IMPURITY LUMINESCENCE CENTERS IN FLUORAPATITE FROM QUARTZ-BEARING PARAGENESIS ACCORDING TO PHOTO-, CATHODE- AND SYNCHROTRON-INDUCED LUMINESCENCE

Apatite is typically characterized by a wide variety of spectrum and kinetic characteristics of luminescence; luminescent images of grains are often zonal. A variety of conditions for the formation of the mineral in various types of associations and in many types of host rocks contributes to the occurrence of impurities of various luminogen ions in its structure. The variety of luminescence is associated with impurities of d-metals, REE, different types of anions, as well as with the effects of co-activation in various combinations. The paper presents the results of a comparative study of photo-, cathode- and synchrotron luminescence of apatite (by the example of samples from crystal-bearing deposits of the Neroi region, Subpolar Urals). Using a Jeol JSM6390LV SEM equipped with a Horiba H-CLUE iHR500 attachment, cathodoluminescence spectra of apatite were obtained in the 200–800 nm range. The spectra and kinetic characteristics of apatite luminescence upon excitation by synchrotron radiation at 10 and 300 K have been analyzed for the first time; the physical nature of the excitation bands of the three main luminescence centers Ce3+, Eu2+ and Mn2+ has been examined; it is shown that the luminescence excitation with the energy transfer can be carried out in processes initially initiated by interband transitions or photoionization. The data obtained are important for expanding the possibilities of mineral cathodoluminescence with spatial and spectral resolution and its use in applied problems

Microcanonical mean-field thermodynamics of self-gravitating and rotating systems

We derive the global phase diagram of a self-gravitating $N$-body system enclosed in a finite three-dimensional spherical volume $V$ as a function of total energy and angular momentum, employing a microcanonical mean-field approach. At low angular momenta (i.e. for slowly rotating systems) the known collapse from a gas cloud to a single dense cluster is recovered. At high angular momenta, instead, rotational symmetry can be spontaneously broken and rotationally asymmetric structures (double clusters) appear.Comment: 4 pages, 4 figures; to appear in Phys. Rev. Let

Classification of phase transitions and ensemble inequivalence, in systems with long range interactions

Systems with long range interactions in general are not additive, which can lead to an inequivalence of the microcanonical and canonical ensembles. The microcanonical ensemble may show richer behavior than the canonical one, including negative specific heats and other non-common behaviors. We propose a classification of microcanonical phase transitions, of their link to canonical ones, and of the possible situations of ensemble inequivalence. We discuss previously observed phase transitions and inequivalence in self-gravitating, two-dimensional fluid dynamics and non-neutral plasmas. We note a number of generic situations that have not yet been observed in such systems.Comment: 42 pages, 11 figures. Accepted in Journal of Statistical Physics. Final versio

Tick-borne encephalitis virus subtypes emerged through rapid vector switches rather than gradual evolution

Tick-borne encephalitis is the most important human arthropod-borne virus disease in Europe and Russia, with an annual incidence of about 13 thousand people. Tick-borne encephalitis virus (TBEV) is distributed in the natural foci of forest and taiga zones of Eurasia, from the Pacific to the Atlantic coast. Currently, there are three mutually exclusive hypotheses about the origin and distribution of TBEV subtypes, although they are based on the same assumption of gradual evolution. Recently, we have described the structure of TBEV populations in terms of a clusteron approach, a clusteron being a structural unit of viral population [Kovalev and Mukhacheva (2013) Infect. Genet. Evol., 14, 22–28]. This approach allowed us to investigate questions of TBEV evolution in a new way and to propose a hypothesis of quantum evolution due to a vector switch. We also consider a possible mechanism for this switch occurring in interspecific hybrids of ticks. It is necessarily accompanied by a rapid accumulation of mutations in the virus genome, which is contrary to the generally accepted view of gradual evolution in assessing the ages of TBEV populations. The proposed hypothesis could explain and predict not only the formation of new subtypes, but also the emergence of new vector-borne viruses

ПРИМЕСНЫЕ ЦЕНТРЫ СВЕЧЕНИЯ ВО ФТОРАПАТИТЕ ИЗ ХРУСТАЛЕНОСНОГО ПАРАГЕНЕЗИСА ПО ДАННЫМ ФОТО-, КАТОДО- И СИНХРОТРОННО-ИНДУЦИРОВАННОЙ ЛЮМИНЕСЦЕНЦИИ

