Error Corrections in a Sampling Sliding Along a Pulse Envelope Based on Decoding Tables

Code combinations of 2 ⁿ symbols +1 and –1 suggested for identification of characteristic features leading edge, trailing edge, maximum, minimum, horizontal portion, start of leading edge, end of leading edge, start of trailing edge, and end of trailing edge in a binary-code envelope of a pulse measured by an eddy-current transducer (ECT) scanning a tested surface generate a group code. This group code ensures for four levels of noise immunity the maximal likelihood in identification of reference sequences distorted by noise. The structure of a product code, which is also generated by the reference fragments, results in a higher capability of correcting for errors in moving samplings of signal envelopes, in particular, it reduces the degree of uncertainty in identification of the most important features of ECT pulses. The paper suggests simple decoding algorithms and regular logical structures that provide a high efficiency of the procedure eliminating errors in binary sequences of coded envelopes.     

Part family formation by memory association

Most of the part family formation methods are concerned with how to form the families as opposed to how to identify the families. However, a more appropriate approach would be to identify naturally occurring families since these methods are based on the production flow analysis, which uses already implemented routing data. This paper presents a new approach using the memory association of neural networks to identify naturally existing families. The developed system, Feature-Based Memory Association Network (FBMAN), operates by the exhaustive association approach which deals with the difficult problem of exceptional parts. Comparison with the results generated by other methods proves the effectiveness of FBMAN.     

A novel representation of tandem systems with inter-stage storage applied to on-line system monitoring

One of the goals of operating a tandem manufacturing system with finite inter-stage storage and asynchronous operations is to meet the demand without over-producing, under-producing or carrying large quantities of material in storage. We believe that analysing the operation of such a system on a real-time basis helps achieve this goal. The first step in this real-time analysis would be to quantitatively associate the causes and effects of over-production or under-production as they occur. This requires determining the cumulative effect that the performance that any stage has on the system, based on its history, the current system state and the interrelationships between the stages. This paper proposes a method which first represents uniquely and completely each stage and surrounding storage as an element. While this system, which consists only of this simple type of element functions in exactly the same way as the original one, each element is put into an ideal world for decoupled measurement. Though an element behaves in exactly the same way whether it is in the ideal world or in the real world, the elapsed times in the two worlds since the beginning of production can be different, since the responses (occurrences and durations of the blockings and starvations) of the two worlds can be different. A phase parameter is introduced for each element to represent this difference. Once the formation of the phase parameter of the output element is formulated, quantitative relationships between causes and effects of over-producing or under-producing can be explained as they occur.     

An Energy Source Based on Helical Explosion–Magnetic Generators for High-Impedance Loads

A transportable standard module developed at the Institute of Experimental Physics as a component of an energy source for modeling current pulses of positive lightning is described. The source is designed as a combination of several unified helical explosion–magnetic generators with output transformers and an inner diameter of the stator of 200 mm. According to our calculations, the source generates current pulses with an amplitude of up to 100 kA in loads with an inductance of 100 H and a resistance of several tens of ohms. The results from testing a typical module operating with a circuit having an inductance of 100 H and a resistance of 4 are presented. The experimental data coincide well with the results of a mathematical simulation of the module's operation.     

A Study of Distortions in Double-Sided Emulsion Films by FoMos

FoMos makes double-sided emulsion tapes. Films of desired size cut from such tapes are used as emulsion trackers. The technique for measuring distortions is described, and the results of measurements are presented for several films cut from different sections of a standard piece of double-sided tape with a length of 7 m and a useable width of 20 cm. The standard plastic base of the tape under investigation is 190 m thick; 50-m-thick layers of diluted PX3 emulsion–gel are applied to its opposite sides.     

Converting 80-character ASCII IGES sequential files into more conveniently accessible direct-access files

One of the main drawbacks of the Initial Graphics Exchange Specification (IGES) is the difficulty of accessing and retrieving the required information stored in the IGES files. This is because IGES files created by CAD systems are sequential. This paper describes a module, called readiges, which is a general-purpose software package for re-storing IGES files in more conveniently accessible direct-access files. Hence, readiges can be used in any research projects that use IGES to integrate CAD systems with other software packages, for example with finite-element packages for mesh-generation purposes or computer-aided process-planning systems.     

