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1

Electrical breakdown characteristics of electroformed copper electrodes in vacuum  

Microsoft Academic Search

The effects of copper deposits produced by three kinds of electroforming techniques on the breakdown characteristics in vacuum were compared. The electroforming was performed in (i) an acid sulfate bath with brighteners, (ii) a pyrophosphate bath, and (iii) an acid copper sulfate bath with periodic reverse electrolysis and electropolishing. Vacuum degassed oxygen-free copper was used as the substrate material. Electrical

S. Kobayashi; K. Sekikawa; R. Shibusawa; Y. Saito; K. Tajiri; Z. Kabeya

2000-01-01

2

The electrical breakdown characteristics of oil-paper insulation under steep front impulse voltages  

SciTech Connect

Disconnecting switch operations in gas insulated equipment cause transient voltages with rise times as steep as 5 to 20 nanoseconds and magnitudes as high as 2.5 pu. There is very little information on the effect of these transients on oil-paper insulated equipment. There have been reports, however of transformer and bushing failures caused by these transients. The electrical breakdown characteristics of oil-paper insulation under steep front impulse were studied in this project, which was co-sponsored by the Canadian Electrical Association and B.C. Hydro. V[sub 50] (50% breakdown probability voltage) breakdown data was obtained with steep front (10 ns/2500 [mu]s), lightning and switching impulse waveforms. Insulation breakdown voltage vs breakdown time (V-t) data and multiple impulse breakdown data were obtained with the steep front impulse waveform. The V[sub 50] results showed that the breakdown strengths were lower for steep front impulses than for lightning impulses. The multiple impulse breakdown results showed that oil-paper insulation breakdown strength can be lower than 100 kV/mm. These results are alarming, since they suggest that oil-paper insulated equipment subjected to steep front transients will fail at voltages below the lightning impulse design level (BIL). The Volt-time data had a discontinuity. The breakdown process at risetime below about 50 ns was different from the breakdown process at rise times above 50 ns.

Vandermaar, A.J.; Wang, M.; Neilson, J.B. (Powertech Labs Inc., Surrey, British Columbia (Canada)); Srivastava, K.D. (Univ. of British Columbia, Vancouver (Canada))

1994-10-01

3

Electrical breakdown and volt-ampere characteristics in water vapor in microgaps  

NASA Astrophysics Data System (ADS)

Although the physics for breakdown initiation in gases in generally well understood, the process of breakdown initiation in liquids is much less clear. A large number of experimental data on the breakdown in water revealed that the breakdown voltage in water is of the same magnitude as in the case of gases. This means that the breakdown in liquids can occur not at the extremely high electric fields required by the Paschen curve, but at those that only slightly exceed the breakdown electric fields in atmospheric-pressure molecular gases. This letter contains the results of experimental study on electrical breakdown characteristics in water vapor in microgaps between two parallel electrodes. Measurements were performed for the pressures of 24.15 torr, 20.85 torr and 14.55 torr with the gap size ranging from 40 ?m to 900 ?m. Considering that the atmospheric pressure sources operate in ambient air which unavoidably contains water vapor it is of great importance to investigate the basic processes and properties of discharges in water vapor.

Klas, M.; Matej?ik, Š.; Radmilovi?-Radjenovi?, M.; Radjenovi?, B.

2012-09-01

4

Electrical breakdown characteristic of nanostructured W?Cu contacts materials  

Microsoft Academic Search

Nanostructured (NS) W?Cu composite powder was prepared by mechanical alloying (MA), and nanostructured bulk of W?Cu contact\\u000a material was fabricated by hot press sintering in an electrical vacuum furnace. The microstructure, electric conductivity,\\u000a hardness and break down voltage of NS W?Cu alloys were measured and compared to those of conventional W?Cu alloys prepared\\u000a by powder metallurgy. The experimental results show

Wang Junbo; Chen Wen'ge; Ding Binjun

2006-01-01

5

Stabilisation of some characteristics of gas-filled diodes by electrical breakdowns  

Microsoft Academic Search

The conditions of the stabilisation of static breakdown voltage Us and time delay of electrical breakdown td with successive electrical breakdowns in gas-filled diodes with cold metallic electrodes have been studied. The diodes had the following electrode-gas combinations: Al-N2, Fe-H2, Cu-N2, CuH2, Fe-Ar, Fe-Kr and Fe-Xe. The number of breakdowns N necessary for stabilisation in the various diodes has been

Dj A. Bosan; D. Simonovic

1984-01-01

6

Experimental Study on the Electrical Breakdown Characteristics of Sub-Cooled Liquid Nitrogen for Designing a High Voltage Superconducting Machine  

Microsoft Academic Search

The electrical breakdown characteristics of liquid nitrogen should be investigated for developing of a high voltage superconducting machine. This paper deals with the experimental study for the verification of dielectric characteristics of sub-cooled in accordance with utilization factors. AC dielectric experiments were carried out by using sphere-plane electrode systems. The utilization factors of simulated electrode systems were controlled by gap

Jin Bae Na; Hyoungku Kang; Young Jin Hwang; Seong Eun Yang; Dong Keun Park; Duck Kweon Bae; Tae Kuk Ko

2010-01-01

7

Laser-induced electric breakdown in solids  

Microsoft Academic Search

A review is given of recent experimental results on laser-induced electric breakdown in transparent optical solid materials. A fundamental breakdown threshold exists characteristic for each material. The threshold is determined by the same physical process as dc breakdown, namely, avalanche ionization. The dependence of the threshold on laser pulse duration and frequency is consistent with this process. The implication of

NICOLAAS BLOEMBERGEN

1974-01-01

8

Effect of de-aeration on the electrical breakdown characteristics of water  

Microsoft Academic Search

In the study of electrical breakdown in liquids, attention is typically paid to the contamination of the liquid, and particularly ionic impurities. However, the purity of the sample is also compromised by dissolved gases as well as ionically charged species. To test the effect of de-aeration, water, a highly gas-soluble liquid, was chosen as the test liquid. The delay time

J. M. Lehr

1998-01-01

9

Breakdown characteristics of cryogenic gaseous helium in uniform electric field and space charge modified non-uniform field  

NASA Astrophysics Data System (ADS)

D.c. breakdown characteristics of gaseous helium in uniform and non-uniform electric fields down to 4.2 K at atmospheric pressure have been investigated. Although helium is a nonelectronegative gas, a negative pulse corona is observed only near the normal boiling point due to the abrupt appearance of quasi-bubble state electrons. Positive ion space charge modifies the electric field distribution in the gap space considerably. The electric field strength on the non-corona electrode in the ion flow field is measured satisfactorily and analysed theoretically using a numerical electric field calculation technique. On the basis of experimental results, methods are proposed to give corona onset criteria and the breakdown voltage preceded by a positive glow corona.

Hara, M.; Suehiro, J.; Matsumoto, H.

10

Influence of the hot filament on the electrical breakdown characteristics in the presence of Ar/N2  

NASA Astrophysics Data System (ADS)

The influence of a hot filament on the electrical breakdown characteristics is studied for different ratios of argon and nitrogen gases for a wide range of pressure. The vacuum tube consists of two parallel plane stainless steels used as cathode and anode accompanied with a tungsten filament located behind the cathode. Paschen's curves are obtained for different ratios of argon and nitrogen as a function of pressure for various electric currents of the hot filament. The first and second Townsend coefficients as well as the ionization efficiency and secondary ionization coefficient are obtained for different filament currents. In addition, the influences of the nitrogen partial pressure on the forgoing parameters are obtained. It is shown that, increase of the filament current causes the decrease of the electrical breakdown voltage which is more pronounced in low pressures. Furthermore, introducing the nitrogen gas leads to the increase of the breakdown voltage and decrease of the ionization efficiency as well as the first and second Townsend coefficients. Moreover, it is concluded that, in the middle range of pressure, the presence of the hot filament results to the electrical breakdown which reveals the linear features.

Borkhari, Arian Fateh; Yasserian, Kiomars

2013-01-01

11

Electrical breakdown characteristic of a Ce-doped W-Cu contact material  

Microsoft Academic Search

W-Cu composite powder doped with Ce (1.5 wt.%) was prepared by mechanical alloying (MA), and the W-Cu contact material was\\u000a fabricated by hot pressing sintering in an electrical vacuum furnace. The microstructure, electric conductivity, hardness,\\u000a and breakdown voltage of the Ce-doped W-Cu alloy were measured and compared with a conventional W-Cu alloy prepared by powder\\u000a metallurgy. The results show that

Kewen Hu; Mianzhi Chen; Heng Ye

2010-01-01

12

Electric Breakdown Characteristics of Silicon Dioxide Films for Use in Microfabricated Ion Engine Accelerator Grids  

NASA Astrophysics Data System (ADS)

Introduction Microfabricated Grid Design Issues Previous Related Research Description of the Experiment Substrate Breakdown Tests Oxide Thickness Dependence Temperature Dependence Visual Post-Test Inspection of Test Samples Surface Breakdown Tests Dependence on Gap Distance Paschen Breakdown Considerations Influence of Surface Morphology Visual Post-Test Inspection of Test Samples Conclusions References

Mueller, Juergen; Pyle, David; Chakraborty, Indrani; Ruiz, Ronald; Tang, William; Marrese, Colleen; Lawton, Russell

13

Electrical Pulse Breakdown of Silicon Oxide Films  

Microsoft Academic Search

Pulse breakdown tests on individual specimens with self-healing breakdowns resulted in information on both the thermal and the electric breakdown properties. Thermal breakdown due to Joule heat was found to occur nearly uniformly over the whole specimen at voltages generally lower than the electric breakdown. voltages. Calculations with relations derived for the thermal breakdown field agreed well with observations showing

N. Klein; E. Burstein

1969-01-01

14

Electrical Breakdown Characteristics of Superconducting Magnet System in Sub-Cooled Liquid Nitrogen  

Microsoft Academic Search

Dielectric characteristics of gaseous helium (GHe) injected into the cooling system to make sub-cooled nitrogen condition with constant pressure is found to be extraordinarily weak in dielectric strength by H. Mitsuii (1998). In high voltage superconducting machines using the sub-cooled nitrogen cooling system, the current lead part in GHe environment could be electrical weak points rather than the superconducting magnet

Hyoungku Kang; Chanjoo Lee; Tae Kuk Ko; Bok-Yeol Seok

2007-01-01

15

Electrical breakdown in low pressure gases  

Microsoft Academic Search

The paper presents the results of investigation of the electrical breakdown in low pressure gases when the secondary electrons released from the cathode play the dominant role in the initiation of electrical breakdown. The secondary electrons are created by the charged and neutral species formed during the previous breakdown and discharge as well as by ?-rays. Electrical breakdown investigations are

Momcilo M Pejovic; Goran S Ristic; Jugoslav P Karamarkovic

2002-01-01

16

Electrical breakdown of small gaps in vacuum  

Microsoft Academic Search

The comparison of the characteristics of an electric arc breakdown in vacuum between two silver or silver-nickel alloy convex electrodes, enabled us to show experimentally that the process initiating discharge in vacuum is the electronic emission at the micrometer scale. Increased content of nickel in the alloy improves the insulation and achieves high resistance to erosion for low power arcs.

N. Zouache; A. Lefort

1997-01-01

17

Electrical Breakdown in Water Vapor  

NASA Astrophysics Data System (ADS)

In this paper investigations of the voltage required to break down water vapor are reported for the region around the Paschen minimum and to the left of it. In spite of numerous applications of discharges in biomedicine, and recent studies of discharges in water and vapor bubbles and discharges with liquid water electrodes, studies of the basic parameters of breakdown are lacking. Paschen curves have been measured by recording voltages and currents in the low-current Townsend regime and extrapolating them to zero current. The minimum electrical breakdown voltage for water vapor was found to be 480 V at a pressure times electrode distance (pd) value of around 0.6 Torr cm (˜0.8 Pa m). The present measurements are also interpreted using (and add additional insight into) the developing understanding of relevant atomic and particularly surface processes associated with electrical breakdown.

Škoro, N.; Mari?, D.; Malovi?, G.; Graham, W. G.; Petrovi?, Z. Lj.

2011-11-01

18

Electrical Breakdown in Water Vapor  

SciTech Connect

In this paper investigations of the voltage required to break down water vapor are reported for the region around the Paschen minimum and to the left of it. In spite of numerous applications of discharges in biomedicine, and recent studies of discharges in water and vapor bubbles and discharges with liquid water electrodes, studies of the basic parameters of breakdown are lacking. Paschen curves have been measured by recording voltages and currents in the low-current Townsend regime and extrapolating them to zero current. The minimum electrical breakdown voltage for water vapor was found to be 480 V at a pressure times electrode distance (pd) value of around 0.6 Torr cm ({approx}0.8 Pa m). The present measurements are also interpreted using (and add additional insight into) the developing understanding of relevant atomic and particularly surface processes associated with electrical breakdown.

Skoro, N.; Maric, D.; Malovic, G.; Petrovic, Z. Lj. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Graham, W. G. [Centre for Plasma Physics, School of Mathematics and Physics, Queens University Belfast, BT7 1NN (United Kingdom)

2011-11-15

19

Electrical Breakdown of Plasma-Polymerized Styrene Thin Films  

NASA Astrophysics Data System (ADS)

The electrical breakdown of plasma-polymerized styrene thin film (PPS) was studied by taking advantage of self-healing. The electric strength FB was almost independent of temperature from -196 to 200°C, and strongly depended on the rate of voltage increase even at a slow rate of increase. The breakdown characteristics were influenced by the electrode metal and the ambient atmosphere, but not by X-ray irradiation or photoillumination. The experimental results are used to discuss the breakdown mechanism of PPS through existing breakdown theories. As a result, no single breakdown process was considered as a possible breakdown mechanism, and we thus obtained important conditions for presenting a new breakdown model; the breakdown of PPS will be determined by a thermal criterion, and it will be closely related to a temperature-independent injection process.

Hikita, Masayuki; Matsuda, Akinori; Nagao, Masayuki; Sawa, Goro; Ieda, Masayuki

1982-03-01

20

Self-healing breakdown characteristics of polyimide thin films-effect of ambient gas on breakdown characteristics  

Microsoft Academic Search

We have been studying the breakdown characteristics of polyimide (PI) thin films to try and take advantage of self-healing breakdown. This paper focuses on the effect of ambient gas (SF6, N2 , O2 and dry air) on breakdown characteristics of PI thin films. At room temperature, electric strength (Fb) in SF6 is higher than in other gases. The Fb in

Y. Muramoto; M. Nagao; M. Kosaki

1997-01-01

21

Laser triggering of electric breakdown in liquids  

Microsoft Academic Search

Electric breakdown in semihomogeneous geometries has been studied in n-hexane and transformer oil using a laser triggering method for fields far below the spontaneous breakdown field. The method uses a laser-produced plasma to initiate the breakdown. Strong self focusing in the liquids was limited by increasing the numerical aperture of the laser beam to >0.20 prior to focusing. Electrical breakdown

Anders Sunesson; P. Barmann; Stefan Kroll; L. Walfridsson

1994-01-01

22

Electrical breakdown in ferroelectric sodium nitrite crystals  

Microsoft Academic Search

The electric strength of sodium nitrite crystals is measured in the temperature range 125–205°C embracing the Curie ferroelectric transition temperature. Single constant-amplitude voltage pulses are used to initiate breakdown. Experimental values of breakdown strength are obtained for time delays to breakdown of 10 and 100 msec. Measurements of high-field electric conductivity are used to determine theoretical impulse thermal breakdown strengths

J. Fok; J. R. Hanscomb

1972-01-01

23

Electrical breakdown of anodic aluminum oxide  

Microsoft Academic Search

Results are presented from a study of electrical breakdown of anodic aluminum oxide in a constant field with a platinum pressure electrode. Statistical breakdown parameters and their dependence on the magnitude and polarity of the applied voltage are obtained. Field and temperature dependences of breakdown delay time t over the interval 10-6–103 sec are determined. It is shown that the

V. A. Laléko; N. Yu. Ershova

1990-01-01

24

Electrical breakdown of anodic aluminum oxide  

Microsoft Academic Search

Results are presented from a study of electrical breakdown of anodic aluminum oxide in a constant field with a platinum pressure electrode. Statistical breakdown parameters and their dependence on the magnitude and polarity of the applied voltage are obtained. Field and temperature dependences of breakdown delay time tau over the interval 10-6 103 sec are determined. It is shown that

V. A. Laléko; N. Yu. Ershova

1990-01-01

25

Electrical Breakdown of Plasma-Polymerized Styrene Thin Films  

Microsoft Academic Search

The electrical breakdown of plasma-polymerized styrene thin film (PPS) was studied by taking advantage of self-healing. The electric strength FB was almost independent of temperature from -196 to 200°C, and strongly depended on the rate of voltage increase even at a slow rate of increase. The breakdown characteristics were influenced by the electrode metal and the ambient atmosphere, but not

Masayuki Hikita; Akinori Matsuda; Masayuki Nagao; Goro Sawa; Masayuki Ieda

1982-01-01

26

Electrical breakdown of dysprosium oxide films  

Microsoft Academic Search

The principal laws governing the electrical breakdown of dysprosium oxide films in silicon metal — insulator — semiconductor structures are investigated. The dependence of the breakdown field Ebr on the rise rate of the voltage on the structure Kv, the temperature, the material and area of the electrode, and the humidity of the environment is studied. The dependence of the

A. I. Petrov; V. A. Rozhkov

1995-01-01

27

Pulsed electric breakdown in adipose tissue  

NASA Astrophysics Data System (ADS)

High voltage pulses of sub-microsecond duration can instigate electrical breakdown in adipose tissue, which is followed by a spark discharge. Breakdown voltages are generally lower than observed for purified lipids but higher than for air. Development of breakdown for the repetitive application of pulses resembles a gradual and stochastic process as reported for partial discharges in solid dielectrics. The inflicted tissue damage itself is confined to the gap between electrodes, providing a method to use spark discharges as a precise surgical technique.

Kolb, Juergen F.; Scully, Noah; Paithankar, Dilip

2011-08-01

28

TOPICAL REVIEW: Electrical breakdown in low pressure gases  

Microsoft Academic Search

The paper presents the results of investigation of the electrical breakdown in low pressure gases when the secondary electrons released from the cathode play the dominant role in the initiation of electrical breakdown. The secondary electrons are created by the charged and neutral species formed during the previous breakdown and discharge as well as by gamma-rays. Electrical breakdown investigations are

Momcilo M. Pejovic; Goran S. Ristic; Jugoslav P. Karamarkovic

2002-01-01

29

Electrical breakdown gas detector featuring carbon nanotube array electrodes.  

