Abstract: Rejection of local oscillator harmonic response is provided in a mixing circuit with a pair of harmonic gating switches serially connected to the outputs of a balanced differential switching mixer and controlled by a gate clock signal having twice the frequency of a local oscillator signal controlling the switching mixer. An aperture or duty cycle of the gate clock signal determines which harmonic is rejected or suppressed, which is preferably a third and/or fifth harmonic since response of the balanced differential switching mixer to even harmonics is negligible. The resulting simple, efficient circuit is readily integrated directly into a phase-alternating mixer structure for a chopper-direct-conversion radio.

Abstract: Rejection of local oscillator harmonic response is provided in a mixing circuit with a pair of harmonic gating switches serially connected to the outputs of a balanced differential switching mixer and controlled by a gate clock signal having twice the frequency of a local oscillator signal controlling the switching mixer. An aperture or duty cycle of the gate clock signal determines which harmonic is rejected or suppressed, which is preferably a third and/or fifth harmonic since response of the balanced differential switching mixer to even harmonics is negligible. The resulting simple, efficient circuit is readily integrated directly into a phase-alternating mixer structure for a chopper-direct-conversion radio.

Abstract: Highly hydrophobic compounds and hydrophobic proteins are solubilized in a non-aqueous solvent containing an electrolyte for electrophoretic separation. The non-aqueous solvent is an ionic liquid or a mixture of an organic solvent containing an ionic liquid in an amount to render the solvent electrically conductive and amenable for electrophoretic separation. The hydrophobic proteins are separated by electrophoresis using an electrophoresis gel that is compatible with the organic solvent and ionic liquid.

Abstract: A hydraulic control and operating system is provided for a railroad car retarder to control the movement of railroad cars in railroad classification yard. The system utilizes a double-acting hydraulic cylinder to operate the retarder mechanism and includes a hydraulic control circuit that provides protection against pressure spikes and high pressure excursions, high and low temperature excursions, low oil levels and oil filter fouling. The above system not only shuts itself down to prevent damage, but provides a warning to maintenance staff that service should be performed long before a need for system shut-down is required. The system includes a central operating panel in the rail yard control center, remote control panel located at the position of the retarder and the system can be connected for operation from a completely remote location.

Abstract: The present invention pertains to an electro-pneumatic retarder control (EPRC) valve for a pneumatic retarder that controls the speed of railroad cars in a marshaling yard. The EPRC valve has a housing that generally encloses and protects its various components. The housing has a lid that can be opened to gain access to a control panel mounted on an interior door. The control panel includes a display, keyboard and programmable logic controller or PLC module that can be adjusted to set the desired pressure levels of the retarder. The EPRC valve has a modular pressure control assembly that includes an intake and exhaust manifold, a retarder supply and return manifold and several interchangeable control lines formed by like-shaped control valves and components. A pilot air control assembly enables the PLC module to selectively open and close the control valves and lines to deliver or release pressurized air to the retarder.