Abstract: Induced material segregation methods of manufacturing a polycrystalline diamond compact (PDC) cutter result in formation of a polycrystalline diamond/tungsten carbide (WC) composite material having a smooth compositional gradient from maximum WC concentration at one face to maximum diamond concentration at another face. Because the compositional gradient is smooth, very little or no mismatch of coefficient of thermal expansion occurs, which improves a service lifetime of the PDC cutter.

Abstract: The present disclosure relates to a polycrystalline diamond compact (PDC) including a gradient interfacial layer between a thermally stable diamond (TSP) table and a base, such as a substrate or an earth-boring drill bit body. The gradient interfacial layer has a gradient of coefficients of thermal expansion between that of the diamond and the base. The disclosure also relates to methods of forming a gradient interfacial layer and a PDC containing such a layer.

Abstract: Apparatus and methods for multi-mode power amplifiers are provided herein. In certain configurations, a wireless device includes a multi-mode power amplifier including a plurality of amplification paths electrically connected in parallel with one another. The plurality of amplification paths includes a first amplification path including an input stage of a first stage type and an output stage of a second stage type, and a second amplification path including an output stage of the second stage type. The first stage type provides non-inverting gain and the second stage type provides inverting gain. The wireless device further includes a transceiver that provides a radio frequency signal to the multi-mode power amplifier, and that operates the multi-mode power amplifier in a selected power mode chosen from a plurality of power modes based on selectively activating one or more of the plurality of amplification paths.

Abstract: Apparatus and methods for multi-mode power amplifiers are provided herein. In certain configurations, a wireless device includes a multi-mode power amplifier including a plurality of amplification paths electrically connected in parallel with one another. The plurality of amplification paths includes a first amplification path including an input stage of a first stage type and an output stage of a second stage type, and a second amplification path including an output stage of the second stage type. The first stage type provides non-inverting gain and the second stage type provides inverting gain. The wireless device further includes a transceiver that provides a radio frequency signal to the multi-mode power amplifier, and that operates the multi-mode power amplifier in a selected power mode chosen from a plurality of power modes based on selectively activating one or more of the plurality of amplification paths.

Abstract: Aspects of this disclosure relate to efficient power amplifiers, such as class-F power amplifiers. A power amplifier transistor can provide an amplified RF signal. A termination can be coupled to an output of the power amplifier transistor and configured to provide a short circuit at a second harmonic. In some instances, the termination circuit can provide an open circuit at a third harmonic. A resonant circuit can be coupled to the output terminal of the power amplifier transistor and configured to provide an open circuit at the third harmonic. In certain embodiments, an input termination circuit coupled to an input terminal of the power amplifier transistor can provide a short circuit at the second harmonic. The power amplifiers of this disclosure can be implemented, for example, in envelope tracking applications.

Abstract: A well seal tool includes a base tubing and a seal element carried on an exterior of the base tubing. The seal element includes a polymer changeable between a compressed state and a sealing state. The seal element has a first stiffness in response to a first strain rate of the polymer and a second, substantially higher stiffness in response to a second, higher strain rate of the polymer.

Abstract: Feedback circuit for power amplifier. In some embodiments, a radio-frequency amplifier can include a bipolar junction transistor configured to amplify a signal, and having an input and an output. The radio-frequency amplifier can further include a feedback circuit implemented between the output and input of the bipolar junction transistor. The feedback circuit can include a parallel assembly of a field-effect transistor and a resistive element such that the resistive element is bypassed when the field-effect transistor is ON and an overall resistance of the feedback circuit includes the resistive element when the field-effect transistor is OFF. Such a feedback circuit can be configured to be capable of providing a plurality of resistance values between the output and input of the bipolar junction transistor to facilitate different gains of the bipolar junction transistor.

Abstract: Circuits and methods for biasing power amplifiers. In some embodiments, a power amplifier circuit can include a transistor having and input and an output, and configured to amplify a signal. The power amplifier circuit can further include a bias circuit configured to provide a bias signal to the input of the transistor. The power amplifier circuit can further include a switchable feed circuit implemented between the bias circuit and the input of the transistor, and configured to provide a plurality of different resistance values for the bias signal between the bias circuit and the input of the transistor.

Abstract: A downhole tool or component thereof comprising a cellulosic derivative, wherein the cellulosic derivative is capable of at least partially degrading in a wellbore environment, thereby at least partially degrading the downhole tool or component thereof. Methods of introducing the downhole tool into a wellbore environment, performing a downhole operation, and at least partially degrading the downhole tool or component therein in the wellbore.

Abstract: Apparatus and methods for multi-mode power amplifiers are provided herein. In certain configurations, a wireless device includes a multi-mode power amplifier including a plurality of amplification paths electrically connected in parallel with one another. The plurality of amplification paths includes a first amplification path including an input stage of a first stage type and an output stage of a second stage type, and a second amplification path including an output stage of the second stage type. The first stage type provides non-inverting gain and the second stage type provides inverting gain. The wireless device further includes a transceiver that provides a radio frequency signal to the multi-mode power amplifier, and that operates the multi-mode power amplifier in a selected power mode chosen from a plurality of power modes based on selectively activating one or more of the plurality of amplification paths.

