Doctor of Philosophy

dissertationOrganic ligands have become an integral part of molecule-based magnetic systems. Incorporation of organic compounds into molecule-based magnets enables control of the physical properties and the blending of phenomena, e.g., photomagnetism. Understanding how to construct molecule-based magnetic systems with organic compounds should lead to new classes of readily functionalized materials. The magnetic behavior of the dimeric form of N,N'- ethylenebis(salicylideniminato)cobalt(II) (CoII(salen)) was reinvestigated as the dimer was seen to exhibit magnetic tristability associated with the dinuclear site. The singlet (S = 0) ground state arises from the antiferromagnetic coupled pair of the CoII ions, each being in the single-ion (S = 1/2) electron configuration. The triplet (S = 1) excited state arises from ferromagnetic coupling of the CoII S = 1/2 ions. As the temperature increases, the thermal energy populates both the singlet and triplet states. This leads to increases in the χT(T) approaching the Curie behavior for the two CoII S = 1/2 doublets at higher temperature. In contrast to salen-like compounds, spin-carrying radical organic ligands have been seen to enhance magnetic properties. Reactions of N,7,7-tricyanoquinonemethanimine (TCQMI), which forms a radical, with precedented cationic building-blocks of molecular magnets have shown mixed results. The expected structural motif of 1-D chains of alternating [TCQMI]•- and [FeCp*2]+ showed weak magnetic ferrimagnetic ordering at low temperatures with a Tc of 3.4. The reaction of TCQMI with MII(CO)x compounds leads to amorphous materials which showed either weak ferromagnetic coupling or paramagnetic behavior at low temperatures. These results indicate that TCQMI is incompatible with forming magnetic systems where direct bonding to metal centers is encountered. Further evidence of the unsuitability of TCQMI was encountered in the reaction with MnTPP(py) (TPP = Tetraphenylporphinato; py = pyridine). The resulting structure consisted of 1-D chains with MnNCNMn linkages of warped MnTPP and a σ-[TCQMI]22- dimer. The reaction of MnTPP(py) with TCQMI is in contrast with that of typical DCNQIs. The structure [MnIIITPP][Me2DCNQI] has been determined by Rietveld refinement of the X-ray powder diffraction method. The nonsolvated structure is composed of linear (1-D) chains of alternating [MnIIITPP]+ and μ-[Me2DCNQI]•-

Examination of current problems in the distribution of transistor semiconductors-cataloguing, foreign competition, and new products.

Thesis (M.B.A.)--Boston Universit

The Church Directory of Bangor and Brewer 1895

Lists churches in Bangor and Brewer, Maine, circa 1895. Photographs of several churches and pastors are included, as are membership rosters for many churches. Advertisments for local business provide added historical context.https://digicom.bpl.lib.me.us/books_pubs/1334/thumbnail.jp

I\u27m Going to Exit

https://digitalcommons.library.umaine.edu/mmb-vp/5832/thumbnail.jp

Opus (1942)

https://digitalcommons.butler.edu/opus/1001/thumbnail.jp

Opus (1941)

https://digitalcommons.butler.edu/opus/1000/thumbnail.jp

Issue Brief: Immigrant Status And Voting Behavior

The United States currently has the highest proportion of immigrants that it has had since the 1920s. These immigrants represent a powerful voting block with behavior that differs in important respects from that of their native-born counterparts

On the uniformly random generation of combinatorial structures

1 online resource (72 pages) : illustrationsIncludes abstract and appendices.Includes bibliographical references (pages 66-67).We consider two algorithmic processes used to sample uniformly from a wide array of combinatorial classes. First, the recursive method which uses the recur- sive decomposition of a class in addition to tables of large integers which count the objects of a given size to generate objects uniformly at random. Second, the more recent Boltzmann model for sampling is considered. Boltzmann models rely on the use of the closed form generating function of a class and address the space constraints imposed by the recursive method with a time efficiency trade off. Implementations for three classes of objects (binary trees, integer partitions, and set partitions) are demonstrated for each method. Comparison and analysis of the two methods are discussed in addition to applications