摘要:
A first embodiment of an improved microaccelerometer includes a seismic mass, a support wafer, a cover wafer and a beam (or beams) for flexibly mounting a seismic mass between the support and cover wafers. A first oscillator includes a resonant circuit whose capacitance comprises conductive plates on one surface of the seismic mass and a conductive coating on an opposed surface of the support wafer. A second oscillator includes a resonant circuit whose capacitance is comprised of conductive coatings on another surface of the seismic mass and on an opposed surface of the cover wafer. A difference circuit provides an acceleration output that is dependent on a difference in oscillation frequencies between the first and second oscillators, when the accelerometer is subjected to an acceleration event. A second embodiment includes a structure similar to the aforedescribed, however, the second oscillator is replaced by an ac levitation circuit that exerts a single direction restoring force on the seismic mass during an acceleration event. A third embodiment provides ac levitational restoring forces when the seismic mass is subject to acceleration in either of two opposed directions. In the latter embodiment, ac levitating circuits are disposed on opposed surfaces of the support and cover wafers.
摘要:
One aspect of the present invention relates to a drug delivery system comprising a layered structure where a drug layer and a biodegradable polymer layer for controlling the release of drugs are alternately laminated. The drug delivery system can easily control an in-vivo drug release rate and a release amount.
摘要:
The silicon etching apparatus using XeF2 includes: a basic structure composed of a loading chamber tot loading XeF2, an expansion chamber for collecting sublimated XeF2 gas, and an etching chamber for performing an etching process; and a means for injecting nitrogen prior to the etching process to eliminate air moisture in the apparatus and thus preventing the formation of HF. The silicon etching apparatus using XeF2 further includes: an injector having a predefined shape provided in the etching chamber for uniformly injecting the XeF2 gas downward on to surface of a wafer; a feedback controller for feedback controlling the internal pressure of the loading chamber in order to prevent sublimation of the residual XeF2 in the loading chamber; and a weight scale for measuring the weight of XeF2 in the loading chamber.
摘要:
Disclosed is a micromechanical system fabrication method using (111) single crystalline silicon as a silicon substrate and employing a reactive ion etching process in order to pattern a microstructure that will be separated from the silicon substrate and a selective release-etching process utilizing an aqueous alkaline solution in order to separate the microstructure from the silicon substrate. According to the micromechanical system fabrication method of the present invention, the side surfaces of microstructures can be formed to be vertical by employing the RIE technique. Furthermore, the microstructures can be readily separated from the silicon substrate by employing the selective release-etching technique using slow etching {111} planes as the etch stop in an aqueous alkaline solution. In addition, etched depths can be adjusted during the RIE step, thereby adjusting the thickness of the microstructure and the spacing between the microstructure and the silicon substrate.
摘要:
Disclosed is a micromechanical system fabrication method using (111) single crystalline silicon as a silicon substrate and employing a reactive ion etching process in order to pattern a microstructure that will be separated from the silicon substrate and a selective release-etching process utilizing an aqueous alkaline solution in order to separate the microstructure from the silicon substrate. According to the micromechanical system fabrication method of the present invention, the side surfaces of microstructures can be formed to be vertical by employing the RIE technique. Furthermore, the microstructures can be readily separated from the silicon substrate by employing the selective release-etching technique using slow etching {111} planes as the etch stop in an aqueous alkaline solution. In addition, etched depths can be adjusted during the RIE step, thereby adjusting the thickness of the microstructure and the spacing between the microstructure and the silicon substrate.
摘要:
One aspect of the present invention relates to a drug delivery system comprising a layered structure where a drug layer and a biodegradable polymer layer for controlling the release of drugs are alternately laminated. The drug delivery system can easily control an in-vivo drug release rate and a release amount.
摘要:
The present invention provides several embodiments of an electrical switch that uses a shape memory alloy (SMA). In one embodiment the electrical switch is an on-off switch and comprises a first support member with a first electrical contact mounted thereon, a second support member with a second electrical contact mounted thereon, and a third support member disposed between the first and second support members. A wire element made from a shape memory alloy (SMA) is attached at either end to the third support member. A switch element made of an electrically-conducting material is attached to the SMA wire element at a position intermediate the ends of the wire element. Heating means are provided for selectively heating sections of the SMA wire element in order to make the SMA wire element turn or rotate, thereby causing the switch element to pivot into contact with either the first electrical contact or the second electrical contact.