PubMed

We demonstrate here detection of dichloro-difluoro-methane and oxygen in mixtures with helium using a carbon nanotube electrical breakdown sensor device. The sensor is comprised of an aligned array of multiwalled carbon nanotubes deposited on a nickel based super-alloy (Inconel 600) as the anode; the counter electrode is a planar nickel sheet. By monitoring the electrical breakdown characteristics of oxygen and dichloro-difluoro-methane in a background of helium, we find that the detection limit for dichloro-difluoro-methane is approximately 0.1% and the corresponding limit for oxygen is approximately 1%. A phenomenologigal model is proposed to describe the trends observed in detection of the two mixtures. These results indicate that carbon nanotube based electrical breakdown sensors show potential as end detectors in gas-chromatography devices. PMID:18468093

Kim, Seongyul; Pal, Sunil; Ajayan, Pulickel M; Borca-Tasciuc, Theodorian; Koratkar, Nikhil

2008-01-01

30

Flashover and breakdown characteristics in low pressure environments  

Microsoft Academic Search

A present trend in aircraft design is the increasing use of 270-Vdc power circuitry. Also, significant voltage spikes may be superimposed on the dc level. In many situations involving unsealed equipment enclosures, electrical insulation is provided by a combination of gaseous medium and spacing between conductors. Consequently, flashover\\/breakdown characteristics of electrical wiring and printed-circuit-board traces depend upon the environment in

Dennis Grosjean; Donald Kasten; Stephen Sebo; Titus Chen; Michael Rupp; Daniel Schweickart

2011-01-01

31

Planned waveguide electric field breakdown studies  

SciTech Connect

This paper presents an experimental setup for X-band rf breakdown studies. The setup is composed of a section of WR90 waveguide with a tapered pin located at the middle of the waveguide E-plane. Another pin is used to rf match the waveguide so it operates in a travelling wave mode. By adjusting the penetration depth of the tapered pin, different surface electric field enhancements can be obtained. The setup will be used to study the rf breakdown rate dependence on power flow in the waveguide for a constant maximum surface electric field on the pin. Two groups of pins have been designed. The Q of one group is different and very low. The other has a similar Q. With the test of the two groups of pins, we should be able to discern how the net power flow and Q affect the breakdown. Furthermore, we will apply an electron beam treatment to the pins to study its effect on breakdown. Overall, these experiments should be very helpful in understanding rf breakdown phenomena and could significantly benefit the design of high gradient accelerator structures.

Wang Faya; Li Zenghai [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

2012-12-21

32

Electrical Breakdown In Nitrogen At Low Pressure - Physical Processes And Statistics  

Microsoft Academic Search

The results of investigation of the electrical breakdown in nitrogen, obtained in combined approach based on measuring of the current-voltage characteristic, modeling of basic physical processes and statistical analysis of the breakdown time delay are presented in this report. Measurement of the current-voltage characteristics with additional monitoring of spatial and temporal distribution of the emission from discharge provides information concerned

S. Gocic

2010-01-01

33

Electrical breakdown in nitrogen at low pressure - physical processes and statistics  

Microsoft Academic Search

The results of investigation of the electrical breakdown in nitrogen, obtained in combined approach based on measuring of the current-voltage characteristic and statistical analysis of the breakdown time delay are presented in this report. Measurement of the current-voltage characteristics with additional monitoring of spatial and temporal distribution of the emission from discharge provides information concerned on development of different regime

S. R. Gocic

2010-01-01

34

Self-healing breakdown and electrical conduction of polyimide thin films  

Microsoft Academic Search

We have been studying the breakdown characteristics of polyimide (PI) thin films by taking advantage of self-healing breakdown. The purpose of this study is to clarify the effect of ambient gas (SF6 , N2, Dry air) and thermal treatment on the self-healing breakdown characteristics of PI thin films in high temperature region. The electric strength (Fb) decreased with temperature and

Y. Muramoto; M. Nagao; F. Mizuno; M. Kosaki

1998-01-01

35

Experimental Investigation of Breakdown Voltage and Electrical Breakdown Time Delay of Commercial Gas Discharge Tubes  

Microsoft Academic Search

This article presents the experimental results of DC dynamic breakdown voltage Ub for small voltage increase rates and electrical breakdown time delay td of commercial gas discharge tubes. It was shown that Ub is a stochastic value with Gauss distribution for voltage increase rates >=2 V\\/s. In order to determine the static breakdown voltage Us as a deterministic quantity, the

Milic Momcilo Pejovic; Momcilo Milic Pejovic; Koviljka Stankovic

2011-01-01

36

Electrical breakdown studies with Mycalex insulators  

SciTech Connect

Insulating materials such as alumina and glass-bonded mica (Mycalex) are used in accelerator systems for high voltage feedthroughs, structural supports, and barriers between high voltage insulating oil and the vacuum beam pipe in induction accelerator cells. Electric fields in the triple points should be minimized to prevent voltage breakdown. Mechanical stress can compromise seals and result in oil contamination of the insulator surface. We have tested various insulator cleaning procedures including ultrasonic cleaning with a variety of aqueous-based detergents, and manual scrubbing with various detergents. Water sheeting tests were used to determine the initial results of the cleaning methods. Ultimately, voltage breakdown tests will be used to quantify the benefits of these cleaning procedures.

Waldron, W.; Greenway, W.; Eylon, S.; Henestroza, E.; Yu, S.

2003-05-01

37

Electrical breakdown of vacuum insulation at cryogenic temperature  

Microsoft Academic Search

A breakdown experiment on vacuum insulation for the development of cryocable and other cryogenic electrical apparatus was performed. The influence of conditioning, pressure, gap spacing, electrode material, and voltage waveform on the breakdown voltage of vacuum insulation was measured at room temperature and at cryogenic temperature. The results indicate that cooling the high-voltage sphere electrode enhances the breakdown strength of

Fengnian Hao; Weihan Wu

1988-01-01

38

Features of Pulsed Electrical Breakdown of Suspensions. Breakdown Polarization Mechanism.  

National Technical Information Service (NTIS)

The breakdown voltage of suspensions was measured in systems in which the liquid phases were transformer oil, tap water, and H2O. The dispersed phases were quartz sand and sulfide ore with a particle size smaller than 0.074 micrometers and glass spheres w...

M. P. Tonkonogov S. V. Kim V. Y. Ushakov

1972-01-01

39

Statistical study of nanosecond electric breakdowns in n -hexane  

Microsoft Academic Search

Methods for analyzing statistical distributions of the breakdown delay time are generalized. A statistical approach is used\\u000a to study electric breakdown in n-hexane in a 2.1-MV\\/cm quasi-uniform electric field at a pulse duration of ?510?8 s. Two different mechanisms for the anode breakdown are shown to coexist and compete with each other. One of them incorporates\\u000a the “bubble” stage, whereas

V. F. Klimkin

2002-01-01

40

Experimental Investigation of Breakdown Voltage and Electrical Breakdown Time Delay of Commercial Gas Discharge Tubes  

NASA Astrophysics Data System (ADS)

This article presents the experimental results of DC dynamic breakdown voltage Ub for small voltage increase rates and electrical breakdown time delay td of commercial gas discharge tubes. It was shown that Ub is a stochastic value with Gauss distribution for voltage increase rates ?2 V/s. In order to determine the static breakdown voltage Us as a deterministic quantity, the mean values of the dynamic breakdown voltage \\bar{U}b as a function of voltage increase rate k were extrapolated until the intersection with \\bar{U}b axis using linear fit. The intersection point (for k = 0) correspond to Us value. Additional experiments were performed in order to verify the temperature stability of these components over the wide temperature range from 25 to 250 °C. The experimental results of electrical breakdown time delay are also presented in the paper. Electrical breakdown time delay if often refereed as delay response and it is also very important parameter of gas filled devices. It was shown when the voltage higher then 310 V is applied to those components, the mean value of electrical breakdown time delay \\bar{t}d insignificantly varies to the value of relaxation time ?? 1 s, while the breakdown probability is close to one for the voltages higher then 380 V. These facts show that the commercial gas discharge tubes are very reliable for the protection for voltages higher then 380 V.

Pejovi?, Mili? Mom?ilo; Pejovi?, Mom?ilo Mili?; Stankovi?, Koviljka

2011-08-01

41

Workshop on Dielectric Properties and Electrical Breakdown of Biological Membranes.  

National Technical Information Service (NTIS)

The topic 'Dielectric Properties and Electrical Breakdown of Biological Membranes' was the topic of a workshop at the Conference on Electrical Insulation and Dielectric Phenomena on October 20, 2002, in Mexico. The workshop, supported by the IEEE Dielectr...

K. H. Schoenbach

2002-01-01

42

Electric field-free gas breakdown in explosively driven generators  

SciTech Connect

All known types of gas discharges require an electric field to initiate them. We are reporting on a unique type of gas breakdown in explosively driven generators that does not require an electric field.

Shkuratov, Sergey I. [Loki Incorporated, Rolla, Missouri 65409 (United States); Baird, Jason [Loki Incorporated, Rolla, Missouri 65409 (United States); Department of Mining and Nuclear Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409-0450 (United States); Talantsev, Evgueni F. [Pulsed Power LLC, Lubbock, Texas 79416 (United States); Altgilbers, Larry L. [U.S. Army Space and Missile Defense Command/Army Forces Strategic Command, Huntsville, Alabama 35807 (United States)

2010-07-15

43

AC breakdown characteristics of epoxy nanocomposites  

Microsoft Academic Search

Experiments were conducted to measure the ac breakdown strength of epoxy alumina nanocomposites with different filler loadings of 0.1, 1 and 5 wt%. The experiments were performed as per the ASTM D 149 standard on samples of thickness 0.5 mm, 1 mm and 3 mm in order to study the effect of thickness on the ac breakdown strength of epoxy

P. Preetha; M. Joy Thomas

2011-01-01

44

Electrical breakdown of vacuum insulation at cryogenic temperature  

Microsoft Academic Search

An experiment on the breakdown of vacuum insulation was performed for the development of cryocables and other cryogenic electrical apparatus. The influence of conditioning, pressure, gap spacing, electrode material and voltage waveshape on the breakdown voltage of vacuum insulation was measured at room temperature and at cryogenic temperature respectively. The results indicate that cooling the high-voltage sphere electrode enhances the

Hao Fengnian; W. Hu

1990-01-01

45

Impulse Electrical Breakdown of High-Purity Water.  

NASA Astrophysics Data System (ADS)

Experiments have been conducted on the electrical breakdown of high-purity water and water mixtures. The electrical regime of interest has been carefully defined and documented to consist of electrical impulses with approximately microsecond rise time and fall time greater than 65 microseconds, on approximately 81-square-centimeter-area planar electrodes with a dielectric gap of approximately one centimeter. The results of over 25,000 shots by a Marx generator have been distilled into database form in an Excel spreadsheet and analysis performed to try to find patterns or indirect evidence into the nature of the breakdown-initiation process. An extensive review of all the experiments, which had been conducted over eight years by the Naval Surface Warfare Center and which had been designed to find the largest water-breakdown fields, was conducted with the intention of delineating the physical factors that led to breakdown. A variety of theoretical models of breakdown initiation were compared to the data, until it became clear that many of the breakdowns were dominated by impurities of various sorts. An extensive study of old and new experiments led to a more detailed understanding of the phenomenology of impurity-dominated water breakdown (such as the process of "conditioning" the electrodes and hysteresis) and the proposal of a number of new experiments to further characterize the intrinsic role of electrode materials on determining high-electric-field dielectric breakdown in water.

Gehman, Victor Herbert, Jr.

1995-01-01

46

Electrical breakdown in thin oxides during bias-temperature ramps  

SciTech Connect

Electrical breakdown in thin oxides is assessed by a new bias-temperature ramp technique. No significant effect of radiation exposure on breakdown is observed for high quality thermal and nitrided oxides, up to 20 Mrad(SiO{sub 2}).

FLEETWOOD,D.M.; RIEWE,LEONARD CHARLES; WINOKUR,PETER S.; SEXTON,FREDERICK W.

2000-02-08

47

Bibliography of Data on Electrical Breakdown in Gases.  

National Technical Information Service (NTIS)

This report consists of a bibliography of currently published data on electrical breakdown in gases. The bibliography contains a list of archival papers and books published since 1950, an index indicating the references that give particular types of data ...

R. J. Van Brunt W. E. Anderson

1984-01-01

48

Electric Breakdown and Conduction through Mylar Films  

Microsoft Academic Search

Dc breakdown studies on Mylar film show that defects cause a decrease in dielectric strength with decreasing film thickness at room temperature but not at ?180°C. The breakdown at defects is associated with moisture content. Using self-healing electrodes to eliminate weak areas, a dc dielectric strength of 6 Mv?cm is found, independent of film thickness. Prebreakdown current measurements indicate ionic

Y. Inuishi; D. A. Powers

1957-01-01

49

Electrical breakdown in nitrogen at low pressure - physical processes and statistics  

NASA Astrophysics Data System (ADS)

The results of investigation of the electrical breakdown in nitrogen, obtained in combined approach based on measuring of the current-voltage characteristic and statistical analysis of the breakdown time delay are presented in this report. Measurement of the current-voltage characteristics with additional monitoring of spatial and temporal distribution of the emission from discharge provides information concerned on development of different regime of low-pressure gas discharge and on processes of the electrical breakdown and discharge maintenance. Also, two new distributions of the statistical time delay of electrical breakdown in nitrogen, the Gaussian and Gauss-exponential ones, are presented. Distributions are theoretically founded on binomial distribution for the occurrence of initiating electrons and described by using analytical and numerical models. Moreover, the correlation coefficient between the statistical and formative time delay of electrical breakdown in nitrogen is determined. Starting from bivariate normal (Gaussian) distribution of two random variables, the analytical distribution of the electrical breakdown time delay is theoretically founded on correlation of the dependent statistical and formative time delay.

Goci?, S. R.

2010-11-01

50

Relation between secondary ionisation coefficient and electrical breakdown in nitrogen  

Microsoft Academic Search

The role of metastables in electrical breakdown processes in a nitrogen-filled (13.33 mbar) diode has been investigated. This investigation was done by measurement of electrical breakdown time delay as a function of passive time tau , electrode gap d and E\\/p ratio in the diode with the bulk copper electrodes of which one is gold-plated. The results show that the

M. M. Pejovic; D. A. Bosan; B. A. Nallbani

1982-01-01

51

Impulse Electric Breakdown of Air and Water Vapor at Increased Pressure.  

National Technical Information Service (NTIS)

The results of an investigation of the volt-second characteristics of the electric breakdown of air and water vapor in a nonhomogeneous electric field at pressures of up to 40 atmospheres for a surge voltage effect time of from 0.0000002 to 0.000002 s are...

A. A. Vorobev A. T. Chepikov I. I. Kalyatskii V. V. Krivko

1972-01-01

52

Electrical Breakdown In Nitrogen At Low Pressure - Physical Processes And Statistics  

NASA Astrophysics Data System (ADS)

The results of investigation of the electrical breakdown in nitrogen, obtained in combined approach based on measuring of the current-voltage characteristic, modeling of basic physical processes and statistical analysis of the breakdown time delay are presented in this report. Measurement of the current-voltage characteristics with additional monitoring of spatial and temporal distribution of the emission from discharge provides information concerned on development of different regime of low-pressure gas discharge and on processes of the electrical breakdown and discharge maintenance. The presented model of the gas discharge includes the kinetics of mains constituents of the nitrogen plasma, charged particles, vibrationally manifold of molecular ground state, molecular singlet and triplet states and nitrogen atoms. The model is applied in case of a homogenous electric field, at electric field to gas density ratio E/N of 1000 Td (1Td = 10^-17 Vcm^2). The obtained results show that the main mechanism of a nitrogen atoms production in this case is the molecular dissociation in a direct electron impact, while influence of highly excited vibrationall states can be neglected. Also, two new distributions of the statistical time delay of electrical breakdown in nitrogen, the Gaussian and Gauss-exponential ones, are presented. Distributions are theoretically founded on binomial distribution for the occurrence of initiating electrons and described by using analytical and numerical models. Moreover, the correlation coefficient between the statistical and formative time delay of electrical breakdown in nitrogen is de- termined. Starting from bivariate normal (Gaussian) distribution of two random variables, the analytical distribution of the electrical breakdown time delay is theoretically founded on correlation of the dependent statistical and formative time delay. Gaussian density dis- tribution of the electrical breakdown time delay goes to Gaussian of the formative time or to Gaussian of the statistical time delay depending on electron yields, while the correlation coefficient is determined in the transition region from the formative time to statistical time dominated statistics .

Gocic, S.

2010-07-01

53

Electric field breakdown in open-cycle disk generators  

NASA Astrophysics Data System (ADS)

Experiments have been performed in the Stanford Inflow Disk Generator facility with clean fuel and with slagging insulator walls to investigate the radial electric field breakdown phenomena. The results indicate that the presence of the magnetic field in the disk geometry has a stabilizing effect on incipient breakdown, in contrast to the previously-reported linear generator case where the B-field increases the breakdown susceptibility. The breakdown voltage threshold and insulator gap resistance both increased with time as the applied field was maintained, possibly indicating the evaporation of condensed seed material in the clean-fuel case, and the polarization and thinning of the slag layer in the coal slurry case. Insulator-initiated breakdown was the dominant breakdown mode in all cases. The plasma-initiated breakdown threshold was examined via the application of short-duration (100 ms) ramp-shaped voltage pulses and was found to be consistently higher than the insulator-initiated breakdown threshold for insulator gaps studied (3.2 mm and 6.4 mm).

Lear, W. E.; Nakamura, T.

1984-01-01

54

Electrical breakdown induced by long lived metastable states in nitrogen  

Microsoft Academic Search

The total time delay of electrical breakdown (td) and its dependence on current, flowing through a discharge in pure nitrogen after breakdown, has been investigated, using three geometrically identical diodes filled at pressures of 1.33, 4.00 and 13.33 mbar. It was shown that curve minima depend on the nitrogen pressure in the diodes and seem to be related to the

M. M. Pejovic; B. Dimitrijevic

1982-01-01

55

Runaway breakdown and electrical discharges in thunderstorms  

NASA Astrophysics Data System (ADS)

This review considers the precise role played by runaway breakdown (RB) in the initiation and development of lightning discharges. RB remains a fundamental research topic under intense investigation. The question of how lightning is initiated and subsequently evolves in the thunderstorm environment rests in part on a fundamental understanding of RB and cosmic rays and the potential coupling to thermal runaway (as a seed to RB) and conventional breakdown (as a source of thermal runaways). In this paper, we describe the basic mechanism of RB and the conditions required to initiate an observable avalanche. Feedback processes that fundamentally enhance RB are discussed, as are both conventional breakdown and thermal runaway. Observations that provide clear evidence for the presence of energetic particles in thunderstorms/lightning include ?-ray and X-ray flux intensifications over thunderstorms, ?-ray and X-ray bursts in conjunction with stepped leaders, terrestrial ?-ray flashes, and neutron production by lightning. Intense radio impulses termed narrow bipolar pulses (or NBPs) provide indirect evidence for RB particularly when measured in association with cosmic ray showers. Our present understanding of these phenomena and their enduring enigmatic character are touched upon briefly.

Milikh, Gennady; Roussel-Dupré, Robert

2010-12-01

56

Impulse Electrical Breakdown of High-Purity Water  

Microsoft Academic Search

Experiments have been conducted on the electrical breakdown of high-purity water and water mixtures. The electrical regime of interest has been carefully defined and documented to consist of electrical impulses with approximately microsecond rise time and fall time greater than 65 microseconds, on approximately 81-square-centimeter-area planar electrodes with a dielectric gap of approximately one centimeter. The results of over 25,000

Victor Herbert Gehman Jr.

