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In this work we propose a method for analysis of postsurgical haemodynamics after femoral
artery treatment of occlusive vascular disease. Patient specific reconstruction algorithm
of 1D core network based on MRI data is proposed as a tool for such analysis. Along with
presurgical ultrasound data fitting it provides effective personalizing predictive method
that is validated with clinical observations.
More than 20000 observations of Near Earth asteroids and comets are collected and reduced in Pulkovo Observatory during last 10 years. For observations of these objects two robotic telescopes are used – ZA-320M (Cassegrain system, D = 320 mm, F = 3200 mm) at Pulkovo and MTM-500M (Maksutov – Cassegrain system, D = 500 mm, F = 4100 mm) at Kislovodsk mountain station. These telescopes perform CCD observations of objects up to 18.0 and 20.5 magnitude, correspondingly. The results of observations are regularly submitted to Minor Planet Center.
We present the fiber-spring elastic model of the arterial wall with atherosclerotic
plaque composed of a lipid pool and a fibrous cap. This model allows us to reproduce
pressure to cross-sectional area relationship along the diseased vessel which is used in
the network model of global blood circulation. Atherosclerosis attacks a region of
systemic arterial network. Our approach allows us to examine the impact of the diseased
region onto global haemodynamics.
There are two mathematical models of elastic walls of healthy and atherosclerotic blood
vessels developed and studied. The models are included in a numerical model of global
blood circulation via recovery of the vessel wall state equation. The joint model allows
us to study the impact of arteries atherosclerotic disease of a set of arteries on
Experimental investigation of thermoelectric properties of nanowires with diameter of about 5 nm was carried out. Chrysotile asbestos (a natural mineral) was used for a sample preparation. Its nano-sized channels were filled under pressure by melted InSb or Te. The measurements showed that temperature dependences of electrical resistance and thermopower of produced quantum wires differ considerably from corresponding dependences of bulk materials. It is possible to conclude that the results obtained are better described by Lattinger liquid model than by usual Fermi gas one.
A hybrid double heterostructure with large asymmetric band offsets, combining AlAsSb/InAs (as a III–V part) and CdMgSe/CdSe (as a II–VI part), has been proposed as a basic element of a mid-infrared laser structure design. The p-i-n diode structure has been successfully grown by molecular beam epitaxy (MBE) and exhibited an intense long-wavelength electroluminescence at 3.12 μm (300K). A II–VI MBE growth initiation with a thin ZnTe buffer layer prior to the CdMgSe deposition results in a dramatic reduction of defect density originating at the II–VI/III–V interface, as demonstrated by transmission electron microscopy. A less than 10 times reduction of electroluminescence intensity from 77 to 300K indicates an efficient carrier confinement in the InAs active layer due to high potential barriers in conduction and valence bands, estimated as ΔEC = 1.28 eV and ΔEV ∼ 1.6 eV. An increase in the pumping current results in a super-linear raising the EL intensity. The type of band line up at the coherent InAs/Cd1−xMgxSe interface is discussed for 0≤x≤0.2, using experimental data and theoretical estimations within a model-solid theory.
Using X-ray structural and transmission electron microscopy analyses, specific features of the phase and structure transformations in armco-iron and steel 45 affected by a high-current electron beam up to 1011 W/cm2 power density have been studied. It was revealed that hardening of steel with martensite structure has a quasi-periodic character that is caused by the action of a shock wave. The action of a shock wave results in formation of a thin layer on the rear side of the samples. The layer is composed of subgrains of ot-ferrite of a regular hexagonal shape with thin layers of graphite on their boundaries.
Using X-ray structural analysis and transmission electron microscopy of thin layers we have studied the mechanism of heat-affected zone formation in as-hardened steel irradiated by a low-energy microsecond high-current electron beam. It has been found that the above zone consists of three characteristic layers. We have analysed the conditions of formation of this layers using thermal calculations.
It is well known that the temperature dependence of Seebeck coefficient of β-iron disilicide has unusual shape that cannot be described by an ordinary theory. A theory describing such a shape is suggested. It is shown this shape can be explained by optical phonon drag effect. Very high value of ZT could be achieved in some material on the base of this effect.
A comparative analysis of different Cd1−xZnxTe (CZT) crystals grown by a vertical high pressure Bridgman (VHPB) method is reported. The results of several analytical techniques, such as triple axis x-ray diffraction (TAD), rocking curves, low temperature photoluminescence (PL), scanning electron microscopy (SEM), and proton induced x-ray emission (PIXE) are discussed. Segregated carbon inclusions were identified by SEM and energy dispersive x-ray fluorescence (EDXRF), and the results are interpreted in terms of constitutional supercooling of the solidifying CZT melt. The carbon inclusions significantly decrease the resistivity, and in some cases, the noise is too large for the fabrication of radiation detectors. Combining these results with other measurements reported by our research team , we identify correlations between the growth and the defects identified in these CZT crystals.
Several analytical techniques have been used in the study of the homogeneity of Cadmium Zinc Telluride (CZT) single crystals grown by the vertical high pressure Bridgman (VHPB) method. The presence of black inclusions and tubular hollow pipes has been observed by a few methods, such as photoluminescence (PL), infrared (IR) transmission microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The crystals investigated were grown commercially in the USA, at the Institute of Single Crystals in Kharkov, Ukraine, and at the Institute of Solid State Physics, Moscow, Russia. We discuss the homogeneity of the various CZT crystals based on the results from these measurement techniques.
In this paper we present a novel method of nonlinear macro model of a cantilever for mixed domain simulation only with SPICE. Based on lumped elements of equivalent circuits a model is developed, which realizes a coupled electro-thermal-mechanical simulation including crosstalk effects. The model is verified with measurement and helps to class and solve crosstalk. With SPICE as electrical circuit simulator the cantilever array could be simulate in conjunction with the excitations and analysis electronics more detailed like the system level models and faster like FEM-simulation.
Single-crystal ingots of CdTe and Cd0,96Zn0.04Te 60–100 mm in
diameter were grown by directional solidification using the self-seeding
technique. The microstructure of the crystals was
checked by optical microscopy, electron microscopy (TEM, SEM and EBIC),
cathodoluminescence, and X-ray diffraction. It was found that crystal
perfection depends to a large measure on the temperature schedule during
Lpostgrowth crystal cooling: special caution should be exercised in the
temperature interval including the polymorphous transformation. A direct
relationship between optical and electronic properties on the one hand
and crystal microstructure on the other hand was established.
This work is devoted to numerical experiments for multidimensional
Spectral Inverse Problems. We check the efficiency of the algorithm
based on the BC-method, which exploits relations between Boundary
Control Theory and Inverse Problems. As a test, the problem for an
ellipse is considered. This case is of interest due to the fact
that a field of normal geodesics loses regularity on a nontrivial
separation set. The main result is that the BC-algorithm works
quite successfully in spite of this complication. A theoretical
introduction to the BC-method is included.