Испытание изоляции вакуумного выключателя на трекингостойкость

Выпускная квалификационная работа содержит 146 с., 45 рисунков, 17 таблиц, 36 источников, 7 приложений. Ключевые слова: трекингостойкость, полиэтилен, стеклотекстолит, полистирол, оргстекло, винипласт, фторопласт, фарфор Объектом исследования являются электроизоляционные материалы подверженные трекингом. Цель работы – определение трекингостойкости различных электроизоляционных материалов. В процессе работы проводились экспериментальные испытания на трекингостойкость различных электроизоляционных материалов, согласно ГОСТ 27473. В результате выполнения работы была сконструирована установка для проведения испытаний на трекингостойкость, проведены эксперименты по определению трекингостойкости, оргстекла, фторопласта-4, фарфора, твердого поливинилхлорида ПВХ, полиэтилена низкого давления.Finale qualifiziert Arbeit enthält 146 p . , 45 Abbildungen, Tabellen 17, 36 Quellen 7-Anwendungen . Stichwort: -verfolgung , Polyethylen, Glasfaser , Polystyrol, Acryl, Vinyl -Liner , Teflon, Porzellan Die Aufgabe der Studie sind Isoliermaterialien anfällig für Verfolgung. Ziel - Definieren Verfolgung verschiedenen Dämmstoffen . In dem Prozess , ein Pilottest- Tracking von verschiedenen elektrischen Isoliermaterialien nach GOST 27473. der Durchführung Als ein Ergebnis der Arbeit für die Installation der on- Tracking- Tests entwickelt wurde, durchgeführten Experimente zu bestimmen -tracking , Plexiglas, PTFE -4 , Porzellan, aus Hart-Polyvinylchlorid PVC , HDPE, eine vergleichende Analyse von Dämmstoffen -tracking

Phase transitions and the internal noise structure of nonlinear Schr\"odi nger equation solitons

We predict phase-transitions in the quantum noise characteristics of systems described by the quantum nonlinear Schr\"odinger equation, showing them to be related to the solitonic field transition at half the fundamental soliton amplitude. These phase-transitions are robust with respect to Raman noise and scattering losses. We also describe the rich internal quantum noise structure of the solitonic fields in the vicinity of the phase-transition. For optical coherent quantum solitons, this leads to the prediction that eliminating the peak side-band noise due to the electronic nonlinearity of silica fiber by spectral filtering leads to the optimal photon-number noise reduction of a fundamental soliton.Comment: 10 pages, 5 figure

Influence of Feeding Regime on Growth and Body Size in the Boa (Boa Imperator)

Because snakes are gape-limited predators, much emphasis has been placed on the role of prey size in inducing plastic changes to trophic morphology. In contrast, few studies have researched the effect of feeding frequency on growth and body size, even though many snakes experience long fasting periods between meals. We conducted an experimental, multiple year study of growth in Boas, (Boa imperator) that experienced different feeding regimes. Three liters of full siblings were randomly assigned into two groups. One group received a meal equal to 5% of their body mass every 7 days and the other group received a meal equal to 25% body mass in food every 35 days. Using x-ray radiographs, we measured body size and a several skeletal morphological variables before the feeding regimes began and annually thereafter. We observed that those boas fed frequently grew larger in body mass and exhibited greater robustness, whereas boas feed infrequently had lower body mass and were laterally compressed. Our results suggest that phenotypic plasticity resulting from feeding frequency may play a role in morphological diversity. Further, the changes we observed mirrored the evolutionary changes of mainland and island populations boas from Central America

