To the modeling of processes with repeated damped collisions

The problem of calculating and analyzing vibro-impact processes with bounce in two colliding subsystems is considered. The nature of these processes depends on the adopted models of energy dissipation and the design features of the colliding objects. A method for constructing the laws of motion is presented, based on the technique of averaging in vibro-impact systems. Examples are given. The determining role of energy dissipation models is shown. The results can be used, for example, in the calculation and analysis of specific phenomena that arise in the elements of switching devices, as well as in many other systems whose operation is accompanied by repeated damped collisions

Comparison of Lower and Middle Riphean sparry magnesite deposits of the Southern Urals province

Sparry magnesite deposits (SMD) of the Lower Riphean (LR) and Middle Riphean (MR) sequences in the western slope of the South Urals have some distinguished peculiarities, which allows to compare them and speculate about the mechanism of ore formation and Mg-source origin. LR magnesites are located in some stratigraphic levels and lie within widespread dolostone horizons. MR magnesites that occur in the lower carbonate member of Avzyan fm. are represented by dolomitized limestones. The shape of LR magnesite body is very often layer-like with sharp contacts. The shape of MR one is sometimes lens like, contacts of ore body are complecated with zones of impregnable magnesites near the hosting dolomites. The crystalline structures of LR magnesites are typically corse-grained with average size of crystalls 10 mm. The magnesite grains of the MR one have 1-3 mm of average size. The chemical composition of MR magnesite ore shows increase of SiO 2 , Al 2 O 3 , FeO and decrease of LREE fractionation in comparison with the LR magnesites. As we assume, metasomatic magnesites of the Lower Riphean time are connected with sedimentation/early diagenesis stage. The source of Mg 2+ came from a crust of weathering of basic and ultramafic rocks in humid climate. Magnesite occurrences in Middle Riphean time are connected with high Fe-contents metasomatic fluids, which were resulted of evaporite Mg-enriched solutions transformation during kathagenesis

Aluminum Single Electron Transistors with Islands Isolated from a Substrate

The low-frequency noise figures of single-electron transistors (electrometers) of traditional planar and new stacked geometry were compared. We observed a correlation between the charge noise and the contact area of the transistor island with a dielectric substrate in the set of Al transistors located on the same chip and having almost similar electric parameters. We have found that the smaller the contact area the lower the noise level of the transistor. The lowest noise value 8*10E-6 e/sqrt(Hz) at f = 10 Hz. has been measured in a stacked transistor with an island which was completely isolated from a substrate. Our measurements have unambiguously indicated that the dominant source of the background charge fluctuations is associated with a dielectric substrateComment: Review paper, latex, 10 pages, 7 figures, to be publ. in JLTP, 2000; Proceeding of "Electron Transport in Mesoscopic Systems", August 12-15, 1999 Geteborg, Sweden, http://fy.chalmers.se/meso_satellite/index.html See also LT22 manuscript: http://lt22.hut.fi/cgi/view?id=S1113

Vibration of string lattice

A two-dimensional system oscillation with massive bodies located in lattice nodes is investigated in this paper. The results of theoretical analysis and of the performed experiments are given. Certain modes of the oscillation of lattices of different dimensions are described

Micromechanical electrometry of single-electron transistor island charge

We consider the possibility of using a micromechanical gate electrode located just above the island of a single-electron transistor to measure directly the fluctuating island charge due to tunnelling electrons.Comment: To appear in Phonons 2001 Proceedings (Physica B

Metallic single-electron transistor without traditional tunnel barriers

We report on a new type of single-electron transistor (SET) comprising two highly resistive Cr thin-film strips (~ 1um long) connecting a 1 um-long Al island to two Al outer electrodes. These resistors replace small-area oxide tunnel junctions of traditional SETs. Our transistor with a total asymptotic resistance of 110 kOhm showed a very sharp Coulomb blockade and reproducible, deep and strictly e-periodic gate modulation in wide ranges of bias currents I and gate voltages V_g. In the Coulomb blockade region (|V| < 0.5 mV), we observed a strong suppression of the cotunneling current allowing appreciable modulation curves V-V_g to be measured at currents I as low as 100 fA. The noise figure of our SET was found to be similar to that of typical Al/AlOx/Al single-electron transistors.Comment: 5 pages incl. 4 fig

Noise in Al single electron transistors of stacked design

We have fabricated and examined several Al single electron transistors whose small islands were positioned on top of a counter electrode and hence did not come into contact with a dielectric substrate. The equivalent charge noise figure of all transistors turned out to be surprisingly low, (2.5 - 7)*10E-5 e/sqrt(Hz) at f = 10 Hz. Although the lowest detected noise originates mostly from fluctuations of background charge, the noise contribution of the tunnel junction conductances was, on occasion, found to be dominant.Comment: 4 pages of text with 1 table and 5 figure

Predictive analysis of rotor machines fluid-film bearings operability

The present paper considers a multi-criteria analysis algorithm of turbo generator fluid-film bearing operability and its connection with rotor machine monitoring system data. It is substantiated that implementation of predictive analysis of load capacity, locus curves and dynamic displacements allows prognosis of useful life of a fluid-film bearings and improvement of reliability of a rotor machine

Temperature Range for Metasomatism at the Bakalskoe Siderite Deposits with Use of Geochemical Data

На основе количественных микрозондовых определений состава парагенезов анкерит-сидерит в семи точках, приуроченных к разным частям Бакальского рудного поля, показано, что околорудные анкериты в западной и центральной частях рудного поля отличаются по средним концентрациям FeCO 3 (соответственно 14,21 и 20,84 мас. %), в то время как в составе сидероплезита этих объектов нет выраженных различий. Расчет температур магнезиально-железистого метасоматоза на основе анкерит-сидеритового и анкерит-брейнеритового геотермометров показал их совпадение при 250°С и выше. Средние температуры сидеритового метасоматоза составляют в центральной части Бакальского рудного поля 250−270°С, в периферической части - не выше 190−220°С и не зависят от положения сидеритовой залежи в стратиграфическом разрезе бакальской свиты.The data obtained with the quantitative microprobe ankerite–siderite composition analysis of seven samples from the different parts of Bakalskoe field showed that the wallrock ankerites in the western and central parts of the ore field differ in average concentrations of FeCO 3 (respectively 14.21 and 20.84 wt.%). However, there is no significant difference in composition of siderites. The calculation of the Mg-Fe metasomatism temperatures based on ankerite-siderite and ankerite-breinerite geothermometers showed the close agreement of the values of both methods at temperatures of 250 °C and above. The average temperatures of siderite metasomatism in the central part of the Bakalskoe ore field are in range 250-270 ° C, and, in the peripheral part, the determined temperature does not exceed 190-220 ° C. These values do not depend on the position of the siderite deposits in stratigraphic level of the Bakalskaya Suite