Abstract: An apparatus includes a transducer assembly including a transducer housing and an ultrasonic transducer disposed within the transducer housing. A transducer horn is disposed at least partially within the transducer housing and includes a probe coupling. A first probe includes a first coupler and a first elongate member coupled to the first coupler. The first coupler has a first coupling portion and a second coupling portion, and the first coupling portion is configured to be releasably coupled to the probe coupling of the transducer horn such that the first probe is coupled to the ultrasonic transducer. A second probe includes a second coupler and a second elongate member coupled to the second coupler. The second coupler has a third coupling portion releasably couplable to the second coupling portion of the first coupler such that the second probe is coupled to the ultrasonic transducer.

Abstract: An apparatus includes a transducer assembly including a transducer housing and an ultrasonic transducer disposed within the transducer housing. A transducer horn is disposed at least partially within the transducer housing and includes a probe coupling. A first probe includes a first coupler and a first elongate member coupled to the first coupler. The first coupler has a first coupling portion and a second coupling portion, and the first coupling portion is configured to be releasably coupled to the probe coupling of the transducer horn such that the first probe is coupled to the ultrasonic transducer. A second probe includes a second coupler and a second elongate member coupled to the second coupler. The second coupler has a third coupling portion releasably couplable to the second coupling portion of the first coupler such that the second probe is coupled to the ultrasonic transducer.

Abstract: An apparatus includes a transducer assembly including a transducer housing and an ultrasonic transducer disposed within the transducer housing. A transducer horn is disposed at least partially within the transducer housing and includes a probe coupling. A first probe includes a first coupler and a first elongate member coupled to the first coupler. The first coupler has a first coupling portion and a second coupling portion, and the first coupling portion is configured to be releasably coupled to the probe coupling of the transducer horn such that the first probe is coupled to the ultrasonic transducer. A second probe includes a second coupler and a second elongate member coupled to the second coupler. The second coupler has a third coupling portion releasably coupiable to the second coupling portion of the first coupler such that the second probe is coupled to the ultrasonic transducer.

Abstract: A power supply apparatus for a magnetic resonance apparatus has a power supply terminal module with a power supply unit and a reference voltage pull-down unit, and a load terminal module with a voltage comparator connected to a load power-feed terminal, which compares a nominal voltage and an actual voltage of the load power-feed terminal. A counter begins counting when the actual voltage is lower than the nominal voltage, and keeps its count unchanged when the actual voltage is equal to the nominal voltage, and emits a signal corresponding to the count to a digital-to-analog converter, connected to a phase inverter, which converts the digital signal to a positive analog voltage. A phase inverter is connected to an output voltage reference terminal of the power supply unit, and inverts the phase of the analog voltage to produce a negative analog voltage that compensates voltage drop loss on a cable between the power supply and the load power-feed terminal.

Abstract: A radio-frequency system for a magnetic resonance apparatus has a local coil, a body coil, and an impedance adjusting shield. The body coil is wirelessly power-coupled with the local coil such that the body coil serves as a transmitting coil for radio-frequency signals and the local coil serves as a receiving coil for magnetic resonance signals. The local coil is disposed in an internal cavity of the impedance adjusting shield. An impedance of the local coil is adjusted by the impedance adjusting shield so as to match the impedance of the local coil and the body coil. The impedance adjusting shield has a frequency modulation element that adjusts the resonance frequency of the local coil. The body coil couples power to the local coil, and the impedance adjusting shield effectively reduces energy transmission efficiency loss caused by reflection, thereby improving energy transmission efficiency.

Abstract: Systems and methods for carrier sense multiple access (CSMA) protocols for power line communications (PLC) are described. In some embodiments, a method may include performing a virtual carrier sensing operation and, in response to the virtual carrier sensing operation indicating that a communication channel is idle, calculating a contention window. The method may also include performing a physical carrier sensing operation subsequent to the virtual carrier sensing operation, the physical carrier sensing operation based, at least in part, upon the contention window. In response to the physical carrier sensing operation indicating that the communication channel is idle, the method may then include transmitting data over the channel. In other embodiments, another method may include determining that a data transmission is a unicast transmission and that an acknowledgement message has not been received.

