal high-quality resonant mode, in steps finer than 0.2 nm, via electron beam induced deposition of carbonaceous nano-dots. The position and size of a nano-dot with a diameter of < 100 nm are controlled to an accuracy on the order of nanometers. The possibility of selective modal tuning is also demonstrated by placing nano-dots at locations pre-determined by theoretical computation. The lasing threshold of a photonic crystal mode tends to increase when a nano-dot is grown at the point of strong electric field, showing the absorptive nature of the nano-dot. (c) 2008 Optical Society of America.One of authors, Min-Kyo Seo, would like to thank Ridah Sabouni, Dr. Kevin Hennessy, and
Prof. Evelyn Hu at University of California at Santa Barbara for helpful discussions. This
work was supported by the Korea Science and Engineering Foundation (KOSEF) (No.ROA-
2006-000-10236-0) and the Korea Foundation for International Cooperation of Science and
Technology (KICOS) (No. M60605000007-06A0500-00710) through grants provided by the
Korean Ministry of Science and Technology (MOST). H. G. P. acknowledges support by the
Seoul R&BD Program
Efficient coil design by electromagnetic topology optimization for electromagnetic sharp edge forming of DP980 steel sheet
No full textThis paper proposes a design method of the tool coil by topology optimization for the electromagnetic sharp edge forming process. Topology optimization is an approach that optimizes material configuration in a given domain to meet the design requirements. The design problem for the tool coil is defined as enhancing efficiency of the forming process and optimization problem is set to be maximization of the Lorentz force induced on the tool coil. A new topology optimization formulation based on the numerical methods for electromagnetism using FEM and BEM is developed for maximization of the Lorentz force. Optimum design of the tool coil is obtained by the topology optimization using the element density approach. The optimized result is compared with other coils which have different configurations to show the effectiveness of the proposed method. The idea of applying topology optimization to the design of the tool coil is successful and this formulation deals effectively for the optimization problems
Arthropoma magniporosum Min, Seo, Grischenko, Lee & Gordon, 2017, n. sp.
No full textArthropoma magniporosum n. sp. (Figs 10–13) Arthropoma cecilii: Okada & Mawatari 1936: 62; Rho & Seo 1986: 39, pl. 8; Seo 2005: 452, pls 181, 182A; Seo 2011: 77, fig. 36, pl. 27. Arthropoma n. sp.: Hirose 2010: 111, pl. 190A–C. Material examined. Holotype: MBRBKSP033, 34.5366° N, 128.7314° E, Hong Island (Hongdo), Gyeongsang Province, collected 1 June 1987 by J.E. Seo and J.G. Je. Paratype: MBRBKSP034, 34.4292° N, 127.2280° E, Dok Island (Dokdo), South Jeolla Province, collected 24 June 2008 by J.E. Seo, B.S. Min and H.J. Yang, 10– 15 m. Other material: Woosuk University Collection—specimens from Chuja Islands, Daepo, Gapa Island, Gu Island, Mijo, Moseulpo and Seogwipo, collected by J.E. Seo, H.J. Kil and J.H. Yoo. Etymology. Latin magnus, large, and porosus, full of holes (Brown 1956), alluding to the relatively large size and distribution of the pseudopores. Arthropoma is neuter in gender, hence the species epithet is also neuter. Description. Colony encrusting, unilaminar, up to 20 mm in diameter. Zooids regularly quincuncial, the distal margin rounded or angular, more rarely truncated, the lateral margins more or less parallel-sided in many zooids. Orifice proportionately large, the anter high-arched, curving proximally to horizontal ‘shoulders’ that bear thin condylar surfaces that project slightly across the entrance to the small U-shaped sinus, constricting it. Operculum with jointed sinus tab. Frontal shield convex, perforated by c. 35–46 relatively large, round pseudopores that are distributed over the most of the surface in the majority of zooids, except for an irregular, smooth narrow area midfrontally that is subumbonate or weakly carina-like in some zooids. Additional pseudopores are distributed around the orifice in an arc of 10–19 pores in an inner series, sometimes with a few other pores in an incomplete second series. No oral spines. No avicularia. Ooecium prominent, hyperstomial, apparently cleithral (subcleithral), with the zooidal operculum able to close both the ooecial orifice and the lower zooidal orifice; ooecial orifice nearly at right angles to the maternal zooidal orifice. Ectooecium wholly membranous except for a thin peripheral rim around the base; endooecium minutely and densely pitted and textured, the pits less obvious frontally. Multiporous mural septula present in lateral and distal walls. Ancestrula not seen. Measurements. ZL 480–636 (540) µm, ZW 287–403 (360) µm; OL 165–197 (177) µm, OW 134–175 (158) µm; OoL 223–310 (277) µm, OoW 295–371 (342) µm. Remarks. Arthropoma magniporosum n. sp. has in the past been identified as Arthropoma cecilii Audouin, 1826, a species from the Mediterranean/ Red Sea that has been accorded a wide distribution in cool-temperate to warm-temperate and tropical waters of the Atlantic and Indo-Pacific, from 25–1235 m depth (summarized by Dick & Grischenko 2017). If the species illustrated by Hayward & Ryland (1999) were to be taken as representing the species in the absence of actual type material, then it differs from A. magniporosum in several features. For example, A. cecilii has more than twice the number of frontal-shield pseudopores (c. 120–130), which are accordingly smaller and denser than in A. magniporosum. The ooecium of A. cecilii has a smoothly calcified rim around the orifice, with a mid-distal extension, and the sides of the ooecium taper more closely towards to proximal orificial rim than in A. magniporosum. Dick & Grischenko’s (2017) illustration of A. cecilii from the Mediterranean