1995-01-01

57

Breakdown Characteristics Study on an 18 Cell X-band Structure  

SciTech Connect

A CLIC designed 18 cells, low group velocity (2.4% to 1.0% c), X-band (11.4 GHz) accelerator structure (denoted T18) was designed at CERN, its cells were built at KEK, and it was assembled and tested at SLAC. An interesting feature of this structure is that the gradient in the last cell is about 50% higher than that in the first cell. This structure has been RF conditioned at SLAC NLCTA for about 1400 hours where it incurred about 2200 breakdowns. This paper presents the characteristics of these breakdowns, including 1) the breakdown rate dependence on gradient, pulse width and conditioning time, 2) the breakdown distribution along the structure, 3) relation between breakdown and pulsed heating dependence study and 4) electric field decay time for breakdown changing over the whole conditioning time. Overall, this structure performed very well, having a final breakdown rate of less than 1e-6/pulse/m at 106 MV/m with 230 ns pulse width.

Wang Faya [Stanford Linear Accelerator Center, Menlo Park, CA 94025 (United States)

2009-01-22

58

Breakdown Characteristics Study on an 18 Cell X-band Structure  

SciTech Connect

A CLIC designed 18 cells, low group velocity (2.4% to 1.0% c), X-band (11.4 GHz) accelerator structure (denoted T18) was designed at CERN, its cells were built at KEK, and it was assembled and tested at SLAC. An interesting feature of this structure is that the gradient in the last cell is about 50% higher than that in the first cell. This structure has been RF conditioned at SLAC NLCTA for about 1400 hours where it incurred about 2200 breakdowns. This paper presents the characteristics of these breakdowns, including (1) the breakdown rate dependence on gradient, pulse width and conditioning time, (2) the breakdown distribution along the structure, (3) relation between breakdown and pulsed heating dependence study and (4) electric field decay time for breakdown changing over the whole conditioning time. Overall, this structure performed very well, having a final breakdown rate of less than 1e-6/pulse/m at 106 MV/m with 230 ns pulse width.

Wang, Faya

2008-11-12

59

Breakdown Strength in Electrical and Elastic Random Networks  

NASA Astrophysics Data System (ADS)

Electrical or elastic networks provide a natural model to study transport processes such as dielectric breakdown to metal insulator transition in disordered inhomogeneous conductors. We present an expression for the mean breakdown strength of such networks. First, we introduce a method to evaluate the redistribution of current due to the removal of a finite number of elements from a hyper-cubic network of conductances. It is used to determine the reduction of breakdown strength due to a fracture of size ?. Numerical analysis is used to show that the analogous reduction due to random removal of elements from electrical and elastic networks follow a similar form. We discuss one possible application, namely the use of bone density as a diagnostic tools for osteoporosis.

Espinoza Ortiz, Julio; Rajapakse, Chamith; Gunaratne, Gemunu

2003-03-01

60

Distribution of time delay of electrical breakdown in nitrogen  

Microsoft Academic Search

Gives the distribution of experimentally obtained values of time delay of electrical breakdown (td). Measurements of td were made on a specially made nitrogen-filled diode at 13.33 mbar pressure. The results show that the distribution form is easily identifiable after about 500 successively measured td values, and that its form may be estimated after about 100 successively measured td values.

M. M. Pejovic; Dj A. Bosan; Z. Nikolic

1982-01-01

61

Statistical analysis of the dynamic voltage electrical breakdown in nitrogen  

Microsoft Academic Search

The statistical analysis of the electrical breakdown in nitrogen at p=20 mbar using dynamic method is presented in this paper. The analysis was performed for the working voltage increase rates 50, 150, and 300 Vs-1. For each working, voltage increase rate a 1000 measurements were done. It was shown that results are lined up accidentally without any systematic trend. New

M. K. Radovic; Cedomir A. Maluckov

2001-01-01

62

Breakdown characteristics of paper-ice composite insulating system in liquid nitrogen  

Microsoft Academic Search

In this paper, we have studied the AC breakdown performance of a paper-ice composite insulating system immersed in liquid nitrogen. This system could be a good candidate for cryogenic electrical insulation systems, since we can expect an improvement of breakdown strength by replacing liquid nitrogen with ice, whose breakdown strength could be higher than that of liquid nitrogen. The breakdown

M. Nagao; T. Higami; J. Yanase; M. Kosaki; T. Shibata; S. Isojima

1995-01-01

63

Laser initiation and early stages of electrical breakdown in charge glasses  

Microsoft Academic Search

A single pulse from a neodymium laser is used to initiate electrical breakdown in glasses which accumulate and preserve a space charge induced by a beam of rapid monoenergetic electrons. Laser initiation permits use of high-speed recording apparatus and study of the initial stage of electrical breakdown in the charged glasses. A time delay in electrical breakdown relative to the

A. I. Akishin; N. V. Zelikin; L. S. Kornienko; V. V. Radchenko; L. P. Trukhanova; Yu. I. Tyutrin

1989-01-01

64

Laser initiation and early stages of electrical breakdown in charged glasses  

Microsoft Academic Search

A single pulse from a neodymium laser is used to initial electrical breakdown in glasses which accumulate and preserve a space charge induced by a beam of rapid monoenergetic electrons. Laser initiation permits use of high-speed recording apparatus and study of the initial stage of electrical breakdown in the charged glasses. A time delay in electrical breakdown relative to the

A. I. Akishin; N. V. Zelikin; L. S. Kornienko; V. V. Radchenko; L. P. Trukhanova; Yu. I. Tyutrin

1988-01-01

65

Fast Diagnostic For Electrical Breakdowns In Vacuum  

SciTech Connect

The design of an inexpensive, small, high bandwidth diagnostic for the study of vacuum insulator flashover is described. The diagnostic is based on the principle of capacitive coupling and is commonly referred to as a D-dot probe due to its sensitivity to the changing of the electric displacement field. The principle challenge for the design proved to be meeting the required mechanical size for the application rather than bandwidth. An array of these probes was fabricated and used in an insulator test stand. Data from the test stand with detailed analysis is presented. A highlight of the application of the probes to the test stand was the ability to detect the charging of the insulator surface by UV illumination as a prelude to the insulator flashover. The abrupt change in the insulator's surface charge during the flashover was also detected.

Houck, T L; Javedani, J B; Lahowe, D A

2008-03-25

66

Electric Breakdown of Solution-Grown Polyethylene Films without Spherulite  

NASA Astrophysics Data System (ADS)

Self-healing breakdown tests are made at room temperature on solution-grown polyethylene (PE) films without heat treatment. The non heat-treated film has no spherulite and consists of randomly oriented lamellae, in contrast to the heat-treated film consisting of two-dimensional spherulites. The variation of electric strength with voltage rising speed and voltage polarity gives a feature similar to the previous results for the heat-treated films and is again interpreted in terms of roughness of the top surface and space charge formation. The electric strength free from both surface roughness and space charge is higher for the non heat-treated films than for the heat-treated films in which breakdown occurs at spherulite boundaries.

Kitagawa, Keiichi; Sawa, Goro; Ieda, Masayuki

1982-08-01

67

Time-lags in the Intrinsic Electrical Breakdown of Glass  

Microsoft Academic Search

WHEN measuring the electrical breakdown strength of lead glass sheets with 1-cm.-diam. sphere electrodes subjected to 0.1\\/1,500 µsec. voltage pulses it was found that the secondary effects, usually present when transformer oil or similar immersion media are used, could be eliminated by using low-conductivity water as the immersion medium. Under these conditions when the edge effects were suppressed it was

M. N. Azam; H. Dickinson

1960-01-01

68

Ioninduced electrical breakdown in metal-insulator-silicon capacitors  

Microsoft Academic Search

Metal-insulator-silicon self-healing capacitors were constructed with thin insulators of either thermal oxide, plasma-enhanced chemical vapor deposition (PECVD) oxide, low-pressure chemical vapor deposition (LPCVD) nitride, PECVD nitride, bilayers of oxide-nitride, or PECVD oxynitrides. Studies were made of the dependence of the ion-induced electrical field breakdown (RIB) on substrate temperature, ion mass, ion energy, and film thickness. For all of the dielectrics,

Alvin A. Milgram; Edward D. Franco

1990-01-01

69

Electric Breakdown of Solution-Grown Polyethylene Films without Spherulite  

Microsoft Academic Search

Self-healing breakdown tests are made at room temperature on solution-grown polyethylene (PE) films without heat treatment. The non heat-treated film has no spherulite and consists of randomly oriented lamellae, in contrast to the heat-treated film consisting of two-dimensional spherulites. The variation of electric strength with voltage rising speed and voltage polarity gives a feature similar to the previous results for

Keiichi Kitagawa; Goro Sawa; Masayuki Ieda

1982-01-01

70

The relationship between microstructure and electrical breakdown in cathodic arc deposited hafnium oxide films  

NASA Astrophysics Data System (ADS)

Hafnium oxide films were deposited with a range of substrate temperatures using a filtered cathodic vacuum arc deposition system. The microstructure, electronic structure, and electrical breakdown of the films were characterized. In films deposited at temperatures above 200 °C, the microstructure became more ordered and x-ray diffraction indicated that the dominant phase was monoclinic hafnium oxide. Evidence for the presence of the tetragonal phase was also found in the films deposited at temperatures above 400 °C. The near edge structure of the oxygen K-edge measured using x-ray absorption spectroscopy, provided further evidence that films prepared at high temperatures contained a combination of the monoclinic and tetragonal phases. Films deposited at room temperature were disordered and exhibited the best electrical breakdown characteristics. The electrical breakdown of the films deteriorated as the crystallinity increased with increasing deposition temperature. These results support the proposition that electrical breakdown paths may occur along grain boundaries in polycrystalline hafnium oxide films and therefore a disordered microstructure is preferable.

Field, M. R.; Partridge, J. G.; Mayes, E. H.; Latham, K.; McCulloch, D. G.

2011-07-01

71

Electrical Breakdown in a V2O3 device at the Insulator to Metal Transition  

NASA Astrophysics Data System (ADS)

We have measured the electrical properties of a V2O3 thin film micro bridge at the insulator metal transition (IMT). Discontinuous jumps to lower voltages in the current voltage characteristic (IV) followed by an approximately constant voltage progression for high currents indicate an electrical breakdown of the device. In addition, the IV curves show hysteresis and a training effect, i.e. the subsequent IV loops are different from the first IV loop after thermal cycling. Low temperature scanning electron microscopy (LTSEM) reveals that the electrical breakdown over the whole device is caused by the formation of electro-thermal domains (ETDs), i.e. the current and temperature redistribution in the device. On the contrary, at the nanoscale, the electrical breakdown causes the IMT of individual domains. In a numerical model we considered these domains as a network of resistors and we were able to reproduce the electro-thermal breakdown as well as the hysteresis and the training effect in the IVs. This work was supported by AFOSR grant number FA9550-12-1-0381.

Guénon, S.; Wang, Siming; Ramírez, J. G.; Schuller, Ivan K.; Scharinger, S.; D; Koelle; Kleiner, R.

2013-03-01

72

Size effect and statistical characteristics of dc and pulsed breakdown of liquid helium  

Microsoft Academic Search

Breakdown time lag in liquid helium is measured over a wide range of electrode sizes and pulsed electric field strengths. The breakdown time lag and dc breakdown strength are statistically analyzed by using the Weibull distribution function and weak link theory. It is found that the time lag depends on both electrical stress and the electrode surface area stressed above

J. Suehiro; K. Ohno; T. Takahashi; M. Miyama; M. Hara

1996-01-01

73

Optical characteristics of red sprites produced by runaway air breakdown  

SciTech Connect

The results of numerical calculations of intensity and spectra of optical emissions from red sprites produced by runaway air breakdown in the atmosphere are presented. It is shown that the optical emissions from red sprites consist of two components: (1) short-term (t{approx}0.3{endash}2thinspms) emissions produced as a result of dissipation of an energetic electron beam in air; (2) long-term (t{approx}2{endash}10thinspms) emissions produced by a population of low-energy electrons in an electric field. The long-term optical emissions are calculated for all low-energy electrons, including the secondary low-energy electrons produced by the relativistic electron beam, ambient background electrons, and electrons produced as a result of regular breakdown. The theoretical results are compared with observational data. {copyright} 1998 American Geophysical Union

Yukhimuk, V.; Roussel-Dupre, R.A.; Symbalisty, E.M. [Space and Atmospheric Sciences, Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Taranenko, Y. [Computational Science Methods, Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

1998-05-01

74

DC electrical breakdown of water in a sub-micron planar gap  

Microsoft Academic Search

Water breakdown subjected to uniform DC electric field in 300 nm planar gaps is experimentally studied. Test devices with microstrip line configurations are fabricated through nanofabrication technology and the results show that water breakdown occurs at ~ 100 kV\\/cm electric field under current system setup. The initiation process of water breakdown in a small gap is discussed. It is most

Chunrong Song; Pingshan Wang

2009-01-01

75

DC electrical breakdown of water in a sub-micron planar gap  

Microsoft Academic Search

Water breakdown subjected to uniform DC electric field in 300 nm planar gaps is experimentally studied. Test devices with microstrip line configurations are fabricated through nanofabrication technology and the results show that water breakdown occurs at ? 100 kV\\/cm electric field under current system setup. The initiation process of water breakdown in a small gap is discussed. It is most

Chunrong Song; Pingshan Wang

2009-01-01

76

Influence of a radial electrical field on the electrical breakdown along the exploding tungsten wire  

Microsoft Academic Search

Experimental results on the influence of a radial electrical field on the electrical breakdown along exploding W wires in vacuum are presented. To create a radial electrical field a wire was set inside of a metal tubule fixed on one of the electrodes. It is shown that a wire explosion inside of the tubule (when the tubule has a negative

Alexander G. Rousskikh; Rina B. Baksht; Alexey Yu. Labetsky; Vladimir I. Oreshkin; Alexander V. Shishlov

2004-01-01

77

Space Charge Formation and Electrical Breakdown at High Temperature Region in PVC for Electrical Wiring Assembly  

NASA Astrophysics Data System (ADS)

The Polyvinyl chloride (PVC), the most popular insulating material, is used as an insulating material of various electric products. When using an electrical wiring assembly code over the power capacity, PVC could melt by the joule heating and cause an electrical breakdown. Therefore, it is necessary to clarify the electrical breakdown phenomena near the melting point (170°C) in PVC. In this paper, space charge distribution and conduction current have been measured in PVC sheets up to the electrical breakdown in the range from room temperature to 200°C under DC electric field. The breakdown strength decreases with temperature in PVC. Small hetero-space charges are accumulated near both of the electrodes at room temperature region. At high temperature region above 100°C, it is observed that positive charges are injected from anode and move toward the cathode; the electric field is emphasized near the cathode due to the packet-like positive charge in PVC. It shows a thermal breakdown process of the electric fields due to positive charge behavior and conduction current increase with temperature near the melting point in PVC.

Miura, Masakazu; Fukuma, Masumi; Kishida, Satoru

78

A system for gas electrical breakdown time delay measurements based on a microcontroller  

Microsoft Academic Search

A new system, called gasmem v1.0, for the measurements of gas electrical breakdown time delay (td), with significantly better characteristics than older systems, has been developed and realized. It is based on the PIC 18F4550 microcontroller and could measure the minimal td of about 1.5 ?s with the resolution of 83.33 ns. The relaxation (afterglow) period (?) could vary from

Miomir Todorovi?; Nikola D Vasovi?; Goran S Risti?

2012-01-01

79

Lightning Impulse Breakdown Characteristics and Electrodynamic Process of Insulating Vegetable Oil-Based Nanofluid  

NASA Astrophysics Data System (ADS)

Insulating vegetable oils are considered environment-friendly and fire-resistant substitutes for insulating mineral oils. This paper presents the lightning impulse breakdown characteristic of insulating vegetable oil and insulating vegetable oil-based nanofluids. It indicates that Fe3O4 nanoparticles can increase the negative lightning impulse breakdown voltages of insulating vegetable oil by 11.8% and positive lightning impulse breakdown voltages by 37.4%. The propagation velocity of streamer is reduced by the presence of nanoparticles. The propagation velocities of streamer to positive and negative lightning impulse breakdown in the insulating vegetable oil-based nanofluids are 21.2% and 14.4% lesser than those in insulating vegetable oils, respectively. The higher electrical breakdown strength and lower streamer velocity is explained by the charging dynamics of nanoparticles in insulating vegetable oil. Space charge build-up and space charge distorted filed in point-sphere gap is also described. The field strength is reduced at the streamer tip due to the low mobility of negative nanoparticles.

Li, Jian; Zhang, Zhao-Tao; Zou, Ping; Du, Bin; Liao, Rui-Jin

2012-06-01

80

Dielectric Breakdown Characteristics of Oil-pressboard Insulation System against AC/DC Superposed Voltage  

NASA Astrophysics Data System (ADS)

This paper describes breakdown characteristics of an oil-pressboard insulation system to a superposition voltage of AC and DC voltages. Although AC electric field is decided by the ratio of the relative permittivity of a pressboard and insulating oil, DC electric field is decided by ratio ? of volume resistivities. From the measurement in this study, 13—78 and 1.8—5.7 are obtained as the volume resistivity ratios ? at temperature of 30°C and 80°C, respectively. The breakdown voltages against AC, DC, and those superposition voltages are surveyed to insulation models. In normal temperature, the breakdown voltage to the superposition voltage of AC and DC is determined by AC electric field applied to the oil duct. Since the ? becomes as low as 2-3 at temperature of 80°C, AC and DC voltages almost equally contribute to the electric field of the oil duct as a result. That is, it became clear that superposed DC voltage boosts the electric field across oil ducts at operating high temperature.

