The high dispersion absorption spectrum of the Ag2 molecule has been photographed in the ~5300–1500-Å region. Observations include the previously reported A ← X, B ← X, C ← X, D ← X, and E ← X transitions and a new H ← X transition which occurs in the vacuum ultraviolet. Extensive spectral blending precluded detailed rotational analyses, but the band structures are consistent with and for D-X and C-X, respectively. The H state is perturbed and probably predissociated. The following molecular constants (in cm?1) were obtained from fitting bandhead data to the usual expressions:
The emission spectrum of the He2 molecule has been rephotographed in the ~4000–~5700 Å region and the , , and transitions analyzed. The 4dδj3Δu, 4dπj3Πu, and states have been characterized through v = 2 and the 4dδJ1Δu, 4dπJ1Πu, , and states for v = 0. The term levels for these perturbed and l-uncoupled states have been confirmed (a) by analyses of bands with common levels from Δv = 0, ±1 sequences and (b) by analyses of the transitions between the above states from 4d and 4s and the and states associated with 3pσ. Molecular constants are reported which have been partially corrected for the effects of l-uncoupling and the homogeneous perturbations between the state pairs J, H and j, h. 相似文献
The nuclear spin induced electric dipole transitions and in 207Pb have been observed in the vacuum ultraviolet absorption spectrum of lead. Utilization of such transitions as a step in the laser isotope separation of 207Pb has the advantage that the selective pumping step involves levels which are separated by the relatively large fine structure spacing rather than the relatively small electronic isotopic and/or hyperfine spacings. The possibility of the separation of other odd mass numbered isotopes in the sixth and seventh periods by similar techniques is discussed briefly. 相似文献
Long time effects in the spin glass Cd1-xMnxTe are investigated by measurements of the low field Faraday rotation effect. Strongly marked fluctuations are observed in the time dependence of the Faraday angle below the critical temperature. That seems to be a new effect in spin glasses. 相似文献
Liquid crystal displays had a humble beginning with wrist watches in the seventies. Continued research and development in
this multi-disciplinary field have resulted in displays with increased size and complexity. After three decades of growth
in performance, LCDs now offer a formidable challenge to the cathode ray tubes (CRT).
A major contribution to the growth of LCD technology has come from the developments in addressing techniques used for driving
matrix LCDs. There are several approaches like passive matrix addressing, active matrix addressing and plasma addressing to
drive a matrix display.
Passive matrix LCD has a simple construction and uses the intrinsic non-linear characteristic of the LCD for driving. Departure
from conventional line by line addressing of a passive matrix has resulted in improved performance of the display. Orthogonal
functions have played a crucial role in the development of passive matrix addressing. Simple orthogonal functions that are
useful for driving a matrix LCD are introduced. The basics of driving several rows simultaneously (multi-line addressing)
are discussed by drawing analogies from multiplexing in communication. The impact of multi-line addressing techniques on the
performance of the passive matrix LCDs in comparison with the conventional technique will be discussed. 相似文献
The He2 band systems and are described in detail, and the i and l states characterized. A number of significant perturbations in the i and l states are identified, and the possible perturber states discussed. The following molecular constants (cm?1) are reported:
The field of proteomics requires methods that offer high sensitivity and wide dynamic range. One of the strategies used to improve the dynamic range is sample prefractionation, such as microsolution isoelectric focusing (IEF). We have modified a commercial solution IEF instrument, the Rotofor, to prefractionate protein mixtures by carrier ampholyte-free solution IEF. The focusing chamber of the Rotofor was divided into several compartments by polyacrylamide membranes with imbedded Immobiline mixtures of specific pH values. When an electric field is applied, each protein migrates to the compartment confined by membranes with pH values flanking its isoelectric point. The approach was demonstrated for the focusing of myoglobin into a predicted compartment, as well as the separation of a complex soluble yeast protein mixture into several distinct fractions. The proteins were dissolved in water or 30% isopropanol. The method is applicable to both gel-based and solution-phase protein identification methods, without the need for further sample preparation. 相似文献
In April-May, 2001, the previously reported experiment to synthesize element 118 using the 208Pb(86Kr,n)293118 reaction was repeated. No events corresponding to the synthesis of element 118 were observed with a total beam dose of 2.6 x 1018 ions. The simple upper-limit cross-sections (1 event) were 0.9 and 0.6 pb for evaporation residue magnetic rigidities of 2.00 Tm and 2.12 Tm, respectively. A more detailed cross-section calculation, accounting for an assumed narrow excitation function, the energy loss of the beam in traversing the target and the uncertainty in the magnetic rigidity of the Z = 118 recoils is also presented. Re-analysis of the primary data files from the 1999 experiment showed the reported element 118 events are not in the original data. The current results put constraints on the production cross-section for synthesis of very heavy nuclei in cold-fusion reactions.Received: 2 September 2002, Revised: 10 April 2003, Published online: 18 November 2003PACS:
25.70.Gh Compound nucleus - 25.70.Jj Fusion and fusion-fission reactions - 27.90. + b
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Ultrasound (US) thermotherapy is used to treat tumours, located deep in human tissue, by heat. It features by the application of high intensity focused ultrasound (HIFU), high local temperatures of about 90 degrees C and short treating time of a few seconds. Dosage of the therapy remains a problem. To get it under control, one has to know the heat source, i.e. the amount of absorbed US power, which shows nonlinear influences. Therefore, accurate simulations are essential. In this paper, an improved simulation model is introduced which enables accurate investigations of US thermotherapy. It combines nonlinear US propagation effects, which lead to generation of higher harmonics, with a broadband frequency-power law absorption typical for soft tissue. Only the combination of both provides a reliable calculation of the generated heat. Simulations show the influence of nonlinearities and broadband damping for different source signals on the absorbed US power density distribution. 相似文献
Emission spectra for the electronic transitions , , , , , , , and of 4He2 are reported and the electronic structure of the triplet states associated with v = 0 of (1σg)2(1σu) nsσ and ndλ characterized. The energy levels comprising the and the manifolds exhibit strong channel mixing, while the mixing of the with the channel structure is relatively minor. Models based on multichannel quantum defect theory are used to aid in the spectral assignments and to correlate the observed level structures. We show that three-limit and two-limit models adequately represent the bulk of the observed and channel structures, respectively. 相似文献