Sea area of Marseille resembles that of Hayward & Ryland (1999) from Britain (presumed, but not stated as such), but has fewer frontal-shield pores (81–96), and there are minor differences in frontal ectooecial sculpturing and placement of the proximolateral corners of the ooecium. Their conspecificity is uncertain. In either case, whether from the Mediterranean or elsewhere, the material from Europe is not the same as A. magniporosum n. sp. It is likely that A. cecilii was originally illustrated and described from Red Sea specimens (at least in part), but, in the absence of type specimens, no further conclusions can be drawn; Savigny’s drawings (d’Hondt 2006, pp. 31, 60) are inconclusive. The synonymy given above does not cite all records of A. cecilii in the northeast Asian region, only those that definitely or almost certainly refer to A. magniporosum n. sp. The record of Okada & Mawatari (1936) is included as the authors stated that their unillustrated specimen from Hatsushima, Sagami Bay, Japan, had “very larger tremopores than the normal form”. Only a few other Recent species of Arthropoma have been described. Arthropoma inarmata Gontar, 1992 from the Kurile Islands differs in having only 21–26 pseudopores in the proportionately short frontal shield, while there is a complete double row of pores in the relatively broad area distal to the orifice. Additionally, Gontar (1992) mentioned that the pores have a radial structure, which would be exceptional among Arthropoma species, suggesting that Cribellopora Gautier, 1957 might be a more appropriate genus to accommodate A. inarmata. Arthropoma lioneli Florence, 2016 from South Africa has distinctive reniform pores. A new species from the west coast of Okinawa (Dick & Grischenko 2017) (East China Sea) has a crescentic suboral umbo that sometimes contributes to a continuous peristomial rim. As Dick & Grischenko (2017) point out, three species, none of them A. cecilii, are illustrated by Hirose (2010) from Japan. One of them corresponds to A. magniporosum n. sp. (see synonymy above). A second (Hirose 2010, pl. 189A, B) corresponds to Arthropoma mediolaevis (Ortmann, 1890). He described the taxon as a ‘variety’ of cecilii, noting that it differed in the “Glattes Feld in der Mitte der Zelle grosser”, i.e. the smooth field in the center of the zooid is greater than in cecilii. The sinus is also very narrow and the pseudopores are very small. The third species, presently undescribed (Hirose’s 2010, fig. 189C, D), differs again in having an almost subcircular sinus and in the small pseudopores occupying the entire frontal shield, or nearly so. Further, this species has a dimorphic zooid with a large orifice and a few distal-oral spines. The proportions of the dimorphic orifice differ from those illustrated by Kirkpatrick (1890) from the South China Sea, and Harmer (1957) from Indonesia, indicating that additional forms need naming as new species. Yet another unnamed species occurs in the Sagami Bay region; this was illustrated by Grischenko & Mawatari (2006, fig. 1G) as A. cecilii, but it differs from all of the forms mentioned above in having a smooth non-pitted endooecium and 3–4 rows of pseudopores between the maternal orifice and developing ooecium. Based on ooecial morphology, and using the terminology of Ostrovsky (2013, pp. 130, 131), the ooecium appears to be the subcleithral form of a cleithral orifice, i.e. having two potential operculum closure positions, with the lower position closing the zooidal orifice. Observations on living material would be required to confirm if this is the case. It is known that the sinus tab of the operculum is hinged, as reflected in the genus name; if and when the operculum closes the ooecial orifice, the sinus tab is almost at right angles to the porta (rest of operculum). Distribution. Korea: South Sea coasts, intertidal to more than 30 m. Japan: Sagami Bay and Sagami Sea, 47– 108 m.Published as part of Min, Bum Sik, Seo, Ji Eun, Grischenko, Andrei V., Lee, Sang-Kyu & Gordon, Dennis P., 2017, Systematics of some calloporid and lacernid Cheilostomata (Bryozoa) from coastal South Korean waters, with the description of new taxa, pp. 471-486 in Zootaxa 4226 (4) on pages 479-481, DOI: 10.11646/zootaxa.4226.4.2, http://zenodo.org/record/26508
한국기상학회 향후 60년을 향한 미래 발전 방안
No full textCelebrating its 60th anniversary, this study suggests the future vision of the Korean Meteorological Society (KMS) for the next 60 years. The vision is "to advance atmospheric science and technology that contributes to human society as well as protect people from not only climate change risks but also weather, climate, and environmental disasters". Based on the suggestions from its members, this study proposes the KMS future development plan as follows. The first plan is to strengthen in leading the development and growth of atmospheric sciences in Korea, especially to improve weather, climate, and environment forecasts and to reduce uncertainty in future climate projections. The second is to enhance interaction not only among its members in academy, Korea Meteorological Administration and related organizations, meteorological industry, and science communicators but also with other related fields such as energy, water resources, agriculture, fishery, and forestry. The third is to enhance in nurturing young scientists by supporting domestic and international networks and training the state-of-the-art sciences, and to create opportunities for young scientists to advance into a wider field. The last is to expand its international activities for solving the challenges facing mankind, such as climate change risks and weather, climate, and environment disasters. The KMS should also continue the efforts to establish an integrative platform for leading fundamental and interdisciplinary research in weather, climate, and environment.
