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1 свойства при високи температури
high-temperature propertiesБългарски-Angleščina политехнически речник > свойства при високи температури
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2 теплостойкость
1) Aviation: heat resisting2) Naval: thermal resistance3) Medicine: thermal stability4) Engineering: antiheat, heat endurance, high-temperature stability, high-temperature strength, thermal endurance, thermal shock resistance, thermal spalling resistance5) Construction: resistance to effects of heat6) Automobile industry: heat-resistance, resistance to effect of heat, thermal shock-resistance7) Metallurgy: heat-resisting quality, heatproof quality8) Electronics: heat stability9) Oil: heat resistance, resistance to heat, thermostability10) Ecology: thermal durability11) Sakhalin energy glossary: temperature stability12) Polymers: heat-distortion temperature, intercept yield temperature13) Automation: heat-resistant feature, high-temperature properties14) Quality control: heat-resistant quality15) Plastics: heat distortion temperature16) Makarov: heat tolerance -
3 свойство
с.property; qualityсвойства, препятствующие проскальзыванию — skid-protection properties
свойства при высоких температурах — hot properties, high-temperature properties
- механические свойствасвойства при низких температурах — cold properties, low-temperature properties
- смазывающие свойства
- характерное свойство -
4 свойства при высоких температурах
Quality control: high-temperature properties, hot propertiesУниверсальный русско-английский словарь > свойства при высоких температурах
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5 термические свойства
1) Engineering: thermal properties2) Polymers: high-temperature propertiesУниверсальный русско-английский словарь > термические свойства
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6 высокотемпературные свойства
Makarov: high-temperature propertiesУниверсальный русско-английский словарь > высокотемпературные свойства
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7 теплостойкость
heat-resistant feature, high-temperature properties, heat resistanceРусско-английский исловарь по машиностроению и автоматизации производства > теплостойкость
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8 явление электрической дуги
явление электрической дуги
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[Интент]Параллельные тексты EN-RU
Electric arc phenomenon
The electric arc is a phenomenon which takes place as a consequence of a discharge which occurs when the voltage between two points exceeds the insulating strength limit of the interposed gas; then, in the presence of suitable conditions, a plasma is generated which carries the electric current till the opening of the protective device on the supply side.
Gases, which are good insulating means under normal conditions, may become current conductors in consequence of a change in their chemical-physical properties due to a temperature rise or to other external factors.
To understand how an electrical arc originates, reference can be made to what happens when a circuit opens or closes.
During the opening phase of an electric circuit the contacts of the protective device start to separate thus offering to the current a gradually decreasing section; therefore the current meets growing resistance with a consequent rise in the temperature.
As soon as the contacts start to separate, the voltage applied to the circuit exceeds the dielectric strength of the air, causing its perforation through a discharge.
The high temperature causes the ionization of the surrounding air which keeps the current circulating in the form of electrical arc. Besides thermal ionization, there is also an electron emission from the cathode due to the thermionic effect; the ions formed in the gas due to the very high temperature are accelerated by the electric field, strike the cathode, release energy in the collision thus causing a localized heating which generates electron emission.
The electrical arc lasts till the voltage at its ends supplies the energy sufficient to compensate for the quantity of heat dissipated and to maintain the suitable conditions of temperature. If the arc is elongated and cooled, the conditions necessary for its maintenance lack and it extinguishes.
Analogously, an arc can originate also as a consequence of a short-circuit between phases. A short-circuit is a low impedance connection between two conductors at different voltages.
The conducting element which constitutes the low impedance connection (e.g. a metallic tool forgotten on the busbars inside the enclosure, a wrong wiring or a body of an animal entered inside the enclosure), subject to the difference of potential is passed through by a current of generally high value, depending on the characteristics of the circuit.
The flow of the high fault current causes the overheating of the cables or of the circuit busbars, up to the melting of the conductors of lower section; as soon as the conductor melts, analogous conditions to those present during the circuit opening arise. At that point an arc starts which lasts either till the protective devices intervene or till the conditions necessary for its stability subsist.
The electric arc is characterized by an intense ionization of the gaseous means, by reduced drops of the anodic and cathodic voltage (10 V and 40 V respectively), by high or very high current density in the middle of the column (of the order of 102-103 up to 107 A/cm2), by very high temperatures (thousands of °C) always in the middle of the current column and – in low voltage - by a distance between the ends variable from some microns to some centimeters.
[ABB]Явление электрической дуги
Электрическая дуга между двумя электродами в газе представляет собой физическое явление, возникающее в тот момент, когда напряжения между двумя электродами превышает значение электрической прочности изоляции данного газа.
При наличии подходящих условий образуется плазма, по которой протекает электрический ток. Ток будет протекать до тех пор, пока на стороне электропитания не сработает защитное устройство.