Ebisawa, Yoshihito; Yamada, Shin; Mori, Shigekazu; Ikeda, Masami

81

Electrical network-based time-dependent model of electrical breakdown in water  

Microsoft Academic Search

A time-dependent, two-dimensional, percolative approach to model dielectric breakdown based on a network of parallel resistor-capacitor elements having random values, has been developed. The breakdown criteria rely on a threshold electric field and on energy dissipation exceeding the heat of vaporization. By carrying out this time-dependent analysis, the development and propagation of streamers and prebreakdown dynamical evolution have been obtained

R. P. Joshi; J. Qian; K. H. Schoenbach

2002-01-01

82

Electrical network-based time-dependent model of electrical breakdown in water  

Microsoft Academic Search

A time-dependent, two-dimensional, percolative approach to model dielectric breakdown based on a network of parallel resistor–capacitor elements having random values, has been developed. The breakdown criteria rely on a threshold electric field and on energy dissipation exceeding the heat of vaporization. By carrying out this time-dependent analysis, the development and propagation of streamers and prebreakdown dynamical evolution have been obtained

R. P. Joshi; J. Qian; K. H. Schoenbach

2002-01-01

83

Hydrogen-sensitive breakdown voltage in the I– V characteristics of tin dioxide-based semiconductors  

Microsoft Academic Search

Current (I)-voltage (V) characteristics of porous SnO2-based specimens have been investigated in air as well as in 1.0% H2 balanced with air in the temperature range from room temperature to 700°C. Pure SnO2 specimens exhibited non-linear I–V characteristics and breakdown-voltage shift to a low electric field upon exposure to 1.0% H2 at 300–500°C. Addition of 1.0 mol% Bi2O3 to pure

Makoto Egashira; Yasuhiro Shimizu; Yuji Takao; Youichi Fukuyama

1996-01-01

84

Analysis of mechanisms which lead to electrical breakdown in argon using the time delay method  

Microsoft Academic Search

The mechanisms leading to initiation of electrical breakdown in geometrically identical argon-filled tubes at different pressures were investigated by the memory curves. It was shown that the positive ions and metastable states, remaining from the previous discharge, have the dominant role in the initiation of breakdown in early and late afterglow periods, respectively. Contributions to the breakdown of gamma photons

Goran S. Ristic

2002-01-01

85

Statistical analysis of electrical breakdown time delay distributions in neon tube at 13.3 mbar  

Microsoft Academic Search

Results of the statistical analysis of the electrical breakdown time delay for a neon-filled tube at 13.3 mbar are presented in this paper. Experimental distributions of the breakdown time delay were established on the basis of 1000 successive and independent measurements, deviating from usual exponential distribution. Breakdown time delay distributions are numerically generated from the composition of two parameters, which

Cedomir A. Maluckov; Jugoslav P. Karamarkovic; M. K. Radovic

2003-01-01

86

The mechanism of self healing electrical breakdown in MOS structures  

Microsoft Academic Search

Capacitor structures with non-shorting breakdowns are considered. Three kinds of breakdown events occur: single -- hole, propagating and total breakdown. Single hole breakdowns are due to thermal instability at weak spots. Destruction occurs by evaporation of a crater in the silicon, of an adjoining hole of about 1 µ diameter through the silicondioxyde and a much larger hole in the

N. Klein

1965-01-01

87

Electrical breakdown of graphene and few-layer graphene structures  

NASA Astrophysics Data System (ADS)

The electrical breakdown of graphene and few-layer graphene (FLG) structures are investigated. To better understand the dynamics of these nano-scale thermal effects, we investigate graphene and FLG nanowires of various dimensions and find that significant joule heating occurs inducing the structures to evolve. A distinct change in the behavior during electrical stressing indicates that different mechanisms occur at the various stages of evolution. The results are compared to detailed thermal modeling of our structures and could have implications on the development of high current carrying nanoscale graphene devices. Supported in part by NSF Award No. DMR-0805136, the Kentucky NSF EPSCoR program, the University of Kentucky Center for Advanced Materials, and the University of Kentucky Center for Nanoscale Science and Engineering.

Sundararajan, Abhishek; Johnson, Stephen; Hunley, D. Patrick; Flores, Roel; Johnson, A. T. Charlie; Strachan, Douglas

2011-03-01

88

Electrical breakdown of graphene and few-layer graphene structures  

NASA Astrophysics Data System (ADS)

The electrical breakdown of graphene and few-layer graphene (FLG) structures are investigated. To better understand the dynamics of these nano-scale thermal effects, we investigate graphene and FLG structures of various dimensions and find that significant joule heating occurs inducing the structures to evolve. A distinct change in the behavior during electrical stressing indicates that different mechanisms and geometrical effects occur at the various stages of evolution. The results could have implications on the development of high current carrying nanoscale graphene devices. Supported in part by NSF Award No. DMR-0805136, the Kentucky NSF EPSCoR program through award EPS-0814194, and the University of Kentucky Center for Advanced Materials.

Sundararajan, Abhishek; Hunley, D. Patrick; Strachan, Douglas. R.

2012-02-01

89

Electrical Breakdown in Lightning Arrestor Connector (LAC) Devices  

NASA Astrophysics Data System (ADS)

Lightning arrestor connector (LAC) devices protect electronic devices by providing a conductive path to ground for electrical power surges caused by lightning. Such devices consist of an insulating material between electrodes. This insulation region is composed of an air gap and a high permittivity dielectric. In this presentation, the physics of the phenomena active in the early stages of the flow of transient electrical current will be described. The conditions that lead to thermal breakdown of the dielectric will also be discussed.--Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Hjalmarson, Harold P.; Kambour, Kenneth; Pineda, Andrew C.

2011-03-01

90

Investigation of the statistical nature and structure of the electrical breakdown time delay in gas diodes filled with neon  

Microsoft Academic Search

The electrical breakdown time delay in gas diodes filled by neon at the low pressures is investigated experimentally and theoretically. Experimental results are obtained measuring the characteristics of gas diodes filled by spectroscopically pure neon. In order to discard any systematic trend during the measurement procedure, checking of the measured values randomness preceded the statistical analysis of the experimental results.

Cedomir A. Maluckov; Jugoslav P. Karamarkovic; Miodrag K. Radovic

2006-01-01

91

Experimental Study on High Electrical Breakdown of Water Dielectric  

Microsoft Academic Search

By means of a coaxial apparatus, pressurized water breakdown experiments with microsecond charging have been carried out with different surface roughness of electrodes and different ethylene glycol concentrations of ethylene glycol\\/water mixture. The experimental results about the breakdown stress and the effective time are presented. The breakdown stress is normalized to the situation that the effective time is transformed to

Zicheng Zhang; Jiande Zhang; Jianhua Yang

2005-01-01

92

Statistical analysis of the electrical breakdown time delay distributions in krypton  

Microsoft Academic Search

The statistical analysis of the experimentally observed electrical breakdown time delay distributions in the krypton-filled diode tube at 2.6 mbar is presented. The experimental distributions are obtained on the basis of 1000 successive and independent measurements. The theoretical electrical breakdown time delay distribution is evaluated as the convolution of the statistical time delay with exponential, and discharge formative time with

Jugoslav P. Karamarkovic´; Miodrag K. Radovic´

2006-01-01

93

Breakdown characteristics of pressurized liquid helium under quench condition of superconducting wires  

Microsoft Academic Search

For practical insulation design of superconducting power apparatus, we have been studying quench-induced dynamic breakdown and prebreakdown characteristics of liquid helium (LHe). We have already pointed out that the insulation performance of LHe may be drastically degraded in thermal bubble disturbance. In this paper, we measured breakdown and prebreakdown characteristics of pressurized LHe under quench conditions and discussed the dynamic

S. Chigusa; H. Maeda; Y. Taniguchi; N. Hayakawa; H. Okubo

1998-01-01

94

Visual and Electrical Evidence Supporting a Two-Plasma Mechanism of Vacuum Breakdown Initiation  

SciTech Connect

The energy available during vacuum breakdown between copper electrodes at high vacuum was limited using resistors in series with the vacuum gap and arresting diodes. Surviving features observed with SEM in postmortem samples were tentatively correlated with electrical signals captured during breakdown using a Rogowski coil and a high-voltage probe. The visual and electrical evidence is consistent with the qualitative model of vacuum breakdown by unipolar arc formation by Schwirzke [1, 2]. The evidence paints a picture of two plasmas of different composition and scale being created during vacuum breakdown: an initial plasma made of degassed material from the metal surface, ignites a plasma made up of the electrode material.

Castano-Giraldo, C. [University of Illinois, Urbana-Champaign; Aghazarian, Maro [ORNL; Caughman, John B [ORNL; Ruzic, D. N. [University of Illinois, Urbana-Champaign

2012-01-01

95

Stretch dependence of the electrical breakdown strength and dielectric constant of dielectric elastomers  

NASA Astrophysics Data System (ADS)

Dielectric elastomers are used for electromechanical energy conversion in actuators and in harvesting mechanical energy from renewable sources. The electrical breakdown strength determines the limit of a dielectric elastomer for its use in actuators and energy harvesters. We report two experimental configurations for the measurement of the stretch dependence of the electrical breakdown strength of dielectric elastomers, and compare the electrical breakdown fields for compliant and rigid electrodes on the elastomer. We show that the electrode configuration strongly influences the electrical breakdown field strength. Further, we compare the stretch dependent dielectric function and breakdown of the acrylic elastomer VHB 4910™ from 3M™, and of the natural rubber ZruElast™ A1040™ from Zrunek rubber technology. While the dielectric permittivity of VHB decreases with increasing stretch ratio, the dielectric constant of rubber is insensitive to stretch. Our results suggest natural rubber as a versatile material for dielectric elastomer energy harvesting.

Tröls, Andreas; Kogler, Alexander; Baumgartner, Richard; Kaltseis, Rainer; Keplinger, Christoph; Schwödiauer, Reinhard; Graz, Ingrid; Bauer, Siegfried

2013-10-01

96

Probability of electrical breakdown: Evidence for a transition between the Townsend and streamer breakdown mechanisms  

Microsoft Academic Search

Spark-breakdown delay times were measured for N2, H2, Ar, SF6, and CCl2F2 in a uniform field gap provided with a small current (~10-15 A) of free electrons by uv illumination of the cathode. Laue plots of the delay times yielded straight lines with slope iP, where i is the photocurrent and P is the breakdown probability. The dependence of the

R. V. Hodges; R. N. Varney; J. F. Riley

1985-01-01

97

High field breakdown characteristics of carbon nanotube thin film transistors  

NASA Astrophysics Data System (ADS)

The high field properties of carbon nanotube (CNT) network thin film transistors (CN-TFTs) are important for their practical operation, and for understanding their reliability. Using a combination of experimental and computational techniques we show how the channel geometry (length LC and width WC) and network morphology (average CNT length Lt and alignment angle distribution ?) affect heat dissipation and high field breakdown in such devices. The results suggest that when WC ? Lt, the breakdown voltage remains independent of WC but varies linearly with LC. The breakdown power varies almost linearly with both WC and LC when WC ? Lt. We also find that the breakdown power is more susceptible to the variability in the network morphology compared to the breakdown voltage. The analysis offers new insight into the tunable heat dissipation and thermal reliability of CN-TFTs, which can be significantly improved through optimization of the network morphology and device geometry.

Gupta, Man Prakash; Behnam, Ashkan; Lian, Feifei; Estrada, David; Pop, Eric; Kumar, Satish

2013-10-01

98

High field breakdown characteristics of carbon nanotube thin film transistors.  

PubMed

The high field properties of carbon nanotube (CNT) network thin film transistors (CN-TFTs) are important for their practical operation, and for understanding their reliability. Using a combination of experimental and computational techniques we show how the channel geometry (length LC and width WC) and network morphology (average CNT length Lt and alignment angle distribution ?) affect heat dissipation and high field breakdown in such devices. The results suggest that when WC ? Lt, the breakdown voltage remains independent of WC but varies linearly with LC. The breakdown power varies almost linearly with both WC and LC when WC ? Lt. We also find that the breakdown power is more susceptible to the variability in the network morphology compared to the breakdown voltage. The analysis offers new insight into the tunable heat dissipation and thermal reliability of CN-TFTs, which can be significantly improved through optimization of the network morphology and device geometry. PMID:24029606

Gupta, Man Prakash; Behnam, Ashkan; Lian, Feifei; Estrada, David; Pop, Eric; Kumar, Satish

2013-09-12

99

Influence of electrode temperature and auxiliary discharge on the electrical breakdown in helium  

Microsoft Academic Search

The influence of electrode temperature and the auxiliary discharge on the statical breakdown voltage and the electrical breakdown\\u000a time delay in helium-filled diodes has been investigated. It was shown that the statical breakdown voltage decreased about\\u000a 20% with increasing the temperature of electrodes up to 450°C. With increasing the temperature, the time delay decreased,\\u000a too, and the current of discharge

M. M. Pejovi?; M. K. Radovi?

1989-01-01

100

Fluid insulation breakdown due to repetitive electric fields  

Microsoft Academic Search

A facility to study the breakdown effects of reprate high v oltage pulsing on insulating materials has been developed. The unique high v oltage and data acquisition and control instrumentation are briefly described. Two insul ting fluids, a transformer oil amplitude, 5.0 microsecond pulses at 1, 10, 100, and 1000 Hz rep-rates until breakdown occurred. These tests demonstrate a quick

Robert Kraus; Michael Treanor

1989-01-01

101

Electrical Breakdown of Dielectrics with a Dipole Structure.  

National Technical Information Service (NTIS)

On the basis of data obtained in the breakdown of water and glycerine, as a function of the variation of the temperature, and also from data concerning breakdown voltages for ice, Seignette salt, and polar liquids, it follows that with the variation of th...

N. A. Prikhodko

1972-01-01

102

Electrical breakdown of insulators by one-carrier impact ionization  

Microsoft Academic Search

Theories for current runaway by one-carrier impact ionization are generalized for insulators, in which the injected and ionizing charge carrier type is subject to trapping. Relations are derived for the critical current runaway field Fr and time to breakdown tr , and written in simple forms, offering physical insight into breakdown processes. A trapped charge of injected carriers is frequently

N. Klein

1982-01-01

103

Electrical breakdown time delay distribution in nitrogen for small values of the afterglow period  

Microsoft Academic Search

The Laue distribution of electrical breakdown time delay (td) in nitrogen for values of afterglow period ( tau ) of the order of milliseconds (when the breakdown is initiated by ionization remaining from the previous discharge) is given. Results show that the Laue distribution is valid for these values of time delay. The formative time (tf), obtained from distribution and

M. Pejovic; V. Markovic; S. Mekic

1991-01-01

104

Influence of electrodes on electrical breakdown along exploding tungsten and aluminum wires  

Microsoft Academic Search

Experimental results on the influence of electrodes on electrical breakdown along exploding W and Al wires in vacuum are presented. It is shown that insulation of any electrode (anode or cathode) leads to a significant increase in both the breakdown delay time and the energy deposited into the wire. The obtained experimental data are compared with the results of the

Alexander G. Rousskikh; Rina B. Baksht; Alexey Yu. Labetsky; Vladimir I. Oreshkin; Alexander V. Shishlov

2004-01-01

105

Electrode material release into a vacuum gap and mechanisms of electrical breakdown  

Microsoft Academic Search

Two types of instabilities of electrodes of vacuum gaps, leading to the electrical breakdown, are analyzed in connection with newly published experimental results on the electrode material release into a gap. It is noted that the cathode material release, in correlation with short time delays of the breakdown, is in agreement with the widely accepted model of explosive emission of

V. A. Nevrovskii; V. I. Rakhovskii

1986-01-01

106

New Models And Distributions Of The Electrical Breakdown Time Delay In Neon  

Microsoft Academic Search

The measurements of the electrical breakdown time delay dt in DC neon glow discharge for a wide range of working voltages and at different preionization levels are presented. The statistical breakdown time delay ts and the discharge formative time ft are experimentally separated and theoretical models of their dependencies on the overvoltage and number densities of residual charges during relaxation

S. N. Stamenkovic

2010-01-01

107

Impulsive electrical breakdown of air at atmospheric pressure guided by a long laser spark  

Microsoft Academic Search

Results of an experimental study of the electrical breakdown of air in a 10-cm-wide discharge gap along the channel of a long laser spark at atmospheric pressure are reported. It is found that the breakdown velocity depends on the delay between the generation of a long laser spark and the superposition of a voltage pulse over the spark, varying in

E. I. Asinovskii; L. M. Vasiliak; O. P. Nesterkin

1987-01-01

108

New models and distributions of the electrical breakdown time delay in neon  

Microsoft Academic Search

The measurements of the electrical breakdown time delay td for a wide range of working voltages and at different preionization levels are presented. The statistical breakdown time delay ts and the discharge formative time tf are experimentally separated and theoretical models of their dependencies on the overvoltage and number densities of residual charges during relaxation are suggested. Several empirical and

S. N. Stamenkovic

2010-01-01

109

Influence of Low Speed Rolling Movement on High Electrical Breakdown for Water Dielectric with Microsecond Charging  

Microsoft Academic Search

By means of a coaxial apparatus, high electrical breakdown experiments are carried out in the rest state and the low speed rolling state with microsecond charging and the experimental results are analyzed. The conclusions are: (1) the breakdown stress of water dielectric in the rolling state is in good agreement with that in Martin formula, and so is that in

Zicheng Zhang; Jiande Zhang; Jianhua Yang

2006-01-01

110

THE ONSET OF ELECTRICAL BREAKDOWN IN DUST LAYERS: I. MICROSPARKING DESCRIBED BY PASCHEN'S LAW  

EPA Science Inventory

This paper describes a study of the onset of electrical breakdown in dust layers, for hand-deposited dust layers in a parallel-plate geometry. It was found that the breakdown was an ordinary electron-avalanche process originating in voids within the dust layer and obeying Paschen...

111

Mechanism of electrical breakdown of gases at very low pressure and inter electrode gap values  

SciTech Connect

In this paper the electrical breakdown mechanism of gases at very low pressures (from 10{sup {minus}4} to 10{sup 5} Pa) and inter-electrode gap values (from 0.1 to 1 mm) is considered. Comparing experimental results and theoretical analysis, the boundaries between areas of different breakdown mechanisms are established. The existence of ``edge breakdown``, which was previously erroneously interpreted by ``anomalous Paschen`s effect`` is explained and proved. The avalanche hypothesis of vacuum breakdown is also experimentally proved.

Osmokrovic, P. [Univ. of Belgrade (Yugoslavia). Faculty of Engineering]|[IRCE Inst. of Energoinvest Co., Sarajevo (Yugoslavia)

1993-12-01

112

Pulsed breakdown voltage characteristics of pressurized carbon dioxide up to supercritical conditions  

Microsoft Academic Search

Statistical characteristics of pulsed breakdown voltage of pressurized carbon dioxide up to supercritical condition were investigated experimentally. The tested gap is a sphere-to-sphere and the gap length and sphere diameter are around 140 ¿m and 20 mm, respectively. The experimental results show the followings: 1) in the supercritical phase, the scattering in measured breakdown voltage increases with increasing the medium

T. Kiyan; K. Miyaji; T. Ihara; M. Hara; H. Akiyama

2009-01-01

113

Characteristics of optical breakdown in ultrapure water induced by nanosecond Nd:YAG laser pulses  

Microsoft Academic Search

Characteristics of dielectric breakdown in ultrapure liquid water using single nanosecond laser pulses have been investigated. The threshold for the systematic occurrence of laser-induced breakdown of ultrapure water has been found to be about one order of magnitude below the threshold of distilled water, and of impurity-rich liquids like ordinary tap water. The behaviour of the threshold value in relation

F. Docchio; A. Avigo; R. Palumbo

1991-01-01

114

Electrical breakdown time delay and breakdown propagation velocity in polypropylene under a highly non-uniform field condition  

Microsoft Academic Search

The electrical breakdown phenomenon in polypropylene for point-to-plane gap configuration has been investigated using a photo-optical current-measuring technique and a 760 ns rectangular high-voltage pulse generator. The waveform of prebreakdown current in polyethylene is essentially the same as that in liquid nitrogen. A linear relation to formative time delay and gap spacing is obtained for gap lengths greater than some

H. Yamada; T. Fujiwara; Y. Suzuoki

1993-01-01

115

Computer Simulation of Electrical Breakdown in Gases; Avalanche and Streamer Formation.  

National Technical Information Service (NTIS)

The paper presents a new method for the simulation of electrical-breakdown phenomena, and plasma phenomena where both binary electron-neutral-gas-molecule collisions and collective interactions among charged particles are important. Elastic, exciting, and...

