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1996

Articles 1 - 13 of 13

Full-Text Articles in Physical Sciences and Mathematics

Astronomy Matters For Chemistry Teachers, Terry Smith, Jay Huebner, Robert Vergenz Jul 2014

Astronomy Matters For Chemistry Teachers, Terry Smith, Jay Huebner, Robert Vergenz

Jay S Huebner

The purpose of this paper is to encourage more chemistry teachers to become familiar with some of the basic ideas described in typical introductory astronomy courses (1 - 9), including those about the origin of elements and forms of matter. These ideas would enrich chemistry courses and help resolve some basic misconceptions that are expressed in many introductory texts (10 - 16) and journal articles for chemistry teachers (17, 18). These misconceptions are typified by statements such as "we can classify all substances as either elements or compounds," and "nature has provided 92 elements out of which all matter is …

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Electrochemistry Of C82: Relationship To Metallofullerene Electrochemistry, Paul Burbank, James Gibson, Harry Dorn, Mark Anderson Oct 1996

Electrochemistry Of C82: Relationship To Metallofullerene Electrochemistry, Paul Burbank, James Gibson, Harry Dorn, Mark Anderson

Mark R. Anderson

Square-wave voltammetry of C82 in pyridine solutions containing 0.10 M tetra-n-butyl ammonium perchlorate indicates that C82 is reduced in four one-electron steps prior to the onset of electrolyte decomposition. The first reduction occurs at potentials positive of the reported first reduction potentials of other empty cage fullerenes, and at approximately the same reported potential for the first reduction of the endohedral metallofullerenes La@C82 and Y@C82. No oxidations were observed for the C82 under these conditions.

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Purification And Crystallization Of Cyclin-Dependent Kinase Inhibitor P21., D. Mayrose, Michael Nichols, Y. Xiong, H. Ke Aug 1996

Purification And Crystallization Of Cyclin-Dependent Kinase Inhibitor P21., D. Mayrose, Michael Nichols, Y. Xiong, H. Ke

Michael A Nichols

p21, a universal inhibitor of mammalian cyclin-dependent kinases (CDK), regulates cell cycle progression by forming various distinct protein complexes with cyclins, CDKs, and the proliferating cell nuclear antigen. We have overexpressed recombinant human p21 in E. coli and purified active p21 to near homogeneity on a large scale. Crystals of recombinant p21 have been grown in the space group P2(1) a = 157.4, b = 152.7, c = 90.6 A, and beta = 92.7 degrees. The diffraction data of the recombinant p21 have been collected to 2.5 and 3.5 A resolution for the native crystal and two heavy atom derivatives …

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A High School-Collegiate Outreach Program In Chemistry And Biology Delivering Modern Technology In A Mobile Van, Chris Craney, April Mazzeo, Kaye Lord Jun 1996

A High School-Collegiate Outreach Program In Chemistry And Biology Delivering Modern Technology In A Mobile Van, Chris Craney, April Mazzeo, Kaye Lord

Chris L. Craney

The "Teachers plus Occidental equals Partnership in Science" van program in Los Angeles CA was launched in June 1992. The program's goal is to improve high school biology and chemistry students' laboratory instruction by enhancing their teachers' knowledge and classroom application of modern instruments, techniques and experiments.

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Direct Dating Of Deformation; U-Pb Age Of Syndeformational Sphene Growth In The Proterozoic Laramie Peak Shear Zone, Phillip G. Resor, Kevin R. Chamberlain, Carol D. Frost, B Ronald Frost, Arthur W. Snoke Jun 1996

Direct Dating Of Deformation; U-Pb Age Of Syndeformational Sphene Growth In The Proterozoic Laramie Peak Shear Zone, Phillip G. Resor, Kevin R. Chamberlain, Carol D. Frost, B Ronald Frost, Arthur W. Snoke

Phillip G Resor

In this paper, we show that deformation can be dated by combining mesoscopic and microscopic structural observations with an understanding of metamorphic mineral reactions and U-Pb ages of newly grown sphene (titanite). This approach can be used on a variety of rock types that have been deformed at a wide range of metamorphic conditions. In an example from the Proterozoic Laramie Peak shear zone of southeastern Wyoming, a single period of syntectonic sphene growth in sheared mafic dikes is documented both by a strong spatial relationship between deformation and metamorphism and by sphene microtextures. U-Pb analyses of sphene separates give …

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The Spectral Function Of Random Resistor Networks, Anthony Day, M. Thorpe Jun 1996

The Spectral Function Of Random Resistor Networks, Anthony Day, M. Thorpe

Anthony Roy Day

The effective complex conductivity [...] of a two-component material can be conveniently expressed as an integral transformation of a spectral function. The spectral function depends only on the geometry of the material, and can be used to calculate [...] for any particular choice of component conductivities. This is a very useful feature if the component conductivities can be varied (by changing the temperature or frequency, for example) at a fixed geometry. We present a derivation of the spectral function that identifies it as a density of states. We have made direct numerical calculations of the spectral function of two-dimensional random …

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Influence Of Solvent On The Interfacial Structure Of Self-Assembled Alkanethiol Monolayers, Mark Anderson, Mark Evaniak, Minhui Zhang Apr 1996

Influence Of Solvent On The Interfacial Structure Of Self-Assembled Alkanethiol Monolayers, Mark Anderson, Mark Evaniak, Minhui Zhang

