Abstract: A pipette tip (10) including: a proximal end (11) and a proximal body region (12) defining a first cavity that receives a flatted pipette member; and a distal end (13) and a distal body region (14) defining a second cavity that receives and discharges a liquid aspirated by the pipette member; the cavities are in gas-liquid communication, the first cavity is defined by various resilient surfaces as defined herein, one cylindrical surface (25) forms a gas-liquid seal with the pipette member, and which surfaces are free of, for example, an internal stop structure, a distinct sealing structure, or both. Methods of making and using the article are also disclosed.

Abstract: A pipette tip (10) including: a proximal end (11) and a proximal body region (12) defining a first cavity that receives a flatted pipette member; and a distal end (13) and a distal body region (14) defining a second cavity that receives and discharges a liquid aspirated by the pipette member; the cavities are in gas-liquid communication, the first cavity is defined by various resilient surfaces as defined herein, one cylindrical surface (25) forms a gas-liquid seal with the pipette member, and which surfaces are free of for example, an internal stop structure, a distinct sealing structure, or both. Methods of making and using the article are also disclosed.

Abstract: Constant envelope angle modulation apparatus comprises a frequency synthesizer for outputting a stepped output waveform having a selectable precise output frequency. The output of the synthesizer provides an input to a mixer for O-QPSK modulating a received information signal. The O-QPSK modulated signal is then hard-limited, for example, via a series of hard limiting amplifier and filter circuits and a divider circuit. Preferably, a data stream for modulation may be filtered via a filter having an approximately 70-100% roll-off characteristic, such as a root raised cosine filter. A hard-limited, constant envelope angle modulated signal results that is easily frequency converted to, for example, microwave frequencies for landline or satellite applications via a simple multiplier circuit. The multiplier circuit preferably comprises a series of stage-filtered multipliers and band pass filters to achieve the desired output microwave frequency.

Abstract: A satellite communications system for dispersing energy over a wide bandwidth includes a transmitter, a communication link, and a receiver. The transmitter takes a digital data signal and modulates that signal at a prescribed carrier frequency. The modulated digital data signal is then spread over M adjacent digital channels (M.gtoreq.2 and being an integer multiple of 2), each channel containing the same information, to disperse the energy over a wide frequency range. The spectral bandwidth of the adjacent digital channels is chosen with compressed spacing to conserve bandwidth. Next, the spread modulated data signal is transmitted via the communication link to the receiver. In particular, a waveform generator at the transmitter generates a phase-aligned multichannel frequency diversity waveform according to a data clock at a predetermined phase relationship to the digital data.