A combined environmental straining specimen holder for high-voltage electron microscopy

A novel specimen holder that enables in situ observation of crack-tip deformation and/or fracture under a controlled environment is developed for a high-voltage electron microscope (HVEM). A window-type environmental cell (EC) that incorporates a uniaxial straining apparatus is built into a side-entry-type single-tilt specimen holder. The gas control in EC, straining apparatus design, limited field of view for crack-tip observation, and specimen preparation for the specimen holder are presented in detail. Experimental results successfully demonstrate that the developed specimen holder is quite useful for the dynamic observation of crack-tip deformation and/or fracture subjected to a hostile environment, such as hydrogen gas.     

In Situ Observation of High Temperature Creep Behavior During Annealing of Steel

Previous studies on creep suggested a close relationship between polycrystal grain size, substructure, and creep rate. At present, however, our understanding of the influence of polycrystal grain size, substructure, and thermal stress on creep deformation behavior seems rather insufficient, especially as there is a general lack of in situ data on structural changes during creep. In this study, the effects of thermal stress, austenite grain size, and cooling rate on slip deformations in C?CMn?CAl steel during annealing were investigated systematically on the basis of in situ observations using high temperature laser scanning confocal microscopy. Finally, a kinetics model based on thermal expansion anisotropy and temperature difference was developed to explain these interesting experimental results. The in situ investigation of slip deformation during annealing greatly contributes to the understanding of high temperature creep behavior.     

Dietary PlsEtn Ameliorates Colon Mucosa Inflammatory Stress and ACF in DMH-Induced Colon Carcinogenesis Mice: Protective Role of Vinyl Ether Linkage

Ethanolamine plasmalogen (PlsEtn), a sub-class of ethanolamine glycerophospholipids (EtnGpl), is a universal phospholipid in mammalian membranes. Several researchers are interested in the relationship between colon carcinogenesis and colon PlsEtn levels. Here, we evaluated the functional role of dietary purified EtnGpl from the ascidian muscle (87.3 mol% PlsEtn in EtnGpl) and porcine liver (7.2 mol% PlsEtn in EtnGpl) in 1,2-dimethylhydrazine (DMH)-induced aberrant crypt foci (ACF) in vivo, and elucidated the possible underlying mechanisms behind it. Dietary EtnGpl-suppressed DMH-induced aberrant crypt with one foci (AC1) and total ACF formation (P < 0.05). ACF suppression by dietary ascidian muscle EtnGpl was higher compared with dietary porcine liver EtnGpl. Additionally, dietary EtnGpl decreased DMH-induced oxidative damage, overproduction of TNF-α, and expression of apoptosis-related proteins in the colon mucosa. The effect of dietary ascidian muscle EtnGpl showed superiority compared with dietary porcine liver EtnGpl. Our results demonstrate the mechanisms by which dietary PlsEtn suppress ACF formation and apoptosis. Dietary PlsEtn attained this suppression by reducing colon inflammation and oxidative stress hence a reduction in DMH-induced intestinal impairment. These findings provide new insights about the functional role of dietary PlsEtn during colon carcinogenesis.     

Lattice distortion of porous Si by Li absorption using two-dimensional photoelectron diffraction

Lithiation and delithiation of porous silicon were studied using reflection high energy electron diffraction (RHEED), two-dimensional photoelectron diffraction, and a stereo atom-scope, which is realized by the combination of a display-type spherical mirror analyzer and circularly polarized soft X-ray. A nanosized porous silicon layer was prepared by electrochemical etching of p-type silicon (001) wafer in ethanolic solutions containing hydrofluoric acid. The morphology of the as-grown porous silicon as observed using SEM was filled with about 9 nm holes. This porous silicon also retains the crystallographic orientation of the wafer from which it was etched and is optically active with visible photoluminescence. The measured RHEED pattern and 2π steradian Si 2p photoelectron diffraction pattern from Si (001) surface showed an increase in lattice constant by lithiation, and that change in lattice constant was restored to its original values by delithiation.     

Development of Nuclear Radiation Detectors by Use of Thick Single-Crystal CdTe Layers Grown on (211) p +-Si Substrates by MOVPE

Development of an electron-collecting-type pixel array by use of an epitaxially grown thick single-crystal CdTe layer on p ⁺-Si substrate is discussed. To achieve such an array with an n-CdTe/p-like CdTe/p ⁺-Si heterojunction diode structure, charge transport at the p-like CdTe/p ⁺-Si heterointerface was studied. It was confirmed that ohmic conduction via holes occurs at this interface. A single-element detector was then fabricated by growth of 40 μm thick undoped p-like CdTe then 5 μm thick n-CdTe layers on the p ⁺-Si substrate. Rectification by the diode detector was good, and its energy-resolving capability was demonstrated by detection of gamma peaks from the ²⁴¹Am source, thus confirming the feasibility of using this structure for fabrication of an electron-collecting-type array.     

