-by- oxidation of Si surfaces has been studied by scanning reflection electron microscopy, which allowed us to obtain plan-view images of buried SiO₂/Si interfaces. We observed atomic steps at the SiO₂/Si(111) interfaces and the periodic reversal of terrace contrast during oxidation of Si(001) surfaces. We found that the initial surface structure was preserved at the interface and that the interfacial steps did not move laterally during oxidation. These results mean that -by- oxidation is governed by random nucleation of nanometer-scale oxide islands and lateral island growth. We also studied the kinetics of initial -by- oxidation of Si(001) surfaces. Our results showed that barrier-less oxidation of the first sub-surface layer, as well as oxygen chemisorption onto the top-layer, occurred at room temperature. The energy barrier of the second-layer oxidation was found to be 0.3eV. The initial oxidation kinetics is discussed based on first-principles calculations.

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In this study, we introduce a -by- (LbL) assembly method to prepare a reverse osmosis (RO) desalination membrane that consists of a hybrid combination of [polyelectrolyte (PE)/montmorillonite (MTM)]_n layers. First, adopting poly(allylamine hydrochloride) (PAH) for a PE layer, an RO test showed that the permeate flux of water through (PAH/MTM)_n multilayer-coated membranes decreased from ∼25.5 to ∼8.3 L·m⁻²·h⁻¹ with the increased bilayer number from n=9 to n=18. At the same time, the corresponding ion rejection with respect to NaCl is increased from ∼30 to ∼81%. Despite the increased ion rejection performance, (PAH/MTM)_n membranes exhibit a poor chlorine resistance, as frequently observed in commercial polyamide-based RO membranes. In our previous study, it was noted that the RO membranes, prepared just from the PE multilayers (i.e., [PAH/poly(acrylic acid) (PAA)]_n layers), showed a marked chlorine tolerance, but concomitantly very low permeate flux (∼4–5 L·m⁻²·h⁻¹). Considering the significant drawback in each case (poor chlorine tolerance for (PAH/MTM)_n layers and low permeate flux for (PAH/PAA)_n layers), we proposed to combine the layer constituents primarily by inserting PAH/PAA layers between two adjacent PAH/MTM layers. Indeed, the flux is maintained at ∼7.5±0.5 L·m⁻²·h⁻¹, comparable to commercial membranes, while the salt rejection ability is as high as ∼75±2.5% and the stability against the chlorine attack is well preserved with ∼74±5.0% ion rejection after the NaOCl treatment.

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真空プロセスを用いずに水系でしかも常温、常圧で製膜できるウェットプロセスとして交互吸着法、スプレー交互吸着法があり、近年研究が活発化している。なかでも、ディスプレイ、光学部材に適応される光学薄膜は、高真空を有するドライプロセスから、より簡易的なウェットプロセスによる光学薄膜が期待される。本研究では、交互吸着法により全水系プロセスで膜厚および屈折率をナノスケールオーダーで制御した光学薄膜を報告する。

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Inspection of 3D prints using 3D scanners becomes important as the range of applications of 3D printing becomes greater. Since the typical 3D printing is

-by- manufacturing, a -by- inspection is intuitive for 3D prints. However, the posture of the object in the scan data is unknown, so we need to estimate the build direction first to locate the positions of layers. In this research, we use X-ray computed tomography to investigate the geometric features of the 3D print made by Fused Deposition Modeling and provide a method to estimates the build direction of 3D print based on the features. A rough estimate of the build direction is obtained first based on the complete shape. Then, we remove the unpredictable parts of the 3D print based on the rough estimation and achieve accurate estimation based on the remaining parts. By checking the slices perpendicular to the estimated build direction, a -by- inspection is achieved where the user can investigate the interior structure of the 3D print. The proposed method lets the build direction can be estimated only based on the scan data, which makes the -by- inspection available for 3D prints without prior knowledge (e.g., CAD model).

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A high performance chemical filter for ammonia gas was established by forming the -by- self-assembly film on the surface of glass fiber. The filter was superior to active carbon filter in the case of removing ammonia gas. The newly developed filter showed remarkably high performance because it can adsorb large amount of odor molecules by chemical adsorption. Ammonia gas react with the polyelectrolytes in the film and was adsorbed into the multilayers of the film. In this paper, we report the high performance filter which can remove ammonia gas.