Efficient generation of correlated photon pairs in a microstructure fiber

We report efficient generation of correlated photon pairs through degenerate four-wave mixing in microstructure fibers. With 735.7 nm pump pulses producing conjugate signal (688.5 nm) and idler (789.8 nm) photons in a 1.8 m microstructure fiber, we detect photon pairs at a rate of 37.6 kHz with a coincidence/accidental contrast of 10:1 with a full-width-at-half-maximum bandwidth of 0.7 nm. This is the highest rate reported to date in a fiber-based photon source. The nonclassicality of this source, as defined by the Zou-Wang-Mandel inequality, is violated by 1100 times the uncertainty.Comment: 11 pages, 3 figure

Three thousand years of sexagesimal numbers in Mesopotamian mathematical texts

The Mesopotamian system of sexagesimal counting numbers was based on the progressive series of units 1, 10, 1\ub760, 10\ub760, …. It may have been in use already before the invention of writing, with the mentioned units represented by various kinds of small clay tokens. After the invention of proto-cuneiform writing, c. 3300 BC, it continued to be used, with the successive units of the system represented by distinctive impressed cup- and disk-shaped number signs. Other kinds of “metrological” number systems in the proto-cuneiform script, with similar number signs, were used to denote area numbers, capacity numbers, etc. In a handful of known mathematical cuneiform texts from the latter half of the third millennium BC, the ancient systems of sexagesimal counting numbers and area numbers were still in use, alongside new kinds of systems of capacity numbers and weight numbers. Large area numbers, capacity numbers, and weight numbers were counted sexagesimally, while each metrological number system had its own kind of fractional units. In the system of counting numbers itself, fractions could be expressed as sixtieths, sixtieths of sixtieths, and so on, but also in terms of small units borrowed from the system of weight numbers. Among them were the “basic fractions” which we would understand as 1/3, 1/2, and 2/3. In a very early series of metro-mathematical division exercises and an equally early metro-mathematical table of squares (Early Dynastic III, c. 2400 BC), “quasi-integers” of the form “integer plus basic fraction” play a prominent role. Quasi-integers play an essential role also in a recently found atypical cuneiform table of reciprocals. The invention of sexagesimal numbers in place-value notation, in the Neo-Sumerian period c. 2000 BC, was based on a series of innovations. The range of the system of sexagesimal counting numbers was extended indefinitely both upward and downward, and the use of quasi-integers was abolished. Sexagesimal place-value numbers were used for all kinds of calculations in Old Babylonian mathematical cuneiform texts, c. 1700 BC, while traditional metrological numbers were retained in both questions and answers of the exercises. Examples of impressive computations of reciprocals of many-place regular sexagesimal place-value numbers, with no practical applications whatsoever, are known from the Old Babylonian period. In the Late Babylonian period (the latter half of the first millennium BC), such computations were still popular, performed by the same persons who constructed the many-place sexagesimal tables that make up the corpus of Late Babylonian mathematical astronomy

Quantum limits to center-of-mass measurements

We discuss the issue of measuring the mean position (center-of-mass) of a group of bosonic or fermionic quantum particles, including particle number fluctuations. We introduce a standard quantum limit for these measurements at ultra-low temperatures, and discuss this limit in the context of both photons and ultra-cold atoms. In the case of fermions, we present evidence that the Pauli exclusion principle has a strongly beneficial effect, giving rise to a 1/N scaling in the position standard-deviation -- as opposed to a $1/\sqrt{N}$ scaling for bosons. The difference between the actual mean-position fluctuation and this limit is evidence for quantum wave-packet spreading in the center-of-mass. This macroscopic quantum effect cannot be readily observed for non-interacting particles, due to classical pulse broadening. For this reason, we also study the evolution of photonic and matter-wave solitons, where classical dispersion is suppressed. In the photonic case, we show that the intrinsic quantum diffusion of the mean position can contribute significantly to uncertainties in soliton pulse arrival times. We also discuss ways in which the relatively long lifetimes of attractive bosons in matter-wave solitons may be used to demonstrate quantum interference between massive objects composed of thousands of particles.Comment: 12 pages, 6 figures. Submitted to PRA. Revised to include more references as well as a discussion of fermionic center-of-mas