Characterization of interface state density of three-dimensional Si nanostructure by charge pumping measurement

Adopting the gated p–i–n diode configuration, the interface state density (D_it) at the Si/SiO₂ interface of Si fin structures on Silicon-on-Insulator (SOI) wafers has been systematically studied using charge pumping method. The optimal forming gas annealing temperature for the three-dimensional (3D) surface is extracted. A new methodology for separately quantifying the local D_it at different regions of the 3D surfaces (i.e., the top/side walls and the corners) is also derived by characterizing the fins with various widths and the planar counterparts. The results validate the necessity to independently consider the corner regions, at which substantially high local D_it situates, and thus further clarify the origin of high D_it at 3D surfaces.     

Reduction of void content of vacuum‐assisted resin transfer molded composites by infusion pressure control

Vacuum‐assisted resin transfer molding is a promising technique for making large and complex composite structures. However, void formation remains a problem. Two primary contributors to void formation, non‐uniform resin flow and continuous evaporation of resin under low pressure, were experimentally studied. Improved pressure control at the vent is proposed to reduce the void content of the manufactured composite material: at the start of the resin infusion, the pressure at the vent is set to the full vacuum of the equipment, while after the resin has saturated all of the reinforcements, the pressure at the vent is increased slightly. The full vacuum at the start of infusion avoids air entrapment, and the slightly higher pressure later in the process restrains the resin evaporation. A lower void content is obtained. POLYM. COMPOS., 36:1629–1637, 2015. © 2014 Society of Plastics Engineers     

Plasma surface treatment of PCL/PC blend sheets

Surface treatments using glow discharge plasmas from O₂ and Ar were applied to blend sheets of poly(?‐caprolactone)‐polycarbonate (PCL/PC), which had been produced by extrusion from melts of the mixture at various blend ratios. As to the reactivity of these two plasmas, O₂‐plasma forms the oxidative species to be reactive in general, while Ar‐plasma is non‐oxidative. Weight loss by the oxidative O₂‐plasma etching increased with the content of PCL in the polymer blends. The surface became hydrophilic by plasma treatment, and the changes were affected also by the blend ratio. PC and the PC‐rich blend sheets became more hydrophilic than the PCL‐rich blends after plasma treatments. The O₂‐plasma treatments were more effective than non‐oxidative Ar‐plasma treatment in increasing the hydrophilicity. Hydrophilic change was related to the increase in the polar contribution of surface energy.     

Chemical Analysis and Comparison of Acid Components of Anal Secretions of Idolothripine Thrips

Anal secretions of 17 species in nine genera of the subfamily Idolothripinae were analzyed by TLC, GC, and GC-MS. From all species, juglone and two or more carboxylic acids with carbon numbers ranging from 10 to 14 were detected; the exception was Gastrothrips sp., from which none was detected. Twelve carboxylic acids were found, of which decanoic acid, (E)-4-decenoic acid, and (Z)-5-tetradecenoic acid were widely found, and acid ingredients were fairly species-specific. The Gastrothrips sp. was the only exception, and it had no secretion components among the tubuliferan species so far analyzed. Juglone is thought to be a potent defensive allomone, and roles of the carboxylic acids are discussed.     

Preparation of large-scale 2D zeolite crystal array structures to achieve optical functionality

We examined a method to refine a technique to prepare close-packed monolayers of cylindrical zeolite L crystals tethered on a substrate through covalent linkages, which was developed recently for popular use. We attempted to fabricate both vertical and horizontal–unidirectional alignments of the zeolite particles. The vertical alignment for centimeter scale large areas was achieved on a flat glass substrate by using flat-based zeolite crystals with an aspect ratio (length divided by width) of 1.1 while the crystals with an aspect ratio of 1.7 failed to align vertically. Thus the parameters important for successful alignment were determined. On the other hand, the unidirectional alignment in the horizontal packing structures was achieved by employing pregrooved substrates. We found that the relationship between the sizes of zeolite crystals and grooves is a crucial factor for the preparation of a close-packed structure. In this respect, our present preparation requires further improvements because it resulted in structures with many void spaces. Furthermore, we prepared the zeolite films loaded with unidirectionally aligned dyes to achieve optical functionalities.     

Compression fatigue failure of CFRP laminates with impact damage

The objective of this study is to investigate failure mechanisms of impact-damaged CFRP laminates subjected to compression fatigue. Two kinds of composite materials, UT500/Epoxy and AS4/PEEK, were used to examine the dependence of failure behavior on the material properties such as interlaminar toughness. Impact-induced delaminations in the UT500/Epoxy specimen were considerably larger than those in the AS4/PEEK specimen. The S–N curves for the UT500/Epoxy specimens with impact damage exhibited a similar tendency to those without impact. The impact-induced delamination in the UT500/Epoxy specimen grew widthwise to the free edge on the rear side of the specimen during the fatigue test. On the other hand, the AS4/PEEK specimens without impact exhibited a more steeply declining S–N curve than those with impact damage. The delaminations in the impacted AS4/PEEK specimen did not reach the free edge before the fatigue fracture.     

Performance of pigeons (Columba livia) on maze problems presented on the LCD screen: In search for preplanning ability in an avian species.

The authors examined how pigeons (Columba livia) perform on 2-dimensional maze tasks on the LCD monitor and whether the pigeons preplan the solution before starting to solve the maze. After training 4 pigeons to move a red square (the target) to a blue square (the goal) by pecking, the authors exposed them to a variety of detour tasks having lines as a barrier. A preview phase was introduced, during which the pigeons were not allowed to peck at the monitor. Results of a set of experiments suggest that our pigeons successfully learned to solve these tasks, that they came to take an efficient strategy as the barriers became complex, and that they possibly preplan its solution, at least on familiar, well-practiced tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of interfacial morphology on the welding strength of injection‐molded polyamide

The effect of interfacial morphology controlled by injection‐molding conditions on the welding strength of injection‐molded polyamide was investigated in this article. The experimental results showed that the first injection‐molding conditions had distinct influence on the welding strength at the low secondary injection‐molding temperature T₂ (≤265°C), but the influence vanishes at T₂ ≥ 285°C. On the other hand, no matter what the first injection‐molding conditions are, the welding strength increases with increasing T₂, and when T₂ ≥ 285°C, the highest welding strength reaches 45 MPa, due to the formation of trans‐crystals at the interface. Morphology studies showed that trans‐crystals grow along the perpendicular direction of the interface, and their nuclei are formed at the surface of the first injection‐molded specimens. For the specimens with high‐welding strength, the welding strength relies on the skin layer of the first injection‐molded specimens in which the fracture induced by shear stress happens. POLYM. ENG. SCI., 47:2164–2171, 2007. © 2007 Society of Plastics Engineers     

Can squirrel monkeys (Saimiri sciureus) learn self-control? A study using food array selection tests and reverse-reward contingency.

Eight squirrel monkeys (Saimiri sciureus) were presented with 2 stimulus arrays, namely 1 and 4 pieces of food, but they received only the array other than the one they reached for. In this reverse-reward condition, all monkeys initially showed a strong preference for the larger array. One monkey learned to reach toward the smaller array when a large-or-none reward contingency was applied (i.e., no reward followed a reach toward the larger array, but this array was given for a reach toward the smaller array). When correction trials and time-out were added to the large-or-none procedure, all remaining monkeys except 1 learned this form of self-control. Performance was maintained when correction trials were discontinued, the original reverse-reward condition was rerun, and novel array-size pairs were presented. This study demonstrates one form of self-control in a New World primate and shows the reverse-reward procedure to be a potentially valuable method for assessing species and individual differences in self-control and numerosity-related abilities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)