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The sense of smell is one of the most important organs in humans, and olfactory imaging can detect signals in the anterior orbital frontal lobe. This study assessed olfactory stimuli using support vector machines (SVMs) with signals from functional near-infrared spectroscopy (fNIRS) data obtained from the prefrontal cortex. These data included odor stimuli and air state, which triggered the hemodynamic response function (HRF), determined from variations in oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb) levels, photoplethysmography (PPG) of two wavelengths (raw optical red and near-infrared data), and the ratios of data from two optical datasets. We adopted three SVM kernel functions (i.e., linear, quadratic, and cubic) to analyze signals and compare their performance with the HRF and PPG signals. The results revealed that oxyHb yielded the most efficient single-signal data with a quadratic kernel function, and a combination of HRF and PPG signals yielded the most efficient multi-signal data with the cubic function. Our results revealed superior SVM analysis of HRFs for classifying odor and air status using fNIRS data during olfaction in humans. Furthermore, the olfactory stimulation can be accurately classified by using quadratic and cubic kernel functions in SVM, even for an individual participant data set.

Electronic excitations of single ZnO rectangular nanorod have been investigated by electron energy-loss spectroscopy in conjunction with scanning transmission electron microscopy (STEM-EELS). We focus primarily on the surface excitations greatly enhanced at the grazing incidence parallel to the surfaces of ZnO nanorods. An uncommon kind of surface excitation known as surface exciton polaritons occurring near interband transitions is found to dominate in the spectral range between the band gap at 3.4 eV and the surface plasmon peak at 15.8 eV. In addition, the dielectric function of ZnO up to 25 eV has also been derived from the bulk excitation spectra using the Kramers–Kronig analysis on a single nanorod. Theoretical EELS simulations are also compared with the experimental results and good agreements are obtained.

Spectroscopic investigations of individual single-crystalline GaN nanowires with a lateral dimensions of approximately 30-90nm were performed using the spatially resolved technique of electron energy-loss spectroscopy in conjunction with scanning transmission electron microscope showing a 2-A electron probe. Positioning the electron probe upon transmission impact and at aloof setup with respect to the nanomaterials, we explored two types of surface modes intrinsic to GaN, surface exciton polaritons at approximately 8.3eV (approximately 150nm) and surface guided modes at 3.88eV (approximately 320nm), which are in visible/ultra-violet spectral regime above GaN bandgap of approximately 3.3eV (approximately 375nm) and difficult to access by conventional optical spectroscopies. The explorations of these electromagnetic resonances might expand the current technical interests in GaN nanomaterials from the visible/UV range below approximately 3.5eV to the spectral regime further beyond.

Vertically aligned indium oxide nanowires were grown on a-plane sapphire substrate by the method of catalyst-assisted carbothermal reduction. The morphology and crystal structure of the nanowires are determined by X-ray diffraction, transmission electron microscopy and field-emission scanning electron microscopy. Two types of In 2 O 3 nanowires were found by controlling the growth conditions. The nanowires with a hexagonal cross-section were shown to grow in [1 1 1] direction, whereas those with a square cross-section grow in [0 0 1] direction. In addition to the temperature effects, the concept of supersaturation in Au catalyst is proposed to explain the formation of these two types of nanowires. Besides, tapering, which is explained with the interplay between the vapor–liquid–solid and vapor–solid growth mechanisms, is observed in the nanowires.

[*] Dr. K. H. Chen, M. H. Wu, W. C. Chen Institute of Atomic and Molecular Sciences, Academia Sinica No. 1, Sec. 4, Roosevelt Rd., Taipei 106 (Taiwan) E-mail: chenkh@pub.iams.sinica.edu.tw Dr. L. C. Chen, Dr. C. H. Chen, Dr. K. H. Chen Center for Condensed Matter Sciences, National Taiwan University No. 1, Sec. 4, Roosevelt Rd., Taipei 106 (Taiwan) E-mail: chenlc@ntu.edu.tw C. H. Lin, Prof. J. H. Lee Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University No. 1, Sec. 4, Roosevelt Rd., Taipei 106 (Taiwan)

This is a study of hybrid photovoltaic devices based on TiO2 nanorods and poly[2-methoxy-5-(2 � -ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV). We use TiO 2 nanorods as the electron acceptors and conduction pathways. Here we describe how to develop a large interconnecting network within the photovoltaic device fabricated by inserting a layer of TiO2 nanorods between the MEH-PPV:TiO2 nanorod hybrid active layer and the aluminium electrode. The formation of a large interconnecting network provides better connectivity to the electrode, leading to a 2.5-fold improvement in external quantum efficiency as compared to the reference device without the TiO2 nanorod layer. A power conversion efficiency of 2.2% under illumination at 565 nm and a maximum external quantum efficiency of 24% at 430 nm are achieved. A power conversion efficiency of 0.49% is obtained under Air Mass 1.5 illumination. (Some figures in this article are in colour only in the electronic version)

We report on the midinfrared emission from electroluminescent devices with quantum cascade active regions based on InGaAs/InP heterostructures. We observe emission at λ∼12 μm from two different structures and compare their emission characteristics based on the different band structure designs. Their relevance in view of the realization of InP-based quantum cascade lasers with aluminum-free waveguides is discussed.

