Soyuz 22: New contribution to earth study from space

The mission of space flight Soyuz-22 was to develop new and improved methods and means for finding tthe Earth's natural resources from outer space to aid the economy. With the help of the new multispectral space camera, MKF-6, the cosmonauts were able to photograph selected areas of U.S.S.R. and the German Democratic Republic in 4 visible and 2 infrared regions of the spectrum. The MKF-6 can simultaneously photograph areas in 6 spectral regions and register both the natural electromagnetic radiation of surface objects and the solar radiation reflected by them

Разработка самоприменимой системы верификации. Теория и практика

As opposed to traditional testing, the deductive verification represents a formal way to examine the program correctness. But what about the correctness of the verification system itself? The theoretical foundations of Hoare’s logic were examined in classical works, and some soundness/completeness theorems are well-known. However, we practically are not aware of implementations of those theoretical methods which were subjected to anything more than testing. In other words, our ultimate goal is a verification system which can be self-applicable (at least partially). In our recent studies we addressed ourselves to the metageneration approach in order to make such a task more feasible.По сравнению с традиционным тестированием дедуктивная верификация предлагает более формальный способ доказательства корректности программ. Но как установить корректность самой системы верификации? Теоретические основы логик Хоара исследовались в классических работах, где были получены различные результаты по непротиворечивости и полноте. Однако нам не известны реализации этих теоретических методов, проверенные чем-либо отличным от обычного тестирования. Иными словами, нас интересует система верификации, которая может быть применена к самой себе (хотя бы частично). В наших исследованиях мы обратились к методу метагенерации, который выглядит многообещающим для этой задачи

ЭЛЕКТРОХИМИЧЕСКИЕ СВОЙСТВА РАСПЛАВЛЕННОЙ ЭВТЕКТИЧЕСКОЙ СМЕСИ ХЛОРИДОВ ЛИТИЯ И КАЛИЯ, ВЫДЕРЖАННОЙ В КОНТАКТЕ С НЕОДИМОМ И ДИСПРОЗИЕМ

The corresponding rare earth metal (REM) ion concentration dependence of the reaction capacity (R) of molten lithium–potassium chloride eutectic mixture held in contact with neodymium and dysprosium has been investigated at 773, 873, and 973 K. The obtained data of R values permitted to determine the charge of Nd and Dy ions that go into the melt in the process of corrosion of REM studied and define concretely the mechanism of current-free transfer of REM onto more electropositive metals (for example, nickel).Изучена зависимость реакционной емкости (R) расплавленной эвтектической смеси хлоридов лития и калия, выдержанной в контакте с неодимом и диспрозием, от содержания в расплаве ионов соответствующего редкоземельного металла (РЗМ) при температурах 773, 873 и 973 К. Полученные сведения о значениях R позволили оценить величину зарядов ионов Nd и Dy, переходящих в расплав в процессе коррозии изученных РЗМ, и конкретизировать механизм их бестокового переноса на более электроположительные металлы (на примере никеля)

Neutron star composition in strong magnetic fields

We study the problem of neutron star composition in the presence of a strong magnetic field. The effects of the anomalous magnetic moments of both nucleons and electrons are investigated in relativistic mean field calculations for a $\beta$-equilibrium system. Since neutrons are fully spin polarized in a large field, generally speaking, the proton fraction can never exceed the field free case. An extremely strong magnetic field may lead to a pure neutron matter instead of a proton-rich matter.Comment: 12 pages, 3 postscript files include

Characterization of extrasolar terrestrial planets from diurnal photometric variability

The detection of massive planets orbiting nearby stars has become almost routine, but current techniques are as yet unable to detect terrestrial planets with masses comparable to the Earth's. Future space-based observatories to detect Earth-like planets are being planned. Terrestrial planets orbiting in the habitable zones of stars-where planetary surface conditions are compatible with the presence of liquid water-are of enormous interest because they might have global environments similar to Earth's and even harbor life. The light scattered by such a planet will vary in intensity and colour as the planet rotates; the resulting light curve will contain information about the planet's properties. Here we report a model that predicts features that should be discernible in light curves obtained by low-precision photometry. For extrasolar planets similar to Earth we expect daily flux variations up to hundreds of percent, depending sensitively on ice and cloud cover. Qualitative changes in surface or climate generate significant changes in the predicted light curves. This work suggests that the meteorological variability and the rotation period of an Earth-like planet could be derived from photometric observations. Other properties such as the composition of the surface (e.g., ocean versus land fraction), climate indicators (for example ice and cloud cover), and perhaps even signatures of Earth-like plant life could be constrained or possibly, with further study, even uniquely determined.Comment: Published in Nature. 9 pages including 3 figure

