The following sixteen reference patterns of boride, silicide, nitride and oxide ceramics represent the second group of reference patterns measured at the National Bureau of Standards under the project “High Quality Reference Patterns and Total Digital Powder Patterns of Technologically Important Ceramic Phases”. Included in the sixteen reference patterns are data for two high Tc superconducting oxide phases (CuSr0.2La1.8O4 and Ba2Cu3YO7) plus one related phase (BaCuY2O5). In addition to these new phases, five other patterns represent phases previously not contained in the PDF and eight represent major corrections to data in the file. The general methods of producing these X-ray powder diffraction reference patterns are described in this journal, Vol. 1, No. 1, pg. 40 (1986).

Fifteen reference patterns of boride, silicide, selenide, telluride and oxide ceramics are reported. Included in the 15 reference patterns are data for three oxide phases which are related to high critical temperature (Tc) superconducting materials: BaCuO2, BaCuSm2O5 and BaCuYb2O5. Four other patterns are included which represent phases previously not contained in the PDF. The remaining six are major corrections of data already included in the file. Reference data for phases Ba2CuY3O6.8 and Ba2Y3CuO6 appeared in the special July superconductor issue of the Advanced Ceramic Materials, 1987. The general methods of producing these X-ray powder diffraction reference patterns are described in this journal, Vol. 1(1), 40 (1986).

Samples were mixed with one or two internal standards: silicon (SRM640a), silver, tungsten, or fluorophlogopite (SRM675). Expected 2θ values for these internal standards are specified in the methods described (ibid.). Data were measured with a computer controlled diffractometer. The POWDER-PATTERN system of computer programs was used to locate peak positions, to calibrate the patterns, and to perform variable indexing and least-squares cell refinement. A check on the overall internal consistency of the data was also provided by a computer program.

This note describes a new class of devices, corrugated polyvinylidene fluoride bimorphs. It describes the fabrication, testing and analysis of one simple configuration and discusses the general potential of the devices. As actuators, they offer promise for applications involving relatively large amplitude displacements and small forces with ease of control. As tactile sensors, the devices offer considerable promise due to their potentially high resolution, selectable compliance, sensitivity and durability.

Forward pricing behavior of random samples of Indiana, Nebraska, andMississippi crop producers was analyzed using Heckman's two-step limitedinformation maximum likelihood estimation procedure. Producers who forwardpriced during the 1995–1998 period generally expected to forward price in1999 using similar techniques. Probit models were estimated for cash forwardcontracts and taking a direct position in futures or options separately andcombined. Results provide limited support for the hypothesis that forwardpricing should be analyzed as an adoption decision. Variables reflectingrisk attitudes do affect the decision to use forward pricing, whilevariables related to economic position affect the level of forwardpricing.