Fracture of Nanostructured Ceramic Coatings on Metal Substrates under Thermal and Mechanical Loadings

Characteristic features of fracture of nanostructured Si-Al-N and Zr-Y-O ceramic coatings on metal substrates subjected to thermal cycling, uniaxial tension and wear tests are studied. The effect of elemental composition of the coatings on their fracture and delamination from the substrate is shown. The effect of bombardment of the Cu substrate by low-energy Zr+ ions on adhesion and fracture of the Si-Al-N heat resistant coatings is investigated. The dependence of the wear resistance of Si-Al-N / Zr-Y-O multilayer coatings on the number of Si-Al-N and Zr-Y-O layers and on their thickness is revealed. It is found that the coating consisting of 6 bilayers is characterized by minimal wear. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3530

Contribution to the knowledge of vespid wasps (Hymenoptera: Vespidae) of the Sikhote-Alin Nature Reserve (Russian Far East)

An annotated list of Vespidae wasps of the Sikhote-Alin Biosphere Nature Reserve contains 28 species, belonging to 10  genera and 3  subfamilies, is given. The species annotations include localities and description of habitats. The present list is not final in our opinion. For comparison, 37  species from 11  genera inhabit Sakhalin Island, and 47 species from 13 genera are known in Lasovsky Nature Reserve in Primorsky Region of Russia. Comlex of Eastern-Asian species includes Vespula shidai, Vespa simillima, Polistes snelleni, P.  diakonovi, P.  riparius, Eumenes septentrionalis, Symmorphus mizuhonis, Ancistrocerus densepilosellus, A.  japonicus, Stenodynerus pappi, Stenodynerus frauenfeldi. Some of these species were registered in Russia only on south of Primorsky Region (Ancistrocerus japonicus, Stenodynerus pappi, Polistes diakonovi). The territory of the Sikhote Alin Reserve is probably a north border of the ranges of these species. The complex of these Eastern-Asian species is not homogeneous and includes several groups belonging to different by origin faunas. For example, ranges of narrow-local Korean and Korean-Japanese Sikhote-Alin subendemic species (Stenodynerus pappi, Polistes diakonovi, Ancistrocerus japonicus, Vespula shidai) are limited by territories near the Sea of Japan (Korean Peninsula, Japanese Islands, Southern Kuril Islands, the eastern part of Sikhote-Alin). Other species of the Eastern Asian complex have wider ranges and are widespread in Southern and South-Eastern Siberia, Mongolia, Korea and Central China. For example, Polistes snelleni is distributed to the Transbaikal region and Yenisei River to the west, and the East Asian Polistes riparius is distributed to the southwest of the West Siberian Plain (Kurgan Region of Russia). The following rare species with a narrow ranges were registered in the Sikhote-Alin Reserve: Stenodynerus pappi, Polistes diakonovi, Ancistrocerus japonicus and Vespula shidai. Two species were common and numerous: Ancistrocerus trifasciatus and Symmorphus bifasciatus. The main faunistic groups and eco-landscape complexes of wasps were identified using a zoogeographical analysis of species. The eco-landscape complex of 15 widespread forestly mesophilous species leads by the number of species on the territory of the Sikhote-Alin Reserve. Dendrophilous and tamno-dendrophilous cavity-nesting wasps is the dominant ecological group in the reserve

The MAO NASU Plate Archive: "observations in the past" of minor planets

The Plate Archive of the Main Astronomical Observatory of the National Academy of Sciences of Ukraine (MAO NASU) includes 20 thousands of direct sky area plates, which have been taken for various astronomical projects during the period of about 50 years. Those plates contain more then hundred thousand images of minor planets with magnitude up to 16.7m. About 10% of minor planets, which may be found on our archive plates were firstly discovered after the time when plates have been taken. So, we can rediscovery them due to the so-called “observations in the past”. In the paper the criteria for choose of objects and methods of their search, identification, and determination of their position are discussed. First results of the search for potentially hazardous asteroids in the MAO plate archive are presented

