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71.
B.I. Dunlap 《Solid State Communications》1980,35(2):141-144
The transformational properties of the polarizing power and the analyzing power of a polarized LEED beam under time reversal, rotations and reflections are derived. A general relationship between and is given, and special cases of equality are noted. 相似文献
72.
S. Jha C. Mitros Amer Lahamer Sherif Yehia Glenn M. Julian R. A. Dunlap G. Stroink Z. M. Stadnik 《Hyperfine Interactions》1989,50(1-4):607-612
Mössbauer effect studies of57Co-doped La2CuO4?y were performed at temperatures between 4.2 K and room temperature. These confirm the antiferromagnetic ordering of these compounds below room temperature. Temperature dependence of the quadrupole splitting shows that the hyperfine field is at an angle with thec-axis. 相似文献
73.
By analysis of a large body of available data, crystal field parameters have been obtained for compounds in the series RERh4B4 (RE = rare-earth). These parameters have then been used to calculate properties related to the electronic and magnetic properties of such compounds, and it is shown that a substantial unification of current information is obtained for properties including bulk magnetization (polycrystalline and single crystal), magnetic susceptibility, magnetic anisotropy, Schottky anomalies in the specific heat and suppression of the superconducting transition temperature due to magnetic impurities. In agreement with previous discussions crystal field effects are found to clarify the systematics of magnetic transition temperature, but not to give a full explanation. Other phenomena, such as discrepancies in the magnetic moment of ErRh4B4 as measured by neutron diffraction and by Mo¨ssbauer spectroscopy cannot be explained as crystal field related phenomena. 相似文献
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77.
The rapidly developing technique of room temperature phosphorimetry is discussed from a practical analytical standpoint in this second part of the review. Basic factors concerning the technique such as methods of sample preparation, special instrumentation employed, and quantitative capability are presented, together with a listing of the variety of organic compounds reported to display room temperature phosphorescence. Potential applications of room temperature phosphorimetry and the advantages of sensitivity and selectivity afforded by this technique are discussed. 相似文献
78.
B. I. Dunlap 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,19(4):255-257
Isomers of pure Fe13 and icosahedral Fe12X clusters are studied using the all-electron linear-combination-of-Gaussian-type-orbital (LCGTO) local-density-functional (LDF) methods that allow the spin and geometry of the cluster to be determined self-consistently. The Fe13 ground state is icosahedral. The icosahedral cluster also has the greatest magnetic moment because of increased symmetry-required orbital degeneracy for electrons of different spins. The central atom of the icosahedral iron cluster has been varied to optimize the spin of the cluster keeping the oribital contribution to the magnetic moment quenched. Varying the central atom under this constraint can alter the magnetic moment by more than 20%. Similar studies have begun on 55-atom icosahedral iron clusters. 相似文献
79.
Durairaj Baskaran John R. Dunlap Jimmy W. Mays Matthew S. Bratcher 《Macromolecular rapid communications》2005,26(6):481-486
Summary: Poly(methyl methacrylate)s (PMMAs) containing a terminal hydroxy group or multiple hydroxy groups as pendants were grafted to multiwalled carbon nanotubes (MWNTs) by esterification in toluene at 100 °C. The recovered polymer with a low level of MWNTs and the PMMA‐g‐MWNTs with up to 12 wt.‐% grafted polymer were characterized using spectroscopic, microscopic, and thermogravimetric analyses. The percentage of polymer present in the PMMA‐g‐MWNT samples is very low based upon the concentration of the acid groups in the tubes.
80.
Louis A. Silks III Jeffrey O. Boles Brenna P. Modi R. Bruce Dunlap Jerome D. Odom 《合成通讯》2013,43(10):1555-1562
A direct and efficient route for the construction of racemic and optically active L-telluromethionine (L-Te-Met) starting from the readily available hydrochloride salt of α-amino-γ-butyrolactone and lithium methyltellurolate is described. The reaction has been successfully scaled up to afford gram quantities of L-Te-Met in 75–80% yield. 相似文献