Hydrophobic organosilicates with controlled morphologies at the nanometer length scale have many potential applications in microelectronics and photonics. Here we report the use of block copolymers...

Visually-induced near-infrared spectroscopy (NIRS) response was utilized to design a brain computer interface (BCI) system. Four circular checkerboards driven by distinct flickering sequences were displayed on a LCD screen as visual stimuli to induce subjects’ NIRS responses. Each flickering sequence was a concatenated sequence of alternative flickering segments and resting segments. The flickering segment was designed with fixed duration of 3 s whereas the resting segment was chosen randomly within 15–20 s to create the mutual independencies among different flickering sequences. Six subjects were recruited in this study and subjects were requested to gaze at the four visual stimuli one-after-one in a random order. Since visual responses in human brain are time-locked to the onsets of visual stimuli and the flicker sequences of distinct visual stimuli were designed mutually independent, the NIRS responses induced by user's gazed targets can be discerned from non-gazed targets by applying a simple averaging process. The accuracies for the six subjects were higher than 90% after 10 or more epochs being averaged.

Simultaneous Localization and Mapping (SLAM) has been an active area of research lately. MonoSLAM is a SLAM frame working with a single camera without odometry information for executing SLAM The camera motion estimation and incremental map building from new landmarks are computed using the Extended Kalman Filter framework In this paper, we propose a revised approach to improve the speed of executing SLAM. We use a stereo camera to acquire two images of the environment at the same time, and use SURF algorithm to detect features in the images. The distance between the landmark and the camera can be calculated by the pair of images using a revised algorithm. Using this approach, we can reduce the time of distance calculation and increase the SLAM execution speed.

A new scanning transmission electron microscopy (STEM) imaging technique using high-order Laue zones (named HOLZ-STEM), a diffraction contrast which has been strenuously avoided or minimized in traditional STEM imaging, can be used to obtain the additional 1D periodic information along the electron propagation axis without sacrificing atomic resolution in the lateral (2D) dimension. HOLZ-STEM has been demonstrated to resolve the 3D long-range Na ordering of ${\mathrm{Na}}_{0.71}{\mathrm{CoO}}_{2}$. Direct evidence of spiral-like Na-trimer chains twisting along the $c$ axis is unambiguously established in real space.

Chemical mapping at atomic-column resolution by energy-dispersive x-ray spectroscopy in a spherical aberration-corrected scanning transmission electron microscope (STEM) has been demonstrated for the 1.47-A dumbbell structure in InGaAs. The structural imaging and the chemical information in the two-dimensional map are directly correlated. Comparisons with the other existing mapping techniques of STEM in conjunction with electron energy-loss spectroscopy were discussed from aspects of ionization interactions.

Surface plasmons (SPs) are quantized collective plasma oscillations of conduction electrons propagating at the surface of metals. The excitations of SPs in the visible spectral regime dictate the color of noble metals. In noble metal nanoparticles (NPs) with only a few tens or hundreds of nanometers, the SP resonances are further tailored by the size, shape, and coupling of the NPs, determining their optical properties ranging from near-infrared to UV spectral regimes as demonstrated in nanoprisms, nanorings, nanostars, (coupled) nanorods, and (coupled/arrayed-) nanospheres.1–3 Using individual and/or coupled NPs with proper designed geometrical constraints, the SPs can, therefore, be tuned to the proximity of the laser energies (wavelengths) conveniently available. The associated resonant excitations have been shown to amplify the electric near-field of the SPs by astronomical orders of magnitudes, opening up the opportunities for several fascinating applications of the NPs such as guiding light beyond the subwavelength limit — photonics and plasmonics, surface enhanced Raman scattering, and scanning near-field optical microscopy (SNOM) with a spatial resolution around 20∼30 nm.4–6

Three-dimensional (3D) building model is one of the most important components in a cyber city implementation and application. This study developed an effective and highly automated system to generate and map (near) photo-realistic texture attributes onto 3D building models using digital video sequences. The system extracted frames with overlapped textures of building facades and integrated them to produce complete texture images. Interest points on the extracted video frames were identified using corner-detectors and matched with normalized cross-correlation for seamless stitching. Shadows and foreign objects were identified and removed with morphological algorithms and mended by mirroring neighborhood textures. Completed mosaicked texture images were mapped onto corresponding model facets by linear or parametric transformation. Test examples demonstrate that the developed system can effective generate seamless photo-realistic texture images and correctly map them onto complicated 3D building models with high efficiency.

