Diffusivity of Cholera toxin subunit B (CTX) bind to GM1 molecules in 1,2-Dioleoyl-sn-Glycero-3-Phosphocholine (DOPC) bilayer was observed by total internal reflection microscope (TIRFM). Numerical analysis based on mean square displacement revealed the presence of higher (D = 0.4 μm²/s) and lower (D < 0.1 μm²/s) diffusive fractions, both of which were an ordered of slower compared to dye-labeled lipid (D = 3.5 μm²/s). The observed difference in CTX-GM1 diffusivity reflects the characteristics of the multivalent CTX-GM1 binding properties. [DOI: 10.1380/ejssnt.2009.74]

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A variety of vertically aligned ZnO nanostrutures, such as nanorods, pencil-like nanorods and nanowalls, was successfully grown on sapphire substrates coated with Au nanocolloidal solutions by atmospheric-pressure CVD using Zn powder and H₂O as source materials. Shapes of the nanorods grown on the sapphire substrates coated with the diluted solution of enhanced metalorganic decomposition for NiO film depended strongly on degree of dilution of the solution. Possibility of diameter control using the Ni particles embedding in zeolite supports as catalytic material was also found. [DOI: 10.1380/ejssnt.2009.78]

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The present work describes the anodic growth of self-organized TiO₂ nanotubes (TiNT) on titanium samples in an electrolyte containing 3% NH₄F and 5% H₂O in glycerol. Two stages anodization were proceeded. Initially, the potential was ramped from 0V to 30, 40 and 60 V. In the second stage the potential was held at the given potential up to 5 hrs. The application of ultrasonic waves during anodization was found to increase the reaction rates as it decreased the concentration gradient of the anodization products around the electric double layer. This resulted in high current and faster growth rates of the nanotubes. The diameters of the TiNT created under ultrasonic wave condition were found to be smaller than the corresponding TiNT created under magnetic stirring. However, the morphology of the TiNT was badly affected as a result of surface perturbation resulting from heterogeneity in surface energy density. A better route for good looking TiNT is to grow them under magnetically stirred solution followed by cleaning by sonication in deionized water for 30 seconds. Increasing the anodization potential from 30 to 60 V increased the dimensions of the TiNT from around 90 nm to around 150 nm, respectively. [DOI: 10.1380/ejssnt.2009.84]

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Self-organized rhodamine aggregates prepared by wetting/dewetting process of an ethanol solution on a hydrophilic glass surface consistently exhibited fluorescence without quenching. Upon annealing, the aggregates exhibited an irreversible transition to quenched state, like H-aggregate, whereas the fluorescence spectrum was unchanged. The as grown fluorescent aggregate is a novel aggregate, neither a J-aggregate nor an H-aggregate, showing a blue-shifted excitation spectrum whereas the emission spectrum is similar to that of molecularly dispersed solution. This fluorescent aggregate was only realized in nonequilibrium by the rapid dewetting process. [DOI: 10.1380/ejssnt.2009.89]

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We researched contribution of a charge transfer (CT) effect to desorption/ionization mechanism in our ultra-high sensitive laser desorption/ionization mass spectrometry based on surface plasmon (SP) excitation (SPLDI-MS). A quantity of CT electrons between a metal surface and sample molecules estimated from Raman measurement is correlated to a mass signal intensity of sample molecule in our SPLDI-MS method. A sample system with a larger quantity of CT electrons gave a higher mass signal intensity. Efficient use of the CT effect would lead to development of a higher sensitive SPLDI-MS and this development would contribute to advancement of various fields. [DOI: 10.1380/ejssnt.2009.93]

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According to dynamical theory of electron diffraction, the incident electron density distribution, or “wave-field”, was calculated for a parallel-dimer structure of Si(001)2×2-Al surface on the condition of medium-energy electron diffraction (MEED). The surface structure and the calculated method were confirmed to be effective by the rocking-curve analysis of diffracted beam intensity. The wave-field at the surface is very sensitive to changes in diffraction conditions, such as the incident glancing angle. The Al(LMM) Auger electron intensity emitted from the Si(001)2×2-Al surface during MEED incident beam rocking, that is named beam rocking Auger electron spectroscopy (BRAES), has been found to be correlated to the calculated wave-field intensity on the Al atomic rows. The BRAES profile of adsorbate Al(LMM) differs from that of substrate Si(LVV). [DOI: 10.1380/ejssnt.2009.97]

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Liquid phase deposition of amorphous carbon (a-C) and carbon nitride (CN_x) film has been attempted by means of electrolysis of organic liquids. The deposition of a-C film is achieved by applying a DC bias voltage to substrate immersed in methanol. Smooth and homogeneous a-C films are deposited on specific substrate materials such as Si, Ti, and Al. The deposition of CN_x films are carried out by using nitrogen-containing electrolyte such as acrylonitrile (CH₂CHCN). Continuous and uniform films are obtained with the application of both negative and positive bias voltages. The atomic ratios of nitrogen to carbon in the grown films are estimated as 0.16–0.28. Those results demonstrate the feasibility of using liquid deposition techniques for the production of carbon related materials. [DOI: 10.1380/ejssnt.2009.102]

