Festschrift in the Honor of Stephen H. White’s 70th Birthday

The Symposium ‘Frontiers in membrane and membrane protein biophysics: experiments and theory’, held this year at the University of California, Irvine (August 19–20), celebrated the 70th Birthday of Stephen H. White by bringing together distinguished experimentalists and theoreticians to discuss the state of the art and future challenges in the field of membrane and membrane protein biophysics. The meeting and this special issue highlight the highly interdisciplinary nature of membrane and membrane protein biophysics, and the tremendous contributions that S. H. White and his lab have brought to the field

Performance Modeling of an RF Coaxial Plasma Thruster

The RF plasma thruster has considerable potential to ease the impact of severe constraints on power, mass, volume and lifetime of microsatellite propulsion systems. This concept is classified as an electrothermal propulsion system and exploits RF capacitively coupled discharge (RFCCD) for heating of a propellant. The plasma is characterized as a low-power discharge possessing a low-current density with high uniformity and propagating through low-pressure gas. To assess computationally the thruster’s propulsive capabilities as a function of mass flow rate, electrode separation, RF frequency and power input, a numerical model comprises particle-in-cell/Monte Carlo (PIC/MCC) and Direct Simulation Monte Carlo (DSMC) algorithms. Thruster performance is investigated by permuting electrode geometry (0.5 - 2 cm), chamber pressure (0.05 - 50 Torr), applied voltage (100 - 500 V), and frequency (10 - 1000 MHz). For this parameter space, PIC/MCC determines overall trends in plasma characteristics. One selected case (3 Torr, 500 V, 200 MHz) and its set of conditions (plasma density, plasma heating, gas temperature, etc.) form the basis for an in-depth flow field and thrust performance analysis with DSMC. Assuming adiabatic wall conditions, the RF plasma thruster achieves a specific impulse of 104.4 s with Argon at the throat Reynolds number of 25. The RF heating increases the specific impulse by 125 %. This study shows that propulsive capability of the RF plasma thruster can be enhanced by increasing the discharge chamber length, redesigning the nozzle contour, and using propellants with lower molecular weights

The use of quantum-correlated D^0 decays for phi3 measurement

We report the results of the Monte-Carlo study of the method to determine the CKM angle phi3 using Dalitz plot analysis of D0 decay from B->DK process. Our main goal is to find the optimal strategy for a model-independent phi3 extraction. We find that the analysis using decays of CP-tagged D mesons only cannot provide a completely model-independent measurement in the case of limited data sample. The procedure involving binned analysis of B->DK and psi(3770)->(K0 pi+ pi-)_D (K0 pi+ pi-)_D decays is proposed, that allows to reach the phi3 precision comparable to unbinned model-dependent fit.Comment: Replaced by journal versio

Enhancement and suppression of tunneling by controlling symmetries of a potential barrier

We present a class of 2D systems which shows a counterintuitive property that contradicts a semi classical intuition: A 2D quantum particle "prefers" tunneling through a barrier rather than traveling above it. Viewing the one particle 2D system as the system of two 1D particles, it is demonstrated that this effect occurs due to a specific symmetry of the barrier that forces excitations of the interparticle degree of freedom that, in turn, leads to the appearance of an effective potential barrier even though there is no "real" barrier. This phenomenon cannot exist in 1D.Comment: 10 pages and 7 figure

Phase diagram of YBa2_2Cu3_3O7−y_{7-y} at T<<Tc_c based on Cu(2) transverse nuclear relaxation

Two maxima in transverse relaxation rate of Cu(2) nuclei in YBa$_2$Cu$_3$O$_{7-y}$ are observed, at T = 35 K and T = 47 K. Comparison of the $^{63}$Cu(2) and $^{65}$Cu(2) rates at T = 47 K indicates the magnetic character of relaxation. The enhancement at T = 47 K of fluctuating local magnetic fields perpendicular to the CuO$_2$ planes is connected with the critical fluctuations of orbital currents. Maximum at T = 35 K is connected with the appearance of inhomogeneous supeconducting phase. Together with data published to date, our experimental results allow to suggest a qualitatively new phase diagram of the superconducting phase.Comment: 4 LaTEX pages + 3 figures in *.ps forma

Composition, Structure and Tribotechnical Properties of TiN, MoN Single-Layer and TiN/MoN Multilayer Coatings

Results of comprehensive investigations of nanostructed TiN and MoN single layer coatings as well as multilayer coatings consisting of TiN/MoN alternating layers have beenconsidered. The coatings have been deposited by a promising modern method of cathode-arc evaporation (vacuum-arc method). The elemental and phase compositions of coatings, their tribological and physico mechanical properties: friction coefficient, wear, adhesion, hardness, and elastic modulus have been studied and the mechanisms of the coatings fracture have been discussedyesBelgorod State Universit

