Ground-based photometry of comets in the spectral interval 3000 to 3500 angstrom

Abundances and production rates of CN, C3, and C2 for fifteen comets were determined and the variation of these parameters with helicentric distance for two comets were monitored. While these measurements provide much information about the similarities and differences among comets, only a small fraction of the total material in any of the comets observed was sampled

A dc to dc converter

The object of the invention is to provide an improved converter for converting one direct current voltage to another. A plurality of phased square wave voltages are provided from a ring counter through amplifiers to a like plurality of output transformers. Each of these transformers has two windings, and S(1) winding and an S(2) winding. The S(1) windings are connected in series, then the S(2) windings are connected in series, and finally, the two sets of windings are connected in series. One of six SCRs is connected between each two series connected windings to a positive output terminal and one of diodes is connected between each set of two windings of a zero output terminal. By virtue of this configuration, a quite high average direct current voltage is obtained, which varies between full voltage and two-thirds full voltage rather than from full voltage to zero. Further, its variation, ripple frequency, is reduced to one-sixth of that present in a single phase system. Application to raising battery voltage for an ion propulsion system is mentioned

Scales for co-compact embeddings of virtually free groups

Let $\Gamma$ be a group which is virtually free of rank at least 2 and let $\mathcal{F}_{td}(\Gamma)$ be the family of totally disconnected, locally compact groups containing $\Gamma$ as a co-compact lattice. We prove that the values of the scale function with respect to groups in $\mathcal{F}_{td}(\Gamma)$ evaluated on the subset $\Gamma$ have only finitely many prime divisors. This can be thought of as a uniform property of the family $\mathcal{F}_{td}(\Gamma)$.Comment: 12 pages; key words: uniform lattice, virtually free group, totally disconnected group, scale function (Error in references corrected in version 2

Commentary on Professor Gabor\u27s Stepchild of the New Lex Mercatoria Symposium: Reflections on the International Unfication of Sales Law

welcome Professor Gabor\u27s analyses of the Hague Draft Convention. 1 The Convention is a natural sequel to the United Nations Sales Convention, which has been ratified by the United States and came into effect on January 1st of this year. This latter convention deals with the substantive law of sales and is designed to play a role for the entire world similar to the one played by the Uniform Commercial Code in the United States. Undoubtedly, many states will be slow to ratify the Sales Convention, and some will not do so at all. Thus, implementation of rules addressing the issue of applicable law in sales, where the states involved have different laws in the area, is desirable. This is the task of the Hague Draft Convention. Professor Gabor argues that the absence of one welldeveloped body of private international law engenders substantial uncertainty and legal insecurity for both United States and foreign citizens contemplating transnational legal relationships. 2 This Commentary will explore the accuracy of Professor Gabor\u27s statement