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In this work Spin-Polarized X-ray Photoelectron Diffraction (SPXPD) is studied on the basis of multiple scattering theory in the relativistic theoretical framework. This approach is inevitable to study XPD and SPXPD spectra from heavy elements (Z > 50), where relativistic effects play some important roles. In the K-edge excitation spin-orbit interaction for photoelectrons is quite important to produce spin-polarization of photoelectrons by use of circularly polarized light, and that this effect has influence on the branching ratio of multiplet splitting in photoemission spectra. In the case of linearly polarized light this phenomenon is expected to be small. We, however, expect that we can see finite contribution in the forbidden direction. In that direction one of important relativistic effects, spin flip scatterings excited by linearly polarized X-ray photons is remarkable not only in heavy atoms but in light atoms. [DOI: 10.1380/ejssnt.2009.115]

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III-V metal-insulator-semiconductor (MIS) structures are recently attracting attentions as possible candidates of high-k gate stack for next generation CMOS transistors on the silicon platform. However, their basic electrical properties are not well understood. In order to further confirm the validity of the recently proposed distributed pinning-spot (DPS) model for anomalous admittance behavior of III-V MIS structures, we have carried out in this paper a detailed experimental and computer simulation study of a HfO₂/GaAs high-k MIS structure controlled by a silicon interface control layer (Si ICL). It is clearly shown that the measured frequency dependences of C-V curves and admittance are far away from the predictions by the standard Si MOS theory. On the other hand, they can be well reproduced by the DPS model which assumes random spatial distribution of pinning spots with high densities of interface states in addition to pinning-free regions with low interface state densities. The model indicates that use of low-dimensional structures such as nanowires and nanodots may be beneficial for removal of pinning spots. [DOI: 10.1380/ejssnt.2009.122]

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Ca-germanide and Ca-silicide crystals were synthesized by mechanical alloying (MA). The resulting powders made from the Ca and Si powders contain Ca₂Si and/or Ca₅Si₃ phases with additional cubic phase crystals. The grown phases, namely Ca₂Si and Ca₅Si₃, can be controlled by the Ca/Si ratio and the Si powder size. For the powders synthesized using the Ca and Ge powders, the cubic crystalline phase was synthesized. It was found that the powders synthesized from the Ca and Ge powders are covered by an amorphous layer that contains oxidized carbons. The Ca-based bulk tablets pressed from the powders show a p-type semiconducting behavior, though the powder surface is heavily oxidized, which might affect the transport property of the bulk. [DOI: 10.1380/ejssnt.2009.129]

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Frictional behaviors between mica surfaces have been investigated with the Surface Force Apparatus under various relative vapor pressures (rvp) of both water and cyclohexane. Stick-slip frictional behaviors were observed only under cyclohexane vapor. At rvp of 20%, stick-slip appeared but faded out with sliding time. At a rvp greater than 50%, the stick-slip pattern was stable without fading. Dependence of sliding velocity and applied load on stick-slip motions indicated that the mechanism of the stick-slips in the high rvp (stable stick-slip) region differs from that of the region of fading stick-slip. In the rvp range between 20% and 50%, where the fading stick-slip is observed, the condensate liquid seeps into the contact area under the influence of the applied tangential force and thus triggers the slip motion. Due to the small condensation volume, the liquid condensed around the contact area is exhausted in the process of repeating stick-slip. At a rvp greater than 50%, where stable sick-slip is observed, the stick-slip caused by essentially the same origin as that observed with mica surfaces sliding in bulk cyclohexane liquid. In vapor, the stick-slip is enhanced by the increase of the negative Laplace pressure in the capillary condensed liquid, thereby forcing the surfaces toward each other more strongly with decreasing rvp. [DOI: 10.1380/ejssnt.2009.137]

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The present paper deals with surface superhydrophilic properties of mesoporous silica thin films containing tungsten oxide species (W-MSTFs) prepared by a sol-gel/spin coating method. The local structure around tungsten oxide species as well as photoinduced surface properties have been investigated by XRD, UV-vis, and water contact angle (CA) measurements. These investigations showed that tungsten oxide species are tetrahedrally-coordinated and exist in isolated states. The water CA measurements also demonstrated that W-MSTFs exhibited the high surface hydrophilic property without the UV-light irradiation. It was also found that the UV-light irradiation led to the decrease in the CA of W-MSTFs, indicating that W-MSTFs showed photoinduced superhydrophilicity. Furthermore, very low CA below 10° was maintained for about three months in the dark conditions after the UV-light irradiation. [DOI: 10.1380/ejssnt.2009.141]