Measurement of the Background Level in the Spectra of Internal-Conversion Electrons Using the МАС-1 Microscope Complex

A method for measuring the spectral lines in an -50 photoemulsion plate with a varying background level is described. The -ray spectrograph of the Joint Institute for Nuclear Research's Laboratory of Nuclear Problems, was used to record the spectra. The plate was exposed to internal-conversion electrons produced by the decay of erbium isotopes (erbium fraction). The spectral measurements were performed using the -1 microscope complex. The distribution of the background level over the plate surface was measured. Using the L-structure of the -ray line of ¹⁶¹Ho with an energy of 175.5 keV as an example, it was shown that the accuracy of the intensity measurements was 10% or better. The accuracy in measuring the background level governed the accuracy in identifying the multipolarity of nuclear transitions. A precision TV system for data readout based on a 768 × 576 pixel CCD matrix provided a measurement accuracy of 0.5 m for both coordinates.     

Local High-Frequency Magnetron Reactive-Ionic Quartz Etching

A high-frequency magnetron reactive-ion etching system for the high-speed quartz glass surface treatment is described. The scanning assembly of the magnetron is located in a separate chamber pumped down to a pressure of 10^–2 Pa. This ensures a highly uniform etching and a high magnetic induction on samples, making it possible to reduce the cathode thickness. The quartz etching was studied in SF₆, CF₄, and CHF₃ with the magnetron operation with and without scanning. The maximum etching rates of 1.6 m/min (with scanning) and 4.2 m/min (without scanning) were attained in CHF₃ with a 1-Pa pressure and 700-W discharge power. 150-m-depth 4-mm-diameter pits were obtained by the quartz etching without scanning. With an increase in the pit depth from 150 to 250 m, the etching rate was reduced from 4.2 to 2.5 m/min.     

A Microwave Generator on a Gunn Diode with an Open Resonator

An oscillator on a Gunn diode with an open resonator is described. The diode is located in a cut of one of two mirrors, which consists of two parts. This mirror simultaneously plays a role of the electrodes and cooling system. The main characteristics of the oscillator operating at a frequency of 40 GHz are as follows: 30 mW (the output power), 20 kHz (the oscillation linewidth), 10^–7 (the relative short-term stability), and up to 2 GHz (the range of mechanical tuning within a single zone at a slope of the tuning characteristic of 1.19 GHz/mm).     

The ТЛ-1МП Thickness Meter for Galvanic Coatings

The specifics for monitoring the thickness of electrically- conductive coatings on a conductive substrate are described. Difficulties involved in designing thickness meters that assist in this task are noted. The technical characteristics and design of a -1 versatile eddy-current sensor are presented.     

A Shipborne Laser Fluorimeter for Studying Sea-Water Fluorescence Spectra

A shipborne laser fluorimeter making it possible to determine promptly the concentration of chlorophyll A in sea water is described. The measurement error is 35% at chlorophyll concentrations of 0.1–3 g/l, and the single-measurement duration is 1 min.     

Optical Transmission of Silica Fibers Exposed to γ Rays

The results of a study of the dynamics of an induced attenuation of light in optical fibers exposed to radiation are presented. The doses were as high as 10 and 100 Mrad at dose rates of 10 and 100 rad/s. Two types (silica–silica and polymer–silica) of fibers produced by INFOS (Russia), Polymicro (USA), and Hestibel (Turkey) were investigated.     

An integral method for measuring the <Emphasis Type="Italic">P</Emphasis>-odd asymmetry on a reactor at neutron polarization switching frequencies higher than the frequencies of the main spectrum of the neutron noise power

P-odd asymmetry is measured when frequencies of switching neutron polarization exceed the frequencies of the reactor power fluctuations that govern the spectral density of noise power. A principle for recording the current signals in these measurements is described. This method was used for the first time at the Konstantinov Institute of Nuclear Physics in Gatchina (Russia). The results suggest that the accuracy of measurements at an increased equipment-switching frequency is even higher than the accuracy obtained using compensation for reactor power fluctuations; hence, this compensation becomes superfluous. Following this method, it is possible to take measurements with a single detector and to dispense with a monitor, thereby rendering the equipment and the measuring technique less complex. A strategy of measurements was developed. An experimental model of the facility was produced and tested with a small-amplitude calibration signal in the presence of reactor power fluctuations caused by rays from reaction ¹⁰B(n )⁷ Li* ⁷Li + . The results from the test measurements of the P-odd effect in reaction ³⁵Cl(n, )³⁶Cl are presented.Translated from Pribory i Tekhnika Eksperimenta, No. 1, 2005, pp. 62–71.Original Russian Text Copyright ¢ 2004 by Vesna, Shulgina.     