J. G. Siambis L. E. Kline

1971-01-01

116

Electrical Structure and Preliminary Breakdown of Lightning Flashes in Three New Mexico Thunderstorms  

NASA Astrophysics Data System (ADS)

In this presentation, we compare propagation characteristics of lightning flashes from Lightning Mapping Array data to simultaneous electric field (E) measurements at different altitudes for three storms. For normal cloud-to- ground flashes, detailed analysis has shown that when a potential well for negative charge exists between the altitude of the flash initiation and ground, the first return stroke occurs only after a period of horizontal negative polarity branching below the initiation altitude. This period of preliminary breakdown, or the delay between the initiation time and the first return stroke, lasted an average of 117 ms for 14 flashes that initiated when a low-level potential well was present. When no low-level potential well was indicated in the E data, the time between flash initiation and first return stroke averaged 15 ms. Existence of preliminary breakdown for more than about 40 ms before the first return stroke of a cloud-to-ground flash thus suggests that a low-level potential well for negative charge is present at that time in the storm. Examples will be shown that give an indication of the rapid temporal evolution in the electrical structure of the storm as it relates to the lightning activity.

Coleman, L.; Stolzenburg, M.; Marshall, T.; Hamlin, T.; Krehbiel, P.; Rison, W.; Thomas, R.; Stanley, M.

2007-12-01

117

Equivalent junction transformation: a semi-empirical analytical method for predicting the breakdown characteristics of cylindrical- and spherical-abrupt P–N junctions  

Microsoft Academic Search

A semi-empirical analytical method called as the equivalent junction transformation has been proposed in this paper for the first time, and used to predict the breakdown characteristics of curved-abrupt P–N junctions. Based on this method, the effects of the radius of curvature of the metallurgical junction and the background doping concentration on the breakdown voltage, peak electrical field and depletion

Jin He; Xing Zhang; Ru Huang; Y. Y Wang

2000-01-01

118

Multipacting mechanism as the origin of breakdown in high-frequency electrical discharges in gases  

Microsoft Academic Search

The mechanism by which gas at low pressure breaks down when subjected to a high-frequency electrical field is considerably different from that of other types of electrical discharge. Provided the pressure is sufficiently low, the breakdown electric field strength is independent of the kind of gas, depending instead on the type, condition and separation of electrode surfaces, and the frequency

G. S. Harmon

1979-01-01

119

Breakdown characteristics of titanium dioxide–silicone–fluorophlogopite nanocomposite coating  

Microsoft Academic Search

In order to improve the high-voltage performance of organic insulators against flashover breakdown, a novel composite coating capable of conductive manipulation by the introduction of suitable amount of titanium dioxide photocatalytic semiconductor was proposed. This composite coating containing organic silicon, titanium dioxide and fluorophlogopite was fabricated on polyamide substrate by the brushing method. X-ray diffraction (XRD), scanning electron microscopy (SEM),

Yakui Bai; Yunhan Ling; Xinde Bai

2011-01-01

120

An investigation into the cumulative breakdown process of polymethylmethacrylate in quasi-uniform electric field under nanosecond pulses  

NASA Astrophysics Data System (ADS)

A group of complete images on the discharge channel developed in PMMA in quasi-uniform electric field under nanosecond pulses are observed with an on-line transmission microscope. The characteristics of the cumulative breakdown process are also generalized, which include initiating from the vicinity of the cathode, developing to the anode with a branch-like shape, and taking on a wormhole appearance when final breakdown occurs. The concluded characteristics are explained by referring to the conceptions of ``low density domain'' and ``free radical'' and considering the initial discharge channel as a virtual needle. The characteristics are helpful for designers to enhance the lifetime of insulators employed on a nanosecond time scale.

Zhao, Liang; Cang Su, Jian; Bo Zhang, Xi; Feng Pan, Ya; Min Wang, Li; Peng Fang, Jin; Sun, Xu; Lui, Rui

2013-08-01

121

A novel method for investigating electrical breakdown enhancement by nm-sized features  

NASA Astrophysics Data System (ADS)

Electrical transport studies across nm-thick dielectric films can be complicated, and datasets compromised, by local electrical breakdown enhanced by nm-sized features. To avoid this problem we need to know the minimal voltage that causes the enhanced electrical breakdown, a task that usually requires numerous measurements and simulation of which is not trivial. Here we describe and use a model system, using a ``floating'' gold pad to contact Au nanoparticles, NPs, to simultaneously measure numerous junctions with high aspect ratio NP contacts, with a dielectric film, thus revealing the lowest electrical breakdown voltage of a specific dielectric-nanocontact combination. For a 48 +/- 1.5 Å SiO2 layer and a ~7 Å monolayer of organic molecules (to link the Au NPs) we show how the breakdown voltage decreases from 4.5 +/- 0.4 V for a flat contact, to 2.4 +/- 0.4 V if 5 nm Au NPs are introduced on the surface. The fact that larger Au NPs on the surface do not necessarily result in significantly higher breakdown voltages illustrates the need for combining experiments with model calculations. This combination shows two opposite effects of increasing the particle size, i.e., increase in defect density in the insulator and decrease in electric field strength. Understanding the process then explains why these systems are vulnerable to electrical breakdown as a result of spikes in regular electrical grids. Finally we use XPS-based chemically resolved electrical measurements to confirm that breakdown occurs indeed right below the nm-sized features.Electrical transport studies across nm-thick dielectric films can be complicated, and datasets compromised, by local electrical breakdown enhanced by nm-sized features. To avoid this problem we need to know the minimal voltage that causes the enhanced electrical breakdown, a task that usually requires numerous measurements and simulation of which is not trivial. Here we describe and use a model system, using a ``floating'' gold pad to contact Au nanoparticles, NPs, to simultaneously measure numerous junctions with high aspect ratio NP contacts, with a dielectric film, thus revealing the lowest electrical breakdown voltage of a specific dielectric-nanocontact combination. For a 48 +/- 1.5 Å SiO2 layer and a ~7 Å monolayer of organic molecules (to link the Au NPs) we show how the breakdown voltage decreases from 4.5 +/- 0.4 V for a flat contact, to 2.4 +/- 0.4 V if 5 nm Au NPs are introduced on the surface. The fact that larger Au NPs on the surface do not necessarily result in significantly higher breakdown voltages illustrates the need for combining experiments with model calculations. This combination shows two opposite effects of increasing the particle size, i.e., increase in defect density in the insulator and decrease in electric field strength. Understanding the process then explains why these systems are vulnerable to electrical breakdown as a result of spikes in regular electrical grids. Finally we use XPS-based chemically resolved electrical measurements to confirm that breakdown occurs indeed right below the nm-sized features. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr30620d

Shpaisman, Hagay; Cohen, Hagai; Har-Lavan, Rotem; Azulai, Daniel; Stein, Nir; Cahen, David

2012-05-01

122

Investigation of the statistical nature and structure of the electrical breakdown time delay in gas diodes filled with neon  

NASA Astrophysics Data System (ADS)

The electrical breakdown time delay in gas diodes filled by neon at the low pressures is investigated experimentally and theoretically. Experimental results are obtained measuring the characteristics of gas diodes filled by spectroscopically pure neon. In order to discard any systematic trend during the measurement procedure, checking of the measured values randomness preceded the statistical analysis of the experimental results. Novel theoretical model is established for interpretation of obtained experimental results on the breakdown time delay. The model is based on the assumptions of the exponential distribution of the statistical time delay and Gaussian distribution of the formative discharge time. Therefore, the density distribution of the breakdown time delay is assumed to be convolution of the statistical and formative time delay distributions. Parameters of the statistical and formative time delay, as stochastic variables, are modeled by the numerical Monte Carlo method. Numerical distributions are tested to the corresponding experimental distributions of the breakdown time delay by varying the distribution parameters. In addition, the asymmetry coefficient and skewness coefficient of the breakdown time delay distribution, and coefficients of the statistical and formative time delay distributions are analyzed. Numerically calculated time delay distributions fit well to the corresponding experimental distributions in gas diodes filled with neon at low pressures.

Maluckov, ?edomir A.; Karamarkovi?, Jugoslav P.; Radovi?, Miodrag K.

2006-12-01

123

Influence of Low Speed Rolling Movement on High Electrical Breakdown for Water Dielectric with Microsecond Charging  

NASA Astrophysics Data System (ADS)

By means of a coaxial apparatus, high electrical breakdown experiments are carried out in the rest state and the low speed rolling state with microsecond charging and the experimental results are analyzed. The conclusions are: (1) the breakdown stress of water dielectric in the rolling state is in good agreement with that in Martin formula, and so is that in the rest state; (2) the breakdown stress of water dielectric in the rolling state is about 5% higher than that in the rest state; (3) the results simulated with ANSYS demonstrate that the breakdown stress of water dielectric decreases when the bubbles appear near the surface of electrodes; (4) the primary mechanism to increase the breakdown stress of water dielectric in the rolling state is that the bubbles are driven away and the number of bubbles near the surface of electrodes is decreased by rolling movement.

Zhang, Zicheng; Zhang, Jiande; Yang, Jianhua

2006-03-01

124

REVIEWS OF TOPICAL PROBLEMS: Runaway breakdown and electric discharges in thunderstorms  

Microsoft Academic Search

This review concerns the theory of the avalanche multiplication of high-energy (0.1 - 10 MeV) electrons in a neutral material, a newly discovered phenomenon known as runaway breakdown (RB). In atmospheric conditions RB takes place at electric fields an order of magnitude weaker than those needed for normal breakdown in air. Experimental work of the past few years has shown

Aleksandr V. Gurevich; Kirill P. Zybin

2001-01-01

125

Laue distribution of large values of time delay of electrical breakdown in nitrogen  

Microsoft Academic Search

This paper gives the Laue distribution of time delay of electrical breakdown (td) for five pressure values of nitrogen in gas-filled diodes. Distributions were obtained for 20% overvoltage, and passive time ( tau ) 5 s and 7.2*103 s. The breakdown in nitrogen is induced by long-lived metastable states formed in the previous gas ionisation. The results show that the

M. M. Pejovic; B. J. Mijovic; Dj A. Bosan

1983-01-01

126

Electrical breakdown of paper-ice composite insulating system in liquid nitrogen  

Microsoft Academic Search

In this paper, we have studied the AC breakdown performance of paper-ice composite insulating system immersed in liquid nitrogen. The electric strength (Fb) in this paper-ice composite system is higher than that of paper-liquid nitrogen system. Furthermore, this system shows a self-healing type breakdown behavior. Among the many kinds of liquid to be immersed and frozen to the ice, deionized

M. Nagao; J. Yanase; M. Kosaki

1997-01-01

127

Mechanism of electrical breakdown in SiO2 films  

Microsoft Academic Search

The breakdown field associated with impact ionization and avalanche is estimated, using simple energy-momentum balance equations, for low-gap semiconductors and for high-gap insulators. Reasonable agreement is obtained in the former case, but estimated fields in the latter case turn out to be nearly an order of magnitude higher than those observed. This suggests that mechanisms other than avalanche are responsible

B. K. Ridley

1975-01-01

128

Analytical investigation of electrical breakdown properties in a nitrogen-SF{sub 6} mixture gas  

SciTech Connect

The electrical breakdown properties in nitrogen gas mixed with SF{sub 6} are analytically investigated in this article by making use of the ionization and attachment coefficients of the mixed gas. The ionization coefficients of nitrogen and SF{sub 6} gas are obtained in terms of the electron temperature T{sub e} by assuming a Maxwellian distribution of the electron energy. The attachment coefficient of SF{sub 6} gas is also obtained in terms of the gas temperature T{sub e}. An algebraic equation is obtained, relating explicitly the electron breakdown temperature T{sub b} in terms of the SF{sub 6} mole fraction {chi}. It was found from this equation that the breakdown temperature T{sub b} increases from approximately 2 to 5.3 eV as the mole fraction {chi} increases from zero to unity. The breakdown temperature T{sub b} of the electrons increases very rapidly from a small value and then approaches 5.3 eV slowly as the SF{sub 6} mole fraction increases from zero to unity. This indicates that even a small mole fraction of SF{sub 6} in the gas dominates the electron behavior in the breakdown system. The breakdown electric field E{sub b} derived is almost linearly proportional to the breakdown electron temperature T{sub b}. The experimental data agree remarkably well with the theoretical results. Therefore, it is concluded that even a small fraction of SF{sub 6} gas dominates nitrogen in determining the breakdown field. In this context, nearly 25% of the SF{sub 6} mole fraction provides a reasonable enhancement of the breakdown field for practical applications.

Uhm, Han S. [Kwangwoon Academy of Advanced Studies, Kwangwoon University, 447-1, Wolgye-Dong, Nowon-Gu, Seoul 137-701 (Korea, Republic of); Byeon, Yong S.; Song, Ki B.; Choi, Eun H. [Department of Electrophysics, Kwangwoon University, 447-1, Wolgye-Dong, Nowon-Gu, Seoul 137-701 (Korea, Republic of); Ryu, Han-Yong; Lee, Jaimin [Agency for Defense Development, 462 Jochiwongil, Yuseong, Daejeon 305-605 (Korea, Republic of)

2010-11-15

129

Analysis of the polarity effects in the electrical breakdown of liquids.  

SciTech Connect

Electrical breakdown simulations are carried out for liquids in response to a sub-microsecond ({approx}100-200 ns) voltage pulse. This model builds on our previous analysis and focuses particularly on the polarity effect seen experimentally in point-plane geometries. The flux-corrected transport approach is used for the numerical implementation. Our model adequately explains experimental observations of pre-breakdown current fluctuations, streamer propagation and branching as well as disparities in hold-off voltage and breakdown initiation times between the anode and cathode polarities. It is demonstrated that polarity effects basically arise from the large mobility difference between electrons and ions. The higher electron mobility leads to greater charge smearing and diffusion that impacts the local electric field distributions. Non-linear couplings between the number density, electric field and charge generation rates then collectively affect the formation of ionized channels and their temporal dynamics.

Woodworth, Joseph Ray; Qian, J. (Old Dominion University, Norfolk, VA); Joshi, Ravindra P. (Old Dominion University, Norfolk, VA); Schamiloglu, Edl (University of New Mexico, Albuquerque, NM); Gaudet, John A. (University of New Mexico, Albuquerque, NM); Lehr, Jane Marie

2005-03-01

130

The application of convolution-based statistical model on the electrical breakdown time delay distributions in neon  

Microsoft Academic Search

The convolution-based model of the electrical breakdown time delay distribution is applied for statistical analysis of experimental results obtained in neon-filled diode tube at 6.5 mbar. At first, the numerical breakdown time delay density distributions are obtained by stochastic modeling as the sum of two independent random variables, the electrical breakdown statistical time delay with exponential, and discharge formative time

Jugoslav P. Karamarkovic´; Miodrag K. Radovic´

2004-01-01

131

Statistical analysis of the electrical breakdown time delay distributions in krypton  

SciTech Connect

The statistical analysis of the experimentally observed electrical breakdown time delay distributions in the krypton-filled diode tube at 2.6 mbar is presented. The experimental distributions are obtained on the basis of 1000 successive and independent measurements. The theoretical electrical breakdown time delay distribution is evaluated as the convolution of the statistical time delay with exponential, and discharge formative time with Gaussian distribution. The distribution parameters are estimated by the stochastic modelling of the time delay distributions, and by comparing them with the experimental distributions for different relaxation times, voltages, and intensities of UV radiation. The transition of distribution shapes, from Gaussian-type to the exponential-like, is investigated by calculating the corresponding skewness and excess kurtosis parameters. It is shown that the mathematical model based on the convolution of two random variable distributions describes experimentally obtained time delay distributions and the separation of the total breakdown time delay to the statistical and formative time delay.

Maluckov, Cedomir A.; Karamarkovic, Jugoslav P.; Radovic, Miodrag K.; Pejovic, Momcilo M. [Technical Faculty in Bor, University of Belgrade, Vojske Jugoslavije 24, 19210 Bor (Serbia and Montenegro); Faculty of Civil Engineering and Architecture, University of Nis, Beogradska 14, 18000 Nis (Serbia and Montenegro); Faculty of Sciences and Mathematics, University of Nis, P.O. Box 224, 18001 Nis (Serbia and Montenegro); Faculty of Electronic Engineering, University of Nis, P.O. Box 73, 18001 Nis (Serbia and Montenegro)

2006-08-15

132

Breakdown phenomena during the growth of anodic oxide films on zirconium metal Influence of experimental parameters on electrical and mechanical breakdown  

SciTech Connect

Different aspects of the breakdown phenomena observed during the growth of anodic films on zirconium metal in aqueous solutions have been investigated. Two different mechanisms of breakdown are suggested as a result of the experimental observations. A mechanical breakdown, which is dependent upon the logarithm of the anodizing current density, has been observed in carbonate and sulfate solutions at low concentrations of salt or aci and/or low anodizing current densities. The appearance of small fissures in the ZrO/sub 2/ films is related to this type o breakdown. An electrical breakdown was observed in sulfamic acid solutions as well as in sulfate and carbonate solutions as high salt or acid concentrations and/or high current densities. In the case of electrical breakdown, the first spark voltage showed a significant dependence upon the value of current density only in carbonate and sulfate anion containing solutions. A possible explanation for this dependence is suggested in agreement with Christov's model, taking into account also the incorporation of anions into the films. The different influences of the electrolytic solutions upon both types of breakdown are presented and discussed.

Di Quarto, F.; Piazza, S.; Sunseri, C.

1984-12-01

133

Breakdown characteristics of high-side lateral double-diffused metal oxide semiconductor devices.  

PubMed

In this paper, we discuss the breakdown characteristics of an LDMOSFET (Lateral Double-diffused Metal Oxide Semiconductor Field Effect Transistor) structure for the optimization of engineering parameters such as the gap between the DEEP N-WELL and the source region and the doping concentration of the N(ADJUST)-layer. The fabricated device exhibits the breakdown voltage (BVdss) over 110 V and the specific on-resistance as low as 2.20 mOmega cm2. The robust breakdown characteristics seem to be due to the migration of the location wherein maximum impact ionization occurs from the gate region to the drain side, which was confirmed by the numerical simulation which verifies that the maximum impact ionization rate of the proposed structure is 2.44 x 10(16) cm(-3) s(-1), while that of the conventional structure being 6.69 x 10(19) cm(-3) s(-1). PMID:22966560

Sung, Kunsik; Kim, Kwangsik; Won, Taeyoung

2012-07-01

134

Microcontroller based system for electrical breakdown time delay measurement in gas-filled devices.  