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The isothermal Brownian-type molecular dynamics simulation was applied to study the melting scenario of noble-metal-based bimetallic clusters. The failure of the simulation results to portend a compatible melting temperature, T_melt, which is defined in the specific heat C_V at its principal peak and in the Lindermann-like parameter at the temperature which it exhibits drastic change, has prompted us to calculate the velocity autocorrelation function VACF or its Fourier-transform, the power spectrum as another useful variable for describing cluster melting. Two bimetallic clusters, namely Ag₁₃Au₁ and Ag₁₃Cu₁, were selected for illustration. We effected comparative studies of the thermal and dynamic properties of the Ag₁₃Au₁, Ag₁₃Cu₁ and Ag₁₄ and explored isothermally the VACF and spectral density of individual atoms in each of these clusters as well as the corresponding whole cluster. We examined, in particular, the influence of the impurity atoms Au and Cu. It is observed that the C_V of Ag₁₄ displays a prepeak which is absent in Ag₁₃Au₁ and Ag₁₃Cu₁. The physical origin of this prepeak feature was studied and its presence is ascribed to the migrational relocation of the adatom in the cluster. From the temperature change of VACF and spectral density, we deduced T_melt. It is found that the calculated T_melt inferred from VACF and power spectrum agrees quite well with that determined from the main peak position of C_V. [DOI: 10.1380/ejssnt.2009.149]

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The control of spatial arrangements of molecular building blocks on surface opens the foundational step of the bottom-up approach toward future nanotechnologies. Contemporarily, the domain size of monolayers exhibiting crystallinity falls in the submicron scale. Developed herein is a method that allows the alignment of polyaromatics with one-single domain for as long as ∼7 mm. Even more exciting is the fact that the method is applicable to every laboratory with negligible cost. The monolayers are prepared simply by placing a piece of folded lens paper against the substrate and the deposition solution containing the compound of interest. The essence of the film preparation is similar to the Couette flow where the laminar flow takes place between two concentric walls, one of which rotates and creates viscous drag proven useful to align macromolecules. The method can induce an edge-on orientation for 3,6,11,14-tetradodecyloxydibenzo[g,p]chrysene (DBC-OC₁₂), hexakis-(4-dodecyl)-peri-hexabenzocoronene (HBC-C₁₂) and 3,6,12,15-tetrakis-(dodecyl)-tetra-benz[a,c,h,j]anthracene (TBA-C₁₂), which would otherwise adopt the face-on arrangement on graphite. [DOI: 10.1380/ejssnt.2009.157]

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Surface and interface effects play significant roles in mechanical properties of nanostructures. Traditional continuum mechanics does not account for surface and interface effects on the elastic behavior of nanostructures. This work presents a general Lagrangian mechanics framework to describe the surface elastic properties. This model includes the surface effects on overall elastic behavior of a nanocantilever. It is demonstrated that the overall elastic behavior of the nanostructures is scale-dependent. Silicon nanocantilever have been fabricated with dimensions from 200 to 8 μm length, 25 to 4 μm width and 1 μm, 340 nm, and 93 nm thicknesses. The resonance behavior is studied and is compared with resonance frequency measurement in order to see at which scale other surface effects become significant. [DOI: 10.1380/ejssnt.2009.161]

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2π steradian (full hemisphere) In 3d photoelectron patterns from InP(001) surface were measured. The circular dichroism of rotational shift around the incident-light axis was observed. The forward focusing peaks (FFPs) at [111] and [-1-11] directions were intense, while the FFPs at [-111] and [1-11] directions were weak. This is because the distance to the scatterer atoms at the former directions are one third of that at the latter directions. Rotational shifts of the FFPs at [111] and [-1-11] directions were large, while the FFPs at [-111] and [1-11] directions were small. These shifts correspond to the parallax in the stereograph of the atomic arrangements of zinc blende structure seen from an In atom. [DOI: 10.1380/ejssnt.2009.181]

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In the article the method of identification of 2D→3D structure phase transition developed for differential reflection spectroscopy is presented. This phase transition was shown to be accompanied by non-linear dependence of differential reflectance Δ R/R versus deposited film thickness h. Formulas were derived for calculation of optical function of 2D and 3D structures involved in phase transition. Use of method for Cr/Si(111) system resulted in obtaining new information about Cr film growth. [DOI: 10.1380/ejssnt.2009.186]

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Resonance enhanced multiphoton ionization (REMPI) spectra of sputtered Fe atoms for three kinds of sample matrices have been measured to confirm the matrix effects for SNMS using Ar⁺ and O₂⁺ beams. It is shown that the intensity of Fe-56 atoms sputtered in higher energy state, that is the ground state multiplets and the first excited state, increases with increasing surface oxygen concentration in the spectra. Depth profile measurements of Fe-54 implanted in SIMOX have been also performed for three kinds of (1+1) schemes by REMPI-SNMS. The depth profile for Fe-54 sputtered in the ground state has corresponded to the SRIM2003 calculation result. On the other hand, the intensity of Fe-54 sputtered in the first excited state has been enhanced in the SiO₂ layer. By a comparison with the result of the REMPI spectrum measurement, this enhancement may be influenced by not only the surface oxygen concentration but also matrix elements in samples. [DOI: 10.1380/ejssnt.2009.191]