Газы, являющиеся хорошим изолятором, при нормальных условиях, могут стать проводником в результате изменения их физико-химических свойств, которые могут произойти вследствие увеличения температуры или в результате воздействия каких-либо иных внешних факторов.
Для того чтобы понять механизм возникновения электрической дуги, следует рассмотреть, что происходит при размыкании или замыкании электрической цепи.
При размыкании электрической цепи контакты защитного устройства начинают расходиться, в результате чего постепенно уменьшается сечение контактной поверхности, через которую протекает ток.
Сопротивление электрической цепи возрастает, что приводит к увеличению температуры.
Как только контакты начнут отходить один от другого, приложенное напряжение превысит электрическую прочность воздуха, что вызовет электрический пробой.
Высокая температура приведет к ионизации воздуха, которая обеспечит протекание электрического тока по проводнику, представляющему собой электрическую дугу. Кроме термической ионизации молекул воздуха происходит также эмиссия электронов с катода, вызванная термоэлектронным эффектом. Образующиеся под воздействием очень высокой температуры ионы ускоряются в электрическом поле и бомбардируют катод. Высвобождающаяся, в результате столкновения энергия, вызывает локальный нагрев, который, в свою очередь, приводит к эмиссии электронов.
Электрическая дуга длится до тех пор, пока напряжение на ее концах обеспечивает поступление энергии, достаточной для компенсации выделяющегося тепла и для сохранения условий поддержания высокой температуры. Если дуга вытягивается и охлаждается, то условия, необходимые для ее поддержания, исчезают и дуга гаснет.
Аналогичным образом возникает дуга в результате короткого замыкания электрической цепи. Короткое замыкание представляет собой низкоомное соединение двух проводников, находящихся под разными потенциалами.
Проводящий элемент с малым сопротивлением, например, металлический инструмент, забытый на шинах внутри комплектного устройства, ошибка в электромонтаже или тело животного, случайно попавшего в комплектное устройство, может соединить элементы, находящиеся под разными потенциалами, в результате чего через низкоомное соединение потечет электрический ток, значение которого определяется параметрами образовавшейся короткозамкнутой цепи.
Протекание большого тока короткого замыкания вызывает перегрев кабелей или шин, который может привести к расплавлению проводников с меньшим сечением. Как только проводник расплавится, возникает ситуация, аналогичная размыканию электрической цепи. Т. е. в момент размыкания возникает дуга, которая длится либо до срабатывания защитного устройства, либо до тех пор, пока существуют условия, обеспечивающие её стабильность.
Электрическая дуга характеризуется интенсивной ионизацией газов, что приводит к падению анодного и катодного напряжений (на 10 и 40 В соответственно), высокой или очень высокой плотностью тока в середине плазменного шнура (от 102-103 до 107 А/см2), очень высокой температурой (сотни градусов Цельсия) всегда в середине плазменного шнура и низкому падению напряжения при расстоянии между концами дуги от нескольких микрон до нескольких сантиметров.
[Перевод Интент]Тематики
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EN
Русско-английский словарь нормативно-технической терминологии > явление электрической дуги
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9 выдерживать
•This material will stand the operating conditions.
•The metal forming the hydride should hold up under many cycles of charging and discharging.
•Pure quicklime sustains a temperature of about 2900 К without decomposition.
•These objects must stand up to tremendous impact forces.
•These materials can tolerate (or endure, or stand up to) high heat and rough handling.
•Joints made with these electrodes will withstand bending and stretching operations satisfactorily.
•The material withstands temperatures up to 1260°C without loss of properties.
•Weights up to 500 Ib can be supported on the worktable.
•In an automotive environment, semiconductor chips have to contend with temperatures from -40° to 125°C, high humidity, salt and oil sprays, and vibration.
•Titanium carbide will tolerate (or withstand) wide variations in cutting speed.
•The amplifiers survived the shock very well.
II•The solution was allowed (or left) to stand for 9 hours.
•The catalyst was conditioned for 16 hours under a high vacuum.
•The solution was "aged" for 24hr by standing at room temperature.
•The furnace temperature was lowered and the specimens were held at 850°C for three days for the terminal etching of the grain boundaries.
•The process is accomplished by heating the metal to a high temperature, holding it at this temperature until...
•To season wood...
* * *Выдерживать -- to stand up to, to survive, to endure, to last, to withstand, to tolerate (выживать, не ухудшая своих свойств); to expose, to hold (в определенных условиях); to keep, to hold, to maintain (сохранять)The principal question to be answered was just how well and how long this type of engine would stand up to the marine environment.All these specimens survived a prescribed number of thermal cycles.Specimens lasted 3000 cycles in mercury at stress levels giving 300,000 cycles in air.The maximum shear stress it can withstand is about 40 MPa.The choice of teflon as a coating was based on its ability to tolerate temperatures up to about 290°C.—выдерживать точные допуски наРусско-английский научно-технический словарь переводчика > выдерживать
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10 выдерживать
•This material will stand the operating conditions.
