Katagiri, Y., & Enikov, E. T. (2006). Proceedings of SPIE - The International Society for Opticl Engineering: Introduction. Proceedings of SPIE - The International Society for Optical Engineering, 6376, ix-x.
Enikov, E. T., & Boyd, J. G. (2000). Finite-element formulation for anodic bonding. Smart Materials and Structures, 9(6), 737-750.
Abstract:
An anodic bond is modeled as a moving non-material line forming the intersection of three material surfaces representing the unbonded conductor, the unbonded insulator, and the bonded interface. The component mass balance equations, Gauss' law, and the linear momentum equations are cast in a finite-element formulation, which is used to predict the evolution of the sodium ion concentration, electric potential, and stress during the anodic bonding of Pyrex glass and silicon. The method is applicable to the viscoplasticity of solid electrolytes, and the volume and interface free energies can be modified to model electromechanical interface phenomena such as debonding, space charge accumulation and sliding at grain boundaries in ionic crystals, and a cohesive zone theory of piezoelectric fracture.
Enikov, E. T., & Nelson, B. J. (1999). MEMS based single cell penetration force sensor. Proceedings of SPIE - The International Society for Optical Engineering, 3834, 40-46.
Abstract:
The rapid development of reproductive biology has created a need for quantifying penetration forces during artificial fertilization. It has been demonstrated that the success of such procedures heavily depends on the mechanics of penetration of the egg's zona and membrane. To quantify the forces during intracytoplasmic injections we have developed a MEMS based force sensor. Deep RIE and fusion bonding are used to fabricate a variable capacitance type sensor. It is designed to measure the penetration force during intracytoplasmic injection of egg cells as well as other applications in the 1-500 μmN force range. The sensor measures tri-axial forces using a system of flexible beams subjected to bending and torsion. The process is relatively simple and allows for easy modification of the force range. A penetration pipette tip is attached to the sensor body using a low temperature bonding technique. Calibration, sensitivity and initial experimental data is provided.
Enikov, E. T., & Lazarov, K. V. (2001). Optically transparent gripper for microassembly. Proceedings of SPIE - The International Society for Optical Engineering, 4568, 40-49.
Abstract:
Production of complex Micro-Opto Electro-Mechanical Systems (MOEMS) often requires assembly of a system from individual components built by mutually incompatible processes. This fabrication step also constitutes the largest portion of the total cost (about 80%), and is one of the major roadblocks to successfully implementing a complex microsystem. Our previous experience with such systems shows, that gripping and manipulation of microparts significantly differs from the assembly of macroscopic devices. The main difference stems from the increased role of the surface electrostatic forces and the reduced influence of body forces such as gravity. This paper describes one possible use of the surface forces in the development of a novel optically transparent electrostatic microgripper. The principle of operation, design and simulation of the new device are described. Several models describing the gripping force are also presented. The out-of-plane and in-plane holding (frictional) forces are measured as a function of the applied voltage for two common materials - silicon and nickel. The fabrication sequence and the materials used are discussed.
McCafferty, S. J., Schwiegerling, J. T., & Enikov, E. T. (2012). Thermal load from a CO2 laser radiant energy source induces changes in corneal surface asphericity, roughness, and transverse contraction. Investigative Ophthalmology and Visual Science, 53(7), 4279-4288.
PMID: 22661462;Abstract:
PURPOSE. We examined corneal surface response to an isolated thermal load. METHODS. Cadaveric porcine eyes were pressurized and stabilized for processing and imaging. A carbon dioxide (CO2) laser (1.75 W) delivered a uniform disk of continuous wave thermal radiant energy to the exposed corneal stromal surface without ablation. Thermal load was determined by measuring corneal surface temperature during CO2 laser irradiation. Corneal profilometry was measured with broadband optical interferometry before and after CO2 laser irradiation. Photomicrographs of the stromal surface were taken before and after irradiation, and the images were superimposed to examine changes in positional marks, examining mechanical alterations in the stromal surface. RESULTS. Thermal load from uniform laser irradiation without ablation produces central corneal steepening and paracentral flattening in the central 3-mm diameter. Q values, measuring asphericity in the central 2 mm of the cornea increased significantly and it was correlated with the temperature rise (R2=0.767). Surface roughness increased significantly and also was correlated with temperature rise (R2=0.851). The central stromal surface contracted and underwent characteristic morphologic changes with the applied thermal load, which correlated well with the temperature rise (R2 = 0.818). CONCLUSIONS. The thermal load created by CO2 laser irradiation creates a characteristic spectrum of morphologic changes on the porcine corneal stromal surface that correlates to the temperature rise and is not seen with inorganic, isotropic material. The surface changes demonstrated with the CO2 laser likely are indicative of temperature-induced transverse collagen fibril contraction and stress redistribution. Refractive procedures that produce significant thermal load should be cognizant of these morphologic changes. © 2012 The Association for Research in Vision and Ophthalmology, Inc.