This paper aims to propose a 3D nanostructured organic-inorganic hybrid photovoltaic device based on the ZnO nanostructures/poly(3-hexylthiophene)(P3HT):TiO 2 nanorods hybrids by solution processes at low temperature. An array of ZnO nanorods with a larger size of ~50 nm in diameter and ~180 nm in length are grown to provide direct pathways for efficient charge collection. TiO 2 nanorods with a size of ~5 nm in diameter and ~20-30 nm in length are incorporated into polymer to facilitate charge separation and transport by providing increased interfacial area and more effective transport pathway. The device performance with the inclusion of TiO 2 nanorods exhibits a seven times increase in the short circuit current with respect to that without TiO 2 nanorods.

Epitaxial ferroelectric SrRuO3/Pb(Zr0.52Ti0.48)O3/SrRuO3 heterostructures have been fabricated employing isotropic metallic oxide electrodes on (100) SrTiO3 and (100) Si with an yttria stabilized zirconia buffer layer. The structures have been grown in situ by 90° off‐axis sputtering, which allows the growth of uniform stoichiometric films over large areas with excellent step coverage. X‐ray diffraction, Rutherford backscattering spectroscopy, and cross‐sectional transmission electron microscopy reveal high crystalline quality and coherent interfaces. They exhibit superior fatigue characteristics over those made with metal electrodes, showing little degradation over 1010 cycles, with a large remnant polarization.

In this article, we have proposed a nanostructured photovoltaic device based on the ZnO nanostructures/poly(3-hexylthiophene)(P3HT):TiO2 nanorod hybrid by solution processes at low temperature. An array of ZnO nanorods with a larger size of ∼50 nm in diameter and ∼180 nm in length are grown to provide direct pathways for efficient charge collection. TiO2 nanorods with a size of ∼5 nm in diameter and ∼20–30 nm in length are incorporated into polymers to facilitate charge separation and transport by providing an increased interfacial area and a more effective transport pathway. The device performance with the inclusion of TiO2 nanorods exhibits a seven times increase in the short circuit current with respect to that without TiO2 nanorods. The device performance can be further enhanced after completely removing the residual surfactant on the TiO2 nanorods using the ligand exchange method, giving a short circuit current density of 2.67 mA cm−2 and a power conversion efficiency of 0.59% under Air Mass 1.5 (100 mW cm−2) illumination.

A “step-edge” model has been proposed to explain the growth of solid nanotips of aluminum nitride (AlN) and indium nitride (InN) grown by thermal and metal organic chemical vapor depositions, respectively. The model predicts a set of apex angles that solid AlN and InN nanotips can have. A statistical distribution of the apex angle in InN nanotips indicates the discrete set of apex angles and its probability of nucleation.

We compare the superlattice modulation, microstructure, and epitaxy of Tl2Ba2Ca2Cu3O10 thin films grown on MgO [100] and SrTiO3 [100] substrates by dc diode sputtering. Films grown on MgO were found to be quite clean with the c axis perpendicular to the substrate. However, no in‐plane orientational relationship to the substrate was found. Films grown on SrTiO3, on the other hand, showed very good epitaxy to the substrate despite the presence of second phases. Films grown on MgO also exhibited a longer coherence length of the superlattice modulation than those grown on SrTiO3 under identical conditions.

The pyrolysis of organic dianhydrides (e.g., 3,4,9,10‐perylenetetracarboxylic dianhydride) in an evacuated system results in the loss of hydrogen, CO, and CO2 and the deposition of a chemically inert, metallic‐appearing mirrolike film. The films are highly conducting (σRT250 Ω−1 cm−1) and can evidence either metallic or semiconducting behavior, depending on the preparation temperature. Superconducting films are obtained when niobium is used as a dopant. Preparation of films on doped silicon semiconductor chips results in the formation of p‐n junctions. ESR spectra exhibit a moderately strong line at g=2.0025. The resonance intensity remains almost constant to 20 °K, characteristic of a highly delocalized spin system.

We have used metal molecular beam epitaxy, sputter deposition with single composite target, and spin‐on/pyrolysis with metallo‐organic precursors to prepare thin films of high Tc oxide superconductors mostly in the Y‐Ba‐Cu‐O system. We report the superconducting properties and the structural characteristics of the films. The processing parameters of these thin‐film techniques are also discussed.