Abstract: Induced material segregation methods of manufacturing a polycrystalline diamond compact (PDC) cutter result in formation of a polycrystalline diamond/tungsten carbide (WC) composite material having a smooth compositional gradient from maximum WC concentration at one face to maximum diamond concentration at another face. Because the compositional gradient is smooth, very little or no mismatch of coefficient of thermal expansion occurs, which improves a service lifetime of the PDC cutter.

Abstract: A multi-layer composite synthetic test bed may be used to model fracture propagation and fracture networks. For example, a fracturing fluid may be introduced into a multi-layer composite synthetic test bed at a pressure and a flow rate sufficient to create a fracture network therein. Then, the fracture network may be analyzed to produce synthetic fracture data, which may be used in a fracture model.

Abstract: The present disclosure relates to a polycrystalline diamond compact (PDC) including a gradient interfacial layer between a thermally stable diamond (TSP) table and a base, such as a substrate or an earth-boring drill bit body. The gradient interfacial layer has a gradient of coefficients of thermal expansion between that of the diamond and the base. The disclosure also relates to methods of forming a gradient interfacial layer and a PDC containing such a layer.

Abstract: Switchable base feed circuit for radio-frequency (RF) power amplifiers. In some embodiments, an RF power amplifier (PA) circuit can include a transistor having a base, a collector, and an emitter, with the transistor being configured to amplify an RF signal. The PA circuit can further include a bias circuit configured to provide a base bias signal to the base of the transistor. The PA circuit can further include a switchable base feed circuit implemented between the bias circuit and the base of the transistor. The switchable base feed circuit can be configured to provide a plurality of different resistance values for the base bias signal between the bias circuit and the base of the transistor. Such a PA circuit can be implemented in products such as a die, a module, and a wireless device.

Abstract: Apparatus and methods for multi-mode power amplifiers are provided herein. In certain configurations, a wireless device includes a multi-mode power amplifier including a plurality of amplification paths electrically connected in parallel with one another. The plurality of amplification paths includes a first amplification path including an input stage of a first stage type and an output stage of a second stage type, and a second amplification path including an output stage of the second stage type. The first stage type provides non-inverting gain and the second stage type provides inverting gain. The wireless device further includes a transceiver that provides a radio frequency signal to the multi-mode power amplifier, and that operates the multi-mode power amplifier in a selected power mode chosen from a plurality of power modes based on selectively activating one or more of the plurality of amplification paths.

Abstract: Feedback circuit for power amplifier. In some embodiments, a radio-frequency amplifier can include a bipolar junction transistor configured to amplify a signal, and having an input and an output. The radio-frequency amplifier can further include a feedback circuit implemented between the output and input of the bipolar junction transistor. The feedback circuit can include a parallel assembly of a field-effect transistor and a resistive element such that the resistive element is bypassed when the field-effect transistor is ON and an overall resistance of the feedback circuit includes the resistive element when the field-effect transistor is OFF. Such a feedback circuit can be configured to be capable of providing a plurality of resistance values between the output and input of the bipolar junction transistor to facilitate different gains of the bipolar junction transistor.

Abstract: Aspects of this disclosure relate to a mode linearization switch circuit that can adjust an effective impedance provided to an output of an amplifier. In an embodiment, an apparatus includes an amplifier configured to amplify a radio frequency (RF) signal and a mode linearization switch circuit electrically coupled to an output of the amplifier. The mode linearization switch circuit can include a capacitor, a switch in series with the capacitor, and a series LC circuit in parallel with the switch.

Abstract: A well system includes a drop plug element and an internal plug seat in an internal flow path of a well tubing. At least one of the plug seat or the drop plug element includes a polymer that is deformable, having a first stiffness when subjected to a first strain rate, to allow the drop plug element to pass through the plug seat. The polymer resists deformation, having a second, higher stiffness when subjected to a second, higher strain rate, to resist allowing the plug element to pass through the plug seat and to seal the plug element and plug seat.

Abstract: A well treatment for treating a well includes discrete stop loss elements to seal a fluid loss opening of a well. The discrete stop loss elements include polymer resistive to deformation with an initial stiffness in response to an initial strain rate of the polymer to produce a specified initial pressure signal and deformable with a subsequent, lower stiffness in response to a subsequent, lower strain rate of the polymer to produce a subsequent, different specified pressure signal.

Abstract: A wellbore cementing plug includes a plug element including a polymer. The polymer is deformable at a first stiffness when subjected to a first strain rate to allow the plug element to pass through a wellbore while sealing against passage of cement past the plug element. The polymer resists deformation at a second, higher stiffness when subjected to a second, higher strain rate to resist allowing the plug element to pass through the wellbore while sealing against passage of cement past the plug element.