PubMed

This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching on the testing device as well as transform the signals that represent the voltage pulse on the device and the device breakdown into the form suitable for detection by a digital subsystem. The insulated gate bipolar transistor IRG4PH40KD driven by TC429 MOSFET driver is used for high voltage switching on the device. The aim of a digital subsystem is to detect the signals from the analog subsystem and to measure the elapsed time between their occurrences. Moreover, the digital subsystem controls various parameters that influence time delay and provides fast data storage for a large number of measured data. For this propose, we used the PIC18F4550 microcontroller with a full-speed compatible universal serial bus (USB) engine. Operation of this system is verified on different commercial and custom made gas devices with different structure and breakdown mechanisms. The electrical breakdown time delay measurements have been carried out as a function of several parameters, which dominantly influence electrical breakdown time delay. The obtained results have been verified using statistical methods, and they show good agreement with the theory. The proposed system shows good repeatability, sensitivity, and stability for measuring the electrical breakdown time delay. PMID:21034116

Pejovi?, Mili? M; Deni?, Dragan B; Pejovi?, Mom?ilo M; Neši?, Nikola T; Vasovi?, Nikola

2010-10-01

135

Microcontroller based system for electrical breakdown time delay measurement in gas-filled devices  

NASA Astrophysics Data System (ADS)

This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching on the testing device as well as transform the signals that represent the voltage pulse on the device and the device breakdown into the form suitable for detection by a digital subsystem. The insulated gate bipolar transistor IRG4PH40KD driven by TC429 MOSFET driver is used for high voltage switching on the device. The aim of a digital subsystem is to detect the signals from the analog subsystem and to measure the elapsed time between their occurrences. Moreover, the digital subsystem controls various parameters that influence time delay and provides fast data storage for a large number of measured data. For this propose, we used the PIC18F4550 microcontroller with a full-speed compatible universal serial bus (USB) engine. Operation of this system is verified on different commercial and custom made gas devices with different structure and breakdown mechanisms. The electrical breakdown time delay measurements have been carried out as a function of several parameters, which dominantly influence electrical breakdown time delay. The obtained results have been verified using statistical methods, and they show good agreement with the theory. The proposed system shows good repeatability, sensitivity, and stability for measuring the electrical breakdown time delay.

Pejovi?, Mili? M.; Deni?, Dragan B.; Pejovi?, Mom?ilo M.; Neši?, Nikola T.; Vasovi?, Nikola

2010-10-01

136

Investigation of the mechanisms leading to the electrical breakdown of a triggered water gaps  

Microsoft Academic Search

The breakdown of a triggered, plane-parallel electrode system with water dielectric has been investigated. The gap was triggered by a discharge initiated at an electrically isolated trigger pin, positioned in the center of one of the electrodes, using a 500 ns voltage pulse. A 5000 fps CCD-camera monitored events occurring in the gap during such a discharge and the intensity

M. Saniei; S. J. MacGreggor; R. A. Fouracre

2003-01-01

137

New distributions of the statistical time delay of electrical breakdown in nitrogen  

Microsoft Academic Search

Two new distributions of the statistical time delay of electrical breakdown in nitrogen are reported in this paper. The Gaussian and Gauss-exponential distributions of statistical time delay have been obtained on the basis of thousands of time delay measurements on a gas tube with a plane-parallel electrode system. Distributions of the statistical time delay are theoretically founded on binomial distribution

V Lj Markovi?; S R Goci?; S N Stamenkovi?

2006-01-01

138

ELECTRICAL BREAKDOWN TIME DELAY IN GASES AT LOW PRESSURES UDC 537.565\\/.568  

Microsoft Academic Search

A review of our investigations on the time delay of electrical breakdown in gases at low pressures has been presented in this paper. Statistical analysis of time delay using Laue distributions and histograms of experimental data has been performed. The influence of different parameters (overvoltage, electrodes' temperature and material, glow current) on time delay has been considered. Memory curves have

139

High Speed Laser Schlieren Studies of Electrical Breakdown in Liquid Hydrocarbons  

Microsoft Academic Search

The events occurring just prior, during, and after electrical break-down in liquid hydrocarbons have been photographed using 15 ns laser pulses produced with a ruby laser, to illuminate the space between two parallel plate electrodes, and schlieren optics. In this manner it was possible to obtain experimental evidence of the density gradients produced by the movement of charge carriers during

E. O. Forster; P. Wong

1977-01-01

140

Microcontroller based system for electrical breakdown time delay measurement in gas-filled devices  

Microsoft Academic Search

This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching

Milic´ M. Pejovic´; Dragan B. Denic; Nikola T. Nesic; Nikola Vasovic

2010-01-01

141

Measurement and Analysis of Time Delay Characteristics of Field-Breakdown Triggered Vacuum Switches  

Microsoft Academic Search

This paper focuses on the delay time and its scattering characteristics of field-breakdown TVS. The experimental circuit of TVS is set up and the experiments are carried out to study the effects of several factors including the voltage across the main electrodes, the polarities of the main gap voltage and the trigger pulse voltage on the performance of TVS. Both

Manling Dong; Junjia He; Yuan Pan; Zheng Cheng

2008-01-01

142

Measurement and Analysis of Time Delay Characteristics of Field-Breakdown Triggered Vacuum Switches  

Microsoft Academic Search

This paper focuses on the delay time and its scattering characteristics of field-breakdown triggered vacuum switch (TVS). The experimental circuit of TVS is set up, and the experiments are carried out to study the effects of several factors including the voltage across the main electrodes, the polarities of the main gap voltage, and the trigger pulse voltage on the performance

Manling Dong; Junjia He; Yuan Pan; Zheng Cheng

2009-01-01

143

Pulsed electrical breakdown from superconducting electrodes in vacuum diodes  

Microsoft Academic Search

Results are presented of investigations of the pulsed electric strength and threshold current densities of YBa2Cu3O7 and Nb cathodes at cryogenic temperatures. It has been shown that the cooling of a Nb cathode from 300 to 4.2 K leads to a 1.5 to 2.5× increase of pulsed electric strength and that the transition of the cathode from the normal to

Sergei I. Shkuratov

1995-01-01

144

Prebreakdown and breakdown characteristics of stainless steel electrodes in vacuum  

Microsoft Academic Search

Measurements of prebreakdown current as a function of applied electric field have been made for polished stainless steel electrodes in vacuum (similar 10?8 mm Hg) for gap separations 0·02

D. W. Williams; W. T. Williams

1974-01-01

145

Numerical methods for two-dimensional analysis of electrical breakdown in a non-uniform gap  

SciTech Connect

A finite difference procedure used to analyze the two-dimensional evolution of the charged particle densities and electrostatic potential during the initial stages of electrical breakdown between a wire and a plane is described. The diffusion flux equations for the charged particle densities and Poisson's equation for the electrostatic potential constitute a set of coupled, two-dimensional, time dependent, nonlinear equations that govern the breakdown phenomena. In this paper, we have solved the problem by two different procedures: (a) a finite difference method that combines upwind difference scheme (UDS) for drift terms, central difference scheme (CDS) for the diffusion terms, and implicit time integration, and (b) a method that combines CDS for drift terms, CDS for the diffusion terms, and implicit time integration. In each case, Crank-Nicolson time integration has also been tried. It is concluded that method (a) is most suitable for discharge breakdown problems.

Ramakrishna, K. (IBM Corp., Endicott, NY (United States)); Cohen, I.M.; Ayyaswamy, P.S. (Univ. of Pennsylvania, Philadelphia (United States))

1993-01-01

146

Propagation of ionizing electron shock waves in electrical breakdown  

Microsoft Academic Search

A numerical solution of a hydrodynamic second-order model shows that the propagation of the first ionizing wave arises from an overgrowth of hot electrons in the wave front in a zone of a greatly disturbed electric field. This gives rise, in the electron shock zone ahead of the wave, to a precursor phenomenon, whose effect is to accelerate the channel

P. Bayle; B. Cornebois

1985-01-01

147

Electrical Breakdown Studies on Electro-active Paper  

Microsoft Academic Search

The concept of using cellulose as a smart material for preparing electro-active paper (EAPap) has been a land mark discovery, since it exhibits an impressive magnitude of actuation at relatively modest voltages. Considering the small thickness of cellulose samples (35 mum) and smaller depth of electrodes (100 nm), even at relatively low operating voltages (7 V), high electrical stresses can

Prathap Basappa; Sangdong Jang; Jaehwan Kim

2007-01-01

148

A system for gas electrical breakdown time delay measurements based on a microcontroller  

NASA Astrophysics Data System (ADS)

A new system, called gasmem v1.0, for the measurements of gas electrical breakdown time delay (td), with significantly better characteristics than older systems, has been developed and realized. It is based on the PIC 18F4550 microcontroller and could measure the minimal td of about 1.5 ?s with the resolution of 83.33 ns. The relaxation (afterglow) period (?) could vary from 1 to 232 ms (?50 days). The successive series of td measurements with various ? could be performed, giving very reliable td data that are stored on the personal computer (PC) hard drive via the USB interface. The td and ? values enable the drawing of memory curves (langtdrang = f(?)) and the analysis of memory effects in the gases. The randomness of td values measured by the gasmem system for more ? values was tested using the nonparametric Wald-Wolfowitz test showing the stochastic nature of obtained results. The memory curves obtained by this system have shown very high reproducibility. In addition, the system has a capability of operating as a stand-alone system (independently of a PC), with the possibility for the implementation of a touch screen for controlling the system and additional memory (e.g. memory card) for data storage.

Todorovi?, Miomir; Vasovi?, Nikola D.; Risti?, Goran S.

2012-01-01

149

Influence of magnetic field on the electric breakdown in penning ion source  

NASA Astrophysics Data System (ADS)

A cold-cathode penning-type ion source has been developed in our laboratory to study the electric breakdown in this type of sources. The breakdown voltage was measured as a function of axial magnetic field, in the range of 440-600 G, and anode length, in steps of 14, 20, and 24 mm. The measurement was performed with stainless steel cathodes in argon gas at pressure of 4 × 10-2 mbar. Furthermore, a model was developed to explain the breakdown voltage data. In the construction of the model, the first Townsend coefficient was not directly used to avoid difficulties originating from the non-uniformity of the electric field. The empirical parameters of the model were obtained using the experimental data. The equation ? = c × (Ez/N)n, expressing the effective secondary emission coefficient in terms of reduced electric field, which was needed in the modeling process, was inspired from previous works. The parameters c and n were then calculated from the empirical parameters of the model. The n parameter turned out to be 0.59, which differs from the value reported by other authors merely by 1.6%. Three values, 0.010, 0.013, and 0.017 corresponding to the three anodes were obtained for the c parameter. These numbers are in good agreement with 0.01, which has been reported in the previous works. It was also found that the value of n has a decisive impact on the breakdown voltage curve in the high breakdown voltage region.

Mahjour-Shafiei, M.; Noori, H.; Ranjbar, A. H.

2011-11-01

150

Forecasting of electrical breakdown in porous silicon using Flicker noise spectroscopy  

NASA Astrophysics Data System (ADS)

Owing to the influence of environment and impact of energy fluxes (electric polarisation, heating, photon irradiation, etc.) physical and chemical properties of porous semiconductors (and other materials as well) experience changes which have to be monitored in order to distinguish the moment when the properties become out of a working range. There is a necessity of forecasting the development of catastrophic events in the porous film. In the present work we study the possibility of predicting the occurrence of the electrical breakdown in thin porous films through analysis of the fluctuations of the electric current in the vicinity of this event using a novel method called Dynamic Flicker Noise Spectroscopy - DFNS.

Parkhutik, V.; Rayon, E.; Ferrer, C.; Timashev, S.; Vstovsky, G.

2003-05-01

151

Investigation of Dielectric Breakdown Characteristics for Double-break Vacuum Interrupter and Dielectric Breakdown Probability Distribution in Vacuum Interrupter  

NASA Astrophysics Data System (ADS)

To investigate the reliability of equipment of vacuum insulation, a study was carried out to clarify breakdown probability distributions in vacuum gap. Further, a double-break vacuum circuit breaker was investigated for breakdown probability distribution. The test results show that the breakdown probability distribution of the vacuum gap can be represented by a Weibull distribution using a location parameter, which shows the voltage that permits a zero breakdown probability. The location parameter obtained from Weibull plot depends on electrode area. The shape parameter obtained from Weibull plot of vacuum gap was 10?14, and is constant irrespective non-uniform field factor. The breakdown probability distribution after no-load switching can be represented by Weibull distribution using a location parameter. The shape parameter after no-load switching was 6?8.5, and is constant, irrespective of gap length. This indicates that the scatter of breakdown voltage was increased by no-load switching. If the vacuum circuit breaker uses a double break, breakdown probability at low voltage becomes lower than single-break probability. Although potential distribution is a concern in the double-break vacuum cuicuit breaker, its insulation reliability is better than that of the single-break vacuum interrupter even if the bias of the vacuum interrupter's sharing voltage is taken into account.

Shioiri, Tetsu; Asari, Naoki; Sato, Junichi; Sasage, Kosuke; Yokokura, Kunio; Homma, Mitsutaka; Suzuki, Katsumi

152

Electrostatic discharge and electrical breakdown study of the head-disk interface in a hard disk drive  

Microsoft Academic Search

A systematic and comprehensive procedure for understanding electrostatic discharge and electrical breakdown at the head-disk interface in a hard disk drive is described. First, the resistance, breakdown and field emission behavior for the individual and combined carbon overcoat films on the disk and slider was determined through current versus voltage testing. Second, different electrostatic mechanisms that can produce a voltage

Albert J. Wallash

2004-01-01

153

Effect of static magnetic fields on the base conductance and electric breakdown of bilayer lipid membranes  

SciTech Connect

Static magnetic fields (MF) having inductions of 0.85 to 1.1 T were found to have an effect on the base conductance and electric breakdown of bilayer lipid membranes (BLM) formed from egg lecithin in decane. In membranes with a low specific resistance (R /SUB SP/ < 10/sup 7/ ..cap omega.. X cm/sup 2/ and membranes in a state of ''stress,'' MF parallel to the BLM plane will increase the conductance, current fluctuations, and probability of rupture. Magnetic fields perpendicular to the membranes have no effect on their conductance. In electric breakdown, MF parallel to the membranes prolong the stage of steady-state currents and shorten that of the prebreakdown fluctuations, while MF perpendicular to the membranes shorten the stage of steady-state currents and have no effect on that of the prebreakdown fluctuations. These effects appear to be due to the influence of MF on the formation probability and diameter of ''hydrophilic'' pores.

Simonov, A.N.; Kuznetsov, A.N.; Livshits, V.A.

1986-07-01

154

Fowler Nordheim tunnelling and electrically stressed breakdown of 3-mercaptopropyltrimethoxysilane self-assembled monolayers  

NASA Astrophysics Data System (ADS)

We report the confirmed occurrence of Fowler-Nordheim (FN) electron tunnelling in p+ Si (SiOx)/self-assembled monolayers of 3-mercaptopropyltrimethoxysilane (MPTMS)/Au structures. The statistically favoured values of the effective mass and energy barrier heights for electrons are determined to be in the ranges 0.15-0.18 me and 1.3-1.5 eV, respectively. The electrically stressed breakdown of the monolayers is observed to take place at very high fields, i.e. 16-50 MV cm-1. Prior to the breakdown, switching of FN currents between different conduction states was observed; this is found to be related to a change in the electrical properties of monolayers owing to the creation of field-induced defects.

Aswal, Dinesh K.; Lenfant, Stephane; Guerin, David; Yakhmi, Jatinder V.; Vuillaume, Dominique

2005-12-01

155

Calculations of Electrical Breakdown in Air at Near-Atmospheric Pressure  

Microsoft Academic Search

A computer program based on the Townsend avalanche model, but explicitly including space charge, has been used to calculate electrical breakdown in air at near-atmospheric pressure. A good fit to Bandel's experimental temporal-current-growth curves may be obtained by using a secondary ionization coefficient that includes 10% ion and 90% photon portions. Only a poorer fit could be obtained when using

A. L. Ward

1965-01-01

156

Field Emission Current and Electrical Breakdown by a Pointed Cathode Coated with Carbon-Nano-Tube  

Microsoft Academic Search

Feature of field emission current and electrical breakdown was experimentally investigated for very short gap in the range of 0.1mum to 3mum between a pointed cathode coated with Carbon-Nano-Tube (CNT) and a plane anode in vacuum environment. The experimental setup, which consists of the CNT coated cathode, the stainless steel anode and the precise positioning mechanisms actuated by piezoelectric devices,

Yoshinori Hirata; Masayoshi Teramoto; Mizue Mizoshiri; Ukyo Ikeda; Takayoshi Ohji; Kimihiro Ozaki

2007-01-01

157

Preliminary Breakdown Pulses Characteristic of Negative Cloud-to-Ground Lightning That Are Not Followed by a Return Stroke Pulse  

NASA Astrophysics Data System (ADS)

In this study, we identify and examine preliminary breakdown pulses that are characteristic of negative cloud- to-ground discharges, but are not followed by return-stroke waveforms. We have termed these events "attempted cloud-to-ground leaders", although some of them may be followed by full-fledged cloud discharges. A total of 2225 electric field records of lightning events that we acquired in Gainesville, Florida, in 2006 were examined, and waveforms in 31 (1.4%) of them were found to satisfy the criteria set for attempted cloud-to- ground leaders. These criteria included the total duration of pulse train (of the order of 1 ms), overall pulse shape (bipolar), polarity of the initial half cycle (same as the initial polarity of negative return stroke pulses and opposite to the polarity of pulses characteristic of the initial breakdown in cloud discharges), overall pulse duration (typically 20 to 40 ?s), interpulse interval (typically 70 to 130 ?s), and overall regularity of pulses in the train. From our analysis of the preliminary-breakdown pulse trains of attempted cloud-to-ground leaders, the amplitude of pulses tended to be smaller at the onset and toward the end of each pulse train. This pulse amplitude variation is similar to that observed in "normal" preliminary breakdown pulse trains followed, typically within several to few tens of milliseconds, by return-stroke waveforms. In addition to bipolar pulses with positive (atmospheric electricity sign convention) initial half-cycle, negative unipolar and negative (initial half- cycle) bipolar pulses were sometimes seen toward the end of the train. We also noted that at the beginning and at the end of the pulse train there were narrower pulses, often having durations in the range of 1-2 ?s, which is more than an order of magnitude shorter than for "classical" preliminary breakdown pulses. Temporally isolated short-duration (sub-millisecond) discharges were observed using the VHF Lightning Mapping Array by Krehbiel et al. (2003). These discharges were described either as precursors of full- fledged lightning flashes or as "spatially limited or attempted breakdown events". At least some of these isolated short-duration discharges might be the attempted cloud-to-ground leaders considered in this study. Since the preliminary breakdown pulses considered here have the same polarity as return-stroke pulses in negative cloud-to-ground flashes and durations of these two types of pulses are comparable (tens of microseconds), some of the attempted cloud-to-ground leaders can be misclassified by the National Lightning Detection Network (NLDN) as low intensity negative cloud-to-ground discharges. If we assume that about 25% of the 2225 records examined here were due to negative cloud-to-ground flashes, and that 25% of these cloud-to-ground flashes had peak currents equal to or less than 10 kA, the expected number of low-intensity (? 10 kA) negative cloud-to-ground events will be 139. If the NLDN recorded all these 139 negative cloud- to-ground events plus all 31 attempted leaders (all assumed to have NLDN intensities ? 10 kA), about 18% of the reported low-intensity cloud-to-ground flashes would be misclassified events.

Nag, A.; Rakov, V. A.