Full three-dimensional subwavelength high-Q surface-plasmon-polariton cavity
No full textWe propose a full three-dimensional subwavelength surface-plasmon-polariton cavity based on a metal-coated dielectric nanowire with an axial heterostructure. Surface plasmon-polaritons are strongly confined at the nanowire-metal interface sandwiched by an effective plasmonic mirror that consists of lower-index nanowire core and metal shelf. Numerical simulations show for a cavity <50 x 50 x 40 nm(3) (mode volume, V 10(-5) mu m(3)) that a quality factor, Q(,) >36000 is achieved at 20 K. This ultrasmall plasmonic cavity can be used as a plasmonic emitter or laser device coupled to a plasmonic waveguide with a high coupling efficiency in deep-subwavelength photonic systems
Far-field Scattering Measurement of a Single Gold Nanorod Using Total-Internal-Reflection Illumination
No full textWe demonstrate a novel method for measuring far-field scattering of a single nanostructure with a high signal-to-background ratio using total-internal-reflection illumination. Direct far-field scanning overcomes the numerical aperture limit of the typical back-focal plane imaging
Far-field Measurement of single gold nanorod scattering using total-internal-reflection illumination
No full textWe made a novel method for measuring far-field scattering distribution of single nanostructure with high signal-to-background ratio using total-internal-reflection illumination. We achieved wide measurement range by direct scanning over limit of numerical-aperture in conventional back-focal-imaging
Corrections to “Dig-Grasping via Direct Quasistatic Interaction Using Asymmetric Fingers: An Approach to Effective Bin Picking†[Apr 21 3033-3040]
No full text1) The authors of [1] would like to gratefully acknowledge the support of Hong KongRGC26209319, in addition to HongKong ITF ITS/240/17FX, ITS/018/17FP, and ITS/104/19FP already acknowledged in [1]. 2) The corresponding author details in [1] need correction. The correct corresponding author is Jungwon Seo (email: [email protected]).</p
Tensile strain-controlled drug delivery system based on a cracked metal structure
No full textRecently, mechanical stimuli-responsive drug delivery systems have received much attention as they have the advantages of being easily accessible for self-administered therapeutics and requiring no additional equipment. In this study, we report a tensile strain-controlled drug delivery system based on a micro-cracked membrane. The membrane consists of a drug-loaded polyurethane polymer layer coated with a biocompatible titanium metal layer. On application of external tensile strain to the membrane, micro-sized cracks are generated and propagate in the metallic layer. The exposed crack region acts as a channel for the drug molecules to diffuse into the surrounding buffer solution. We utilized the membrane as a drug delivery system by controlling the exposed crack region, which is dependent on the applied strain. Our results indicated that the amount of released drug increased with the applied strain, and the drug release profile had a highly linear correlation with the ‘ratio of exposed region’ in both experimental and numerical results (greater than 0.9). Although the developed crack-based drug release system has limitations such as drug leakage under the 0% strain condition, we believe that this drug release system can be a useful tool as an on-demand mechanically stimulated controlled drug delivery system, especially for applications requiring continued and long-term drug delivery.11sciescopu
Elimination of cross-talk in waveguide intersections of triangular lattice photonic crystals
No full textWe design an intersection for crossing waveguides in triangular lattice photonic crystals with cross-talk smaller than 10(-5). The cross-talk to the transverse waveguides is suppressed by symmetry mismatch between the cavity mode and the waveguide mode or by the mode-gap effect induced by air hole radius modulation of the waveguides. The transmission behavior of the crossing waveguides are illustrated by numerical simulations through finite difference time domain method. (C) 2008 Optical Society of America.The authors would like to thank Thomas Sünner for fruitful discussions
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