Abstract: A method for receiving feedback on a quality of multicast transmissions in a Wireless Local Access Network (WLAN) including a source electronic device (e.g., an access point) and a plurality of electronic devices is disclosed, according to some embodiments. The method can include (i) transmitting a plurality of multicast packets addressed to a subset of the plurality of electronic devices by the source electronic device; (ii) concurrently polling the subset of the plurality of electronic devices by the source electronic device; and (iii) receiving a plurality of block acknowledgements (BAs) from at least the subset of the plurality of electronic devices by the source electronic device. Each BA may include information on a quality of reception of two or more multicast packets received at an electronic device.

Abstract: A power supply apparatus for a magnetic resonance apparatus has a power supply terminal module with a power supply unit and a reference voltage pull-down unit, and a load terminal module with a voltage comparator connected to a load power-feed terminal, which compares a nominal voltage and an actual voltage of the load power-feed terminal. A counter begins counting when the actual voltage is lower than the nominal voltage, and keeps its count unchanged when the actual voltage is equal to the nominal voltage, and emits a signal corresponding to the count to a digital-to-analog converter, connected to a phase inverter, which converts the digital signal to a positive analog voltage. A phase inverter is connected to an output voltage reference terminal of the power supply unit, and inverts the phase of the analog voltage to produce a negative analog voltage that compensates voltage drop loss on a cable between the power supply and the load power-feed terminal.

Abstract: An RF choke resonator assembly has a cylindrical magnetic field shielding case with openings at two ends thereof, a magnetic field shielding plate and a winding skeleton, and a capacitive plate inside the case. The magnetic field shielding plate closes the opening at one end of the case, and has a through-hole allowing a cable to pass there through. The cable is wound on the winding skeleton. The capacitive plate is disposed opposite the magnetic field shielding plate in the case, separated therefrom by the winding skeleton, and is electrically connected to the case in a closed manner. The capacitive plate has a through-hole allowing the cable to pass there through. The capacitive plate is remote from the other opening case end opposite the opening closed by the magnetic field shielding plate. An insulation space is formed at that other opening, having a length in the axial direction greater than or equal to one quarter of the length of the magnetic field shielding case in the axial direction.

Abstract: A radio-frequency system for a magnetic resonance apparatus has a local coil, a body coil, and an impedance adjusting shield. The body coil is wirelessly power-coupled with the local coil such that the body coil serves as a transmitting coil for radio-frequency signals and the local coil serves as a receiving coil for magnetic resonance signals. The local coil is disposed in an internal cavity of the impedance adjusting shield. An impedance of the local coil is adjusted by the impedance adjusting shield so as to match the impedance of the local coil and the body coil. The impedance adjusting shield has a frequency modulation element that adjusts the resonance frequency of the local coil. The body coil couples power to the local coil, and the impedance adjusting shield effectively reduces energy transmission efficiency loss caused by reflection, thereby improving energy transmission efficiency.

Abstract: Systems and methods for carrier sense multiple access (CSMA) protocols for power line communications (PLC) are described. In some embodiments, a method may include performing a virtual carrier sensing operation and, in response to the virtual carrier sensing operation indicating that a communication channel is idle, calculating a contention window. The method may also include performing a physical carrier sensing operation subsequent to the virtual carrier sensing operation, the physical carrier sensing operation based, at least in part, upon the contention window. In response to the physical carrier sensing operation indicating that the communication channel is idle, the method may then include transmitting data over the channel. In other embodiments, another method may include determining that a data transmission is a unicast transmission and that an acknowledgement message has not been received.

Abstract: An RF choke resonator assembly has a cylindrical magnetic field shielding case with openings at two ends thereof, a magnetic field shielding plate and a winding skeleton, and a capacitive plate inside the case. The magnetic field shielding plate closes the opening at one end of the case, and has a through-hole allowing a cable to pass there through. The cable is wound on the winding skeleton. The capacitive plate is disposed opposite the magnetic field shielding plate in the case, separated therefrom by the winding skeleton, and is electrically connected to the case in a closed manner. The capacitive plate has a through-hole allowing the cable to pass there through. The capacitive plate is remote from the other opening case end opposite the opening closed by the magnetic field shielding plate. An insulation space is formed at that other opening, having a length in the axial direction greater than or equal to one quarter of the length of the magnetic field shielding case in the axial direction.

