Optical microcantilever consisting of channel waveguide for scanning near-field optical microscopy controlled by atomic force

We develop a novel optical microcantilever for scanning near-field optical microscopy controlled by atomic force mode (SNOM/AFM). The optical microcantilever has the bent channel waveguide, the corner of which acts as aperture with a large tip angle. The resonance frequency of the optical microcantilever is 9 kHz, and the spring constant is estimated to be 0.59 N/m. The optical microcantilever can be operated in contact mode of SNOM/AFM and we obtain the optical resolution of about 200 nm, which is as same size as the diameter of aperture. We confirm that the throughput of optical microcantilever with an aperture of 170 nm diameter would be improved to be more than 10⁻⁵.     

Polypyrrole-supported graphite felt for Heck reaction in solid phase synthesis

Substrate immobilization on graphite felt for solid phase Heck reaction was achieved by electrochemical polymerization of the substrate precursor containing a pyrrole side chain, where the amount of substrate on the electrode surface was easily controlled by the number of repeated cyclic voltammetric scanning. Couplings between olefins and the 4-iodobenzoic acid-modified graphite felt electrode or aromatic halides and the 4-vinylbenzoic acid-modified graphite felt electrode in the presence of palladium catalyst proceeded smoothly in satisfactory yields. The used substrate-modified electrode was reproduced by the treatment of used electrode with activated ester species of 4-vinylbenzoic acid, and was able to be recycled to Heck reaction in solid phase synthesis.     

Role of nitrogen addition in stabilizing the γ phase of Biomedical Co–29Cr–6Mo alloy

Three-dimensional atom probe observations and thermodynamic calculations revealed that the mechanism of γ-phase stabilization by N addition in the Co–29Cr–6Mo alloy is different from that in stainless steel: N addition does not lower the free energy of the γ phase in Co–29Cr–6Mo but increases the energy barrier and thus lowers the kinetic rate of the γ → ? transition through the formation of Cr–N short range order.     

State-of-the-Art on numerical simulation of fiber-reinforced thermoplastic forming processes

Summary Short fiber reinforced composites have gained increasing technological importance due to their versatility that lends them to a wide range of applications. These composites are useful because they include a reinforcing phase in which high tensile strengths can be reached, and a matrix that allows to hold the reinforcement and to transfer applied stress to it. It is a well-known fact, that such materials can have excellent mechanical, thermal and electrical properties that make them widely used in industry. During the manufacture process, fibers adopt a preferential orientation that can vary significantly across the geometry. Once the suspension is cooled or cured to make a solid composite, the fiber orientation becomes a key feature of the final product since it affects the elastic modulus, the thermal and electrical conductivities, and the strength of the composite material. In this work we analyzed the state-of-the-art and the recent developments in the numerical modeling of short fiber suspensions involved in industrial flows.     

Bonding characteristics and diffusion barrier effect of the TiC phase formed at the bonding interface in an explosively welded titanium/high- carbon steel clad

Microstructural aspects and bonding characteristics of the explosively welded titanium/high-carbon steel clad of the as-welded and postannealed states were investigated. Amorphous and βTi phases were observed at the interface in the as-welded clad. These were considered to be the trace of melting and subsequently rapid solidification of thin layers along the contact surface of both the parent materials. The melting layer was considered to be responsible for the substantial bonding. The TiC layer was formed at the bonding interface by postannealing, which served as a barrier for diffusion of species across the interface and suppressed the formation of Fe-Ti intermetallic compounds. As a result, high bonding strength was preserved even after prolonged annealing at elevated temperatures.     

Change in viscosity of softening coal upon heating with its liquid content. Part I: linear relationship between logarithm of viscosity and liquid fraction

A variable-force-loading needle penetrometry and a proton magnetic resonance analysis were performed for in situ measurements of shear-rate-independent viscosity of softening coal pellet upon heating, η, and the fraction of mobile hydrogen existing in the liquid phase, φ_mh, respectively. During isothermal heating of the pellet at temperature in a range from 680 to 730 K, φ_mh changed with time via a maximum while η did inversely. At every temperature examined, the time for the maximum φ_mh coincided with that for the minimum η. This result qualitatively validated the experimental definition of the liquid fraction in the softening coal as a liquid/solid suspension by φ_mh. Further analysis of the results revealed that the logarithm of η, which changes in a range from 10¹⁰ to 10⁴ Pa s upon isothermal heating, is correlated linearly with the liquid fraction ranging from 0.1 to 0.5. For each of the pellets made of two different coals, it was found that the logarithm η and φ_mh varied being governed by a single linear relationship upon both isothermal heating and non-isothermal heating. Such a single relationship, which was valid over a temperature range from 600 to 800 K, suggested fairly small temperature dependency of the viscosity of liquid in the softening coal.     

Synaptic target recognition at Drosophila neuromuscular junctions

Every synaptogenesis begins with "synaptic target recognition," a cell-cell recognition event in which a neuron and its target stably adhere. Despite its importance in developing nervous systems, synaptic target recognition has been difficult to study in complex systems. The relatively simple and genetically accessible Drosophila NMJ model system provides a repertoire of target recognition cues. We describe how these molecules control the targeting of specific growth cones in either a positive (synaptogenic) or negative (anti-synaptogenic) manner. We also propose two alternate signaling paradigms to explain how these initial cell recognition events are coupled to the intracellular signaling pathways that begin the process of synapse maturation.