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Measurements that indicate that the surface-acoustic-wave (SAW) temperature coefficients of delay and velocity over approximately room temperature to +100 degrees C for the popular cuts of lithium niobate are presented. These values of delay coefficient are close to the value previously given for Y-cut LiNbO(3) but are significantly different from values given for the rotated cuts.

A novel surface-acoustic-wave (SAW) device for continuous-wave (CW) delay-difference measurement or wideband interference-rejection at VHF frequencies is described and test results are given. The delay-difference device (DDD) operates at a center frequency of 160 MHz with a 31-MHz bandwidth over which root-mean-square amplitude ripple is 0.13 dB and need not be operated in a gated mode. A pair of input signals to the CW DDD may be at any frequency within the bandwidth of the DDD, modulated in any form, and even amplitude unbalanced to some degree by system amplifiers and still the CW DDD and its associated electronics will accurately measure the relative delay of the signals and interpret that as direction of arrival or phase as desired. Used in an interference cancelling mode the device tested shows an average 25-dB signal rejection over its 31-MHz bandwidth.

The cloned murine B-cell lymphoma line (BCL1) that expresses surface IgM and IgD is considered to be a model for the immunoglobulin gene expression of the mature virgin B cell. Of particular interest is the mechanism by which a single VH gene is shared by two CH genes. We examined the organization of the immunoglobulin heavy chain genes in BCL1 DNA. A single arrangement of CH genes was found with the expressed VHDJH gene complex just 5' to the Cmu gene. The complete DNA sequence of the VH gene was determined. No rearrangement occurred in the intervening DNA between the JH and C mu genes or between the C mu and C delta genes. We conclude that dual expression of mu and delta heavy chains using a single VH gene is accomplished by alternate processing of a primary transcript that encompasses the the VHDJH complex and both CH genes.