Computer simulation of local lattice distortion in Cu-Au solid solution

The local lattice-distortion effects in Cu-25 at Pct Au solid solution were investigated using a computer simulation in which the nearest-neighbor Lennard-Jones interactions with thermal vibration effects were assumed. The investigation revealed that the average displacements of Cu-Cu and Au-Au pairs in the nearest neighbor were negative and positive directions, respectively, with respect to the rigid lattice before the relaxation, and that the diffuse scattering intensity due to local lattice distortion and local atomic configuration can be calculated by taking the short-range configuration up to the 12th nearest-neighbor pairs into account. The results reproduced the overall tendency of the experimental observations. Formerly Graduate Student, Department of Metallurgical Engineering, Hokkaido University.     

Compatibilizing effect of a maleic anhydride functionalized SEBS triblock elastomer through a reaction induced phase formation in the blends of polyamide6 and polycarbonate—III. Microscopic studies on the deformation mechanism

Microscopic studies on the deformation mechanism of the blends of polyamide6 (PA6) and polycarbonate (PC) compatibilized with triblock copolymer of poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) functionalized with maleic anhydride (SEBSgMA) were carried out. As described in our previous paper, significant improvement of mechanical properties of this blend series can be achieved by the use of the combination of SEBSgMA and unmodified SEBS (unSEBS) as compatibilizers. Especially, when the composition of the blends of PA6/PC is and the total amount of added SEBS is 20 phr, drastic enhancement of the impact strength and of the elongation at break in the tensile stress-strain tests can be achieved by varying the ratio of SEBSgMA to unSEBS. The encapsulation by SEBS on the PC domains gradually become incomplete as the increase of the ratio of unSEBS to SEBSgMA and then the mechanical properties can be maximized. We observed the deformed zone of the specimens loaded to the tensile stress-strain tests and to the Izod impact tests using transmission electron microscopy (TEM) in order to find out the origin of this enhancement of the mechanical properties. It has revealed that voids tend to be generated at the PA6/PC interface easily due to the incompletion of the encapsulation achieved by the use of the combination of SEBSgMA and unSEBS, and thereby the local shear yielding of the matrix is promoted to dissipate the tensile and the impact energy. © 1997 Elsevier Science Ltd.     

Histological features of the vomeronasal organ in the giraffe,Giraffa camelopardalis

The vomeronasal organ (VNO) that preferentially detects species‐specific substances is diverse among animal species, and its morphological properties seem to reflect the ecological features of animals. This histological study of two female reticulated giraffes (Giraffa camelopardalis reticulata) found that the VNO is developed in giraffes. The lateral and medial regions of the vomeronasal lumen were covered with sensory and nonsensory epithelia, respectively. The vomeronasal glands were positive for periodic acid‐Schiff and alcian blue (pH 2.5) stains. The VNO comprises several large veins like others in the order Cetartiodactyla, suggesting that these veins function in a pumping mechanism in this order. In addition, numerous thin‐walled vessels located immediately beneath the epithelia covering the lumen entirely surrounded the vomeronasal lumen. This sponge‐like structure might function as a specific secondary pump in giraffes.     

Synthesis and applications of silicone oil–soluble fluoroalkyl end‐capped cooligomers

Fluoroalkyl end‐capped cooligomers containing polydimethylsiloxane and polyoxyethylene segments were prepared under very mild conditions by the cooligomerizations of fluoroalkanoyl peroxides with methacrylate monomers containing the corresponding segments and comonomers such as dimethylacrylamide and acryloylmorpholine. These obtained fluorinated cooligomers exhibited amphipathic characteristics and became soluble in water and common organic solvents. In particular interest, fluoroalkyl end‐capped cooligomers containing polyoxyethylene units were soluble not only in poly(methylphenylsiloxane) (silicone oil) but also in water, including common organic solvents except for hexane. Additionally, these fluorinated cooligomers were able to reduce the surface tension of water and m‐xylene quite effectively, to around 15 and 20 mN/m levels, respectively. In these fluorinated cooligomers, fluoroalkyl end‐capped acryloylmorpholine cooligomers containing polyoxyethylene segments were applicable as a novel emulsifying agent against water and silicone oil. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1467–1476, 2005     

Multi-shot flash lamp annealing method for electroless-plated Ni-P film on UV-surface-modified ABS

The multi-shot flash lamp annealing (FLA) method as a rapid annealing technique was developed for an electroless-plated Ni-P film on UV-surface-modified acrylonitrile–butadiene-styrene (ABS) in place of the conventional annealing method. The new multi-shot FLA method continuously irradiates a Xe flash discharge with low irradiance (<1?J?cm^–2) with a frequency of 3?Hz. An adhesion strength between the electroless Ni-P film and ABS of more than 1.2?kN?m^–1 was achieved in a short time of approximately 30?s; this adhesion strength was larger than that obtained in the conventional method of 1?h duration. The etching effect of the FLA method was assessed by a study of the surface morphologies of the Ni-P films. XRD spectra of the Ni-P films showed an improvement in the crystallinity of the films. Considering surface elemental analyses of the peeled Ni-P-film/ABS, a cohesive failure, which implies high adhesion, was observed in the ABS. The proposed FLA method is expected to efficiently improve the adhesion and significantly reduce the annealing time in the electroless plating process.     

Performance of gain-tuned harmonic drive torque sensor under loadand speed conditions

Addresses the topic of torque sensing by using strain gauges, which are cemented directly onto the flexspline of a harmonic drive gear reducer. Conventionally, two or four strain gauges are used to reduce the ripple signal, which is generated by the gear operation. However, our analysis shows that an odd number of strain gauges is more suitable for the ripple compensation. The method does not need online calculations and reduces the needed accuracy of the strain gauges positioning, so it can be practically implemented. Two techniques to define the gains are presented in the paper. One is based on a mathematical model of the fluctuation signal, and the other employs a heuristic approach. Practical results show effectiveness and usefulness of the proposed method. We present the new method and evaluate its performance under load torque and rotational speed conditions. No significant deterioration of the performance under load torque and at various rotational speeds was confirmed