Mark R. Anderson

Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) is used to study the structure of octadecanethiol, tetradecanethiol, and decanethiol monolayers in the presence of air, deuterium oxide, and acetonitrile-d3. It is found that the structure of the monolayer is dependent on both the adjacent environment and the initial structural order of the monolayer. In the D2O solutions, spectral changes are similar for the three monolayers and are characteristic of interaction predominantly between the solvent and the terminal portion of the monolayers. This correlates with electrochemical capacitance measurements that indicate little permeation of the aqueous electrolyte in the monolayer, even with the …

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Development And Evaluation Of Internet-Based Hypermedia Chemistry Tutorials, Brian Tissue, Ronald Earp, Ching-Wan Yip, Mark Anderson Apr 1996

Development And Evaluation Of Internet-Based Hypermedia Chemistry Tutorials, Brian Tissue, Ronald Earp, Ching-Wan Yip, Mark Anderson

Mark R. Anderson

This progress report describes the development and student use of World-Wide-Web-based prelaboratory exercises in senior-level Instrumental Analysis during the 1995 Fall semester. The laboratory preparation exercises contained hypermedia tutorials and multiple-choice questions that were intended to familiarize the students with the experiments and instrumentation before their laboratory session. The overall goal of our work is to explore ways in which computer and network technology can be applied in education to improve the cost-effectiveness and efficacy of teaching. The course material can be accessed at http://www.chem.vt.edu/chem-ed/4114/Fall1995.html.

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Scanning Local‐Acceleration Microscopy, Nancy Burnham, A. Kulik, G. Gremaud, P. Gallo, F. Oulevey Feb 1996

Scanning Local‐Acceleration Microscopy, Nancy Burnham, A. Kulik, G. Gremaud, P. Gallo, F. Oulevey

Nancy A. Burnham

By adapting a scanning force microscope to operate at frequencies above the highest tip–sample resonance, the sensitivity of the microscope to materials’ properties is greatly enhanced. The cantilever’s behavior in response to high‐frequency excitation from a transducer underneath the sample is fundamentally different than to its low‐frequency response. In this article, the motivations, instrumentation, theory, and first results for this technique are described.

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Materials’ Properties Measurements: Choosing The Optimal Scanning Probe Microscope Configuration, Nancy Burnham, G Gremaud, A Kulik, P Gallo, F Oulevey Feb 1996

Materials’ Properties Measurements: Choosing The Optimal Scanning Probe Microscope Configuration, Nancy Burnham, G Gremaud, A Kulik, P Gallo, F Oulevey

Nancy A. Burnham

Rheological models are used to represent different scanning probe microscope configurations. The solutions for their static and dynamic behavior are found and used to analyze which scanning probe microscope configuration is best for a given application. We find that modulating the sample at high frequencies results in the best microscope behavior for measuring the stiffness of rigid materials, and that by modulating the tip at low frequencies and detecting the motion of the tip itself (not its position relative to the tip holder) should be best for studying compliant materials in liquids.

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Vanadium(Iv) Complexes With Mixed O,S Donor Ligands. Syntheses, Structures, And Properties Of The Anions Tris(2-Mercapto-4-Methylphenolato)Vanadate(Iv) And Bis(2-Mercaptophenolato)Oxovanadate(Iv), Paul Klich, Andrew Daniher, Paul Challen, David Mcconville, Wiley Youngs Jan 1996

Vanadium(Iv) Complexes With Mixed O,S Donor Ligands. Syntheses, Structures, And Properties Of The Anions Tris(2-Mercapto-4-Methylphenolato)Vanadate(Iv) And Bis(2-Mercaptophenolato)Oxovanadate(Iv), Paul Klich, Andrew Daniher, Paul Challen, David Mcconville, Wiley Youngs

Paul R. Challen

Reaction of VO(acac)2 with 2-mercaptophenol (mpH2) in the presence of triethylamine gives the mononuclear tris complex (Et3NH)2[V(mp)3] (1), in which the vanadyl oxygen has been displaced. An analogous reaction using 2-mercapto-4-methylphenol (mmpH2) afforded (Et3NH)(PNP)[V(mmp)3] (2), which was structurally characterized. 2 crystallizes in the orthorhombic space group Pna21 with unit cell parameters (at −163 °C) a = 23.974(7) Å, b = 9.569(4) Å, c = 25.101(6) Å, and Z = 4. The coordination geometry around the vanadium is between octahedral and trigonal prismatic. Reaction of VO(acac)2 with the sodium salt of 2-mercaptophenol produces the vanadyl(IV) complex Na(Ph4P)[VO(mp)2]·Et2O (3), which crystallizes in …

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Lion-Tailed Macaques (Macaca Silenus) In A Disturbed Forest Fragment: Activity Patterns And Time Budget, Shaily Menon, Frank Poirier Dec 1995

Lion-Tailed Macaques (Macaca Silenus) In A Disturbed Forest Fragment: Activity Patterns And Time Budget, Shaily Menon, Frank Poirier

Shaily Menon

We describe the activity patterns and time budget of a feral group of lion-tailed macaques that were confined to a disturbed forest fragment of 65 ha and compare the results with those obtained for groups in protected forests. The degraded nature of the study site was reflected in low tree densities, low specific diversity, gaps in the girth distribution of trees, and frequent disturbance by humans. The study group of 43 subjects was twice as large as lion-tailed macaque groups in protected habitats. They spent the most time ranging (34.0%), followed by foraging (23.7%), feeding (17.9%), resting (16.0%), and other …

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Animating Calculus: Mathematica Notebooks For The Laboratory, E. Packel, Stan Wagon Dec 1995

Animating Calculus: Mathematica Notebooks For The Laboratory, E. Packel, Stan Wagon

Stan Wagon, Retired

No abstract provided.

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