Room‐Temperature Printing of Organic Thin‐Film Transistors with π‐Junction Gold Nanoparticles

Printing semiconductor devices under ambient atmospheric conditions is a promising method for the large‐area, low‐cost fabrication of flexible electronic products. However, processes conducted at temperatures greater than 150 °C are typically used for printed electronics, which prevents the use of common flexible substrates because of the distortion caused by heat. The present report describes a method for the room‐temperature printing of electronics, which allows thin‐film electronic devices to be printed at room temperature without the application of heat. The development of π‐junction gold nanoparticles as the electrode material permits the room‐temperature deposition of a conductive metal layer. Room‐temperature patterning methods are also developed for the Au ink electrodes and an active organic semiconductor layer, which enables the fabrication of organic thin‐film transistors through room‐temperature printing. The transistor devices printed at room temperature exhibit average field‐effect mobilities of 7.9 and 2.5 cm² V^?1 s^?1 on plastic and paper substrates, respectively. These results suggest that this fabrication method is very promising as a core technology for low‐cost and high‐performance printed electronics.     

Concept of feedback‐controlled differential evolution and its realization

This paper first proposes a novel concept of differential evolution (DE) with an automatic parameter adjustment that controls its search situation to be a promising situation by the error feedback. It is called feedback‐controlled differential evolution (FCDE), whose adjustment mechanism consists of three parts: Evaluator, Referencer, and Controller. Evaluator calculates an evaluation index which measures the search situation. Referencer generates a reference index being a target of the evaluation index which corresponds to a promising situation. Controller operates the parameters to make the evaluation index follow the reference index using its error feedback. Further, this paper realizes a method in FCDE for a typical DE called “DE/best/1/bin" by designing the three parts. The effectiveness of the proposed method is confirmed through various computational experiments from the viewpoints of controllability and performance. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Polymer‐Based Organic Field‐Effect Transistors with Active Layers Aligned by Highly Hydrophobic Nanogrooved Surfaces

In this study, polymer‐based organic field‐effect transistors (OFETs) that exhibit alignment‐induced mobility enhancement, very small device‐to‐device variation, and high operational stability are successfully fabricated by a simple coating method of semiconductor solutions on highly hydrophobic nanogrooved surfaces. The highly hydrophobic nanogrooved surfaces (water contact angle >110°) are effective at inducing unidirectional alignment of polymer backbone structures with edge‐on orientation and are advantageous for realizing high operational stability because of their water‐repellent nature. The dewetting of the semiconductor solution is a critical problem in the thin film formation on highly hydrophobic surfaces. Dewetting during spin coating is suppressed by surrounding the hydrophobic regions with hydrophilic ones under appropriate designs. For the OFET array with an aligned terrace‐phase active layer of poly(2,5‐bis(3‐hexadecylthiophene‐2‐yl)thieno[3,2‐b]thiophene), the hole mobility in the saturation regime of 30 OFETs with channel current direction parallel to the nanogrooves is 0.513 ± 0.018 cm² V^?1 s^?1, which is approximately double that of the OFETs without nanogrooves, and the intrinsic operational stability is comparable to the operational stability of amorphous‐silicon field‐effect transistors. In other words, alignment‐induced mobility enhancement and high operational stability are successfully achieved with very small device‐to‐device variation. This coating method should be a promising means of fabricating high‐performance OFETs.     

Structure simulation in unidirectionally solidified turbine blade by dendrite envelope tracking model（Ⅰ）： numerical modeling

A 3D dendrite envelope tracking model was developed for estimating the solidification structure of unidirectionally solidified turbine blade. The normal vector of dendrite envelope was estimated by the gradient of dendrite volume fraction, and growth velocity of the dendrite envelope （dendrite tips） was calculated with considering the anisotropy of grain growth. The solute redistribution at dendrite envelope was calculated by introducing an effective solute partition coefficient（ke）. Simulation results show that the solute-build-up due to the rejection at envelope affects grain competition and consequently the solidification structure. The lower value of ke leads to more waved dendrite growth front and higher solute rejection. The model was applied to predict the structure of turbine-blade-shape samples showing good ability to reproduce the columnar and single grain structures.