Abstract: Systems and methods for carrier sense multiple access (CSMA) protocols for power line communications (PLC) are described. In some embodiments, a method may include performing a virtual carrier sensing operation and, in response to the virtual carrier sensing operation indicating that a communication channel is idle, calculating a contention window. The method may also include performing a physical carrier sensing operation subsequent to the virtual carrier sensing operation, the physical carrier sensing operation based, at least in part, upon the contention window. In response to the physical carrier sensing operation indicating that the communication channel is idle, the method may then include transmitting data over the channel. In other embodiments, another method may include determining that a data transmission is a unicast transmission and that an acknowledgement message has not been received.

Abstract: An apparatus includes a generator including a control module that is operably coupled to a power module. The power module is configured to produce an electronic signal to be received by an ultrasonic energy delivery assembly. The ultrasonic energy delivery assembly is characterized by a natural frequency, and the electronic signal is characterized by a frequency. The control module is configured to send a control signal to the power module to randomly vary the frequency of the electronic signal within a range defined at least in part by the natural frequency.

Abstract: Methods and devices are described for wireless communications associated with a multidimensional algorithm for roaming. In one aspect, an access point (or like device) transmits a beacon signal. The access point receives, from a station in receipt of the beacon signal, a probe signal including at least one metric. The access point transmits a response signal based at least in part on the received probe signal, the response signal including information associated with the at least one metric.

Abstract: A shoulder coil for a magnetic resonance system includes a receiving part. The shoulder coil also includes a transmitting part used for coupling a radio-frequency magnetic field of a body coil of the magnetic resonance system.

Abstract: A system and method for reducing transmission collisions. In one embodiment, a transmitter for communicating of a smart grid power line network includes an arbiter. The arbiter is configured to select a transmission interval during which the transmitter can transmit. The interval is selected from a plurality of available transmission intervals reserved for contending transmissions, and selected based on a level of a hierarchical network at which the transmitter is located. The interval selected is different from any interval used by a different transmitter spaced two hierarchical levels away from the level of the hierarchical network at which the transmitter is located.

Abstract: An apparatus includes a generator including a control module that is operably coupled to a power module. The power module is configured to produce an electronic signal to be received by an ultrasonic energy delivery assembly. The ultrasonic energy delivery assembly is characterized by a natural frequency, and the electronic signal is characterized by a frequency. The control module is configured to send a control signal to the power module to randomly vary the frequency of the electronic signal within a range defined at least in part by the natural frequency.

Abstract: An apparatus includes a transmission member having a proximal end portion and a distal end portion. The transmission member is configured to be inserted into a bodily lumen, and is configured to transfer ultrasonic energy from the proximal end portion to the distal end portion. The transmission member defines a lumen along a longitudinal center line of the transmission member. The distal end portion of the transmission member includes a concave engagement surface and a distal end surface. The distal end surface defines a plane that intersects the longitudinal center line of the transmission member at an angle of between about 75 degrees and about 105 degrees. The engagement surface is configured to engage a target tissue within the bodily lumen to limit movement of the target tissue along the longitudinal center line. The engagement surface defines an opening in fluid communication with the lumen.

Abstract: Methods, systems, devices, and apparatuses are described for wireless communications in which first type of traffic may be transmitted from a gateway access point (AP) directly to a station. Beacon signals transmitted to the station are transmitted as part of the first type of traffic. A second type of traffic may be transmitted from the gateway AP to the station via at least one relay AP. The first type of traffic may include low-throughput traffic and may be transmitted over a long-range radio link (e.g., 2 GHz band link or sub-1 GHz band link). The second type of traffic may include high-throughput traffic and may be transmitted over at least one short-range radio link (e.g., 5 GHz band link). The gateway AP may receive low-throughput traffic directly from the station and high-throughput traffic from the station via the at least one relay AP.