The use of wavelet transformations to measure the angular dependence of the reflection coefficient of radio-absorbing coatings over a superbroad frequency band

A method of measuring the angular dependence of the power reflection coefficient of a radio-absorbing coating over a superbroad frequency band using the decomposition and approximation of the pulse characteristics by wavelet functions is considered. __________ Translated from Metrologiya, No. 3, pp. 22–30, March, 2008.     

Method of determining dynamic adiabatic compression curves of powders

A method is described for investigating the dynamic adiabatic compression curves of powders by measuring of the pulsed pressure in a powder pressed uniaxially by an elastic instrument. The instantaneous powder density is determined by numerical solution of a pulsed spectral problem using the pressing pressure pulse and the known characteristics of the pressing instrument and the external force. Pis’ma Zh. Tekh. Fiz. 23, 76–80 (July 12, 1997)     

Instruments for measuring the energy parameters of kinetron fluxes

Practical methods of measuring the energy parameters of kinetron fluxes using the Lorentz effect, due to the excitation of kinetron fluxes by a moving magnetic field, which initiate a current in the collector coil of a measuring system, are considered. Fairly simple specific designs of the measuring instruments are described. Translated from Izmeritel’naya Tekhnika, No. 5, pp. 62–66, May, 2009.     

An investigation of the uncertainty in reproducing the units of pulsed electric and magnetic field strengths in a standard system for producing very-short electromagnetic pulses with a rise time of 20 psec

A method of reproducing the units of pulsed electric and magnetic field strength in a standard system with a pulse rise time of less than 20 psec, constructed using a “cone over a plane” field-generating system is considered. The components of the uncertainty in reproducing the units are analyzed. The extended uncertainty is not greater than 6.5%.     

脉冲测试系统最佳带宽的数值计算

由于受测试系统带宽的限制，脉冲信号在测试过程中其能量将受到不同程度的损失。本文用Romberg数值积分法计算出在一定能量损耗限值要求下的脉冲信号频谱宽度，并用付氏级数对其进行了信号重构验证，据此得出了脉冲信号测试系统带宽的最佳值。     

Features of the procedure for measuring the amplitude backscattering diagrams of very large objects using ground radar measuring systems

A procedure for measuring the backscattering diagrams of large objects is considered, which reduces the components of the error due to the long-term instability of the parameters of radar measuring stations, when using a calibration without removing the object being investigated from the operating region of the measuring system. The results of an experimental check of the procedure are presented. __________ Translated from Izmeritel’naya Tekhnika, No. 6, pp. 48–50, June, 2008.     

Measurement of piezoelectric modulus by pulsed excitation of piezoelectric ceramic elements

The possibility of measuring the piezoelectric modulus by exciting piezoelectric ceramic components with a radio pulse is considered. It is shown that there is a relation between the piezoelectric modulus and the rate of change of the current envelope at the beginning of the transient. Theoretical relations are derived. __________ Translated from Izmeritel’naya Tekhnika, No. 10, pp. 71–72, October, 2006.     

A method of improving the metrological characteristics of contactless conductometers

A method of improving the metrological characteristics of monitoring instruments, based on the use of a system of coupled oscillations as a highly sensitive recorder of the state of balance of a measuring circuit and simultaneously as a converter of the measured and compensating quantities in the information signal is considered. It is shown that it is possible to improve the metrological characteristics by constructing an intelligent measuring mechanism using a system of active interacting components. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 58–61, May, 2007.     

Development of single frame X-ray framing camera for pulsed plasma experiments

A single-frame X-ray framing camera has been set up for fast imaging of X-ray emissions from pulsed plasma sources. It consists of two parts, viz. an X-ray pin-hole camera using an open-ended microchannel plate (MCP) detector coupled to a CCD camera, and a high voltage short duration gate pulse for the MCP. The camera uses a 10-Μm pin-hole aperture for imaging on the MCP detector with a magnification of 6 X. The high voltage pulser circuit generates a pulse of variable duration from 5 to 30 ns (at 70% of peak amplitude) with variable amplitude from 800 V to 1.25 kV, and is triggered through a laser pulse synchronized with the event to be recorded. The performance of the system has been checked by recording X-ray emission from a laser-produced copper plasma. A reduction factor of ∼ 6.5 is seen in the dark current contribution as the MCP gate pulse is decreased from 250Μs to 5 ns duration.     

