560 research outputs found
Cylindrical chains of water drops condensing on microstructured lubricant-infused surfaces
We studied the condensation of water drops on a micro-structured lubricant-infused surfaces. Hierarchical micro-prism surfaces were fabricated by soft imprinting with wet TiO2 nanoparticle paste. After hydrophobization, the patterned surfaces were infused with silicone oil as a lubricant. When cooling at high humidity (over 80%), water drops nucleate and start growing on the surface. Once they have reached a certain size, the drops at neighboring channels of the micro-prisms attract each other and spontaneously form cylindrical chains. These chains of drops align perpendicular to the prism array. The morphology and the length-to-width ratio of the chains of drops depend on the thickness of the lubricant layer. This new concept of water drop alignment on lubricant-infused surfaces offers a new route for pattern formation with condensed drops.N
Indigenous tourism in Australia: Time for a reality check
Indigenous tourism is positioned as an integral part of Australia's tourism product offering. Yet participation in Indigenous tourism experiences by both international and domestic markets is in decline. The demand for, and interest in, Australia's indigenous culture that has been consistently portrayed by Australian government agencies has not translated into sustainable visitor flows for many indigenous tourism businesses. Therefore, the aim of this research was to explore visitor demand for indigenous tourism through interviews with 1357 international and domestic tourists. To overcome some of the limitations of previous indigenous tourism studies, this study used the 'Attrition Curve of Tourist Demand' to determine if insights could be gained by analysing the consumer decision making process (awareness, preferences and intentions). The results of the research show that while there has been much progress in the development of this niche tourism sector, there is low awareness, preference and intention to participate in indigenous tourism experiences in Australia
Structural changes of polyaniline/montmorillonite nanocomposites and their effects on physical properties
Polyaniline/montmorillonite (MMT) nanocomposites containing different PANI contents were prepared by the intercalation of aniline monomer into pristine MMT followed by the subsequent oxidative polymerization of the aniline in the interlayer spacings. The polyaniline/MMT nanocomposite structure intercalated with polyaniline (PANI) was examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). From the full-width at half-maximum (FWHM) of the (001) reflection peaks in the XRD patterns, the PANI/MMT nanocomposite containing 12.3 wt% PANI (PMN12) was found to be in the most disordered state. The physical interaction between the intercalated PANI and the basal surfaces of MMT was monitored by FT-IR. The room-temperature conductivity (RT) varied from 9.1 Ă 10â9 to 1.5 Ă 100 S cmâ1 depending on the PANI content in the nanocomposites. The temperature dependence of dc conductivity (dc(T)) of all the samples follows the quasi-1D variable range hopping (quasi-1D VRH) model (i.e., dc(T) exp [â(T0/T)1/2]). The charge transport behavior of this system was interpreted from the slopes (T0) of the dc curves and the highest T0 value was found for the PANI/MMT nanocomposite with 12.3 wt% PANI (PMN12). The FT-IR, dc(T) and RT results for the nanocomposites with varying content of PANI are consistently related to the structure of the PANI/MMT nanocomposites discussed in the XRD analysis. The structural argument was further supported by scanning electron microscopy (SEM) of all the samples. Thermogravimetric analysis (TGA) showed improved thermal stability for the intercalated nanocomposites in comparison with the pure PANI and a simple PANI/MMT mixture.We are very grateful for the financial support from the
National Research Laboratory Fund from the Ministry of
Science and Technology (MOST), the Korean Ministry of
Education through the Brain Korea 21 Program, and the
Research Institute of Advanced Materials (RIAM) at Seoul
National University. We also thank Mrs Mee Jeong Kang for
her kind SEM and TEM measurements
Physical properties of transparent perovskite oxides (Ba,La)SnO3 with high electrical mobility at room temperature
Transparent electronic materials are increasingly in demand for a variety of
optoelectronic applications. BaSnO3 is a semiconducting oxide with a large band
gap of more than 3.1 eV. Recently, we discovered that La doped BaSnO3 exhibits
unusually high electrical mobility of 320 cm^2(Vs)^-1 at room temperature and
superior thermal stability at high temperatures [H. J. Kim et al. Appl. Phys.
