Research of Adhesion Bonds Between Gas-Thermal Coating and Pre-Modified Base

Nature of adhesive bonds between gas-thermal nickel alloy coating and carbon steel base was examined using laser profilometry, optical metallography, transmission and scanning electron microscopy. The steel surface was plastically pre-deformed by an ultrasonic tool. Proved that ultrasound pre-treatment modifies the steel surface. Increase of dislocation density and formation of sub micro-structure are base elements of surface modification. While using high-speed gas-flame, plasma and detonation modes of coatings, surface activation occurs and durable adhesion is formed. Ultrasonic pre-treatment of base material is effective when sprayed particles and base material interact through physical-chemical bond formation. Before applying high-speed gas flame and plasma sprayed coatings, authors recommend ultrasonic pretreatment, which creates periodic wavy topography with a stroke of 250 microns on the steel surface. Before applying detonation sprayed coatings, authors recommend ultrasound pretreatment that create modified surface with a uniform micro-topography

Research of surface activating influence on formation of adhesion between gas-thermal coating and steel substrate

Estimation of influence of physical and thermal activating on adhesion between steel substrates and thermal coatings has been performed. The substrates with surfaces obtained by and ultrasonic surface plastic deformation were used. To evaluate physical activating, preheating of the substrates to 600°С was performed. To evaluate the effect of thermal activating, the substrate surfaces after interfacial detachment were examined. Bonded areas on the substrate surfaces were measured by means of optical profilometry. The experiments have shown that surface physical activating is the main factor in formation of the adhesive bond between the coating and the substrate processed with the proposed methods

Effect of initial microtopography and ultrasonic treatment mode on steel surface layer quality

The article presents results of studies on the effect of pre-lathed surface micro-relief on surface micro-hardness after ultrasonic plastic treatment, as well as the effect of ultrasonic treatment on structure and properties of surface layers of steels 20 and 40X. The effect of ultrasonic treatment processing modes on roughness and micro-hardness of the surface layers was studied. It is shown that roughness values as well as form of ridges and grooves, obtained by pre-lathing, effect the growth of micro-hardness values after ultrasonic plastic treatment

Ultrasonic plastic deformation of steels

In the work we demonstrate the possibility of forming thin surface and near-surface layers with submicrocrystalline structure under ultrasonic plastic deformation of machined steels. Formation of fine gradient textures up to nanocrystalline allows significant changing physical and mechanical properties of machined steels. Ensures improvement of microstructure, produces internal compressive strains which improves the cyclic strength of machine parts

Automated verification of countermeasure against detector-control attack in quantum key distribution

Attacks that control single-photon detectors in quantum key distribution using tailored bright illumination are capable of eavesdropping the secret key. Here we report an automated testbench that checks the detector's vulnerabilities against these attacks. We illustrate its performance by testing a free-running detector that includes a rudimentary countermeasure measuring an average photocurrent. While our testbench automatically finds the detector to be controllable in a continuous-blinding regime, the countermeasure registers photocurrent significantly exceeding that in a quantum regime, thus revealing the attack. We then perform manually a pulsed blinding attack, which controls the detector intermittently. This attack is missed by the countermeasure in a wide range of blinding pulse durations and powers, still allowing to eavesdrop the key. We make recommendations for improvement of both the testbench and countermeasure.Comment: 11 pages, 11 figures. Revised after referee reports from EPJ Quantum Techno

Interferon lambda protects the female reproductive tract against Zika virus infection

Zika virus infections can cause devastating congenital birth defects but the underlying interactions with the host immune system are not well understood. Here, the authors examine the immune basis of vaginal protection and susceptibility to Zika viral infection, and identify a hormonal dependent role for interferon-lambda-mediated protection against disease

Effect of nanosecond repetitive pulsed microwave exposure on proliferation of bone marrow cells

The purpose was to study the proliferative activity of bone marrow mononuclear cells (BMNCs) of rats after irradiated by nanosecond repetitive pulsed microwave (RPM). It was found that the irradiated by nanosecond microwave pulses can affect the BMNCs proliferation in vitro. It is important that both stimulation and inhibition of proliferation were observed after exposure. The effect depended on the pulse repetition frequency. The amount of BMNCs increased after exposure to pulse repetition frequency of 13 Hz up to 30% in comparison with a control cells and up to 51% in comparison with a falseirradiated cells. In contrast, there was inhibition up to 40% of BMNCs after exposure to a frequency of 8 Hz, in comparison with a control group