2006-12-01

158

Comparative Study of the Electrical Properties and Characteristics of Thermally Sprayed Alumina and Spinel Coatings  

Microsoft Academic Search

In this study, APS and HVOF processes have been used to prepare alumina (Al2O3) and magnesium spinel (MgAl2O4) coatings designed for insulating applications. The electrical characteristics, i.e., dielectric strength and electrical\\u000a resistance (electrical resistivity) were investigated using different methods: dielectric breakdown test, direct current (DC)\\u000a measurements, and electrochemical impedance spectroscopy (EIS). The electrical resistance was measured at room temperature\\u000a at

Filofteia-Laura Toma; Stefan Scheitz; Lutz-Michael Berger; Viktar Sauchuk; Mihails Kusnezoff; Sven Thiele

2011-01-01

159

New models and distributions of the electrical breakdown time delay in neon  

NASA Astrophysics Data System (ADS)

The measurements of the electrical breakdown time delay td for a wide range of working voltages and at different preionization levels are presented. The statistical breakdown time delay ts and the discharge formative time tf are experimentally separated and theoretical models of their dependencies on the overvoltage and number densities of residual charges during relaxation are suggested. Several empirical and semiempirical models are used to describe the formative time delay dependence on working voltages tf (U). The empirical and theoretical models from the literature are also applied to the experimental data, without and with empirical corrections. Moreover, several new distributions are experimentally obtained: Gauss-exponential, Gaussian and double Gaussian ones for the statistical time delay, as well as Gaussian and double Gaussian distributions for the formative time. The measurements of the breakdown time delay at different preionization levels (afterglow periods) td (?) obtained with a galvanic layer of gold and a sub-layer of nickel on the copper cathode are compared to the measurements with a vacuum deposited gold layer on the cathode surface. It was found that the surface charges retaining on a galvanic layer of gold influence the breakdown time delay which leads to double Gaussian distributions of the formative and statistical time delay.

Stamenkovi?, S. N.

2010-11-01

160

Electrical transport and breakdown in graphene multilayers loaded with electron beam induced deposited platinum.  

PubMed

We demonstrate here the effect of electron beam induced deposited platinum on the electrical transport through multilayer graphene sheets. Platinum metal is deposited at different positions on the graphene multilayers, i.e., including as well as excluding the bottom contact sites and the change in electrical conductance of the same multilayer graphene sheets before and after platinum deposition is segregated. An improvement in electrical conductance is observed even if the metal is deposited at the part of the graphene sheets that does not touch the bottom gold electrodes, and hence this experimental approach directly demonstrates that the contact improvement is not the sole reason for the improved electrical conduction. The improvement in electrical performance of the graphene sheets is explained in terms of the doping of graphene sheets caused by the charge transfer between the deposited metal and the graphene and thereby modified density of states for electrical conduction. Metal deposition also leads to the increased interlayer interaction of the graphene sheets as revealed by the transmission electron microscopy analysis. Further, two types of breakdown behaviors viz. sharp and stepped breakdowns observed for these graphene devices are explained in terms of the effective graphene-metal contact area. These studies reveal the implications of top metal contact fabrication on graphene for electronic devices. PMID:23489064

Kulshrestha, Neha; Misra, Abhishek; Koratkar, Nikhil; Misra, D S

2013-04-04

161

Simulation of Spectral Characteristics of Sprites From Runaway and Conventional Breakdown Processes and Comparison to Measurements  

NASA Astrophysics Data System (ADS)

The breakdown processes that lead to sprite formation are still being debated. Are sprites formed through conventional breakdown, runaway breakdown, or a combination of both? What are the thunderstorm electrical conditions that produce one or the other or both processes? This study describes the improved two-dimensional fully electromagnetic Unified Maxwell (UNIMAX) model and an updated methodology to derive the associated optical spectra using the Physics-based Optical Emission Model (POEM). These models allow us to study the differences between conventional and runaway breakdown processes and obtain a better understanding of what information can be garnered from sprite spectral measurements. A detailed kinetic computational tool, Plume, has been developed to compute the self-consistent evolution of a seed electron population with energies from 0 to 50 MeV in the presence of a steady-state, spatially-uniform electric field (see Colman et al. abstract submitted to this meeting). This information is used to compute steady-state emission rates as a function of the applied electric field for 13 Nitrogen and 3 Oxygen band systems. These rates can be combined with the number and energy of electrons from the UNIMAX sprite model and quantum transition information from POEM to separate the band system into individual lines and generate simulated spectral images. Cascading between different bands is also included. Spectral measurements of sprites represent a temporal and spatial superposition of emissions. These emissions emanate from a wide variety of electrical and gas discharge conditions that exist along the body of the sprite and which change as a function of time. Interpretation of the spectra to obtain the properties of the gas is made difficult by this inherent averaging process and the fundamental discharge mechanism can be obscured. Thus, we fold in the properties of spectrometers (i.e. spatial and temporal averaging, slit size, atmospheric absorption, etc.) to compare with measurements and assess the effect of temporal and spatial averaging. These spectra can then be used to elucidate what would be theoretically observed separately from runaway and conventional breakdown and to suggest potential measurements that could differentiate between the different processes.

Triplett, L. A.; Roussel-Dupre, R. A.; Colman, J. J.; Symbalisty, E. M.

2004-12-01

162

Ion-induced electrical breakdown in metal-oxide-silicon capacitors  

SciTech Connect

Metal-oxide-silicon (MOS) capacitors used in the breakdown mode were constructed to detect {sup 252}Cf fission fragments. The physical effects related to radiation-induced breakdown were studied and found to have a relationship to intrinsic dielectric breakdown. Physical studies were made of the effect of oxide annealing temperature between 100 and 400 K, oxide thickness, differing metal electrodes, and the materials interaction due to the spark discharge breakdown. By means of both silicon-ion and cesium-ion implants near the metal-SiO{sub 2} interface of the MOS capacitor, the current emission into the SiO{sub 2} was found to be significantly enhanced; however, the enhanced emission was found to have no effect on increasing the sensitivity to lower specific ionization radiation as seen by fission-fragment detection. The results indicate that the radiation-induced breakdown mechanism occurs within the bulk, or body, of the SiO{sub 2} film and is not influenced by conditions at the dielectric interfaces. It was found that thin films of the refractory metals HfO{sub 2} or ZrO{sub 2} between the oxide film and a top aluminum electrode prevented Al-SiO{sub 2} interaction during discharge and allowed operation of the MOS capacitor at higher electric fields. Obtaining higher operating fields significantly improved the minimum specific ionization detectability to 14 MeV cm{sup 2}/mg from a prior value of 22 MeV cm{sup 2}/ mg.

Milgram, A.A. (Aracor, 425 Lakeside Drive, Sunnyvale, California 94086 (US))

1990-02-01

163

Ion-induced electrical breakdown in metal-oxide-silicon capacitors  

NASA Astrophysics Data System (ADS)

Physical effects related to radiation-induced intrinsic electrical breakdown in metal-oxide-silicon capacitors used for the detection of Cf-252 fission fragments were investigated, with special attention given to the effect of the oxide annealing temperature between 100 and 400 K, the oxide thickness, the differing metal electrodes, and the material interaction due to the spark discharge breakdown. It was found that the current emission into the SiO2 was significantly enhanced by means of both Si-ion and Cs-ion implants near the metal-SiO2 interface of the capacitors. However, the enhanced emission had no effect on increasing the sensitivity to lower specific ionization radiation as seen by fission-fragment detection, indicating that the radiation-induced breakdown mechanism occurs within the bulk of the SiO2 film and is not influenced by conditions at the dielectric interfaces. It was also found that thin films of HfO2 or ZrO2 placed between the oxide film and a top electrode prevented the Al-SiO2 interaction during the discharge and made it possible to operate the capacitor at higher electric fields.

Milgram, Alvin A.

1990-02-01

164

Preliminary Breakdown Pulses Characteristic of Negative Cloud-to-Ground Lightning That Are Not Followed by a Return Stroke Pulse  

Microsoft Academic Search

In this study, we identify and examine preliminary breakdown pulses that are characteristic of negative cloud- to-ground discharges, but are not followed by return-stroke waveforms. We have termed these events \\

A. Nag; V. A. Rakov

2006-01-01

165

Application of dynamic displacement current for diagnostics of subnanosecond breakdowns in an inhomogeneous electric field  

NASA Astrophysics Data System (ADS)

The breakdown of different air gaps at high overvoltages in an inhomogeneous electric field was investigated with a time resolution of up to 100 ps. Dynamic displacement current was used for diagnostics of ionization processes between the ionization wave front and a plane anode. It is demonstrated that during the generation of a supershort avalanche electron beam (SAEB) with amplitudes of ~10 A and more, conductivity in the air gaps at the breakdown stage is ensured by the ionization wave, whose front propagates from the electrode of small curvature radius, and by the dynamic displacement current between the ionization wave front and the plane electrode. The amplitude of the dynamic displacement current measured by a current shunt is 100 times greater than the SAEB. It is shown that with small gaps and with a large cathode diameter, the amplitude of the dynamic displacement current during a subnanosecond rise time of applied pulse voltage can be higher than 4 kA.

Shao, Tao; Tarasenko, Victor F.; Zhang, Cheng; Burachenko, Alexandr G.; Rybka, Dmitry V.; Kostyrya, Igor'D.; Lomaev, Mikhail I.; Baksht, Evgeni Kh.; Yan, Ping

2013-05-01

166

Application of dynamic displacement current for diagnostics of subnanosecond breakdowns in an inhomogeneous electric field.  

PubMed

The breakdown of different air gaps at high overvoltages in an inhomogeneous electric field was investigated with a time resolution of up to 100 ps. Dynamic displacement current was used for diagnostics of ionization processes between the ionization wave front and a plane anode. It is demonstrated that during the generation of a supershort avalanche electron beam (SAEB) with amplitudes of ~10 A and more, conductivity in the air gaps at the breakdown stage is ensured by the ionization wave, whose front propagates from the electrode of small curvature radius, and by the dynamic displacement current between the ionization wave front and the plane electrode. The amplitude of the dynamic displacement current measured by a current shunt is 100 times greater than the SAEB. It is shown that with small gaps and with a large cathode diameter, the amplitude of the dynamic displacement current during a subnanosecond rise time of applied pulse voltage can be higher than 4 kA. PMID:23742550

Shao, Tao; Tarasenko, Victor F; Zhang, Cheng; Burachenko, Alexandr G; Rybka, Dmitry V; Kostyrya, Igor' D; Lomaev, Mikhail I; Baksht, Evgeni Kh; Yan, Ping

2013-05-01

167

Pulsed Dielectric Breakdown of Aluminum Oxide (ALOX) Filled Epoxy Encapsulants: Effects of Formulation and Electric Stress Concentration  

SciTech Connect

Aluminum oxide (ALOX) filled epoxy is the dielectric encapsulant in shock driven high-voltage power supplies. ALOX encapsulants display a high dielectric strength under purely electrical stress, but minimal information is available on the combined effects of high voltage and mechanical shock. We report breakdown results from applying electrical stress in the form of a unipolar high-voltage pulse of the order of 10-{micro}s duration, and our findings may establish a basis for understanding the results from proposed combined-stress experiments. A test specimen geometry giving approximately uniform fields is used to compare three ALOX encapsulant formulations, which include the new-baseline 459 epoxy resin encapsulant and a variant in which the Alcoa T-64 alumina filler is replaced with Sumitomo AA-10 alumina. None of these encapsulants show a sensitivity to ionizing radiation. We also report results from specimens with sharp-edged electrodes that cause strong, localized field enhancement as might be present near electrically-discharged mechanical fractures in an encapsulant. Under these conditions the 459-epoxy ALOX encapsulant displays approximately 40% lower dielectric strength than the older Z-cured Epon 828 formulation. An investigation of several processing variables did not reveal an explanation for this reduced performance. The 459-epoxy encapsulant appears to suffer electrical breakdown if the peak field anywhere reaches a critical level. The stress-strain characteristics of Z-cured ALOX encapsulant are measured under high triaxial pressure and we find that this stress causes permanent deformation and a network of microscopic fractures. Recommendations are made for future experimental work.

ANDERSON, ROBERT A.; LAGASSE, ROBERT R.; SCHROEDER, JOHN L.; ZEUCH, DAVID H.; MONTGOMERY, STEPHEN T.

2001-09-01

168

Comparative Study of the Electrical Properties and Characteristics of Thermally Sprayed Alumina and Spinel Coatings  

NASA Astrophysics Data System (ADS)

In this study, APS and HVOF processes have been used to prepare alumina (Al2O3) and magnesium spinel (MgAl2O4) coatings designed for insulating applications. The electrical characteristics, i.e., dielectric strength and electrical resistance (electrical resistivity) were investigated using different methods: dielectric breakdown test, direct current (DC) measurements, and electrochemical impedance spectroscopy (EIS). The electrical resistance was measured at room temperature at different relative humidity (RH) levels (from 6% RH to 95% RH) as well as at 200 °C. The coating microstructure, phase composition, and water vapor sorption were studied. Differences in the electrical insulating properties due to the different coating system characteristics are discussed. Of the coatings and conditions investigated in this study, the HVOF spinel coatings showed superior dielectric breakdown strength and electrical resistance stability at high humidity levels.

Toma, Filofteia-Laura; Scheitz, Stefan; Berger, Lutz-Michael; Sauchuk, Viktar; Kusnezoff, Mihails; Thiele, Sven

2011-01-01

169

The Impulse Breakdown Voltage and Time-Lag Characteristics of Long Gaps in Air. I. The Positive Discharge  

Microsoft Academic Search

The electrical breakdown of rod\\/rod, rod\\/sphere and rod\\/plane gaps in the atmosphere has been examined oscillographically and photographically. Positive polarity impulse potentials of crest value up to 1 MV, of wave-front variable between 0\\\\cdot 06 and 2\\\\cdot 0 mu s and of wave tail 2 ms were used. It has been found that the lack of a sharply defined breakdown

R. T. Waters; R. E. Jones

1964-01-01

170

New Models And Distributions Of The Electrical Breakdown Time Delay In Neon  

NASA Astrophysics Data System (ADS)

The measurements of the electrical breakdown time delay dt in DC neon glow discharge for a wide range of working voltages and at different preionization levels are presented. The statistical breakdown time delay ts and the discharge formative time ft are experimentally separated and theoretical models of their dependencies on the overvoltage and number densities of residual charges during relaxation are suggested. Several empirical and semiempirical models are used to describe the formative time delay dependence on working voltages tf (U). The empirical and theoretical models from the literature are also applied to the experimental data, without and with empirical corrections. Good agreements with experimental data are found primarily at low overvoltages and with empirical corrections even at high overvoltages. Several new distributions are experimentally obtained: Gauss-exponential, Gaussian and double Gaussian ones for the statistical time delay, as well as Gaussian and double Gaussian distributions for the formative time. The measurements of the breakdown time delay at different preionization levels (afterglow periods) dt (t) obtained with a galvanic layer of gold and a sub-layer of nickel on the copper cathode are compared to the measurements with a vacuum deposited gold layer on the cathode surface. It was found that the surface charges retaining on a galvanic layer of gold influence the breakdown time delay. The surface charges mask the exponential Ne2+ decay in afterglow, as well as, the conversion maximum due to molecular nitrogen ions production in Ne2+ collisions with nitrogen impurities Ne2+ + N2 ? N2+ + 2Ne . The formative and statistical time distributions are double Gaussians due to combined effects of surface and gas-phase charges from the preceding glow. Presence of surface regions with reduced conductivity on a galvanic layer of gold retaining the surface charges is confirmed by scanning electron microscopy (SEM) images and energy dispersive X-ray (EDX) spectrum.

Stamenkovic, S. N.

2010-07-01

171

Contribution of interface capacitance to the electric-field breakdown in thin-film Al-AlOx-Al capacitors  

NASA Astrophysics Data System (ADS)

We present a systematic study of the dependence of breakdown voltages on oxide thickness d in Al-AlOx-Al thin-film capacitor structures. For sufficiently thin dielectrics, we find that a significant portion of the measured breakdown potential Vb occurs across the electrode interfaces, thereby leading to an overestimate (Vb/d) of the true breakdown electric field Eb across the dielectric. By modeling this interface contribution as an ``interface'' capacitance in series with the geometric ``bulk'' capacitance, we find for high-quality rf magnetron-sputtered AlOx dielectrics that Eb is independent of d over the range 30-300 Å.

Singh-Bhalla, Guneeta; Du, Xu; Hebard, Arthur F.

2003-09-01

172

Effects of void size and gas content on electrical breakdown in lightweight, mechanically compliant, void-filled dielectrics  

Microsoft Academic Search

Dielectric potting materials (encapsulants) are used to prevent air breakdown in high-voltage electrical devices. We report breakdown strengths in void-filled encapsulants, stressed with unipolar voltage pulses of the order of 10 mus duration. High strengths, on the order of 100 kV mm-1, are measured under these test conditions. The materials studied include low-density open celled gel-derived foams with cell sizes

R. A. Anderson; R. R. Lagasse; E. M. Russick; J. L. Schroeder

2002-01-01

173

Effects of void size and gas content on electrical breakdown in lightweight, mechanically compliant, void-filled dielectrics  

Microsoft Academic Search

Dielectric potting materials (encapsulants) are used to prevent air breakdown in high-voltage electrical devices. We report breakdown strengths in void-filled encapsulants, stressed with unipolar voltage pulses of the order of 10 ?s duration. High strengths, on the order of 100 kV mm?1, are measured under these test conditions. The materials studied include low-density open celled gel-derived foams with cell sizes

R. A. Anderson; R. R. Lagasse; E. M. Russick; J. L. Schroeder

2002-01-01

174

Effect of Al 2 O 3 Content on Electrical Breakdown Properties of Al 2 O 3 \\/Cu Composite  

Microsoft Academic Search

Al2O3\\/Cu composites were prepared by external addition of Al2O3, and the effect of Al2O3 content on microstructure, density, hardness, electrical conductivity and vacuum electrical breakdown properties was studied.\\u000a The results show that with increasing Al2O3 addition, the density of Al2O3\\/Cu composite significantly decreases, the hardness sharply increases and then slowly decreases, but the electrical conductivity\\u000a invariably decreases. The vacuum breakdown

Xianhui Wang; Shuhua Liang; Ping Yang; Zikang Fan

2010-01-01

175

Electrical measurements at the microscale: Air breakdown and silicon Coulomb blockade devices  

NASA Astrophysics Data System (ADS)

In this thesis I describe the work performed in two different areas of research, electrical breakdown of air for small electrode separations and measurements of silicon (Si)-based tunable-barrier single electron transistors (SETs). In this work, I describe a new method for measuring the breakdown of air for the range of electrode separation of interest. This method has several advantages compared to ones found in the literature, namely it allows for a measurement of electrode separation before each breakdown measurement; it has a parallel plate geometry and the surface roughness of the electrodes used is very small. Using the results obtained with this method I have made a quantitative comparison between the predictions of the standard theory of the field (field emission of electrons) and our data, something that has not been done before. In this thesis I describe analytically both the theory and the analysis of our data. I conclude that the standard theory used in this field fails for the range of electrode separations of interest (400 nm to 45 mum). Also, I describe electrical measurements performed on a Si-based tunable-barrier device fabricated in the group of Neil Zimmerman at the National Institute of Standards and Technology (NIST) using the fabrication facilities of Cornell University. I demonstrate that this device can be operated as an SET. I continue by describing measurements of the charge offset drift (Q 0(t)) for this device and show that it is almost 3 orders of magnitude smaller than in metal devices, and comparable to previously measured Si devices of this type. All of the previously measured devices originated from the same fabrication source, NTT, Japan. Our ability to demonstrate the same low drift in devices fabricated at Cornell, USA, indicates that the small values of Q0(t) is a robust property of Si-based devices, and not sensitive to the details of fabrication.