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Several types of carbon nanomaterial were produced using a simple method involving arc discharge in foam, and Fe-C composite materials were produced using this technique in foam containing Fe particles. In TEM observation, it was observed that the surfaces of the Fe particles were covered with a 20-50 carbon layer. Spherical objects with complex shapes were also observed on the nanomaterials, and varied from 200 nm to above 600 nm in size. It was found that these spherical objects formed a twisted graphite sheet. [DOI: 10.1380/ejssnt.2009.195]

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Reflection electron energy loss spectroscopy (REELS) experiments at various emission angles were carried out using an inclined sample holder. The inclined sample holder can provide a wide range of emission angles to the surface normal (15°-75°) by rotating the sample holder. The REELS spectra for Si were measured for electron beam energies from 500 to 4500 eV. The experimental λ K (Δ E) spectra of Si, which are the product of the inelastic mean free path and the differential inverse inelastic mean free path, were obtained from the REELS spectra. It clearly showed the variation of relative contribution of bulk and surface loss in these series of the λ K (Δ E) spectra. We found that the bulk plasmon and surface plasmon contribution varied with the incident beam energies and emission angles. [DOI: 10.1380/ejssnt.2009.199]

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Atomic structures of iron-silicide ultra-thin films epitaxial grown on Si(111) were investigated by x-ray crystal-truncation-rod scattering measurements. Two films, each of them respectively exhibited 1×1 and 2×2 periodicities in ultra high vacuum, were measured with the x-ray diffraction under ambient air. Both of the films showed essentially the same Laue peaks. The Laue peaks directly indicate that both films have the CsCl-type (so-called c-FeSi) structure whose stacking orientation is rotated by 180° with respect to the substrate. Quantitative structural analysis, which includes degree of the film roughness as fit parameters, reveals that the interfacial Fe atom is 8-fold coordinated to Si atoms (so-called B8 model). The determined interlayer spacing in the silicide film and the Fe-Si bond length at the interface are respectively ∼6 % and ∼9 % larger than those in the hypothetical c-FeSi. [DOI: 10.1380/ejssnt.2009.513]

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We reports observation of giant switching currents in nanopillar transistors at 300 K. It is found that these signals represent mechanical vibration due to the interaction of charging electron and the elastic materials of silicon and silicon nitride. Specifically, when an electron is charged to penetrate the SiN_x/Si/SiN_x multilayer, an electrical force will be initiated to make it vibrate. In addition, such motion will couple to the electronic state in the central Si island for the optimal exchange of elastic and quantum energy. As a consequence, in some mechanical modes, these coupled vibrations will make the transistor functioning like a self-coordinated switching pump for persistent tunnel of electrical current. [DOI: 10.1380/ejssnt.2009.518]

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By using STM, the surface structures of different cobalt coverage grown on √3 × √3-Ag/Ge(111) surface are investigated. We found that two kinds of structures appear on the cobalt films, one is √13 × √13 named Structure I, and the other is 2 × 2 named Structure II. Structure I is the structure of the islands with the height under 2 atomic levels, whereas the islands with other heights are Structure II. When the coverage of Co was increased, the transformation of structures reveals a two-stage evolution. The percentage of the Structure II increases rapidly at the coverage of about 1ML and 3 ML. However, the methods for these two elevations are different. The first stage of increasing results from sufficiency of cobalt atoms to form Structure II islands, but the second stage is due to the limitation of cobalt covered areas. The cobalt covered areas reach the limitation of 50% at the coverage of 3.5 ML. Moreover, for the cobalt island of 3.7 nm height, the configuration on the top still exhibits Structure II. This result manifests that large amount of cobalt atoms do not transform into its bulk structure, instead, those cobalt atoms maintain the same structure with the bottom 2 × 2 layers. This coverage-dependent substitution of structures indicates that the transformation of cobalt islands is not due to phase transition. Besides, the exchange between cobalt atoms and the bottom silver layer can also be denied. [DOI: 10.1380/ejssnt.2009.521]

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An X-ray holographic method that reconstructs a single layer of atoms at the interface between ultra-thin film and substrate crystal is studied. We applied the method to the analysis of the interface structure of iron-silicide grown on the Si(111) surface, the structure of which is considered to be the CsCl-type FeSi. First we confirmed by simulations that the method is useful to discriminate whether an additional layer at the interface exists or not, using calculated X-ray intensities. Next we applied the method to the analysis of experimental data obtained for Si(111)-2×2-Fe. The result indicated the existence of the interface atoms, corresponding to the B8 model for CsCl-type FeSi. [DOI: 10.1380/ejssnt.2009.525]

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Proton transport properties of three thin films (110, 240, and 360 nm thick films) on R-plane (1102) sapphire substrates for oligomeric poly[(1, 2-propanediamine)-alt-(oxalic acid)] were investigated. The maximum proton conductivity of the thin film is 1.7 × 10^-3 S cm^-1 at the RH of 80%, which is five times higher than that of the bulk sample (3.0 × 10^-4 S cm^-1). The activation energies of the 110, 240, and 360 nm thick films are found to 0.74, 0.67, and 0.68 eV at the RH of 80%, respectively. [DOI: 10.1380/ejssnt.2009.530]

