Scanning superconducting quantum interference device on a tip for magnetic imaging of nanoscale phenomena

We describe a new type of scanning probe microscope based on a superconducting quantum interference device (SQUID) that resides on the apex of a sharp tip. The SQUID-on-tip is glued to a quartz tuning fork which allows scanning at a tip-sample separation of a few nm. The magnetic flux sensitivity of the SQUID is 1.8 μΦ(0)/Hz and the spatial resolution is about 200 nm, which can be further improved. This combination of high sensitivity, spatial resolution, bandwidth, and the very close proximity to the sample provides a powerful tool for study of dynamic magnetic phenomena on the nanoscale. The potential of the SQUID-on-tip microscope is demonstrated by imaging of the vortex lattice and of the local ac magnetic response in superconductors.     

Resonant control of an atomic force microscope micro-cantilever for active Q control

Active Q control may be used to modify the effective quality (Q) factor of an atomic force microscope (AFM) micro-cantilever when operating in tapping mode. The control system uses velocity feedback to obtain an effective cantilever Q factor to achieve optimal scan speed and image resolution for the imaging environment and sample type. Time delay of the cantilever displacement signal is the most common method of cantilever velocity estimation. Spill-over effects from unmodeled dynamics may degrade the closed loop system performance, possibly resulting in system instability, when time delay velocity estimation is used. A resonant controller is proposed in this work as an alternate method of velocity estimation. This new controller has guaranteed closed loop stability, is easy to tune, and may be fitted into existing commercial AFMs with minimal modification. Images of a calibration grating are obtained using this controller to demonstrate its effectiveness.     

Variable heat flux in numerical simulation of grinding temperatures

In this paper, temperature results obtained by numerical simulations based on three different methods of defining the heat flux load distribution are compared to directly measured temperatures acquired using infrared camera measurement techniques. The heat flux calculations are based on recorded instantaneous grinding power, average grinding power, and power calculated by multiplying the measured tangential forces and the cutting velocity (referred to as calculated power). The results show that the method applied to characterize the input flux load in the numerical model has a significant effect on the estimated grinding temperatures and that the calculated power data produce the best temperature results.     

Studying the Possibility of Using Avalanche Photodetectors in the Single-photon Registration Mode to Create Quantum Random-number Generators

The possibility of using avalanche photodiodes that operate in the single-photon registration mode as a source of a random physical quantity in generators of random number sequences was evaluated. The operating modes of avalanche photodiodes were determined that allow generation of streams of random events, whose statistical characteristics are similar to those of a Poisson stream. Estimates of the similarity of the properties of generated random binary sequences to the properties of a uniformly distributed sequence are presented.     

Measurement of the Dead Time of an Optoelectronic Streak Camera with Different Linear Sweep Ranges

A method for measuring the dead time of an optoelectronic streak camera with different linear sweep ranges is described. The proposed method was used for the PN-1 streak camera. Photographs of the time-resolved emission of a DRSh350-2 mercury arc flash lamp for linear sweep ranges of 50 and 100 ns are presented. The dead times of the PN-1 streak camera for linear sweep ranges of 25, 50, and 100 ns were 5, 75, and 105 ns, respectively. The photographs of time-resolved second-harmonic spectra emitted by plasmas of copper and aluminum targets that were obtained in experiments on the interaction of nanosecond laser radiation with the matter using a streak camera are presented.     

DIUS-1.15M Mobile Hardware–Software Structuroscopy System

It is shown that by measuring the magnetic field in a specially shaped hole made in the magnetic circuit of a measuring transducer and the tangential component of the magnetic field in the transducer’s interpolar space near the surface of an object being magnetized, it is possible to locally determine the relative values of the magnetic properties of the test-object substance. The physical rationale is provided for a technique that makes it possible to determine the entirety of hysteresis characteristics and significantly expand the ranges of measurement of magnetic properties. The difference is established between the structural sensitivities of magnetic properties locally determined in terms of “flux–internal field” (the properties of matter) and “flux in the product–current in the windings” (the properties of “body”) coordinates. It is shown that it is possible and expedient to simultaneously measure and jointly analyze the magnetic characteristics of matter and “body”. Information is provided on the DIUS-1.15M mobile hardware–software system, intended for implementing single- and multiparameter techniques of monitoring the structure–phase and stress–strain states of ferromagnetic materials and objects based on the proposed measurement procedures.     

Vision of Genesis of Presentation of Hi-Tech Project during Competitive Selection

The presentation of high-tech projects (including research and development projects) submitted to funding competitions is considered. Two-stage development of such presentations is proposed. The first step is to ensure that the selected set of characteristics is representative and may be estimated with sufficient precision. The next step is to introduce a mathematically formalized business model of the project, permitting its financial evaluation. This model must adequately and transparently identify the financial potential of the economic cluster that will implement the submitted project. Embodied in software, this model must support stress testing of the high-technology project and optimization of its characteristics.     

Assessing the Difficulty and Cost of Research and Development for the Case of Distributed Aviation Systems

Assessment of the difficulty and cost of research and development relating to distributed aviation systems is considered. A problem is that the participants in development projects may assess them subjectively. Analysis of the basic methods used to assess the difficulty and cost of research and development in industry and associated fields reveals their deficiencies.     

Mechatronic Motorized Spindle with Hydrostatic Bearings and a Piezohydraulic Generator of Resonant Axial Microoscillations

A mechatronic motorized spindle with hydrostatic bearings and a contact-free piezohydraulic generator of resonant axial spindle microoscillations is proposed. The boundary problem is solved for a nonsteady Reynolds equation in laminar motion, with no cavitation of the working fluid. On that basis, analytical formulas are derived for the dynamic-pressure distribution of the working fluid and the dynamic axial force created in the gap of the piezohydraulic generator.