Universal sextic effective interaction at criticality

The renormalization group approach in three dimensions is used to estimate the universal critical value g_6^* of the dimensionless sextic effective coupling constant for the Ising model. The four-loop RG expansion for g_6 is calculated and resummed by means of the Pade-Borel and Pade-Borel-Leroy procedures resulting in g_6^* = 1.596, while the most accurate estimate for g_6^* is argued to be equal to 1.61.Comment: 6 pages, TeX, no figure

Hamiltonian systems of hydrodynamic type in 2 + 1 dimensions

We investigate multi-dimensional Hamiltonian systems associated with constant Poisson brackets of hydrodynamic type. A complete list of two- and three-component integrable Hamiltonians is obtained. All our examples possess dispersionless Lax pairs and an infinity of hydrodynamic reductions.Comment: 34 page

Critical thermodynamics of two-dimensional N-vector cubic model in the five-loop approximation

The critical behavior of the two-dimensional N-vector cubic model is studied within the field-theoretical renormalization-group (RG) approach. The β functions and critical exponents are calculated in the five-loop approximation, RG series obtained are resummed using Pade-Borel-Leroy and ´ conformal mapping techniques. It is found that for N = 2 the continuous line of fixed points is well reproduced by the resummed RG series and an account for the five-loop terms makes the lines of zeros of both β functions closer to each other. For N > 3 the five-loop contributions are shown to shift the cubic fixed point, given by the four-loop approximation, towards the Ising fixed point. This confirms the idea that the existence of the cubic fixed point in two dimensions under N >2 is an artifact of the perturbative analysis. In the case N = 0 the results obtained are compatible with the conclusion that the impure critical behavior is controlled by the Ising fixed point.В рамках теоретико-польового підходу ренормалізаційної групи (РГ) вивчається критична поведінка двовимірної N-векторної кубічної моделі. β функції і критичні показники обчислюються в п’ятипетлевому наближенні, отримані РГ ряди пересумовуються з використанням техніки Паде-Бореля-Лєруа і конформного перетворення. Знайдено, що для N = 2 неперервна лінія нерухомих точок добре відтворюється пересумованими РГ рядами і врахування п’ятипетлевих членів робить лінії нулів обох β функцій ближчими один до одного. Показано, що для N > 3 п’яти-петлеві внески зсувають кубічну нерухому точку, отриману в чотири-петлевому наближенні, до нерухомої точки Ізинґа. Це підтверджує ідею, що існування кубічної нерухомої точки в двох вимірах під N > 2 є результатом пертурбативного аналізу. У випадку N = 0 отримані результати є сумісні з висновком, що критична поведінка, пов’язана з домішками, контролюється нерухомою точкою Ізинґа

Исследование оптоэлектронного датчика угловых смещений на основе глубокой отражательной фазовой дифракционной решётки

An optoelectronic device for measurements of small angular displacements based on a diffraction of a laser beam on a deep reflective phasetype grating was suggested and investigated. The grating's depth is about several wavelengths. The zero diffraction order's power dependency on the incident angle of a laser beam was investigated theoretically and experimentally. There were found conditions when linear conversion of angular vibrations into changes of power of zero order took place. The experimentally measured sensitivity of the device was rad with channel bandwidth of 800 Hz and signal-to-noise ratio 10.Предложен и исследован оптоэлектронный датчик малых угловых перемещений на основе дифракции лазерного пучка на глубокой отражательной фазовой дифракционной решётке. Проведён теоретический анализ и экспериментальные исследования характеристик датчика

ИЗУЧЕНИЕ ВОЗМОЖНОСТИ РЕГУЛЯЦИИ АНГИОГЕНЕЗА IN VITRO С ПОМОЩЬЮ РЕКОМБИНАНТНЫХ ФРАГМЕНТОВ ИНГИБИТОРОВ АНГИОГЕНЕЗА ЭНДОСТАТИНА, ТУМСТАТИНА И PEDF

