81 research outputs found
Resonant and non-resonant Tunneling through a double barrier
An explicit expression is obtained for the phase-time corresponding to
tunneling of a (non-relativistic) particle through two rectangular barriers,
both in the case of resonant and in the case of non-resonant tunneling. It is
shown that the behavior of the transmission coefficient and of the tunneling
phase-time near a resonance is given by expressions with "Breit-Wigner type"
denominators. By contrast, it is shown that, when the tunneling probability is
low (but not negligible), the non-resonant tunneling time depends on the
barrier width and on the distance between the barriers only in a very weak
(exponentially decreasing) way: This can imply in various cases, as well-known,
the highly Superluminal tunneling associated with the so-called "generalized
Hartman Effect"; but we are now able to improve and modify the mathematical
description of such an effect, and to compare more in detail our results with
the experimental data for non-resonant tunneling of photons. Finally, as a
second example, the tunneling phase-time is calculated, and compared with the
available experimental results, in the case of the quantum-mechanical tunneling
of neutrons through two barrier-filters at the resonance energy of the set-up.Comment: replaced with some improvements in the text and in the references:
pdf (11 pages) produced from a source-file in Word; including one Figur
Use Of The Multispectral Light Source For The Processing and Analysis Of Skin Pathologies Images
The article deals with the problems arising in the malignant skin neoplasms diagnosis. The inconsistency of modern methods of diagnostics on the basis of data obtainedwhile visual assessment of skin conditions is shown. The necessity of new means for early diagnostics of skin pathologies realization, for example, on the basis of a multispectral radiation source in the short-wave optical, ultraviolet and infra-red ranges proposed in the work is proved. A series of images of the skin area with a benign neoplasm were taken in selected optical bands, and differences in the images when illuminated with the used wavelengths were analyzed. The need in digital processing of the obtained images is demonstrated to minimize disturbances caused by irregularities in the skin covering as well as by the presence of non-informative skin structures such as hairs, keratinized epithelium, etc. The images were improved by means of their equalization as well as the complex use of the Laplace filter and the spatial maximumfilte
Multipolar model of bremsstrahlung accompanying proton-decay of nuclei
Emission of bremsstrahlung photons accompanying proton decay of nuclei is
studied. The new improved multipolar model describing such a process is
presented. The angular formalism of calculations of the matrix elements is
stated in details. The bremsstrahlung probabilities for the ,
, and nuclei decaying from
the state, the and nuclei decaying from the state, the and nuclei decaying from the
state are predicted. Such spectra have orders of values similar to the
experimental data for the bremsstrahlung photons emitted during the
-decay. This indicates on real possibility to study bremsstrahlung
photons during proton decay experimentally and perform further measurements.Comment: 14 pages, 6 figure
Cooperation between Russian research organizations and industrial companies: factors and problems
The study is focused on the cooperation of Russian companies with research organizations in implementing R&D projects during technological innovation. Taking into account behavioral changes, authors carry out a micro-level analysis based on empirical data of executive survey of over 600 Russian industrial firms (2011—2012) and about 350 research organizations and universities (2012). The authors emphasize the key factors of firms’ demand for outsourcing R&D reveal the main barriers to the development of university-industry cooperation and their particularities for different cooperation actors.
The analysis shows that there is a positive relation between the size of a company and R&D outsourcing. As for the factor of age, the highest cooperation activity of Russian firms is observed among enterprises founded over 20 years ago. As far as concernes cooperation activity of research organizations, large ones are significantly more likely to cooperate with business. A common prerequisite for research organizations' R&D cooperation with business is sufficient academic ranking.
Business and science evaluate differently various obstacles to effective cooperation. For firms, the main problems are the inflated costs of national R&Ds, insufficient research organizations’ orientation at company needs, and low quality of developments. As for representatives of research organizations, they mention as barriers primarily the lack of companies' receptivity to innovation and inadequate information about promising developments. Businesses are more optimistic about cooperation with science if they already have a relevant experience of interaction. In the case of research organizations we observe a different pattern: most problems seem more significant to organizations conducting R&D in business interests
Method of cyclotron U-240 isochronous field calculation
Method of analytical calculation of cyclotron U-240 isochronous field is described
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