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991.
992.
D. Beck F. Ames G. Audi G. Bollen H.-J. Kluge A. Kohl M. König I. Martel D. Lunney R.B. Moore H. Raimbault-Hartmann M. de Saint Simon E. Schark S. Schwarz J. Szerypo the ISOLDE Collaboration 《Hyperfine Interactions》1997,108(1-3):219-225
First direct mass measurements on rare earth isotopes around 146Gd have been performed with the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. More than 40 isotopes of the elements
Pr, Nd, Pm, Sm, Eu, Dy and Ho have been measured with an accuracy of typically 1 × 10-7. In the case of 141Sm isomeric and ground state (ΔE = 175 keV) were resolved. Since isobaric contaminations are present in the ISOLDE beam, these
measurements on rare earth isotopes became only possible after the installation of a new cooler trap which acts an isobar
separator.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
993.
The thermal stability of the monodiazohydroborate NMe4[1‐N2B10H9] was studied by thermogravimetric analysis. Under two different atmospheres (air and argon), the thermal decomposition starts at a temperature between 140 and 160 °C. The decomposition residue obtained was separated on a silica gel column. 11B NMR, IR and electrospray mass spectroscopy analyses of the different fractions separated showed that the above decomposition produces (NMe4)2[B20H18] as major product (90%), along with smaller amounts of residual NMe4[1‐N2B10H9] (5%), (NMe4)2[B12H12] and boric acid. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
994.
Grace-Davidson silica pellets (SMR-057-015) are found to be optimal for surface grafting of (RO)3Si(CH2)3FG reagents. While loadings of up to 2.1 mmol g−1 can be attained (ca. 0.05 mmol per pellet) access of further reagents to the graft sites is problematic above loadings of 0.8 mmol g−1. 13C CPMAS NMR studies may be carried out on individual pellets (using natural abundance substrates) and the resulting spectra are diagnostic in identifying successful subsequent coupling reactions. 相似文献
995.
Ahmed Bdoui Joëlle Mayrargue Henri Moskowitz Claude Thal 《Journal of heterocyclic chemistry》1992,29(2):547-550
A stereoselective synthesis of unknown spirobenzodihydropyrancyclohexanes is described starting from arylcyclohexenes alkylated and cyclized via a coumarin intermediate and leading to new amino derivatives which are rigid analogs of dopamine. 相似文献
996.
Henri Moereels Ludo De Bie Jan P. Tollenaere 《Journal of computer-aided molecular design》1990,4(2):131-145
Summary Today, more than 40 protein amino acid (AA) sequences of membrane receptors coupled to guanine nucleotide binding proteins (G-proteins) are available. For those working in the field of medicinal chemistry, these sequences present a new type of information that should be taken into consideration. To make maximal use of sequence data it is essential to be able to compare different protein sequences in a similar way to that used for small molecules. A prerequisite, however, is the availability of a processing environment that enables one to handle sequences in an easy way, both by hand and by computer. In order to meet these ends, the package CGEMA (Colour Graphics Editor for Multiple Alignment) was developed in our laboratory. The programme uses a user-definable colour coding for the different AAs. Sequences can be aligned by hand or by computer, using VGAP, and both approaches can be combined. VGAP is a novel in-house written alignment programme with a variable gap penalty that also handles consecutive alignments using one sequence as a probe. In addition, secondary structure prediction tools are available.From the 20 protein sequences, available for the muscarinic acetylcholine receptor, 13 different sequences were selected, covering the subtypes m1 to m5. By comparing the sequences, two major groups are revealed that correspond to those found by considering the transducing system coupled to the various receptor subtypes. Different parts of the protein sequences are identified as characterizing the subtype and binding the ligands, respectively. 相似文献
997.
The formation of HfO2 and ZrO2 oxides in Hf and Zr hydrides has been detected by181Ta PAC spectroscopy. The oxides were identified by their181Ta quadrupole frequency and asymmetry parameter. The growth of the oxide contamination in a H2 atmosphere has been investigated as a function of temperature and time. 相似文献
998.
999.
Michael X. Yang Phillip W. Kash Dong-Hong Sun George W. Flynn Brian E. Bent Michael T. Holbrook Simon R. Bare Daniel A. Fischer John L. Gland 《Surface science》1997,380(2-3):151-164
The bonding and reactions of chloroethylenes (vinyl chloride, trans- and cis-dichloroethylene, trichloroethylene) on a Cu(100) surface have been investigated by temperature-programmed desorption and reaction, near-edge X-ray absorption fine structure (NEXAFS) studies and measurements of changes of the surface work function. The monolayer molecules adsorb molecularly intact at 95 K via π coordination. The molecules orient with their molecular planes parallel to the surface with little increase (<0.02 Å) in the C---C bond distance compared with the gas phase values. The degree of thermal dissociation increases with the extent of halogenation, and no chlorine is present in the hydrocarbon reaction products liberated from the surface. Both cis- and trans-1.2-chloroethylene produce acetylene and a small amount of benzene, while dissociation of trichloroethylene generates acetylene and deposits a carbon residue on the surface. Vinyl chloride desorbs from Cu(100) without reaction. 相似文献
1000.