Evolution of transition metal dichalcogenide film properties during chemical vapor deposition: from monolayer islands to nanowalls.

Unique properties possessed by transition metal dichalcogenides (TMDs) attract much attention in terms of investigation of their formation and dependence of their characteristics on the production process parameters. Here, we investigate the formation of TMD films during chemical vapor deposition (CVD) in a mixture of thermally activated gaseous HS and vaporized transition metals. Our observations of changes in morphology, Raman spectra, and photoluminescence (PL) properties in combination withmeasurements of the electrical conductivity of the deposits formed at various precursor concentrations and CVD durations are evidence of existence of particular stages in the TMD material formation.

Nano- and micro-crystalline diamond film structuring with electron beam lithography mask.

Direct current plasma enhanced chemical vapor deposition (CVD) was employed to create polycrystalline diamond films from CH/Hgaseous mixture at 98 mbar pressure and various substrate temperatures between 720 °C and 960 °C. The Si chips with patterns of periodic masked and open seeded zones were used as substrates. The mask free seeded areas evolved into polycrystalline diamond films after CVD process.

Nano-graphite field-emission cathode for space electric propulsion systems.

Improving the thruster efficiency is a crucial challenge for the development of space electric propulsion systems, especially advanced air-breathing thrusters utilizing the surrounding rarefied atmosphere as fuel. A significant reduction in thruster power consumption can be achieved by using field emission (FE) cathodes that do not require heating and have the highest energy efficiency. In this work, we study FE from nano-graphite thin films, consisting of carbon nanostructures with a high aspect ratio, and demonstrate their suitability for use in the space electric propulsion systems.

Single-Crystal Diamond Needle Fabrication Using Hot-Filament Chemical Vapor Deposition.

Single-crystal diamonds in the form of micrometer-scale pyramids were produced using a combination of hot-filament (HF) chemical vapor deposition (CVD) and thermal oxidation processes. The diamond pyramids were compared here with similar ones that were manufactured using plasma-enhanced (PE) CVD. The similarities revealed in the morphology, Raman, and photoluminescent characteristics of the needles obtained using the hot-filament and plasma-enhanced CVD are discussed in connection with the diamond film growth mechanism.

Macro-, Micro- and Nano-Roughness of Carbon-Based Interface with the Living Cells: Towards a Versatile Bio-Sensing Platform.

Integration of living cells with nonbiological surfaces (substrates) of sensors, scaffolds, and implants implies severe restrictions on the interface quality and properties, which broadly cover all elements of the interaction between the living and artificial systems (materials, surface modifications, drug-eluting coatings, etc.). Substrate materials must support cellular viability, preserve sterility, and at the same time allow real-time analysis and control of cellular activity.

Circular photocurrent in the carbon nanowall film.

We report the helicity-dependent photocurrent in the carbon nanowall film synthesized on the silicon substrates by the chemical vapor deposition technique. The film is composed of multilayer graphene flakes grown along the substrate normal. We measured the transverse photocurrent generated in the film under irradiation with nanosecond laser pulses by depositing two conductive electrodes along the plane of incidence.

Conduction mechanisms and voltage drop during field electron emission from diamond needles.

We report results of experimental investigation of field electron emission from diamond nanoemitters. The measurements were performed with single crystal diamond needles fixed at tungsten tips. The voltage drop along diamond needles during emission was revealed and measured using electron energy spectroscopy.

Photoassisted and multiphoton emission from single-crystal diamond needles.

Practical realization of stable and high brightness sources of ultra-short electron pulses is an important issue in the development of time-resolved electron microscopy for the study of ultra-fast dynamics in materials. Here, we report on the experimental investigation of static (in the dark) and pulsed (under illumination by sub-picosecond laser pulses at 1040 nm) electron emission from single-crystal diamond needles. A significant increase of electron emission current was detected under laser illumination.

[Degenerative alterations of the afferent artery in long-functioning arteriovenous fistula].

Discussed in the article is the literature data on the background, causes, and mechanisms of the development of degenerative aneurysmatic transformation of the afferent artery in a long-functioning arteriovenous fistula. This is followed by presenting two own clinical case reports concerning the development of pronounced dilatation of arteries during 13 and 25 years of the existence of posttraumatic arteriovenous anastomoses, with a detailed description of the variants of surgical treatment of these patients.

Optical Contactless Measurement of Electric Field-Induced Tensile Stress in Diamond Nanoscale Needles.

The application of a high electrostatic field at the apex of monocrystalline diamond nanoscale needles induces an energy splitting of the photoluminescence lines of color centers. In particular, the splitting of the zero-phonon line of the neutral nitrogen-vacancy complex (NV) has been studied within a laser-assisted tomographic atom probe equipped with an in situ microphotoluminescence bench. The measured quadratic dependence of the energy splitting on the applied voltage corresponds to the stress generated on the metal-like apex surface by the electrostatic field.

Single Crystal Diamond Needle as Point Electron Source.

Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported.

Structural peculiarities of single crystal diamond needles of nanometer thickness.

Diamond is attractive for various applications due to its unique mechanical and optical properties. In particular, single crystal diamond needles with high aspect ratios and sharp apexes of nanometer size are demanded for different types of optical sensors including optically sensing tip probes for scanning microscopy. This paper reports on electron microscopy and Raman spectroscopy characterization of the diamond needles having geometrically perfect pyramidal shapes with rectangular atomically flat bases with (001) crystallography orientation, 2-200 nm sharp apexes, and with lengths from about 10-160 μm.

[Diagnosis and treatment of peripheral arterial aneurysms in lower limbs].