Wide-field plate archives stored in the Ukrainian observatories

The latest version of the Wide-Field Plate Database Catalogue of Wide-Field Plate Archives (April 2008) contains 43 archives stored at some Ukrainian observatories, namely, at the Main Astronomical Observatory of the National Academy of Sciences of Ukraine (Golosiiv, Kyiv), at the Crimean Astrophysical Observatory (Nauchnyi and Simeiz), at the Kyiv, L’viv, and Odesa University Observatories, and at the Mykolaiv Observatory. About 126 000 plates were obtained from 1898 to 2005.Последняя версия каталога архивов широкоугольных пластинок (Catalogue of Wide-Field Plate Archives, April 2008) содержит 43 архива, хранящихся в нескольких обсерваториях Украины: в Главной астрономической обсерватории НАН Украины (Голосиив, Киев), в Крымской астрофизической обсерватории (Научный и Симеиз), в обсерваториях Киевского, Львовского и Одесского университетов и в Николаевской обсерватории. Около 126 000 пластинок было получено в период с 1898 по 2005 гг.Остання версія каталогу архівів ширококутних платівок (Catalogue of Wide-Field Plate Archives, April 2008) містить 43 архіви, що зберігаються в декількох обсерваторіях України: у Головній астрономічній обсерваторії НАН України (Голосіїв, Київ), Кримській астрофізичній обсерваторії (Научний і Сімеїз), в обсерваторіях Київського, Львівського й Одеського університетів і в Миколаївській обсерваторії. Близько 126000 платівок отримано з 1898 по 2005 рр

STUDY OF ACOUSTIC SIGNAL DURING LASER HYDROACOUSTIC PROCESSING OF BIOLOGICAL TISSUE BY MICROSECOND PULSES OF YTTERBIUM-ERBIUM GLASS LASER RADIATION

Subject of Research.The paper describes the research results of an acoustic signal recorded by a hydrophone while effect on a liquid by microsecond pulses of laser radiation with a wavelength of 1.54 μm and different time substructure. We discuss the influence of energy and time substructure of the laser pulse on the magnitude of generated pressure drops in the liquid and removal efficiency of cataract eye lens tissues. Method. Microsecond pulses of ytterbium-erbium glass laser radiation with different peak power of the "leading" spike and equivalent energy were delivered to the volume of distilled water through an optical fiber. The acoustic signal was registered with "NP 10-1" needle hydrophone (Dapco Inc., USA). An in vitro hydroacoustic treatment of cataract human eye lens was performed. Main Results. We obtained the dependences of the amplitude of the first (thermo-optical) and the second (associated with "collapse-rebound" process of a steam-gas cavity) components of the acoustic signal on the pulse energy for laser pulses with different time substructures. It was established that with an increase in the peak power of the "leading" spike of microsecond pulse, the threshold for the appearance of the second component decreases, and the maximum amplitude of both components increases. The angular distributions of the amplitude of acoustic signal components were obtained. It was found that the first component has a pronounced maximum amplitude in a direction perpendicular to the optical axis of the fiber, whereas the angular distribution of the second component is more uniform. In the in vitro experiment, it was shown that an increase in the peak power of the "leading" spike results in a significant increase in the removed volume and removal efficiency of the human cataract eye lens. Practical Relevance. The obtained results can be used to optimize the parameters of laser radiation for processing of tissue surrounded by a liquid, for example, during laser cataract extraction

JINR-IAP FEM oscillator with Bragg resonator

A FEM-oscillator with a reversed guide magnetic field and a Bragg resonator as a RF radiation source for collider applications was studied. The configuration with a step of the corrugation phase is proved to be advantageous. It possesses such features as a high efficiency, precise tunability of the operating frequency and a narrow spectral band. It is demonstrated experimentally that such an oscillator is capable of operating at frequencies of ~30 GHz in single-mode regime with the frequency tuning in interval up to 6%. Frequency and spectrum measurements have been performed with precision of ~0.1%

