Study of machining indentations over the entire surface of a target ball using the force modulation approach

A modified five-axis cutting system using a force control cutting strategy was to machine indentations in different annuli on the entire surface of a target ball.The relationship between the cutting depths and the applied load as well as the microsphere rotation speed were studied experimentally to reveal the micromachining mechanism.In particular,aligning the rotating center of the high precision spindle with the microsphere center is essential for guaranteeing the machining accuracy of indentations.The distance between adjacent indentations on the same annulus and the vertical distance between adjacent annuli were determined by the rotating speed of the micro-ball and the controllable movement of the high-precision stage,respectively.In order to verify the feasibility and effect of the proposed cutting strategy,indentations with constant and expected depths were conducted on the entire surface of a hollow thin-walled micro-ball with a diameter of 1 mm.The results imply that this machining methodology has the potential to provide the target ball with desired modulated defects for simulating the inertial confinement fusion implosion experiment.

Interaction of Plasma Proteins with Tri-quaternary Ammonium Salt Cationic Surfactant Studied by QCM-D

A tri-quaternary ammonium salt cationic surfactant was synthesized.Its structure was confirmed by using Fourier-transform infrared spectroscopy,^(1)H nuclear magnetic resonance spectroscopy,and X-ray photoelectron spectroscopy analyses.Three model surfaces,including Au-CH_(3),Au-OH and Au-COOH,were fabricated.Adsorptions of surfactant on the three model surfaces and subsequent plasma proteins adsorption were investigated by quartz crystal microbalance with dissipation(QCM-D).The mass of surfactant on the Au-COOH surface was the largest,followed by that on the Au-CH_(3)surface,and that on the Au-OH surface.These results suggested that the main driving force of surfactant immobilization was electrostatic interaction followed by hydrophobic interaction.Based on the results obtained,we concluded that the protein mass adsorbed on Au-CH_(3)-S,Au-OH-S,and Au-COOH-S surfaces depended on the protein size and orientation.The mass and thickness of S on the Au-COOH surface is the largest and the protein adsorption capacity of Au-COOH-S surface is inferior to that of Au-CH_(3)-S.The Au-COOH-S surface could inhibit lysozyme adsorption,maintain the adsorption balance of bovine serum albumin,and induce fibrinogen-binding protein adsorption.