Authors analyzed a five years experience of the diagnosis and treatment of peripheral arterial aneurysms in the Center of vascular surgery of the multidisciplinary military hospital. Authors give the assessment of different diagnostic instrumental methods and demonstrate results of surgical treatment. The possibility and effectiveness of endovascular-traumatic method of surgical correction of this pathology of lower limb arteries are given.

All-optical control of ultrafast photocurrents in unbiased graphene.

Graphene has recently become a unique playground for studying light-matter interaction effects in low-dimensional electronic systems. Being of strong fundamental importance, these effects also open a wide range of opportunities in photonics and optoelectronics. In particular, strong and broadband light absorption in graphene allows one to achieve high carrier densities essential for observation of nonlinear optical phenomena.

[Treatment of rupture of abdominal aortic aneurism in multi-field military hospital].

For the last 5 years in the center of vascular surgery of Vishnevskiy 3rd Central Military Clinical Hospital 218 patients with abdominal aortic aneurism were treated, 96 planned surgical operations for abdominal aortic aneurism (post-operative mortality 3.1%) were performed. 11 patients underwent urgent surgical operation because of rupture of abdominal aortic aneurism.

A nano-graphite cold cathode for an energy-efficient cathodoluminescent light source.

The development of new types of light sources is necessary in order to meet the growing demands of consumers and to ensure an efficient use of energy. The cathodoluminescence process is still under-exploited for light generation because of the lack of cathodes suitable for the energy-efficient production of electron beams and appropriate phosphor materials. In this paper we propose a nano-graphite film material as a highly efficient cold cathode, which is able to produce high intensity electron beams without energy consumption.

[Treatment of vascular implants' infections in aortic position].

Nowadays the infection of a vascular implants in abdominal aorta is the heaviest and terrible complication in vascular surgery. Frequency of suppuration of vascular implants in aortic position is from 1 up to 3,5%, with lethality from 21 up to 80%. Average age is 61,4 +/- 4,3 years.

[Successful treatment of aneurysm of iliac artery in old patient with widespread atherosclerosis of aorta].

Disclosure of aneurysm of abdominal aorta indicates severity and prevalence of atherosclerotic process which means high probability of combined occlusive affections in other arterial circulations. Authors treated the patient with aneurysm of iliac artery with widespread atherosclerosis of aorta taking into account the abovementioned facts. Right stage surgical tactics assured success.

[Surgical treatment of chronic abdominal ischemia].

The study includes data of 139 patients with chronic abdominal ischemia, due to hemodynamically significant occlusion of impaired visceral aortic branches. The diagnosis was confirmed by aortography, computed tomoangiography and duplex color angioscanning. Immediate and long-term results of 49 reconstructive and conditionally reconstructive operations, 11 transcutaneous endovascular angioplasty, as well as postoperative complications, were analyzed.

Broadband light-induced absorbance change in multilayer graphene.

We report the ultrafast light-induced absorbance change in CVD-grown multilayer graphene. Using femtosecond pump-probe measurements in 1100-1800 nm spectral range, we revealed broadband absorbance change when the probe photon energy was higher than that of the pump photon. The observed phenomenon is interpreted in terms of the Auger recombination and impact ionization playing a significant role in the dynamics of photoexcited carriers in graphene.

Invited article: Electric solar wind sail: toward test missions.

The electric solar wind sail (E-sail) is a space propulsion concept that uses the natural solar wind dynamic pressure for producing spacecraft thrust. In its baseline form, the E-sail consists of a number of long, thin, conducting, and centrifugally stretched tethers, which are kept in a high positive potential by an onboard electron gun. The concept gains its efficiency from the fact that the effective sail area, i.

[Topographic-anatomic grounding cervical-distalvertebral reconstruction of V3 segment vertebral artery vertebral artery].

Using 10 block-mounts "brain-base of skull- cervical spine" there were detected morphometric peculiarities of vertebral artery on the level C(I)-C(II) of spines of vertebra and of premastoidal part of cervical artery. Were effectuated 20 distalvertebral reconstructions. Were precised stages and technique of realization.

Single crystal diamond tips for scanning probe microscopy.

Single crystal diamond tips with perfect pyramidal geometry were obtained by a combination of chemical vapor deposition and selective oxidation of polycrystalline films. The parameters of the deposition process were chosen to provide growth of a textured film consisting of micrometer sized diamond crystallites embedded into nanodiamond ballas-like material. The heating of the film in an air environment was used for selective oxidation of the nanodiamond component.

[Diagnosis and surgical methods of managing patients with chronic abdominal ischaemia].

Presented herein are the findings of examination of sixty-two patients with clinical manifestations of chronic abdominal ischaemia predominantly induced by stenosis of the celiac trunk. The authors carried out a comparative analysis of efficacy of instrumental methods of diagnosis of chronic abdominal ischaemia syndrome, having also investigated the lesions of the visceral branches by the findings of angiography. Also presented herein are the outcomes of various methods of surgical correction: 47 reconstructive and conditionally reconstructive operations, 10 transcutaneous endovascular angioplasties, also considering complications of the immediate postoperative period as well as short- and long-term outcomes of surgical treatment.

A novel method for metal oxide nanowire synthesis.

Nanowires (NWs) of metal oxides (Fe(2)O(3), CuO, V(2)O(5) and ZnO) were grown by an efficient non-catalytic economically favorable method based on resistive heating of pure metal wires or foils at ambient conditions. The growth rate of iron oxide NWs exceeds 100 nm s(-1). Produced NWs were typically 1-5 microm long with diameters from 10 to 50 nm.