Thermophysical Analysis of Sandstone by Pulse Transient Method

Stones belong to porous materials where water in pores plays an important role during the freeze–thaw process. A thermophysical analysis based on the pulse transient method has been used to study an ageing cycle, namely the freeze–thaw cycle. Thermophysical analysis is based on measuring the thermophysical properties under specific thermodynamic conditions. The transient method determines the specific heat, thermal diffusivity, and thermal conductivity by a single measurement. A specimen of Sander sandstone was analyzed in both dry and water-saturated states. Typical anomalies of all thermophysical parameters at the freeze–thaw point as well as differences for the dry and saturated states were found. The changes of thermophysical parameters measured when using freeze–thaw cycles correspond to stone ageing. The freeze–thaw cycle can often be encountered in building physics, concrete construction, etcPaper presented at the Seventh Asian Thermophysical Properties Conference, August 23–28, 2004, Hefei and Huangshan, Anhui, P. R. China.     

On non-fourier temperature wave and thermal relaxation time

In this paper, the non-Fourier effects in a material under heating flux with an actual pulse and periodic temporal profile are investigated after introducing the physical mechanism of the thermal relaxation model. By using the analytical solution of the non-Fourier hyperbolic conduction equation, a discussion about the wave characteristics of non-Fourier conduction is given, and the manner in which relaxation time affects the temperature behavior is discussed. Then a measuring method for the relaxation time is suggested for these two kinds of heating flux. Paper presented at the Fourth Asian Thermophysical Properties Conference, September 5–8, 1995, Tokyo, Japan.     

New Method for Measuring Statistical Distributions of Partial Discharge Pulses

A new digital detection system is described for measuring pulsating partial discharges (PDs). The PD detection system can continuously record all PD pulses that occur over extended periods of time, with a minimum inter-pulse time separation of 6 μs and a vertical amplitude resolution of 12 bits. Earlier PD detection systems detected PD pulse amplitude and time using complex custom-designed hardware while the present system continuously records the complete electrical waveform that carries the PD pulses using a commercial data acquisition board and extracts, in real time, the time and amplitude information of all PD pulses in software. The current approach considerably reduces the development and maintenance cost of the PD detection system, significantly increases the system portability, and may prove to be a crucial step for transferring the digital PD detection and analysis technology developed in laboratories to industry. The features of the new system are illustrated by the study of dc-excited PD pulses occurring in a point-to-plane gap in air. A new surface-mediated burst mode of PDs is discovered in which a PD pulse has a certain probability to induce another pulse. The probability is determined for several gap voltages and is found to vary strongly with the applied voltage.     

The growth and characterisation of Ni5Zn21 dendrites

We have investigated the growth of Ni–Zn alloys by a dc electrodeposition method and a pulse dc electrodeposition method with different pulse frequencies, under otherwise the same growth conditions. Dendritic growth is found in the Ni–Zn alloys produced by pulse dc electrodeposition, whereas such growth is absent in those fabricated by dc electrodeposition. The morphology of the as-grown Ni–Zn dendrites is highly influenced by the pulse frequency. The possible growth mechanism has been discussed. The corresponding magnetic properties are investigated at 5 K using a superconducting quantum interference device. We have observed a clear variation in the magnetisation behaviour as the pulse frequency is changed, which is likely to be attributable to the presence of precipitation of Ni nanoparticles.     