The Tribological Properties of Monolayer KCl Films on Iron in Ultrahigh Vacuum: Modeling the Extreme-Pressure Lubricating Interface

The friction coefficients of thin KCl films deposited onto clean iron in ultrahigh vacuum are measured using a tungsten carbide tip. A rapid decrease is found in the friction coefficient from 2 for clean iron to 0.27 ± 0.03 after the deposition of 40 Å of KCl. Based on previous contact resistance measurements, this was proposed to be due to the completion of the first layer of KCl. The first-layer KCl coverage was measured by adsorbing deuterium onto an iron surface partially covered by KCl, where deuterium selectively adsorbs onto the iron. This revealed that the first monolayer is complete after the deposition of 40 Å of KCl and that the first-layer KCl film coverage _KCl ⁽¹⁾ is given by _KCl ⁽¹⁾ = 1 - exp(-0.39±0.02t), where t is the film thickness. XPS data suggest that heating a KCl film to 550 K causes it to wet the surface. This leads to decreases in the friction coefficients for thin KCl films in accord with the idea that friction is reduced by the first monolayer of KCl on iron. Temperature-programmed desorption data indicate that KCl in the first monolayer is 5 kJ/mol more stable than the multilayer consistent with the wetting behavior. Finally, the kinetic data are analyzed to suggest that the first-layer film is 2.6 Å thick.     

A Streak-Camera Neutron Monitor

The principle of a high-speed neutron monitor is based on neutron–proton conversion in a polyethylene converter. Protons thus produced are detected by an X-ray image-converter tube with a CsI photocathode. The monitor efficiency is 1.5 × 10^–3, its time resolution is 30 ps, and its spatial resolution is 100 m. The instrument is used to measure the time parameters of neutron fluxes in the ISKRA installations.     

A Position-Sensitive Detector for the Polarized-Neutron Spectrometer

A linear detector of thermal neutrons, developed at the Laboratory for High Energies (Joint Institute for Nuclear Research), is used in the polarized-neutron spectrometer of the -2 reactor (JINR). The data are acquired in the regime of frame-by-frame survey to select neutrons with a wavelength = 1–12 Å by the time of flight. The neutron-detection efficiency is 70% for a wavelength of 2 Å. The detector exhibits a low sensitivity to -rays, a differential nonlinearity of 1.5%, and a spatial resolution of 1.5 mm at counting rates of 10⁵events/s.     

Detection of the Increment of an Instantaneous Phase in a Long-Base Laser Meter of Small Vibrations

A phase meter for processing signals of a laser meter of small displacements and vibrations at long base distances is described. Vibrations of objects are transformed into small increments of a signal phase at an RF carrier, which are detected by the phase meter and are outputted as signals proportional to microvibrations in the acoustic range. At a given carrier frequency f _c = 10.7 MHz, vibrations are detected within a band f = 3 kHz. Such vibrations produce phase fluctuations of 10^–42, which correspond to magnitudes of 1 nm for a laser wavelength 10 m.     

Efficient Generation of Microwave Oscillations at Harmonics of the Conductance of a Gunn Diode

Basic characteristics of prototype oscillators operating at the second (19 GHz) and third (36 GHz) harmonics of the negative conductance of a 3715 Gunn diode are presented. The output power of these oscillators is 1.5–8.0 mW and the range of electronic frequency tuning is up to 390 MHz.     

A Combination β–γ-Radiometer and Dose-Rate Meter with an Extended Dynamic Range

A MKC-07 –-radiometer and dose-rate meter based on Geiger–Muller tubes is described. By using an unconventional signal-processing method, it is possible to extend the dynamic range of the instrument by a factor of 10–50, depending on the type and number of detectors in use, and to significantly reduce the error in measuring time-dependent ionizing-radiation intensities. The combination radiometer and dose-rate meter is used to determine the characteristics of constant and nonstationary ionizing-radiation fields.     

Measurement of Sub-Nanometer Lubricant Films Using Ultra-Thin Film Interferometry

The ultra-thin film interferometric method of measuring the thickness of very thin films in lubricated contacts has been refined so as to be able to measure films down to 0.3nm with a standard deviation of 0.15nm. The main remaining source of measurement variation for films below 3nm thick is the surface roughness of the contacting solids. This modified technique has been applied to study the film-forming properties of three fluids, hexadecane, a dilute solution of surfactant in hexadecane, and cyclohexane. Purified hexadecane shows a very slightly enhanced oil-film thickness below 1nm. The long-chain surfactant forms a boundary film 2nm thick. Cyclohexane behaves as though it forms a surface layer about 1nm thick with viscosity three times the bulk fluid viscosity.