•The metal forming the hydride should hold up under many cycles of charging and discharging.
•Pure quicklime sustains a temperature of about 2900 К without decomposition.
•These objects must stand up to tremendous impact forces.
•These materials can tolerate (or endure, or stand up to) high heat and rough handling.
•Joints made with these electrodes will withstand bending and stretching operations satisfactorily.
•The material withstands temperatures up to 1260°C without loss of properties.
•Weights up to 500 Ib can be supported on the worktable.
•In an automotive environment, semiconductor chips have to contend with temperatures from -40° to 125°C, high humidity, salt and oil sprays, and vibration.
•Titanium carbide will tolerate (or withstand) wide variations in cutting speed.
•The amplifiers survived the shock very well.
II•The solution was allowed (or left) to stand for 9 hours.
•The catalyst was conditioned for 16 hours under a high vacuum.
•The solution was "aged" for 24hr by standing at room temperature.
•The furnace temperature was lowered and the specimens were held at 850°C for three days for the terminal etching of the grain boundaries.
•The process is accomplished by heating the metal to a high temperature, holding it at this temperature until...
•To season wood...
Русско-английский научно-технический словарь переводчика > выдерживать
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11 Le Chatelier, Henri Louis
SUBJECT AREA: Metallurgy[br]b. 8 November 1850 Paris, Franced. 17 September 1926 Miribel-les-Echelle, France[br]French inventor of the rhodium—platinum thermocouple and the first practical optical pyrometer, and pioneer of physical metallurgy.[br]The son of a distinguished engineer, Le Chatelier entered the Ecole Polytechnique in 1869: after graduating in the Faculty of Mines, he was appointed Professor at the Ecole Supérieure des Mines in 1877. After assisting Deville with the purification of bauxite in unsuccessful attempts to obtain aluminium in useful quantities, Le Chatelier's work covered a wide range of topics and he gave much attention to the driving forces of chemical reactions. Between 1879 and 1882 he studied the mechanisms of explosions in mines, and his doctorate in 1882 was concerned with the chemistry and properties of hydraulic cements. The dehydration of such materials was studied by thermal analysis and dilatometry. Accurate temperature measurement was crucial and his work on the stability of thermocouples, begun in 1886, soon established the superiority of rhodium-platinum alloys for high-temperature measurement. The most stable combination, pure platinum coupled with a 10 per cent rhodium platinum positive limb, became known as Le Chatelier couple and was in general use throughout the industrial world until c. 1922. For applications where thermocouples could not be used, Le Chatelier also developed the first practical optical pyrometer. From hydraulic cements he moved on to refractory and other ceramic materials which were also studied by thermal analysis and dilatometry. By 1888 he was systematically applying such techniques to metals and alloys. Le Chatelier, together with Osmond, Worth, Genet and Charpy, was a leading member of that group of French investigators who established the new science of physical metallurgy between 1888 and 1900. Le Chatelier was determining the recalescence points in steels in 1888 and was among the first to study intermetallic compounds in a systematic manner. To facilitate such work he introduced the inverted microscope, upon which metallographers still depend for the routine examination of polished and etched metallurgical specimens under incident light. The principle of mobile equilibrium, developed independently by Le Chatelier in 1885 and F.Braun in 1886, stated that if one parameter in an equilibrium situation changed, the equilibrium point of the system would move in a direction which tended to reduce the effect of this change. This provided a useful qualitative working tool for the experimentalists, and was soon used with great effect by Haber in his work on the synthesis of ammonia.[br]Principal Honours and DistinctionsGrand Officier de la Légion d'honneur. Honorary Member of the Institute of Metals 1912. Iron and Steel Institute Bessemer Medal.Further ReadingF.Le Chatelier, 1969, Henri Le Chatelier.C.K.Burgess and H.L.Le Chatelier, The Measurement of High Temperature.ASDBiographical history of technology > Le Chatelier, Henri Louis
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12 при переходе к
При переходе к-- L plane properties are lower at room temperature but change less in going to high temperature.Русско-английский научно-технический словарь переводчика > при переходе к
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13 необходимый для
Необходимый для - essential to (+ inf.); essential in (+ gerund); essential for (+ noun); a must for, for, relevant to (+ noun); necessary to, needed to, required to (+ inf.)These coatings contain elements essential to provide hot-corrosion protection. (... необходимый для обеспечения защиты от высокотемпературной коррозии)These elements are essential in forming and maintaining the protective scale during high-temperature exposure.A must for casing work and handy for all-around service and maintenance, this welder-generator is a worthwhile option for any rig. (... генератор, необходимый для)The suspension should also provide high adhesion for good tractive and braking efficiencies.Few mechanical properties relevant to fracture-resistant design have been measured for maraging steels at low temperatures.This time was based on an analysis of the time necessary to evaluate the maximum POB from the platform using one Mi-8 helicopter.The temporary refuge is able to survive the time needed to evacuate the platform.Table lists DIP switch settings at the S1 position required to complete the setup of your meter.Русско-английский научно-технический словарь переводчика > необходимый для
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14 отборочные испытания
Отборочные испытания-- Apart from these sorting tests the author is unaware of any other evidence for an effect of high gas pressure on the tribological properties of high temperature materials.Русско-английский научно-технический словарь переводчика > отборочные испытания
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15 восстанавливать
♦Some manufacturers have reclaimed cylinder liners by turning or boring them oversize and then plating the inside walls with chrome.
