Synthesis and Properties of Functionalized [6] Helicenes by the Thermal Domino Radical Cycloaromatization of Acyclic Polyynes

Non-conjugated aromatic hexaynes and heptaynes undergo thermal domino radical cycloaromatization under mild conditions to yield indenol ring-fused fluoranthene and indenol ring-fused benzo[a]rubicene skeletons with helicity. The structure and thermal racemization of [6]helicene derivatives (12 and 13) are also described.     

Nearmiss Count Between Flying Head and Magnetic Disk by Detecting Electrical Potential of Voltage-Applied Slider

A simple in-situ measurement of flying head dynamics is developed, making use of weak conductive sliders and media as capacitance and resistance sensors. This method is confirmed to detect such abnormal functioning occurring in the head-medium interface as nearmiss, contact or crash. Flying head dynamics are quantitatively studied, using a simple and effective method wherein the slider is excited by externally pressurized air flow. Without this disturbance, the nearmiss count is almost zero, with the number tending to increase up to a resonant frequency governed by the slider inertia and air film stiffness with increasing disturbance, presenting a maximum value at a disk velocity of 3 to 5 m/s.     

Transient Piezothermoelastic Analysis for a Functionally Graded Thermopiezoelectric Hollow Cylinder

This paper is concerned with the theoretical treatment of transient piezothermoelastic problem involving a functionally graded thermopiezoelectric hollow cylinder due to uniform heat supply. The transient one-dimensional temperature is analyzed by the method of Laplace transformation. The thermal, thermoelastic and piezoelectric constants of the hollow cylinder are expressed as power functions of the radial coordinate. We obtain the one-dimensional solution for the temperature change in a transient state, and piezothermoelastic response of a functionally graded thermopiezoelectric hollow cylinder. Some numerical results for the temperature change, the displacement, the stress and electric potential distributions are shown. Furthermore, the influence of the nonhomogeneity of the material upon the temperature change, displacement, stresses and electric potential is investigated.     

Characteristics of hydrophobicity loss on silicone rubber surface during a dynamic drop test with direct current voltage application

Dynamic drop test for studying the temporal lowering of hydrophobicity on the surface of silicone rubber with direct current voltage application was carried out. In this study, we evaluated the influence of the temporal lowering of hydrophobicity under various conductivities and dropping rates for water droplets. As a result, it was found that the dropping rate and the conductivity of water droplets greatly influenced the hydrophobicity loss time on the surface of silicone rubber.