An Improved Quantum Molecular Dynamics Model and its Applications to Fusion Reaction near Barrier

An improved Quantum Molecular Dynamics model is proposed. By using this model, the properties of ground state of nuclei from $^{6}$Li to $^{208}$Pb can be described very well with one set of parameters. The fusion reactions for $^{40}$Ca+$^{90}$Zr, $^{40}$Ca+$^{96}$Zr and $^{48}$Ca+$^{90}$Zr at energy near barrier are studied by this model. The experimental data of the fusion cross sections for $^{40}$Ca+$^{90,96}$Zr at the energy near barrier can be reproduced remarkably well without introducing any new parameters. The mechanism for the enhancement of fusion probability for fusion reactions with neutron-rich projectile or target is analyzed.Comment: 20 pages, 12 figures, 3 table

Dynamic study on fusion reactions for 40,48^{40,48}Ca+90,96^{90,96}Zr around Coulomb barrier

By using the updated improved Quantum Molecular Dynamics model in which a surface-symmetry potential term has been introduced for the first time, the excitation functions for fusion reactions of $^{40,48}$Ca+$^{90,96}$Zr at energies around the Coulomb barrier have been studied. The experimental data of the fusion cross sections for $^{40}$Ca+$^{90,96}$Zr have been reproduced remarkably well without introducing any new parameters. The fusion cross sections for the neutron-rich fusion reactions of $^{48}$Ca+$^{90,96}$Zr around the Coulomb barrier are predicted to be enhanced compared with a non-neutron-rich fusion reaction. In order to clarify the mechanism of the enhancement of the fusion cross sections for neutron-rich nuclear fusions, we pay a great attention to study the dynamic lowering of the Coulomb barrier during a neck formation. The isospin effect on the barrier lowering is investigated. It is interesting that the effect of the projectile and target nuclear structure on fusion dynamics can be revealed to a certain extent in our approach. The time evolution of the N/Z ratio at the neck region has been firstly illustrated. A large enhancement of the N/Z ratio at neck region for neutron-rich nuclear fusion reactions is found.Comment: 21 pages, 7 figures,3 table

Chaotic scattering on surfaces and collisional damping of collective modes

The damping of hot giant dipole resonances is investigated. The contribution of surface scattering is compared with the contribution from interparticle collisions. A unified response function is presented which includes surface damping as well as collisional damping. The surface damping enters the response via the Lyapunov exponent and the collisional damping via the relaxation time. The former is calculated for different shape deformations of quadrupole and octupole type. The surface as well as the collisional contribution each reproduce almost the experimental value, therefore we propose a proper weighting between both contributions related to their relative occurrence due to collision frequencies between particles and of particles with the surface. We find that for low and high temperatures the collisional contribution dominates whereas the surface damping is dominant around the temperatures $\sqrt{3}/2\pi$ of the centroid energy.Comment: PRC su

Автоматическая верификация C-программ на основе смешанной аксиоматической семантики

The development of the C-light project resulted in the application of new formalisms and implementation techniques which facilitate the verification process. The mixed axiomatic semantics proposes a choice between simplified and full-strength deduction rules depending on program objects and their properties. The LLVM infrastructure helps greatly in writing the C-light program analyzer and translator. The semantical labeling technique, proposed earlier, can now be safely kept in verification conditions during their proof. Two programs from the well-known verification benchmarks illustrate the applicability of the system.Развитие проекта C-light привело к применению новых формализмов и реализации методов, которые облегчают процесс верификации С-программ. Смешанная аксиоматическая семантика предлагает выбор между упрощенными и общими правилами вывода условий корректности (УК) в зависимости от программных объектов и их свойств. Инфраструктура LLVM значительно упрощает реализацию анализатора и транслятора C-light программ. Метод семантических меток, предложенный ранее, теперь может быть безопасно исполь- зован в условиях корректности при их доказательстве. Рассмотрен пример из соревнования по верификации, иллюстрирующий применение нашей системы