Higher Partial Waves in p+p->p+p+eta near Threshold

Exclusive measurements of the production of eta mesons in the p+p->p+p+eta reaction have been carried out at excess energies of 16 and 37 MeV above threshold. The deviations from phase space are dominated by the proton-proton final state interaction and this influences particularly the energy distribution of the eta meson. However, evidence is also presented at the higher energy for the existence of an anisotropy in the angular distributions of the eta meson and also of the final proton-proton pair, probably to be associated with D-waves in this system interfering with the dominant S-wave term. The sign of the eta angular anisotropy suggests that rho-exchange is important for this reaction.Comment: 16 pages, LaTeX2e, 3 EPS Figures, Updated version, Accepted for publication in Phys. Lett.

ТИПОЛОГІЧНА СТРУКТУРА НАСАДЖЕНЬ ЛІСОВОГО ЗАКАЗНИКА «СУРАЗЬКА ДАЧА»

The article presents the results of the research on the typological structure of forests in the forest reserve «Surazka dacha» on the territory of Shumsk United Territory Community (UTC) in Ternopil region. The total area of the under research forests is 3657.5 hectares. The study of the typological structure of forests was carried out according to the methodology of the forestry and ecological school of Alekseev-Pogrebniak forest typology. The trophogenic diversity of the vegetations in the forest reserve "Surazka Dacha" is represented from subors (B) to dubravas (D). Thus, among them, sudubravas are represented by the largest share (73.6% of the total area of the land covered with forest vegetation). The share of dubrava area is 26.3% of the total area covered by forest vegetation, the rest is subors (0.1%).On the territory of the research facility the forest managers have identified 9 types of forest. Thus, only 1 type of forest is allocated in subors, 5 types in sudubravas, and 3 types in dubravas.The most widespread types of forest in the territory of the reserve «Surazka Dacha»" are fresh hornbeam-oak-pine sudubrava (70.5% of the total area covered by forest vegetation) and fresh hornbeam dubrava (21.6%).Species diversity of forests is represented by 13 types of trees. Thus, among these tree species the largest area is occupied by common oak – 44.9% of the total area covered by forest vegetation, and common pine – 38.3%.The distribution of tree species according to the number of forest types is diverse. Thus, common oak, common pine, European spruce, hanging birch occur in 6 forest types, common hornbeam – in 5 forest types, red oak and black alder – 4 forest types, common ash – in 3 forest types, European larch and white willow – 2 types of forest, white acacia, forest beech and sharp-leaved maple – in 1 type of forest.Vegetations of artificial origin dominate on the territory of the research facility (82.1% of the total area of land covered with forest vegetation), the rest of natural origin – 17.9%.The age structure of the vegetations in the reserve «Surazka dacha» is unbalanced. Plantations of age classes V–VIII predominate – 50.3% of the total area of land covered with forest vegetation, plantations of age classes IX–XII represent a slightly smaller share – 32.7%. The share of I–IV and XIII and older age classes is almost the same and amounts to 10.8 and 6.2%, respectively. Plantations with a completeness of 0.61–0.8, which is 67.7% of the total area of land covered with forest vegetation, dominate by a relative completeness. The share of plantations with completeness 0.81–1.0 (20.8%) and up to 0.6 (11.5%) is somewhat smaller.By the classes of bonitette there dominate the vegetations of I, ІА and higher classes of bonitette – 84.9% of the total area of land covered with forest vegetation. Thus, the share of the II, III and IV classes of bonitette varies from 0.2 to 11.4% of the total area of forests. The results of the work are recommended to be used when forming state environmental policy as well as in the educational process.У статті наведено результати досліджень типологічної структури лісів на території лісового заказника «Суразька дача» на території Шумської ТГ в Тернопільській області. Загальна площа досліджуваних лісів становить 3657,5 га.Дослідження типологічної структури лісів здійснювали за методикою лісівничо-екологічної школи лісової типології Алексєєва-Погребняка.Наведено результати досліджень типологічної і лісівничотаксаційної структури насаджень лісового заказника «Суразька дача» за типами лісорослинних умов (субір, сугруд, груд), типами лісу, деревними породами, за походженням (природне і штучне), віковою структурою (I–IV, V–VIII, IX–XII, XIII і більших класів віку), відносною повнотою (до 0,6; 0,6–0,80; 0,81–1), класами бонітету (Іа , І, ІІ, ІІІ, IV). Результати наукових досліджень можна використовувати в освітньому процесі та під час дослідження таксаційної структури лісового заказника «Суразька дача»