Apatite is typically characterized by a wide variety of spectrum and kinetic characteristics of luminescence; luminescent images of grains are often zonal. A variety of conditions for the formation of the mineral in various types of associations and in many types of host rocks contributes to the occurrence of impurities of various luminogen ions in its structure. The variety of luminescence is associated with impurities of d-metals, REE, different types of anions, as well as with the effects of co-activation in various combinations. The paper presents the results of a comparative study of photo-, cathode- and synchrotron luminescence of apatite (by the example of samples from crystal-bearing deposits of the Neroi region, Subpolar Urals). Using a Jeol JSM6390LV SEM equipped with a Horiba H-CLUE iHR500 attachment, cathodoluminescence spectra of apatite were obtained in the 200–800 nm range. The spectra and kinetic characteristics of apatite luminescence upon excitation by synchrotron radiation at 10 and 300 K have been analyzed for the first time; the physical nature of the excitation bands of the three main luminescence centers Ce3+, Eu2+ and Mn2+ has been examined; it is shown that the luminescence excitation with the energy transfer can be carried out in processes initially initiated by interband transitions or photoionization. The data obtained are important for expanding the possibilities of mineral cathodoluminescence with spatial and spectral resolution and its use in applied problems.Для минерала апатита типично широкое разнообразие спектра и кинетических характеристик люминесценции; люминесцентные изображения зерен часто зональны. Разнообразие условий формирования минерала в разных типах ассоциаций и вмещающих пород способствует появлению в его структуре примесей различных ионов-люминогенов. Разнообразие люминесценции связано с примесями d-металлов, РЗЭ, разных типов анионов, а также с эффектами соактивации в различных комбинациях. В работе представлены результаты сравнительного исследования фото-, катодо- и синхротронной люминесценции фторапатита (на примере проб из хрусталеносных месторождений Неройского района, Приполярный Урал). С использованием СЭМ Jeol JSM6390LV, оборудованного приставкой Horiba H-CLUE iHR500, получены спектры катодолюминесценции фторапатита в диапазоне 200–800 нм. Впервые проанализированы спектры и кинетические характеристики люминесценции фторапатита при возбуждении синхротронным излучением вакуумного ультрафиолетового диапазона при 10 и 300 К; рассмотрена физическая природа полос возбуждения трех основных центров свечения Ce3+, Eu2+ и Mn2+; показано, что возбуждение люминесценции с передачей энергии может осуществляться в процессах, первоначально инициированных межзонными переходами или фотоионизацией. Полученные данные важны для расширения возможностей катодолюминесцентной спектроскопии зерен минерала с пространственным и спектральным разрешением и использования ее в решении прикладных минералого-геохимических задач

Impurity Luminescence Centers in Fluorapatite from Quarz-Bearing Paragenesis According to Photo-, Cathode- and Synchrotron-Induced Luminescence

Apatite is typically characterized by a wide variety of spectrum and kinetic characteristics of luminescence; luminescent images of grains are often zonal. A variety of conditions for the formation of the mineral in various types of associations and in many types of host rocks contributes to the occurrence of impurities of various luminogen ions in its structure. The variety of luminescence is associated with impurities of d-metals, REE, different types of anions, as well as with the effects of co-activation in various combinations. The paper presents the results of a comparative study of photo-, cathode- and synchrotron luminescence of apatite (by the example of samples from crystal-bearing deposits of the Neroi region, Subpolar Urals). Using a Jeol JSM6390LV SEM equipped with a Horiba H-CLUE iHR500 attachment, cathodoluminescence spectra of apatite were obtained in the 200-800 nm range. The spectra and kinetic characteristics of apatite luminescence upon excitation by synchrotron radiation at 10 and 300 K have been analyzed for the first time; the physical nature of the excitation bands of the three main luminescence centers Ce$^{3+}$, Eu$^{2+}$ and Mn$^{2+}$ has been examined; it is shown that the luminescence excitation with the energy transfer can be carried out in processes initially initiated by interband transitions or photoionization. The data obtained are important for expanding the possibilities of mineral cathodoluminescence with spatial and spectral resolution and its use in applied problems

Microcanonical mean-field thermodynamics of self-gravitating and rotating systems

The global phase diagram of a self-gravitation N-body system, enclosed in a finite three-dimensional spherical volume V, was derived. The derivation of global phase diagram was done as a function of total energy and angular momentum, employing a microcanonical mean-field approach. The results showed that, at low angular momenta, the known collapse from a gas cloud to a single dense cluster was recovered and at high angular momenta, rotational symmetry could be spontaneously broken