This invention invention provides photonic crystal devices, device components and methods for preventing transmission of electromagnetic radiation from one or more...
This invention invention provides photonic crystal devices, device components and methods for preventing transmission of electromagnetic radiation from one or more laser sources or laser modes so as to provide an optical shield for protecting a users eyes or an optical sensor. The invention also provides dynamic photonic crystals and devices incorporating dynamic photonic crystals for optically modulating the intensity of one or more beams of electromagnetic radiation and other optical switching applications.
A wireless communication device includes multiple antennas spaced apart from each other. Also included is a dielectric substrate with electrically conductive...
A wireless communication device includes multiple antennas spaced apart from each other. Also included is a dielectric substrate with electrically conductive ground areas along the substrate opposite the antennas. Signal coupling is decreased between the antennas by connecting the ground areas together with an isolation structure. In one nonlimiting form, this structure includes an electrically conductive meander line structure.
MEMS stages comprising a plurality of comb drive actuators provide micro and up to nano-positioning capability. Flexure hinges and folded springs that operably...
MEMS stages comprising a plurality of comb drive actuators provide micro and up to nano-positioning capability. Flexure hinges and folded springs that operably connect the actuator to a movable end stage provide independent motion from each of the actuators that minimizes unwanted off-axis displacement, particularly for three-dimensional movement of a cantilever. Also provided are methods for using and making MEMS stages. In an aspect, a process provides a unitary MEMS stage made from a silicon-on-insulator wafer that avoids any post-fabrication assembly steps.
Further provided are various devices that incorporate any of the stages disclosed herein, such as devices requiring accurate positioning systems in applications including scanning probe microscopy, E-jet printing, near-field optic sensing, cell probing and material characterization.
A device that incorporates teachings of the present disclosure may include, for example, a memory array having a first array of nanotubes, a second array of...
A device that incorporates teachings of the present disclosure may include, for example, a memory array having a first array of nanotubes, a second array of nanotubes, and a resistive change material located between the first and second array of nanotubes. Other embodiments are disclosed.
This technology is a method to eliminate voltage overshoot in cables used to connect AC electric motors and pulse width modulation (PWM) inverters. As a function...
This technology is a method to eliminate voltage overshoot in cables used to connect AC electric motors and pulse width modulation (PWM) inverters. As a function of cable length and voltage rise time, voltage overshoot occurs when high frequency currents reflect between the motor and source ends of a cable. University of Illinois researchers have devised a compensator that shapes the output of the PWM inverter in order to eliminate these reflections; the method only requires knowledge of the transmission line characteristic impedance and propagation delay. This technique extends the life of motor insulation and protects voltage-sensitive devices.
Voltage overshoot occurs when high frequency currents reflect between the motor and source ends of an electrical cable. Reflective waves of current can build up, causing motor insulation failure as well as damage to voltage-sensitive devices. While there have been techniques developed to compensate for voltage overshoot, many are complex, need load characteristics, and often require the use of bulky and expensive equipment.
The University of Illinois technique provides a mathematically exact solution that modifies the output of the PWM inverter in order to eliminate wave reflection. This technique is designed to eliminate voltage overshoot in the cable that connects alternating current (AC) electric motors to pulse width modulation (PWM) inverters that use insulated gate bipolar transistors (IGBT). IGBT motor drive cables are particularly susceptible to voltage overshoot due to their extremely fast switching speeds. The compensator, which attaches to either the source or motor end of a cable, is a filter that uses an appropriate linear combination of voltages and currents to transform the transmission line into a pure delay transfer. This prevents wave reflection and thus voltage overshoot. Users do not need to know the motor or drives characteristics; however, they do need to know the transmission line impedance and the propagation delay in order to use this device.
This invention improves on existing solutions to voltage overshoot by providing an exact solution rather than approximation.
Applications:
The range of applications that use AC motors is vast, examples include:
Heavy Industrial Machines or Manufacture: Heavy industries including automotive, materials handling, mining operations, plastic and rubber production, ceramics, textile, and utilities.
Workshops: Metalworking, printing and woodworking shops.
Chemical Industries: Chemical refining, pharmaceutical production, and plastic fabrication.
Benefits
Cost-Effective: Eliminates damaging wave reflection, prolonging the usefulness of motors and voltage-sensitive devices.
Low-Cost and Small: No large or expensive equipment is needed to implement this technology.
Self-Adapting: Modifies waveform as transmission cable properties change over time.
Versatile: Can be implemented at either the motor or source side of a cable, allowing users to select the side that is easier to maintain.
Current methods of performing tensile tests on micro-nano scale material samples have an inherent flaw, namely that true uniaxial loads are difficult to achieve....
Current methods of performing tensile tests on micro-nano scale material samples have an inherent flaw, namely that true uniaxial loads are difficult to achieve. Part of this stems from the adaptation of macro-scale testing methods to the micro-nano scale, which has been shown to be inadequate. Accordingly, this technology seeks to achieve true uniaxial loads on micro-nano scale material samples to achieve more reliable test results.
The current technology is a new method for testing micro-nano scale material samples. It is designed to achieve true uniaxial loads on such materials in a manner different than a mere shrinking of macro-scale tests. The technology achieves this goal all while being able to take mechano-electrical measurements through the use of an SEM or TEM. Finally, the technology can also test material samples in harsh conditions.
The technology offers a new method of testing the tensile properties of materials. It offers more accurate and reliable test result compared with technologies which mimic macro-scale testing methods at the micro-nano scale. By employing a new method of testing, the technology can put a more truly uniaxial load on the material sample
The material for the testing stage additionally allows these tests to be performed under harsh conditions. For example, the stage and sample may be heated to ~1000_0 C and then tested to see how the material properties change under extreme temperatures.
Finally, the technology provides a material independent method. The sample material must be shaped in an appropriate manner for the testing environment; however, any material which can be shaped appropriately may be tested using the instant method.
Applications
Materials Testing: This technology is for testing the tensile and compression behavior of micro-nano scale materials.
MEMS Devices: This serves MEMS based devices well providing more accurate estimates of material behavior allowing for more accurate MEMS devices.
Benefits:
True Uniaxial Loads: Allows for improved consistency and accuracy of material test results.
Material Independent: The testing procedure and self-aligning mechanism are material independent allowing the same apparatus to test a variety of materials In situ
Testing in SEM or TEM: Allows mechano-electrical tests to be performed on the material sample at the same time as tensile strength tests.