Express. 5, 061102 (2012)]. Following that work, we report various physical
properties of (Ba,La)SnO3 single crystals and films including
temperature-dependent transport and phonon properties, optical properties and
first-principles calculations. We find that almost doping-independent mobility
of 200-300 cm^2(Vs)^-1 is realized in the single crystals in a broad doping
range from 1.0x10^19 to 4.0x10^20 cm^-3. Moreover, the conductivity of ~10^4
ohm^-1cm^-1 reached at the latter carrier density is comparable to the highest
value. We attribute the high mobility to several physical properties of
(Ba,La)SnO3: a small effective mass coming from the ideal Sn-O-Sn bonding,
small disorder effects due to the doping away from the SnO2 conduction channel,
and reduced carrier scattering due to the high dielectric constant. The
observation of a reduced mobility of ~70 cm^2(Vs)^-1 in the film is mainly
attributed to additional carrier-scatterings which are presumably created by
the lattice mismatch between the substrate SrTiO3 and (Ba,La)SnO3. The main
optical gap of (Ba,La)SnO3 single crystals remained at about 3.33 eV and the
in-gap states only slightly increased, thus maintaining optical transparency in
the visible region. Based on these, we suggest that the doped BaSnO3 system
holds great potential for realizing all perovskite-based, transparent
high-frequency high-power functional devices as well as highly mobile
two-dimensional electron gas via interface control of heterostructured films.Comment: 31 pages, 7 figure
A Case of Intramuscular Hemangioma Presenting with Large-angle Hypertropia
Purpose: To report the case of a patient with large-angle hypertropia of an intramuscular hemangioma of the right superior rectus muscle (SR). Methods: A 63-year-old man with progressive vertical deviation of the right eye for the past 6 months visited our strabismus department; his condition was not painful. An examination indicated that he had 60PD of right hypertropia at distance and near in primary gaze. Additionally, a significant limitation of his downgaze was noted. The right eye appeared mildly proptotic, and the upper and lower eyelids were slightly edematous. Corrected vision was 20/20 in both eyes. Results: Orbital magnetic resonance imaging (MRI) studies revealed fusiform enlargement of the right superior rectus muscle, with prominent but irregular enhancement following gadolinium administration. Incisional biopsy revealed an intramuscular hemangioma in the superior rectus muscle with cavernous-type vessels. Conclusions: This case demonstrates that intramuscular hemangioma should be considered in the differ-ential diagnosis of isolated extraocular muscle enlargement and unusual strabismus. Korean Journal o
Simultaneous Intrinsic and Extrinsic Parameter Identification of a Hand-Mounted Laser-Vision Sensor
In this paper, we propose a simultaneous intrinsic and extrinsic parameter identification of a hand-mounted laser-vision sensor (HMLVS). A laser-vision sensor (LVS), consisting of a camera and a laser stripe projector, is used as a sensor component of the robotic measurement system, and it measures the range data with respect to the robot base frame using the robot forward kinematics and the optical triangulation principle. For the optimal estimation of the model parameters, we applied two optimization techniques: a nonlinear least square optimizer and a particle swarm optimizer. Best-fit parameters, including both the intrinsic and extrinsic parameters of the HMLVS, are simultaneously obtained based on the least-squares criterion. From the simulation and experimental results, it is shown that the parameter identification problem considered was characterized by a highly multimodal landscape; thus, the global optimization technique such as a particle swarm optimization can be a promising tool to identify the model parameters for a HMLVS, while the nonlinear least square optimizer often failed to find an optimal solution even when the initial candidate solutions were selected close to the true optimum. The proposed optimization method does not require good initial guesses of the system parameters to converge at a very stable solution and it could be applied to a kinematically dissimilar robot system without loss of generality