JINR activity in microwave sources for TeV range linear colliders

Results of theoretical and experimental studies of the microwave radiation sources on the base of the induction linac LIU-3000 (JINR, Dubna) are presented. In particular, a FEM-oscillator with the reversed guide magnetic field and Bragg resonator as well as an electron beam buncher in the two-beam accelerator (TBA) driver was studied

Current-induced highly dissipative domains in high Tc thin films

We have investigated the resistive response of high Tc thin films submitted to a high density of current. For this purpose, current pulses were applied into bridges made of Nd(1.15)Ba(1.85)Cu3O7 and Bi2Sr2CaCu2O8. By recording the time dependent voltage, we observe that at a certain critical current j*, a highly dissipative domain develops somewhere along the bridge. The successive formation of these domains produces stepped I-V characteristics. We present evidences that these domains are not regions with a temperature above Tc, as for hot spots. In fact this phenomenon appears to be analog to the nucleation of phase-slip centers observed in conventional superconductors near Tc, but here in contrast they appear in a wide temperature range. Under some conditions, these domains will propagate and destroy the superconductivity within the whole sample. We have measured the temperature dependence of j* and found a similar behavior in the two investigated compounds. This temperature dependence is just the one expected for the depairing current, but the amplitude is about 100 times smaller.Comment: 9 pages, 9 figures, Revtex, to appear in Phys. Rev.

Non-perturbative calculations for the effective potential of the PTPT symmetric and non-Hermitian (−gϕ4)(-g\phi^{4}) field theoretic model

We investigate the effective potential of the $PT$ symmetric $(-g\phi^{4})$ field theory, perturbatively as well as non-perturbatively. For the perturbative calculations, we first use normal ordering to obtain the first order effective potential from which the predicted vacuum condensate vanishes exponentially as $G\to G^+$ in agreement with previous calculations. For the higher orders, we employed the invariance of the bare parameters under the change of the mass scale $t$ to fix the transformed form totally equivalent to the original theory. The form so obtained up to $G^3$ is new and shows that all the 1PI amplitudes are perurbative for both $G\ll 1$ and $G\gg 1$ regions. For the intermediate region, we modified the fractal self-similar resummation method to have a unique resummation formula for all $G$ values. This unique formula is necessary because the effective potential is the generating functional for all the 1PI amplitudes which can be obtained via $\partial^n E/\partial b^n$ and thus we can obtain an analytic calculation for the 1PI amplitudes. Again, the resummed from of the effective potential is new and interpolates the effective potential between the perturbative regions. Moreover, the resummed effective potential agrees in spirit of previous calculation concerning bound states.Comment: 20 page

First results of the renewed Uragan-2M torsatron

The results of experimental investigation on the vacuum magnetic surfaces in the l=2 torsatron with an additional toroidal field Uragan-2M at wide varying operation parameters are presented. Also the first results on the wall conditioning in the Uragan-2M with the ECR and RF discharges in atmosphere of hydrogen in steady-state mode at low magnetic field, plasma production and heating with RF power are described.Представлено результати експериментального дослідження вакуумних магнітних поверхонь в l=2 торсатроні з додатковим магнітним полем Ураган-2М для широкої зміни операційних параметрів. Також описані перші результати підготовки першої стінки в Урагані-2М за допомогою ЕЦР і ВЧ розрядів в атмосфері водню в стаціонарному режимі при низькому магнітному полі, створення і нагріву плазми ВЧ потужністю.Представлены результаты экспериментального исследования вакуумных магнитных поверхностей в l=2 торсатроне с дополнительным магнитным полем Ураган-2М для широкого изменения операционных параметров. Также описаны первые результаты подготовки первой стенки в Урагане-2М при помощи ЭЦР и ВЧ разрядов в атмосфере водорода в стационарном режиме при низком магнитном поле, создания и нагрева плазмы ВЧ- мощностью