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When gold is deposited onto the Si(553) surface, a highly ordered surface with a quasi-one-dimensional electronic structure can be prepared. This Si(553)-Au surface was investigated by surface X-ray diffraction to determine the surface structure. A structure model was constructed from the Patterson function of the experimental diffracted intensities. There is one gold atom in the primitive unit cell. It substitutes for a top-layer silicon atom on the terraces. The silicon atoms near the step edge reconstruct to form a honey-comb chain. [DOI: 10.1380/ejssnt.2009.533]

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We report the polarization symmetry of vertical photoluminescence from columnar InAs/GaAs quantum dots (QDs) that were formed by stacking small InAs islands directly in the growth direction. QD samples were grown with various stacking numbers using molecular beam epitaxy. We investigated the polarization dependence of the vertical photoluminescence intensity. The polarization dependence was enhanced by increasing the stacking number. We also found that the polarization direction shifted at random from the [1-10] direction both with the stacking number and the measurement position on the sample. Transmission electron microscopy observations suggested that the polarization features might be governed by problems in the growth process such as the bending of the stacking direction during the formation of QDs with a high aspect ratio. [DOI: 10.1380/ejssnt.2009.537]

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The electronic structure modifications by radial deformation are investigated for an armchair (21,21) single-walled carbon nanotube (SWNT), on which scanning tunneling spectroscopy (STS) measurements have recently been made [C. E. Giusca et al., Phys. Rev. B 76, 035429 (2007)]. Plausible radial deformations under hydrostatic pressure are predicted using a semiempirical method based on the continuum elastic shell model [M. Hasegawa and K. Nishidate, Phys. Rev. B 74, 115401 (2006)]. It is found by density-functional electronic-structure calculations that the collapsed (21,21) tube is a semiconductor with small band gap of ≈ 62 meV. This result is consistent with the previous investigations for much thinner armchair SWNTs but contradicts the STS measurements, which indicate that the collapsed tube is metallic with finite density of states at the Fermi level. A possible origin of this contradiction is briefly discussed. [DOI: 10.1380/ejssnt.2009.541]

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We showed that our new single wall carbon nanotubes substrate (SWCNTs substrate) with a nano-sized network structure on its all surface areas was very efficient for high performance ionization of analyte molecules. A preparation procedure of our SWCNTs substrate requires mainly two processes that are a well dispersion of SWCNTs in preparing solution and a very thin laying-up on a surface of base plate. Moreover, we found that base plates for laying-up of SWCNTs determines its analytical performance and a SUS plate is a good base plate. We expect that further investigation of base plates in our SALDI-MS technique using the SWCNTs leads to more efficient ionization. [DOI: 10.1380/ejssnt.2009.546]

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The breaking process of silver nanocontacts (NCs) was observed in situ at room temperature by high-resolution transmission electron microscopy. Simultaneously, the conductance of the NCs was measured. During breaking, the conductance showed a stepwise variation and the step height corresponded to integer multiples of 2e²/h, i.e., the quantized conductance levels. Using a conductance feedback control, the NCs exhibiting a certain conductance were observed continuously. The relationship between the structure and conductance of the NCs was investigated; the conductance at a quantized level was associated with NCs with several types of atomistic configurations. [DOI: 10.1380/ejssnt.2009.549]

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Low-temperature synthesis and characterization of ITO thin films prepared by cathodic arc ion plating (CAIP) have been demonstrated. The correlation between structural properties and electrical results are revealed in this work. At present, the in-house ITO films with the lowest resistivity and highest transparence of 4.8 × 10^-4 (Ω-cm) and 80% can be obtained. Such the low-temperature fabrication technique is very promising for the potential applications of flexible electronic devices or dye-sensitized solar cells. [DOI: 10.1380/ejssnt.2009.553]

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In the present work the photoelectric emission from island sodium films was investigated. Appreciable deviations from Fowler's law as well as an increase of the photoelectrons yield for the island films were discovered. The dependences of the photoeffect efficiency on the films structural parameters, on the polarization and the angle of incidence of the laser radiation were studied. [DOI: 10.1380/ejssnt.2009.563]

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We fabricated a boronic acid-surface on a flat silica surface for optical detection of recognition of catechol structure. The boronic acid-surface was obatained by chemical reaction between 4-carboxyphenylboronic acid (CPB) and the primary amine group of 3-aminopropyltriethoxysilane (APS) modified onto the silica surface. The UV-vis spectroscopic and the X-ray photoelectron spectroscopic (XPS) measurements indicated that 90% of the primary amines of APS reacted with CPB. Recognition of the catechol structure on the CPB surface was observed with in-situ time dependent measurement using optical configuration of surface plasmon spectroscopy. Injection of phosphate buffers containing 1.0 mM dopamine (DA) and catechol, respectively, at pH 7.0 allowed increase of the reflectivity, suggesting complexation between DA or catechol and the boronic acid of CPB. On the other hand, increasing of the reflectivity (Δ R) in the case of tyramine, which is very similar in chemical structure to DA but has no catechol structure, was quite small. The ratio of Δ R between DA and tyramine (DA/tyramine) was experimentally estimated to be 5.5, which briefly shows that the CPB-modified surface can recognize catechol structure. The Δ R behaviors of DA differed from the pH of buffers. At pH 8.1, polymerization of DA was observed on the CPB-modified surface while no recognition at pH 6.0. The efficient pH for the 1:1 complexation between DA and boronic acid of the CPB-modified surface is thought to be around 7.0. [DOI: 10.1380/ejssnt.2009.571]