A 1000-measurement frames/second ERT data capture system with real-time visualization

This paper describes the design of a 16-electrode high-speed (1000 frames/s) electrical resistance tomography system with real-time visualization. The instrument utilizes a switched dc current pulse technique in conjunction with parallel data acquisition to achieve the high-data capture rates. The reconstruct algorithm is implemented using a single iteration Newton-Raphson method, which executes in under 1 ms. Data sets are presented that verify its operation. A calibration technique is described which improves the sensitivity of the current pulse measuring system and allows phenomena such as the dynamics of nonuniform slurries and gas distribution in aeration systems to be investigated. Furthermore, the calibration scheme described compensates significantly for the effect of impellers and baffles present in the measuring tank and allows more accurate reconstructions to be performed in the areas of interest.     

基于随动测量系统的步进电机跟踪精度研究

利用ARM控制系统实现齿轮测量仪的两轴随动控制,完成齿轮螺旋线高精度测量.根据步进电机脉冲信号和步距角的线性关系,采用ARM系统输出频率脉冲控制步进电机,由于步进电机只有周期误差而无累积误差,系统能够实现齿轮螺旋线偏差快速、准确测量.与现有系统比较,本系统具有控制精度高、测量速度快、误差精度高的特点,能够实时、动态显示测量误差.     

Block diagrams for information measuring systems of physicochemical composition and substance properties

Block diagrams for information measuring systems of physicochemical composition and substance properties are considered and it is noted that within their composition there should be first level systems that are either independent measuring systems, or measuring sub-systems of a second level system, or management information measuring systems. Translated from Izmeritel’naya Tekhnika, No. 10, pp. 57–60, October, 2008.     

Measurements of the Thermal Effusivity of a Drop-Size Liquid Using the Pulse Transient Hot-Strip Technique

The thermal effusivity of drop-size liquids was measured by the pulse transient hot-strip technique. A strip sensor, used as a thermometer and heat source, is deposited on a smooth surface of an electrically insulating background material – onto which an insulating liquid sample is applied, completely covering the strip probe. Experiments can be made controlling the thermal penetration depth to within some 10 μm of the liquid sample – here demonstrated by measuring a drop of water at about 1% uncertainty. Measurements were made on water and a series of silicone oils (kinematic viscosity from 5 to 50 cSt; 1 cSt = 10⁻⁶ m²· s⁻¹) in microgravity conditions using a 10 m drop tower (10⁻³ g, 1.4 s), to investigate if any potential natural convection in the liquid at normal gravity condition is present, influencing the results. However, no such influence was observed. Paper presented at the Fifteenth Symposium on Thermophysical Properties, June 22–27, 2003, Boulder, Colorado, U.S.A.     

An estimate of the accuracy of object positioning using the mobile communications infrastructure

An estimate of the limit accuracy and the possible construction of an autonomous object positioning system using the mobile communications infrastructure (relay towers, cellphones, and additional measuring systems) without constantly making use of satellite navigation systems are presented. It is shown that, using such a system, one can determine the position of objects with an error of 10–20 mm.     

Designing a computerized metrological production support system based on cals technologies

Designing a computerized metrological support system is considered, which incorporates not only metrological considerations on measuring instruments but also the computerized choice of production preparation facilities. Representations are considered for information on measuring instruments that allow one to integrate the metrological system in a unified CALS system for the organization. __________ Translated from Izmeritel’naya Tekhnika, No. 6, pp. 22–26, June, 2006.     

Transient processes near the threshold of subharmonic resonance

Instability of a dynamical system near a subharmonic resonance is manifested in the prolongation of transient processes. It is shown for nonlinear pulsations of a gas bubble under the action of an acoustic carrier signal modulated by a pulse that the subharmonic radiation observed experimentally below the generation threshold can be explained by the contribution of characteristic oscillations which arise at the moment the pulse arrives and have a damping time comparable to the pulse duration, due to the parametric energy transfer. Pis’ma Zh. Tekh. Fiz. 25, 1–6 (September 12, 1999)