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Rev Sci Instrum ; 90(9): 095102, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31575248


In this paper, we demonstrate the use of a surface condensation sensor board for characterizing interior space in a damp heat chamber. The sensor board is approximately 18 in. × 12 in. in dimension. A total of 324 sense electrodes are designed on the board. The uniform gap between the sense electrodes is 250 µm throughout the surface area of the board. First, the surface leakage current of the sensor board is characterized with other commercially available humidity sensors. The relationship of leakage current to humidity is determined. Surface leakage current is spatially measured inside the chamber, and localized condensation spots are identified at 85 °C/85%RH stress condition. The main goal of this article is to characterize interior space and identify less-risky locations prior to qualification of semiconductor components, optical subassemblies, and optical modules.

Rev Sci Instrum ; 81(10): 105114, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21034126


In this work, we describe the development and testing of a three degree of freedom meso/micromanipulation system for handling micro-objects, including biological cells and microbeads. Three-axis control is obtained using stepper motors coupled to micromanipulators. The test specimen is placed on a linear X-stage, which is coupled to one stepper motor. The remaining two stepper motors are coupled to the Y and Z axes of a micromanipulator. The stepper motor-micromanipulator arrangement in the Y and Z axes has a minimum step resolution of ∼0.4 µm with a total travel of 12 mm and the stepper motor-X stage arrangement has a minimum resolution of ∼0.3 µm with a total travel of 10 mm. Mechanical backlash error is ∼0.8 µm for ∼750 µm of travel. A MEMS microgripper from Femtotools™ acts as an end-effector in the shaft end of the micromanipulator. The gripping ranges of the grippers used are 0-100 µm (for FT-G100) and 0-60 µm (for FT-G60). As the gripping action is performed, the force sense circuit of FT-G100 measures the handling force. This force feedback is integrated to a commercially available three degree of freedom haptic device (Novint Falcon) allowing the user to receive tactile feedback during the microscale handling. Both mesoscale and microscale controls are important, as mesoscale control is required for the travel motion of the test object whereas microscale control is required for the gripping action. The haptic device is used to control the position of the microgripper, control the actuation of the microgripper, and provide force feedback. A LABVIEW program was developed to interlink communication and control among hardware used in the system. Micro-objects such as SF-9 cells and polystyrene beads (∼45 µm) are handled and handling forces of ∼50 µN were experienced.

Eletroquímica/instrumentação , Fenômenos Mecânicos , Microtecnologia/instrumentação , Animais , Linhagem Celular , Microesferas , Polímeros/química , Software , Spodoptera/citologia