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Bahat M Yurdakul S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(5):933-939
The results of an infrared and Raman spectroscopic study are reported for seven new metal(II) pyrimidine tetracyanonickelate complexes, M(pyr)2Ni(CN)4 [where (pyr) = pyrimidine; M = Mn, Fe, Co, Zn, Ni, Cu or Cd] and an IR spectroscopic study is presented for new cadmium pyrimidine tetracyanometalate complex, Cd(pyr)2Cd(CN)4. The spectral data suggest that the first seven compounds belong to the Hofmann-type and the last compound belongs to the Hofmann-Td-type of complexes. 相似文献
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The torsional barriers and nonlinear optical properties for all phenylpyridine molecules were calculated by using Hartree-Fock
(HF) theory and Becke three-parameter functional (B3LYP) hybrid approaches within the density functional theory framework
with the 6-31++G(d, p) basis set, and via the GAUSSIAN 98W. The torsional barrier computations show that dihedral angle between
the two rings increases with the number of H-H vicinal interactions and torsional barriers with dihedral angles for 3-, 4-phenylpyridines
are too similar for both HF and B3LYP level calculations. Also, HOMO-LUMO energy gaps, polarizabilities, anisotropy of polarizabilities,
and static hyperpolarizabilities are calculated as a function of dihedral angle between benzene and pyridine rings. The study
reveals that the phenylpyridines show very low nonlinear optical properties. The calculated torsional barrier, equilibrium
dihedral angle and molecular dipole moment results for these molecules were compared with available experimental and other
results determining from different computational methods. 相似文献
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New time-dependent Benioff strain (TDBS) release diagrams were analyzed for acoustic emission during various loading tests and for electromagnetic (EM) radiation emanating during compression and, tension, which end in failure. TDBS diagrams are Benioff diagrams that are built consecutively, each time using a greater number of events (acoustic or EM emissions) using the last event as if it were associated with the ‘actual failure’. An examination of such TDBS diagrams shows that at a certain time point (this time point is denoted by the term ‘alarm’ time), a comparatively short interval prior to actual collapse, their decreasing part is broken by a positive ‘bulge’. This ‘bulge’ is quantified and an algorithm proposed for its assessment. Using the alarm time and other parameters of the failure process (fall, bulge size and escalation factors, bulge slope and slope fall time), a criterion for estimating the time of the actual collapse is developed and shown to agree well with laboratory experimental results. 相似文献
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In addition to short individual high-frequency signals and their strings, which are well known and analysed, electromagnetic radiation measured during percussion drilling of glass showed a group of lengthy pulses usually appearing in pairs (denoted a-b). In order to understand their origin a polarization-depolarization process is invoked. Thus it is assumed that, during drilling, stress is accumulated in the sample, its increase being accompanied by a polarization increase, which is undetected by the equipment. When stress reaches a critical value, large crack propagation ('chip' fragmentation) begins, and a group a signal is emitted. Crack propagation causes stress and polarization relaxation, and the latter is detected as a group b signal. 相似文献
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