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A 3D-printed-layered structure for forming the compliant bipolar electrostatic gripper is proposed. A prototype gripper module, which consists of an array of elastically deformable bipolar micro-probes, is fabricated using a conventional 3D printer. Experiments are conducted to examine the attractive force and the pick-and-place performance of the prototype. Experimental results show that the prototype module can generate the maximum attractive pressure of 87.1 Pa, which can pick and hold a piece of xerographic paper of 31.2 mg successfully. The effects of residual charges and the probe-tips flattening process on the attractive force are also discussed.

Electrostatic gripper is a technology that has seen many advancements in the last few decades. Its popularity among researchers is due mainly to many advantages it offers, e.g. its ability of a simple force control by adjusting the applied voltage to the electrodes. The electrostatic gripper with voltages of positive and negative polarities is particularly deemed promising as it can handle various materials, especially dielectrics, by the principle of polarization due to the electric fields. In this work, an electrostatic gripper with a beam-array structure made of conductive polymeric fibers is considered. The structure of coaxial electrodes has been understood to sport a superior performance; however no comparative analysis has been reported so far. Thus, this work offers an empirical comparison between fibers consisting of coaxial and parallel electrodes by experiments which are validated by numerical simulations. Furthermore, utilizing numerical simulations, design guidelines, especially concerning the voltage polarity patterns are established. The results are expected to shed an insight toward the development of a full-fledged electrostatic gripper for industrial use.

The terahertz vibrational modes of crystalline salicylic acid at 1–6 THz were investigated using a vibrational calculation method in which the diagonalization of force constant matrix was estimated by periodic density functional calculations. The result proved sufficient to enable the terahertz vibrational modes to be assigned to lattice modes at 32.2–64.9 cm-1 coupled with translational and rotational modes, intermolecular bending modes at 67.0–132.1 cm-1 including the torsion of carboxyl groups, and out-of-plane intramolecular bending modes at 162.0–175.4 cm-1. The theoretical model presented allows for the interpretation of the terahertz spectra of organic crystals with a hydrogen-bonded dimer lacking the molecular vibrations of a large amplitude, by including effects arising from crystal periodicity.

Using a simple discharge circuit, we have investigated effects of the circuit parameters on glow-to-arc transition behaviour. A direct current power source is used with a capacitor and resistors. Plasma is generated between thoriated tungsten electrodes at atmospheric pressure in argon. Current and voltage are recorded while capturing plasma images.A variation of the charge on the capacitor causes a fluctuation in discharge current. Due to the current fluctuation, the electric power dissipated between the electrodes increases during a temporary glow phase and decreases during a temporary arc phase. The cathode tip has been heated in the glow mode and a glow-to-arc transition occurs finally. The current fluctuation can be reduced by increasing the resistance. The temporary arc and glow durations are affected by the time constant of the circuit.

First-principles calculations of the crystalline vibrations of a lactose monohydrate crystal in the terahertz (THz) region were performed using periodic density functional theory calculations. The calculated vibrational modes in the THz region were derived from group motions with different sizes: molecules of lactose and crystal water, pyranose rings, and intramolecular frames. The intermolecular modes with large vibrational amplitude of lactose of 17.5–100.6 cm-1 and of crystal-water of 136.1–237.7 cm-1 were clearly separated. This article especially refers to the intermolecular vibrational modes of crystal water with the THz absorption, which provide detectable spectral features of hydrated crystals.

The density distribution of point-contact current is theoretically investigated. Finite current is introduced to a semi-infinite body from the outside. The following assumptions are made: the contact area is circular, magnetic effects are ignored, the contact area is equipotential, the potential equals zero at an infinite distance from the contact area, and the electric permittivity and resistivity are constant. The density distribution of point-contact current for a non-steady state is obtained in an integral form and the derivation process is discussed. The results show that the current density distribution for the non-steady state agrees with that for the steady state. Further, the results suggest that the analytical solution of the density distribution of point-contact current for the steady state is applicable to thermal analysis as well.

A multi-beam structure using Ti-Ni wire to grip rough surfaces and control detachment was manufactured. The grip-and-release mechanism of the structure was investigated. The experimental results were analyzed with a model assuming beam theory and using a fracture criterion at the adhered interface. The fracture criterion of the adhesion interface is suggested to depend on the shear stress.

The recent papers Saito et al 2013 Smart Mater. Struct. 22 015019 and Dhelika et al 2013 Smart Mater. Struct. 22 095010 described studies of an electrostatic chuck that mimics the structure of gecko-like toes. Earlier work published by the authors and other researchers is cited to further illustrate the origin and motivation of the research.

This note reports on an experimental demonstration of non-impact deposition for electrostatic micromanipulation of a conductive particle by a single probe. The experimental system consists of a probe, a 30-micrometers-in-diameter particle, and a substrate plate. The particle, initially adhering to the probe tip, is detached and deposited onto the substrate by rapid change of the probe?substrate voltage designed on the basis of calculation by a boundary element method. The feasibility is experimentally shown; furthermore, the method of modifying the voltage sequence to improve the rate of success by considering the finite slew rate of the power source is discussed.A correction was made to this article (in the introduction) on 18 September 2008. The corrected electronic version is identical to the print version.

The nickel-like silver x-ray laser with the wavelength of 13.9 nm is used as a high power EUV excitation source to evaluate a scintillator for EUV lithography. The time resolved spectrum of zinc oxide exciton emission at around 380 nm was observed. The determined fluorescence lifetime of 1.1 ns is sufficiently short for characterizing EUV lithography light sources having a few nanoseconds duration. It is also shown that the x-ray laser is an excellent tool for spectroscopic characterization of materials intended for next-generation lithography applications.