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Lipid membrane has a significant role to retain waters on its surface due to high hydrophilicity of head groups of lipid molecules. Although many physical chemical properties such as thickness, phase state, fluidity etc. can be measured by the recent experimental equipments, the water retaining capacity of membrane is still difficult to be analyzed. Molecular dynamics simulation was performed to theoretically estimate the retaining time of waters on membrane surface. Different kinds of lipid bilayers were modeled using sphingomyelin molecules, which is one of the typical components of biomembrane. Our simulation successfully generated the stable and equilibrated bilayer structures of sphingomyelin with different carbon chain length. Thickness, area per lipid, order parameter, and gauche ratio were deduced from the simulation data. In this work, we propose a technique to estimate the distribution function of waters on membrane surface, which enables us to evaluate the water retaining time on membrane. Our calculation technique will be helpful for design an artificial membrane whose moisture property is controlled. [DOI: 10.1380/ejssnt.2009.591]

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We measured the polarized X-ray absorption fine structure (XAFS) for Zn K- and Mg K-edge of Mg_0.06Zn_0.94O film fabricated on (11-20) Al₂O₃substrate by Hericon Wave excited Plasma Sputtering Epitaxy (HWPSE) method. The local structures around Zn and Mg atoms were investigated for both vertical and horizontal directions to the sample plane. The non-linear-least-square-fitting was applied to Zn K-EXAFS (extended XAFS) and the simulation calculation was also applied to the Mg K-edge X-ray absorption near edge structure (XANES). Mg atoms are suggested to be distributed randomly in the Mg_0.06Zn_0.94O layer for both directions of the vertical and horizontal to the sample plane. [DOI: 10.1380/ejssnt.2009.596]

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Interactions between self-assembled monolayers (SAMs) with various non-dissociative terminal groups were explored with an atomic force microscope (AFM). In the pure water, hydrophobic CH₃-terminated SAMs showed long-range repulsion (> 50 nm) indicating that hydroxide ions are concentrated at the water-SAM interface. On the other hand, hydrophilic OH-terminated SAMs exhibited only short-range attraction and no repulsion originated from ions accumulated at the SAM-water interface. The interaction between SAMs of oligo(ethylene glycol)-terminated alkanethiols strongly depend on the substrate (Au and Ag). That is, the hydroxide ions were concentrated near the Au-supported SAM, whereas no accumulation of the ions near the Ag-supported SAM was observed. Our results demonstrated that not only the terminal groups but also the density of the molecules constituting the SAM critically govern the redistributions of ions at the SAM-water interfaces. [DOI: 10.1380/ejssnt.2009.601]

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Imprinting the relief of anodic electrode in glass surface in the course of DC electric field polarization of the glass is studied using atomic force microscopy. Square grid with rectangular relief produced on silicon by e-beam lithography and ion etching (relief height 120 nm, line width 0.5 μm, and periodicity 1 μm), and lead-silicate glass microchannel plate (channel diameter 9.5 μm and distance between the channels 12.5 μm) possessing electronic conductivity along the channels walls were used as anodic electrodes. The height of the relief formed on glass surface after polarization varied from 5 to 15 nm depending on the conditions of the processing. The mechanism of relief formation is discussed. [DOI: 10.1380/ejssnt.2009.617]

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We observed the tensile deformation process of silver nanocontacts (Ag NCs) in situ at room temperature by high-resolution transmission electron microscopy. Simultaneously, the conductance and the tensile force of the NCs were measured. Stress-strain relationship of Ag NC was investigated. Typical saw-tooth curves showing elastic and plastic deformations of NCs were observed. The Young's modulus of NCs was estimated from the stress-strain curve. [DOI: 10.1380/ejssnt.2009.621]