Neovascular diseases of visual organ such as age-related macular degeneration, retinopathy of prematurity, diabetic retinopathy, thrombosis of central retina vein and its branches, neovascular glaucoma, choroid and retina tumors have the leading positions in the list of ophtalmopatologies that result in blindness and incapacity. The variety of angiostatic medications of applied ophtalmology is scant. The aim of work was to study the possibile approaches to angiogenesis regulation in vitro with the help of recombinant fragments of natural inhibitors of angiogenesis such as endostatin, tumstatin and PEDF (pigment epithelial derived factor), and also their ability to be the base of potentially feasible and pharmacologically active substances. It is determined that endostatin, tumstatin and PEDF, as well as the comparison medication Bevacizumab in vitro have pro- or antiangiogenic influence. The direction of the biological effect depends on the cultivation conditions, peptide concentration in the cultural fluid and stage of angiogenesis. Неоваскулярные заболевания органа зрения, такие как возрастная макулярная дегенерация, ретинопатия недоношенных, диабетическая ретинопатия, тромбозы центральной вены сетчатки и ее ветвей, неоваскулярная глаукома, опухоли хориоидеи и сетчатки, занимают лидирующие позиции в перечне офтальмопатологии, приводящей к слепоте и инвалидизации, а также к социальной и психологической дезадаптации. Арсенал ангиостатических препаратов в практической офтальмологии скуден. Цель настоящей работы заключалась в изучении возможности регуляции ангиогенеза in vitro с помощью рекомбинантных фрагментов природных ингибиторов ангиогенеза эндостатина, тумстатина и PEDF (pigment epithelial derived factor) и применения их в качестве потенциально возможных фармакологически активных субстанций. Установлено, что in vitro эндостатин, тумстатин и PEDF, как и препарат сравнения бевацизумаб, оказывают про- или антиангиогенное действие. Направленность биологического эффекта зависит от условий культивирования, концентрации пептида в культуральной жидкости и этапа ангиогенеза.

Non-homogeneous systems of hydrodynamic type possessing Lax representations

We consider 1+1 - dimensional non-homogeneous systems of hydrodynamic type that possess Lax representations with movable singularities. We present a construction, which provides a wide class of examples of such systems with arbitrary number of components. In the two-component case a classification is given.Comment: 22 pages, latex, minor change

Природное выщелачивание урана и механизм разрушения рудных тел и пород

Leaching of the metal begins after the filing of a working solution to the array and ends in a short time. The process of leaching in the microcracks is long, and the process of leaching in the mikropores is longer. An important parameters of leaching of uranium are: the area of actively surface cultivating of minerals, which means а destruction of ores and rocks.Выщелачивание металла начинается после подачи рабочего раствора в массив и заканчивается в короткие сроки. Длительным является процесс выщелачивания в микротрещинах, и более продолжительным - процесс выщелачивания в микропоровом пространстве. Важным параметром выщелачивания урана является площадь активной поверхности обрабатываемых минералов, что означает разрушение руд и пород

Sinteza backstepping regulatora za praćenje maksimalne proizvodnje energije u fotonaponskim sustavima

This work presents a new control method to track the maximum power point of a grid-connected photovoltaic (PV) system. A backstepping controller is designed to be applied to a buck-boost DC-DC converter in order to achieve an optimal PV array output voltage. This nonlinear control is based on Lyapunov functions assuring the local stability of the system. Control reference voltages are initially estimated by a regression plane, avoiding local maximum and adjusted with a modified perturb and observe method (P&O). Thus, the maximum power extraction of the generating system is guaranteed. Finally, a DC-AC converter is controlled to supply AC current in the point of common coupling (PCC) of the electrical network. The performance of the developed system has been analyzed by means a simulation platform in Matlab/Simulink helped by SymPowerSystem Blockset. Results testify the validity of the designed control method.Ovaj rad predstavlja novu metodu upravljanja za slije.enje točke maksimalne snage fotonaponskog (PV) sustava. Dana je sinteza backstepping regulatora za primjenu u silazno-uzlaznom DC-DC pretvaraču za postizanje optimalnog izlaznog napona PV-a. Ova je nelinearna metoda upravljanja zasnovana na Ljapunovim funkcijama osiguravajući tako lokalnu stabilnost sustava. Upravljačke reference napona prvo su estimirane korištenjem regresijske ravnine izbjegavajući lokalne maksimume, a zatim podešene tzv. modificiranom perturbiraj i uoči metodom (P&O). Prema tome, zagarantirano je maksimalno izvlačenje energije iz sustava proizvodnje. Naposlijetku, DC-AC pretvaračem upravlja se na način da osigurava željena izmjenična struja u točki zajedničkog spoja (PCC) elektroenergetske mreže. Ponašanje razvijenog sustava analizirano je kroz simulacije provedene u Matlab/Simulink okruženju uz korištenje SymPowerSystem biblioteke

Measurement of RudsR_{\text{uds}} and RR between 3.12 and 3.72 GeV at the KEDR detector

Using the KEDR detector at the VEPP-4M $e^+e^-$ collider, we have measured the values of $R_{\text{uds}}$ and $R$ at seven points of the center-of-mass energy between 3.12 and 3.72 GeV. The total achieved accuracy is about or better than $3.3\%$ at most of energy points with a systematic uncertainty of about $2.1\%$. At the moment it is the most accurate measurement of $R(s)$ in this energy range

Search for narrow resonances in e+ e- annihilation between 1.85 and 3.1 GeV with the KEDR Detector

We report results of a search for narrow resonances in e+ e- annihilation at center-of-mass energies between 1.85 and 3.1 GeV performed with the KEDR detector at the VEPP-4M e+ e- collider. The upper limit on the leptonic width of a narrow resonance Gamma(R -> ee) Br(R -> hadr) < 120 eV has been obtained (at 90 % C.L.)