Abstract: This invention relates to methods, compositions, and apparatuses for producing macrocyclic compounds. First, one or more reactants are provided in a reaction medium, which are capable of forming the macrocyclic compound through a desired reaction pathway that includes at least cyclization, and which are further capable of forming undesired oligomers through a undesired reaction pathway that includes undesirable oligomerization. Oligomerization of such reactions in the reaction medium is modulated to reduce formation of undesired oligomers and/or to reduce separation of the undesired oligomers from the reaction medium, relative to a corresponding unmodulated oligomerization reaction, thereby maximizing yields of the macrocyclic compound. The macrocyclic compound so formed is then recovered from the reaction medium. Preferably, the macrocyclic compound spontaneously separates from the reaction medium via phase separation.

Abstract: An object identification system includes a monitor and a plurality of transceivers that communicate over a common medium. The monitor includes a first transmitter, a first receiver, and a processor. Each transceiver includes a resonant circuit, a transmitter, a receiver, and an antenna coupled to the resonant circuit. The processor performs a method for performing transceiver communication that includes the steps of: (a) transmitting from the first transmitter a first frequency for a first duration; (b) after lapse of the first duration, receiving via the first receiver a response signal from at least one of the resonant circuits; (c) determining a second frequency from the received response signal; and (d) performing transceiver communication using the second frequency.

Abstract: A radio frequency identification device includes a transceiver having a resonant circuit, a rectifier, a charge pump, a state machine, and a transmitter. The resonant circuit includes an antenna and has a resonant frequency. The rectifier is coupled to the resonant circuit to provide a rectified signal in response to energy from the antenna. The charge pump is enabled in response to the rectified signal to provide a first logic signal. The state machine provides a second logic signal in response to the first logic signal. The transmitter includes an amplifier coupled to the resonant circuit to form a Colpitts oscillator that is enabled by the second logic signal to transmit a response signal for identifying the radio frequency identification device.