♦Remagnetization after high-temperature exposure does not restore the original properties of...
♦A great variety of broken or worn tools can be restored by this process.
♦The initial state of the device can be regained if the traps are discharged by a reverse-voltage pulse.
♦To recapture (or reconstruct) the full history of the earth,...
* * *Восстанавливать -- to restore; to reclaim (деталь); to reinstate (1. в правах; 2. изношенное оборудование); to recover (свойства); to renew (обновить)The user may reclaim the cracked surface by arc-air gauging to sound metal and subsequent finish grounding.Русско-английский научно-технический словарь переводчика > восстанавливать
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16 восстанавливать
♦Some manufacturers have reclaimed cylinder liners by turning or boring them oversize and then plating the inside walls with chrome.
♦Remagnetization after high-temperature exposure does not restore the original properties of...
♦A great variety of broken or worn tools can be restored by this process.
♦The initial state of the device can be regained if the traps are discharged by a reverse-voltage pulse.
♦To recapture (or reconstruct) the full history of the earth,...
Русско-английский научно-технический словарь переводчика > восстанавливать
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17 механические характеристики при высоких температурах
Quality control: high-temperature mechanical propertiesУниверсальный русско-английский словарь > механические характеристики при высоких температурах
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18 открывать возможности для
Открывать возможности дляDevelopment of advanced ceramic materials with improved properties in recent years has opened the potential for their use in the severe, high-temperature environment of gas turbines.Recent advances in tool materials have opened the possibility of substantially reducing the machining time.The introduction of robots in the textile industry offers the potential for significant gains in manufacturing productivity.Tribological principles hold the potential for energy savings, material savings and improved machine performance.Русско-английский научно-технический словарь переводчика > открывать возможности для
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19 средний
Средний (участок)-- The duct was designed so that the midsection of its upper wall could be readily removed to provide easy access to the test section. Средний - average, mean (о значении); middle, mid... (в пространстве); medium (по качеству, степени); overall (по поверхности, объёму); bulk (по массе); intermediate (промежуточный); moderate (умеренный)The latter comparison shows an average deviation of less than four percent.For this work, the free stream temperature was replaced by the mean temperature.The main component of the apparatus was a flat rectangular duct whose middle length served as the test section.Inland blends high-volatile Illinois coal with medium-volatile West Virginia coal for its batteries.Second, the overall heat transfer data are presented and compared to the theoretical predictions of Ch. [...] for low Grashof numbers.Most wear alloys consist of several phases of different microhardness and the bulk hardness is related to the size and distribution of these second phases.The particulate size distributions are shown for the intermediate and high firing rates in Figs.... and..., respectively.At high and moderate levels of starvation the optimum L/D ratio is independent of load.Средний из (четырех отсчётов)-- Except as noted (*), all values represent an average of 4 readings. Средний между-- Physical properties occurring in the correlations have been taken at a temperature equal to the mean of the inlet temperature and the adiabatic flame temperature.—отличаться в среднем на—отличаться от среднего значения не более, чем наРусско-английский научно-технический словарь переводчика > средний
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20 материал
material• Большая часть материала дана в форме таблиц, чтобы помочь разработчику... - Much of the material is in tabular form to assist the designer in...• Большая часть материала, представленного в данной главе, была посвящена... - Much of the material presented in this chapter has dealt with...• В настоящее время изучаются свойства данного материала. - The properties of this material are presently being studied.• Материал данной книги организован так, что... - The material in this book is organized so that...• Материал не меняет своих свойств в широком температурном диапазоне. (= Материал сохраняет свои свойства в широкой области температур. ) - The material retains its properties over a wide temperature range.• Материал усилен стальными брусами. - The material is reinforced with steel rods.• Огромный интерес вызывают свойства этого нового материала. - Great interest is focused on the properties of this new material....• Сначала мы приведем некоторый дополнительный материал относительно... - We begin with some additional material relating to...• Этот материал может выдержать очень высокие температуры. - This material can withstand very high temperatures.
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