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Both hcp-Ti and CaF₂-type TiH_x (x ∼ 1.5) with preferred orientations have been grown in as-deposited Ti flims on NaCl (001) substrates held at room temperature (RT). In order to clarify atomistic growth processes of TiN_y films due to the implantation of nitrogen ions (N₂⁺) with 62 keV into Ti films, changes of the crystallographic and electronic structures of Ti thin films by heating and by nitriding during N-implantation were investigated by in-situ transmission electron microscope (TEM) observations combined with electron energy loss spectroscopy (EELS), with the aid of molecular orbital calculations. H atoms which constituted TiH_x in the as-deposited Ti films were released with heating up, and were completely released at 350°C. The H-released unstable fcc-Ti sublattice was then epitaxially transformed into hcp-Ti. The loss peak observed by EELS for TiH_x shifted to the lower energy side with the decrease in the electron density in the hybridised valence band due to the release of H atoms from TiH_x during heating. On the other hand, the TiN_y was epitaxially formed by the N-implantation into the hcp-Ti, through the transformation of the hcp-Ti to fcc-Ti sublattice, partially inheriting the atomic arrangement of the hcp-Ti and accompanying the occupation of O-sites of the fcc-Ti by N atoms. The loss peak during N-implantation into the hcp-Ti films gradually shifted to the higher energy side with the increase in dose, due to the increase in the electron density in the hybridised valence band. Taking into account the bonding interaction of Ti sublattices with ligand H or N atoms, the transformation mechanisms between fcc-Ti sublattices and hcp-Ti sublattices due to the release of H atoms or due to the implantation of N atoms will be clarified. [DOI: 10.1380/ejssnt.2009.625]

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Co/SiO₂ Fischer-Tropsch synthesis (FTS) catalysts were prepared by a novel preparation method, where aqueous Co nitrate solutions containing various organic acids and/or chelating agents were used as impregnating solutions. FTS activities were investigated at 503 K and 1.1 MPa. Preparation using some chelating agents improved the FTS activity of Co/SiO₂ catalyst. Especially, the catalyst prepared using nitrilotriacetic acid (NTA) showed the FTS activity ca. 3 times greater than the catalyst without chelating agents. A volcano-type dependency giving a maximum with NTA was found when the FTS activity of these catalysts was plotted against logarithmic complex formation constants with Co ion in the aqueous solution, suggesting that the formation of Co complex with moderate stability (i.e. NTA-Co complex) is crucial for obtaining higher FTS activity. Hydrogen chemisorption measurements on reduced catalysts showed that the preparation of the catalysts using these chelating agents and/or organic acids leads to the formation of fine metallic Co clusters with 1-5 nm size. TOF of these catalysts was independent of the metallic cluster size in 1-17 nm range, which was evidently different from those reported previously. The formation mechanism of fine metallic clusters was also investigated by means of XPS and Co K-edge EXAFS. [DOI: 10.1380/ejssnt.2009.633]

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The dispersion structure of the hole subband in a p-type space charge layer on Si(001) was investigated for the first time by angle-resolved photoelectron spectroscopy. The space charge layer was made via adsorption of Pb. The dispersion curves were in qualitative agreement with the parabolic dispersion curves with bulk effective masses obtained by the k·p perturbation method. The observed energy levels had smaller binding energy than the levels calculated by the triangle potential approximation. This was interpreted to reflect a change of the dopant atom concentration in the subsurface region due to diffusion of dopant during flashing. [DOI: 10.1380/ejssnt.2009.641]

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Photoswitchable spiropyran functionalised silica microbeads have been packed into an optically transparent silica capillary using a monolithic silica frit synthesised in-situ and preliminary results showing selective metal ion binding behaviour demonstrated using UV-vis spectroscopy. [DOI: 10.1380/ejssnt.2009.649]

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We found that closely packed submicro-scale Ag islands (each ∼370 nm across and ∼90 nm in height on the average) produced not only extremely short-range fluorescence enhancement for rhodamine dye (RhB) placed only ∼1 nm away from the metal surface, but also a novel, long-range enhancement for the same dye for the metal—molecule distance up to ∼50 nm. The net enhancement factor for the spin-coated RhB, with a fluorescence quantum yield of ∼2 % in the absence of Ag islands, was as high as ∼20-folds at the metal--molecule distance of ∼30 nm. We propose that strong interparticle surface plasmon interactions involving such large Ag islands play crucial roles for the long-range fluorescence enhancement. [DOI: 10.1380/ejssnt.2009.653]

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Organic semiconductor nonvolatile memory devices were successfully fabricated from organic thin-film transistors (OTFTs) embedded with nanocrystal carbon (nc-C) dots incorporating pentacene as an active layer. The nc-C dots were arranged in the channel region by a focused ion beam (FIB) technique using a precursor of low energy Ga⁺ ions and a carbon source. The formation and morphology of nc-C dot arrays were investigated using a scanning ion microscopy (SIM) and atomic force microscopy (AFM), respectively. The SIM and AFM images show that the nc-C dot array was successfully grown on the SiO₂ layer. The density of the two-dimensional nc-C dots was 5× 10⁹ cm^-2. The current-voltage (I-V) characteristics at room temperature show that the fabricated OTFTs exhibit a memory effect upon the application of forward and reverse bias. Under the effect of gate bias, on and off states were induced and a threshold voltage shift (ΔV_th = 0.23 V) was obtained. The charge carrier mobility (μ) of the OTFTs is similar in both on and off states. The memory effect was attributed to the nc-C dots in the pentacene-dielectric interface. [DOI: 10.1380/ejssnt.2009.665]