Optical investigation on the electronic structures of Y_{2}Ru_{2}O_{7}, CaRuO_{3}, SrRuO_{3}, and Bi_{2}Ru_{2}O_{7}
We investigated the electronic structures of the bandwidth-controlled
ruthenates, YRuO, CaRuO, SrRuO, and BiRuO, by optical conductivity analysis in a wide energy region of 5 meV
12 eV. We could assign optical transitions from the systematic changes
of the spectra and by comparison with the O 1 x-ray absorption data. We
estimated some physical parameters, such as the on-site Coulomb repulsion
energy and the crystal-field splitting energy. These parameters show that the
4 orbitals should be more extended than 3 ones. These results are also
discussed in terms of the Mott-Hubbard model.Comment: 12 pages (1 table), 3 figure
Push-Pull Design of Bis(tridentate) Ruthenium(II) Polypyridine Chromophores as Deep Red Light Emitters in Light-Emitting Electrochemical Cells
Breivogel A, Park M, Lee D, et al. Push-Pull Design of Bis(tridentate) Ruthenium(II) Polypyridine Chromophores as Deep Red Light Emitters in Light-Emitting Electrochemical Cells. European Journal of Organic Chemistry. 2014;2014(2):288-295.Light-emitting electrochemical cells (LECs) with a simple device structure were prepared by using heteroleptic bis(tridentate) ruthenium(II) complexes [1](PF6)(2)-[3](PF6)(2) as emitters. The push-pull substitution shifts the emission energy to low energy, into the NIR region. The devices emit deep red light up to a maximum emission wavelength of 755 nm [CIE (International Commission on Illumination) coordinates: x = 0.731, y = 0.269 for [3](PF6)(2)], which, to the best of our knowledge, is the lowest emission energy for LECs containing bis(tridentate) ruthenium(II) complexes. A device structure of ITO/PEDOT:PSS/ruthenium(II) complex/Ag was used, and the thickness of the emitting layer was measured by AFM [ITO: indium tin oxide, PEDOT: poly(3,4-ethylenedioxythiophene), PSS: poly(styrenesulfonate), AFM: atomic force microscopy]. To enhance the external quantum efficiency (EQE), cells were fabricated with and without poly(methyl methacrylate) (PMMA) as additive in the emitting layer
Push-Pull Design of Bis(tridentate) Ruthenium(II) Polypyridine Chromophores as Deep Red Light Emitters in Light-Emitting Electrochemical Cells
Breivogel A, Park M, Lee D, et al. Push-Pull Design of Bis(tridentate) Ruthenium(II) Polypyridine Chromophores as Deep Red Light Emitters in Light-Emitting Electrochemical Cells. European Journal of Organic Chemistry. 2014;2014(2):288-295.Light-emitting electrochemical cells (LECs) with a simple device structure were prepared by using heteroleptic bis(tridentate) ruthenium(II) complexes [1](PF6)(2)-[3](PF6)(2) as emitters. The push-pull substitution shifts the emission energy to low energy, into the NIR region. The devices emit deep red light up to a maximum emission wavelength of 755 nm [CIE (International Commission on Illumination) coordinates: x = 0.731, y = 0.269 for [3](PF6)(2)], which, to the best of our knowledge, is the lowest emission energy for LECs containing bis(tridentate) ruthenium(II) complexes. A device structure of ITO/PEDOT:PSS/ruthenium(II) complex/Ag was used, and the thickness of the emitting layer was measured by AFM [ITO: indium tin oxide, PEDOT: poly(3,4-ethylenedioxythiophene), PSS: poly(styrenesulfonate), AFM: atomic force microscopy]. To enhance the external quantum efficiency (EQE), cells were fabricated with and without poly(methyl methacrylate) (PMMA) as additive in the emitting layer
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