Electronic, magnetic, and vibrational properties of the molecular magnet Mn4 monomer and dimer

A new type of the single-molecule magnet [Mn_4 O_3 Cl_4 (O_2 CEt)_3(py)_3] forms dimers. Recent magnetic hysteresis measurements on this single-molecular magnet revealed interesting phenomena: an absence of quantum tunneling at zero magnetic field and tunneling before magnetic field reversal. This is attributed to a significant antiferromagnetic exchange interaction between different monomers. To investigate this system, we calculate the electronic structure, magnetic properties, intramolecular and intermolecular exchange interactions using density-functional theory within the generalized-gradient approximation. Our calculations agree with experiment. We also calculate vibrational infrared absorption and Raman scattering intensities for the monomer which can be tested experimentally.Comment: submitted to Journal of Physics and Chemistry of Solid

Libraries as Bridges across the Digital Divide: Partnerships and Approaches Used in the U.S. Technology Opportunities Program, 1994-2005

The purpose of the poster is to show how libraries used government funds and community partnerships to close the digital divide in the United States. Part of the mission of libraries is to bridge the digital divide. As an answer to the digital divide, the U.S. government started a grant program in 1994. Over ten years, the Technologies Opportunities Program (TOP) awarded $230 million to 600 communities to promote network technology and community partnership. The digital divide is a rich concept rather than a simple binary divide. It?s something that is nuanced, multidimensional and ever-changing. Everyone is immersed in the digital divide in one respect or another because none of us are on the same plane of learning and expertise. We have learned much from the plethora of research that has taken place in communities in the United States and abroad. This study sheds like on the digital divide and how libraries have addressed it. Of the 600 projects funded by TOP, 25 were library-led: approximately 10 took place in public libraries, three in academic libraries, and 12 in library networks or other settings. This research uses the TOP Data Archive, which we created with the help of others including the U.S. Department of Commerce itself, to examine these 25 projects. We have constructed tables and word clouds to find trends and analyze the projects and partnerships and will use established network analytical methods as well. Interviews with key leaders in each of the projects will help ascertain how each project developed over time. Our governing theory is that social capital and social networks contribute to ICT use. Our questions include: How did the partnerships between the library and other organizations affect each project? How did they define success, and did they achieve it? Our first finding is that libraries adapted the grant program to their own strategic activities and did not set library work aside. Second, the libraries took three main approaches: to build computer networks with wires and fiber-optics, to build the human-computer infrastructure known as a Freenet, or to create new library programs to help their community use technology. We will also present data on the programs and the size and shape of the partnerships that carried them out. Our research has found a total of 80 partnerships across 25 separate library-led TOP projects. Each project had an average of 4.3 partnerships; with the maximum being 11 and the minimum number of partnership being one. Our analysis included a typology of partners: education, corporations, government, and organization. Educational partners include schools, colleges, universities, and other educational organizations. Corporate entities are defined as businesses or companies. Government partners maybe municipal, city, state or national government entities. Lastly, organization is a broad category that fits every type of non-profit organization, whether it be community, environmental, educational, etc. There are also four sub-categories: library, health, art, and communications. Library partners may be local, state, college, or university libraries. Health institutions are any health organization, whether government or community, or hospitals. Art partners involve art museums, local art organizations, etc. Lastly, communications partners are communication corporations, TV or radio stations, or government communication entities. The categories will allow us to investigate the relationship between the type of partners in each project and the scope and outcome of each project. The data includes 33 education partners, 28 government, 23 organization, 8 libraries, 8 communications 6 corporation, 5 health, and 3 art. In December and January we will use NetDraw to create a visual representation of the egocentric network of a library and its partners, and look for patterns. We will also carry out telephone interviews with the leaders of each project. The phone interviews will tell us about long-term projects outcomes and how the partnerships advanced or impeded each project. This poster will provide insights and suggestions to libraries that are working on the digital divide or on building partnerships. Since the U.S. has yet to catch up with the rest of the world in terms of broadband speed and utilization, the government has started another round of grants called the Broadband Technology Opportunities Program; our findings will also inform that work. Libraries have the responsibility to serve increasingly disparate populations and our poster provides an analysis of an important group of library projects which have never been presented to an international audience. This topic will be of interest to many people in the library profession, especially those dedicated to serving the public through the use of innovative technology. Relevant links: TOP archive at the University of Michigan: http://quod.lib.umich.edu/cgi/f/findaid/findaid-idx?c=sclead&idno=umich-spc-Power-Top Broadband Technology Opportunities Program: http://www.ntia.doc.gov/broadbandgrants

Density-Functional-Based Determination of the CH3-CH4 Hydrogen Exchange Reaction Barrier

Due to the overbinding that is inherent in existing {\em local} approximations to the density-functional formalism, certain reaction energies have not been accessible. Since the generalized gradient approximation significantly decreases the overbinding, prospects for density-functional-based reaction dynamics are promising. Results on the generalized-gradient based determination of the CH3-CH4 hydrogen exchange reaction are presented. Including all Born-Oppenheimer effects an energy barrier of 9.5 kcal/Mole is found which is a very significant improvement over the local-density approximation.Comment: 5 twocolumn pages (needs twocolumn.sty), revtex, 3 figures, To appear in Chem.Phys.Let

Magnetic ordering, electronic structure and magnetic anisotropy energy in the high-spin Mn10_{10} single molecule magnet

We report the electronic structure and magnetic ordering of the single molecule magnet [Mn$_{10}$O$_{4}$(2,2'-biphenoxide)$_{4}$Br$_{12}$]$^{4-}$ based on first-principles all-electron density-functional calculations. We find that two of the ten core Mn atoms are coupled antiferromagnetically to the remaining eight, resulting in a ferrimagnetic ground state with total spin S=13. The calculated magnetic anisotropy barrier is found to be 9 K in good agreement with experiment. The presence of the Br anions impact the electronic structure and therefore the magnetic properties of the 10 Mn atoms. However, the electric field due to the negative charges has no significant effect on the magnetic anisotropy.Comment: 4 pages, submitted to PR

A REPRESENTATIVE MARKET MODEL OF FARMLAND BID PRICES

A land bid-price model is formulated which integrates asset pricing models form prior studies to illustrate the singular and joint effects of ordinary and capital gains taxes, growth of returns, diseconomies of size, and risk behavior on farmland prices. An application of the model to primary data from cash grains farms illustrates that the ceteris paribus effect of increased marginal tax rates on a perpetual, growing income stream is to increase its present value. Larger farms in higher marginal tax brackets are shown to have a competitive advantage over smaller, lower tax bracket farms.Land Economics/Use,

Low distortion automatic phase control circuit

A voltage controlled phase shifter is rendered substantially harmonic distortion free over a large dynamic input range by employing two oppositely poled, equally biased varactor diodes as the voltage controlled elements which adjust the phase shift. Control voltages which affect the bias of both diodes equally are used to adjust the phase shift without increasing distortion. A feedback stabilized phase shifter is rendered substantially frequency independent by employing a phase detector to control the phase shift of the voltage controlled phase shifter

AGRICULTURAL LOAN REVIEW AND RISK RATING FOR COMMUNITY BANKS

Agricultural Finance,

Low distortion automatic phase control circuit

Circuit for generation and demodulation of quadrature double side band signals in frequency division multiplexing system is described. Circuit is designed to produce low distortion automatic phase control. Illustration of circuit and components is included

Japan – Country Study

human development, climate change