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V-shaped grooves were prepared by patterning of line and space (LS) using photolithography and BHF etching, and anisotropic etching using hot KOH solution on patterned 100 nm-SiO₂/Si(001) substrate. The V-shaped grooves consist of two <111> planes. The width of grooves was varied from 2 to 10 μm while keeping intervals (<001> planes with 1 μm width) between grooves. The heteroepitaxial growth of InSb films on the V-grooved Si(001) substrate was carried out by using a two-step growth procedure in an ultra-high vacuum chamber. The samples were characterized by X-ray diffraction (XRD) and scanning electron micrograph as a function of the space width of LS. From comparison of the XRD pattern of InSb films grown on Si(001) substrate with and without the V-grooves, we found that InSb crystals were heteroepitaxially grown not only on the <111> surface of the V-shaped grooves but also on the narrow (at least <3 μm) (001) surfaces. [DOI: 10.1380/ejssnt.2009.669]

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Miniaturization, integration, and functionality of microelectromechanical systems are limited in water. One solution to this problem is to apply the micrometer-scale motors from biological systems. A suitable biological motor is a linear motor found in microorganisms such as Vorticella. We developed a method to attach artificial material onto Vorticellas through streptavidin biotin binding. We biotinylated Vorticellas and coupled them to streptavidin coated particles of 1, 2, 6 and 8 μm diameter. The binding force of streptavidin and biotin was strong enough to endure a high speed contraction of a Vorticella (several mm/s). This attachment process of artificial material is a crucial step to fabricate a microsystem powered by filaments of Vorticellas. [DOI: 10.1380/ejssnt.2009.673]

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A new immune technique based on the nanostructured silicon and intended for the quantitative determination of some toxic substances is offered. The main principle of the proposed immune biosensor work is consisted in the measurement of the changes of the photocurrent of the photosensitive nanostructured silicon at the interaction of its surface preliminary treated by the specific antibodies with the toxin solution. The sensitivity of such biosensor allows determining T-2 mycotoxin at the concentration of 10 ng/ml during several minutes. Overall time of the analysis of one sample including of all procedures is about 40 min. These indexes fit with the practice demands. [DOI: 10.1380/ejssnt.2009.677]

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BiOCH₃COO and EDTA-4Na were dissolved in 2 mol/dm³ CH3COOH-2 mol/dm³ CH₃COONa buffer solution, and was adjusted to pH4.1 by adding 2 mol/dm³ CH₃COOH or 2 mol/dm³ CH₃COONa. 100 cm³ of this electrolyte was used. Electroplated film was obtained in the range of 10-100 mA/cm². Sono-electroplating was carried out smoothly, because the mass transfer accelerated with ultrasonic agitation and Bi ion was supplied to electrode surface. The mass transfer and crystallization processes were most affected with micro-jet and shock wave pressure. Best conditions of sono-electroplating were 0.10 mol/dm³ BiY^-, pH 4.0-5.5, 298 K and 10 mA/cm². Exchange current density and reaction rate constant in the sonication increased compared with that in the stationary state. As for this, an electron reaction became fast by the micro-jet or a shock wave pressure. The plated film was smoothness and denseness in sonication compared with that in stationary state. It was concluded that main factor that the surface became smooth was shock wave pressure. [DOI: 10.1380/ejssnt.2009.688]

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The time-evolution of the wavepacket inside chaotic and integrable two-dimensional (2D) nanostructures is numerically studied. We have found the enhancement around the classical periodic orbits during the time-evolution in the stadium billiard. It is similar to the scars in the standing wave of the chaotic billiards. The initial position and velocity, and the shape of the wavepacket are crucial for the enhancement, but we can observe that the remnant of the initial wavepacket travels along the unstable periodic orbit. Then the wavepacket gradually diffuses around the structure. This behavior has close relation to the dynamical properties of electrons in the structure, e.g., the conductivity, the magneto-resistance etc. The quantum fidelity, which can measure the robustness of dynamical states inside the nanostructures, is also discussed. [DOI: 10.1380/ejssnt.2009.721]

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We propose a method to attach probe DNAs with a homogeneous population for quantitative measurement of a minimum number of target DNA/RNA for the next generation of DNA chip. To control the homogeneous population of DNA probes, polymer films having neighboring reactive groups at the same distance, i.e., aromatic polyurea film formed with 3,5-diaminobenzonic acid (DBA) and methylenedi(p-phenylene) diisocyanate (MDI) and aliphatic polyurea film formed with DBA and hexamethylene diisocyanate (HDI), were polymerized directly on the surface of a chip substrate by vapor deposition polymerization. The spatial arrangement and homogeneity of the reactive groups on the surfaces of the substrates were examined by observing the immobilization of DNA fragments bound to 20-nm gold nano-particles on the polymer films. The results showed that physical adsorption of the DNA was effectively inhibited on the DBA/HDI film in contrast to the DBA/MDI film and the conventional aminosilane surface. Moreover, the distribution of the particles was homogeneous on the DBA/HDI film, unlike on the other surfaces. These results indicate that the aliphatic polyurea film could be used to control the selectivity and uniformity of reactive groups on the surface of substrates for more precise quantitative measurement of DNA chip technology. [DOI: 10.1380/ejssnt.2009.728]

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