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Hydrogen titanate nanowires were prepared by hydrothermal method in 10 M NaOH followed by ion-exchanging process. Titanate nanowire thin films were successfully obtained by spray -by- (spray LbL) method within a short time. Due to the good dispersion state of the nanowires in an aqueous suspension and their linear morphology, titanate nanowires effectively adsorbed on the glass substrate. As a reference, TiO₂-anatase nanoparticle thin films were also prepared by spray LbL method.

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Organized organic-inorganic ultrathin films have been constructed from the fabrication of smectite unit layers and an amphiphilic ruthenium (II) complex monolayer using the conventional Langmuir-Blodgett (LB) technique. According to the method, a chloroform solution of an amphiphilic ruthenium (II) complex, [Ru (phen) ₂ (dC18bpy)] ²⁺ (phen=1, 10-phenanthroline, dC18bpy=4, 4'-dioctadecyl-2, 2'-bipyridyl as shown in Figure. 1), was spread onto an aqueous subphase containing either exfoliated saponite or hectorite suspension. Brewster angle microscopy (BAM) observation showed that Ru (II) complex molecules formed a self-assembled monolayer on a water surface and that clay particles were adsorbed by the monolayer from an aqueous subphase. A composite film of a Ru (II) complex and a clay particle thus formed was transferred onto a hydrophilic glass plate by the vertical dipping method. The surface structure of a deposited film was studied with an atomic force microscope (AFM). As a results, a glass substrate was covered with the single sheet of a clay on which amphiphilic metal complexes were attached

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The aims of this study were to identify the optimal concentration of coated orthodontic elastomerics using a

-by- technique that can release chlorhexidine (CHX) as an antimicrobial material, and to measure the physical properties and antimicrobial effects of the coated elastomerics. Ethyl cellulose (EC) was used as the polymer, and five study groups with various combinations of solvents (i.e., ethanol and dichloromethane [DCM]) were included. The coated elastomerics were evaluated with a spectrophotometer to confirm the release of CHX, and their surfaces were observed by SEM. The CHX+EC+DCM group sustained antimicrobial release for the longest period (168 h, p<0.001) and exhibited the largest antimicrobial effect in an inhibition zone test using S. mutans for 7 days (p<0.05). This group had most effective physical properties and antimicrobial effects of coated elastomerics produced using a layerby-layer technique, and so its composition should be considered for use in clinical applications in orthodontics.

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We present an overview of the preparation and properties of -by- (LbL) deposited thin films and microcapsules in relation to their use in the development of biosensors and controlled release systems. Enzyme biosensors can be constructed by immobilizing enzymes on the surface of electrodes by LbL deposition without loss of their catalytic activity. In addition to synthetic polymers, binding proteins, such as avidin and lectin, are also used for constructing LbL films through avidin-biotin and lectin-sugar interactions. The performance characteristics of LbL film-based biosensors can be tuned by controlling the number of layers and by the choice of film components. The permeability of polyelectrolyte LbL films to ions and molecules is discussed in relation to the use of the films for eliminating interference in biosensors. The possible use of polysaccharide LbL film-coated electrodes for the construction of biosensors is highlighted, and examples of LbL film- and microcapsule-based optical sensors are described. We then focus on the use of LbL films and microcapsules as vehicles for controlled release, in particular on recent progress in the controlled release of insulin from LbL films and microcapsules. LbL films composed of insulin and polymers are sensitive to environmental pH, and release insulin in response to pH changes, suggesting that insulin LbL films can be used in the development of orally administered insulin. The construction of glucose-dependent insulin release systems using LbL insulin microcapsules functionalized with phenylboronic acid, lectin, and glucose oxidase is also examined.

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Inorganic semiconductor multilayer thin films of CdS nanoparticles and titania nanosheet (TNS) were prepared by an electrostatic -by- accumulation technique. The absorbance of immobilized CdS and TNS linearly increased in proportion to the number of accumulated films, but the photoluminescence of CdS nanoparticles was dramatically quenched by being tucked into the TNS layer. Accumulation of the TNS/CdS layer remarkably enhanced the photocurrent generation compared to the case of films -by--deposited with CdS nanoparticles and polystyrene sulfonate of an inert polymer. These observations can be explained by the efficient photoinduced electron transfer from photoexcited CdS nanoparticles to adjacent TNS layers.

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