Hourdakis, Emmanouel Spyros

176

Simulation of initial electric field distribution for prediction of lightning-caused breakdown paths to underground cables  

Microsoft Academic Search

Information about the initial electric field distribution in soil is fundamental to the prediction of lightning-caused breakdown paths and performance of struck underground cables. Field calculations in existing models assume homogeneous soils and ignore presence of cables. In this paper, the initial electric field distribution is calculated using a 2-dimensional model which recognizes the presence of cables and soil inhomogeneity.

Zeqing Song; M. R. Raghuveer; Jingliang He

2002-01-01

177

The mechanism of self-healing electrical breakdown in MOS structures  

Microsoft Academic Search

The mechanism of single-hole and propagating breakdown is investigated in metal-oxide-silicon capacitors with nonshorting breakdown, the substrate resistivity varying from 10-3to 103?-cm. Magnitude of destruction of single-hole breakdowns and duration of breakdown event depend strongly on polarity and resistivity of file substrate and the duration varies from nano- to microseconds. Average temperature of the metal on breakdown was found spectroscopically

N. Klein

1966-01-01

178

Super junction LDMOS with enhanced dielectric layer electric field for high breakdown voltage  

NASA Astrophysics Data System (ADS)

The lateral super junction (SJ) power devices suffer the substrate-assisted depletion (SAD) effect, which breaks the charge balance of SJ resulting in the low breakdown voltage (BV). A solution based on enhancing the electric field of the dielectric buried layer is investigated for improving the BV of super junction LDMOSFET (SJ-LDMOS). High density interface charges enhance the electric field in the buried oxide (BOX) layer to increase the block voltage of BOX, which suppresses the SAD effect to achieve the charge balance of SJ. In order to obtain the linear enhancement of electric field, SOI SJ-LDMOS with trenched BOX is presented. Because the trenched BOX self-adaptively collects holes according to the variable electric field strength, the approximate linear charge distribution is formed on the surface of the BOX to enhance the electric field according to the need. As a result, the charge balance between N and P pillars of SJ is achieved, which improves the BV of SJ-LDMOS to close that of the idea SJ structure.

Wenlian, Wang; Bo, Zhang; Zhaoji, Li

2011-02-01

179

Tether electrical characteristics design report.  

National Technical Information Service (NTIS)

The design of a tether system for use in electric and magnetic fields requires an analysis of the equivalent electrical circuit of the baboon and tether. The response of this equivalent circuit to an electric or magnetic field is dependent on the connecti...

J. H. Lucas

1989-01-01

180

Induction voltage adder architectures and electrical characteristics  

Microsoft Academic Search

In this paper we use three different designs for induction voltage adders to be used in radiographic X-ray sources to illustrate the differences between possible IVA architectures, and between their electrical characteristics as these affect the radiographic diodes that the IVAs drive. The architectures are chosen considering the spaces in which the FVAs must fit, and the electrical characteristics are

I. Smith; P. Corcoran; V. Carboni; V. Bailey; H. Kishi; D. L. Johnson; J. Maenchenb; I. Molinab; R. Carlson; D. Fulton; K. Hahnc; J. Smith; D. Droemerd; K. Thomas; M. Phillips; S. Croxon; R. Forgan

2003-01-01

181

Tether electrical characteristics design report  

SciTech Connect

The design of a tether system for use in electric and magnetic fields requires an analysis of the equivalent electrical circuit of the baboon and tether. The response of this equivalent circuit to an electric or magnetic field is dependent on the connection of the tether system to the baboon. The tether will be designed so that the currents induced in the tethered baboon are approximately the same as those induce in an untethered baboon. 6 figs., 3 tabs.

Lucas, J.H.

1989-03-24

182

Experimental study and analysis of breakdown characteristics of long air gaps with short tail lightning impulse  

SciTech Connect

This paper describes experimental study and analysis of breakdown characteristics of long air gaps with short tail lightning impulse, which appears across the insulator strings on the transmission line by a lightning stroke. At first, starting conditions of leader propagation and leader developing process with the short tail lightning impulse are clarified by experiments. A new flashover model based on the experimental results is proposed in this paper. The proposed model consists of simple two equations, that give expression to the leader developing process, and can be realized very easily on the EMTP and other transient`s programs. A comparison of results calculated by the proposed model with the experimental results shows good agreements.

Motoyama, Hideki [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan)

1996-04-01

183

Collisional phenomena and current buildup in the electrical breakdown of hydrogen  

SciTech Connect

The electrical breakdown of hydrogen has been examined by means of a two-dimensional mathematical model applied to the case of a 0.50-mm gap at atmospheric pressure. The calculations indicated a very rapid discharge development, characterized by a marked deviation of the axial density profiles from an exponential dependence but with an approximately exponential variation of the discharge current. The axial electron and ion density profiles were similar in form and nearly balanced in magnitude. Notwithstanding the small magnitude of the space charge field. The radial profiles of the electron and ion density display a definite tendency towards constriction, i.e., the incipient formation of a spark-type channel.

Novak, J.P.; Bartnikas, R. (IREQ, Institut d'Recherche Hydro, 1800 Montee Ste-Juli, Varenne, Quebec JOL 2PO (CA))

1990-10-01

184

New distributions of the statistical time delay of electrical breakdown in nitrogen  

NASA Astrophysics Data System (ADS)

Two new distributions of the statistical time delay of electrical breakdown in nitrogen are reported in this paper. The Gaussian and Gauss-exponential distributions of statistical time delay have been obtained on the basis of thousands of time delay measurements on a gas tube with a plane-parallel electrode system. Distributions of the statistical time delay are theoretically founded on binomial distribution for the occurrence of initiating electrons and described by using simple analytical and numerical models. The shapes of distributions depend on the electron yields in the interelectrode space originating from residual states. It is shown that a distribution of the statistical time delay changes from exponential and Gauss-exponential to Gaussian distribution due to the influence of residual ionization.

Markovic, V. Lj; Gocic, S. R.; Stamenkovic, S. N.

2006-08-01

185

Influence of light from nitrogen-filled lamps on the time delay of electrical breakdown in nitrogen-filled tubes  

Microsoft Academic Search

Investigations of the effect of illumination by nitrogen-filled discharge lamps on nitrogen-filled tubes have shown a decrease of electrical breakdown time delay td, and dependence of td on the light intensity and overvoltage. The decrease of td is a consequence of the increased production of secondary electrons from the cathode induced by the photoelectric effect, which has been confirmed by

M. M. Pejovic; G. S. Ristic; Z. Lj Petrovic

1999-01-01

186

Analysis of mechanisms which lead to electrical breakdown in a krypton-filled tube using the time delay method  

Microsoft Academic Search

Contributions of krypton ions and krypton metastables, as well as contributions of gamma-radiation and cosmic rays to the electrical breakdown in a krypton-filled tube have been analysed by use of the time delay method. The experimental results have shown that each of these contributions strictly depends on the afterglow period. The time delay method has enabled the determination of both

Momcilo M. Pejovic; Goran S. Ristic

2000-01-01

187

Improvement of breakdown characteristics of an AlGaN/GaN HEMT with a U-type gate foot for millimeter-wave power application  

NASA Astrophysics Data System (ADS)

In this study, the physics-based device simulation tool Silvaco ATLAS is used to characterize the electrical properties of an AlGaN/GaN high electron mobility transistor (HEMT) with a U-type gate foot. The U-gate AlGaN/GaN HEMT mainly features a gradually changed sidewall angle, which effectively mitigates the electric field in the channel, thus obtaining enhanced off-state breakdown characteristics. At the same time, only a small additional gate capacitance and decreased gate resistance ensure excellent RF characteristics for the U-gate device. U-gate AlGaN/GaN HEMTs are feasible through adjusting the etching conditions of an inductively coupled plasma system, without introducing any extra process steps. The simulation results are confirmed by experimental measurements. These features indicate that U-gate AlGaN/GaN HEMTs might be promising candidates for use in millimeter-wave power applications.

Kong, Xin; Wei, Ke; Liu, Guo-Guo; Liu, Xin-Yu

2012-12-01

188

Bilayer graphene on h-BN substrate: investigating the breakdown voltage and tuning the bandgap by electric field.  

PubMed

By performing density functional theory calculations we show that it is possible to make the electronic bandgap in bilayer graphene supported on hexagonal boron nitride (h-BN) substrates tunable. We also show that, under applied electric fields, it is possible to insert states from h-BN into the bandgap, which generate a conduction channel through the substrate making the system metallic. In addition, we verify that the breakdown voltage strongly depends on the number of h-BN layers. We also show that both the breakdown voltage and the bandgap tuning are independent of the h-BN stacking order. PMID:22293938

Padilha, José Eduardo; Pontes, Renato Borges; Fazzio, Adalberto

2012-02-01

189

On the Electric Breakdown Field of the Mesosphere and the Influence of Electron Detachment  

NASA Astrophysics Data System (ADS)

The breakdown field of the atmosphere, Ek, is commonly understood as the field value at which the ionization rate equals the attachment rate of electrons to neutrals. This description has worked well for the lower atmosphere and has been applied to the discharges of the mesosphere, the sprites and giant jets, with much success. However, in the dilute mesosphere, where neutral densities are 4-5 orders of magnitude lower than at sea level, the process of electron associative detachment from negative atomic oxygen ions is also important and provides an additional source of free electrons. We show that the introduction of the detachment process allows for electron avalanche growth for any electric field magnitude, provided the exposure time is long enough. The concept of a threshold field therefore itself breaks down. For realistic source electric fields, the threshold may be as low as 0.7 Ek, which relaxes the requirement on the field magnitude for initiation of sprites. We find that the detachment process does not affect the time delays of sprites, as has been proposed by others, and that detachment may decrease the conductivity of streamers.

Neubert, Torsten; Chanrion, Olivier

2013-04-01

190

Model Assessment of Cell Membrane Breakdown in Clusters and Tissues Under High-Intensity Electric Pulsing  

Microsoft Academic Search

This paper presents a simulation study of cell membrane electroporation in clusters by high-intensity voltage pulses. The focus is on assessing effects associated with: 1) the variability in shape and randomness of the cells within clusters; 2) the density of clusters; 3) the effects in heterogeneous tissues; 4) the role of pulse width on fractional electroporation for given electrical characteristics;

Ravindra P. Joshi; Ashutosh Mishra; Karl H. Schoenbach

2008-01-01

191

DC Breakdown Experiments  

SciTech Connect

In the context of the CLIC (Compact Linear Collider) project investigations of DC breakdown in ultra high vacuum are carried out in parallel with high power RF tests. From the point of view of saturation breakdown field the best material tested so far is stainless steel, followed by titanium. Copper shows a four times weaker breakdown field than stainless steel. The results indicate clearly that the breakdown events are initiated by field emission current and that the breakdown field is limited by the cathode. In analogy to RF, the breakdown probability has been measured in DC and the data show similar behaviour as a function of electric field.

Calatroni, S.; Descoeudres, A.; Levinsen, Y.; Taborelli, M.; Wuensch, W. [CERN, European Organization for Nuclear Research, Geneva (Switzerland)

2009-01-22

192

Investigation on critical breakdown electric field of hot sulfur hexafluoride/carbon tetrafluoride mixtures for high voltage circuit breaker applications  

NASA Astrophysics Data System (ADS)

Sulfur hexafluoride (SF6) gas, widely used in high-voltage circuit breakers, has a high global warming potential and hence substitutes are being sought. The use of a mixture of carbon tetrafluoride (CF4) and SF6 is examined here. It is known that this reduces the breakdown voltage at room temperature. However, the electrical breakdown in a circuit breaker after arc interruption occurs in a hot gas environment, with a complicated species composition because of the occurrence of dissociation and other reactions. The likelihood of breakdown depends on the electron interactions with all these species. The critical reduced electric field strength (the field at which breakdown can occur, relative to the number density) of hot SF6/CF4 mixtures corresponding to the dielectric recovery phase of a high voltage circuit breaker is calculated in the temperature range from 300 K to 3500 K. The equilibrium compositions of hot SF6/CF4 mixtures under different mixing fractions were determined based on Gibbs free energy minimization. Full sets of improved cross sections for interactions between electrons and the species present are presented. The critical reduced electric field strength of these mixtures was obtained by balancing electron generation and loss mechanisms. These were evaluated using the electron energy distribution function derived from the Boltzmann transport equation under the two-term approximation. The result indicates that critical electric field strength decreases with increasing heavy-particle temperature from 1500 to 3500 K. Good agreement was found between calculations for pure hot SF6 and pure hot CF4 and experimental results and previous calculations. The addition of CF4 to SF6 was found to increase the critical reduced electric field strength for temperatures above 1500 K, indicating the potential of replacing SF6 by SF6/CF4 mixtures in high-voltage circuit breakers.

Wang, Weizong; Murphy, Anthony B.; Rong, Mingzhe; Looe, Hui M.; Spencer, Joseph W.

2013-09-01

193

Mechanisms on electrical breakdown strength increment of polyethylene by acetophenone and its analogues addition: a theoretical study.  

PubMed

A theoretical investigation is completed on the mechanism of electrical breakdown strength increment of polyethylene. It is shown that it is one of the most important factors for increasing electrical breakdown strength of polyethylene through keto-enol isomerization of acetophenone and its analogues at the ground state S0 and the lowest triplet state T1. The minimum structures and transition states of the keto- and the enol-tautomer of acetophenone and its analogues at the S0 and T1 states are obtained at the B3LYP/6-311+G(d,p) level, as well as the harmonic vibration frequencies of the equilibrium geometries and the minimum energy path (MEP) by the intrinsic reaction coordinate (IRC) theory at the same level. The two C-C bond cleavage reaction channels have been identified in acetophenone. The calculated results show that the energy barriers of keto-enol isomerization of acetophenone and its analogues at S0 and T1 states are much smaller than the average C-C bond energy of polyethylene, and the acetophenone doping or bond linked into polyethylene can increase the electrical breakdown strength and inhibit polyethylene electrical tree initiation and aging. PMID:23934300

Zhang, Hui; Shang, Yan; Zhao, Hong; Han, Baozhong; Li, Zesheng

2013-08-11

194

Effect of Milling Time on Electrical Breakdown Behavior of Al2O3/Cu Composite  

NASA Astrophysics Data System (ADS)

In order to clarify the relationship between the microstructure and the arc erosion behavior of metal-matrix composite, Al2O3/Cu composites with different distributions of Al2O3 particles were prepared by high energy ball milling and powder metallurgy. The effect of milling time on microstructure, properties, and arc erosion behavior of Al2O3/Cu composite was investigated. The results show that the distribution of Al2O3 particles improves significantly with increase of milling time, but Al2O3 particles will be aggregated if milling time is too long. The optimal milling time is 24 h in the range of experiments. A uniform distribution of Al2O3 particles in copper matrix can improve the hardness, electrical conductivity, average breakdown strength, chopping level, and arc life. With improvement in the distribution of Al2O3 particles, the erosion area becomes larger, and the erosion pits become shallower and are dispersed more uniformly.

Wang, Xianhui; Liang, Shuhua; Yang, Ping; Fan, Zhikang

2010-08-01

195

Electrical breakdown strength of 5 kV XLPE cable with imperfections under combined AC-DC voltage  

Microsoft Academic Search

This paper presents data on electrical breakdown strength of 5 kV XLPE cable with imperfection under AC voltage, DC voltage and superimposed AC upon DC voltage (pulsate voltage). In the later case, the measurement was taken over a wide range of pulsate ratio, which is defined as p=Vac\\/Vdc. Comparison with the former measurement results for sound cables shows that the

S. Grzybowski; J. Fan

1996-01-01

196

Effect of Al2O3 Content on Electrical Breakdown Properties of Al2O3/Cu Composite  

NASA Astrophysics Data System (ADS)

Al2O3/Cu composites were prepared by external addition of Al2O3, and the effect of Al2O3 content on microstructure, density, hardness, electrical conductivity and vacuum electrical breakdown properties was studied. The results show that with increasing Al2O3 addition, the density of Al2O3/Cu composite significantly decreases, the hardness sharply increases and then slowly decreases, but the electrical conductivity invariably decreases. The vacuum breakdown test shows that with increasing Al2O3 addition, the breakdown strength first sharply increases and then decreases when the Al2O3 content exceeds 1.2 wt.%; the chopping current always exhibits a decreasing trend and the arc life first increases and then decreases. According to the morphology of arc erosion and analysis, the arc erosion resistance increases and then decreases sharply. In the range of experiments, the optimal arc erosion resistance of Al2O3/Cu composite can be obtained with the addition of 1.2 wt.% Al2O3.

Wang, Xianhui; Liang, Shuhua; Yang, Ping; Fan, Zikang

2010-12-01

197

New operating limits for applications with electroactive elastomer: effect of the drift of the dielectric permittivity and the electrical breakdown  

NASA Astrophysics Data System (ADS)

Dielectric elastomer generators are a promising solution to scavenge energy from human motion, due to their lightweight, high efficiency low cost and high energy density. Performances of a dielectric elastomer used in a generator application are generally evaluated by the maximum energy which can be converted. This energy is defined by an area of allowable states and delimited by different failure modes such as: electrical breakdown, loss of tension, mechanical rupture and electromechanical instability, which depend deeply on dielectric behaviors of the material. However, there is controversy on the dielectric constant (permittivity) of usual elastomers used for these applications. This paper aims to investigate the dielectric behaviors of two popular dielectric elastomers: VHB 4910 (3M) and Polypower (Danfoss). This study is undertaken on a broad range of temperature. We focus on the influence of pre-stretch in the change of the dielectric constant. An originality of this study is related to the significant influence of the nature of compliant electrodes deposited on these elastomers. Additionally, the electrical breakdown field of these two elastomers has been studied as a function of pre-stretch and temperature. Lastly, thanks to these experiments, analytic equations have been proposed to take into account the influence of the temperature, the pre-stretch and the nature of the compliant electrodes on the permittivity. These analytic equations and the electrical breakdown field were embedded in a thermodynamic model making it possible to define new limits of operation closer to the real use of these elastomers for energy harvesting applications.

Vu-Cong, T.; Jean-Mistral, C.; Sylvestre, A.

2013-04-01

198

Electrical breakdown in solid insulators: Duration of the discharge channel formation  

Microsoft Academic Search

The duration of the discharge channel formation is calculated for 0.01-to 0.5-mm-thick insulators in terms of the avalanche-streamer\\u000a theory. At this stage of breakdown development, the statistical delay is assumed to be the time from the instant the testing\\u000a voltage becomes equal to the breakdown value to the instant of streamer origination and that the formation time is the interval

V. M. Rozhkov

2003-01-01

199

Equivalent Electrical Circuit Model for the Post-Breakdown Current in SiO2\\/TiO2 Gate Stacks  

Microsoft Academic Search

In this work we examine the electrical behavior of thin (~10 nm) SiO2\\/TiO2 gate insulator stacks in MOS capacitors that have undergone multiple hard breakdown events. The post-breakdown current is modeled using a simple equivalent electrical circuit consisting of a diode with series and parallel resistances. We show that the current flowing through the non-damaged oxide area still plays a

E. Miranda; J. Tinoco; I. Garduno; M. Estrada; A. Cerdeira

2007-01-01

200

Transition dynamics in the electrical breakdown of the quantum Hall effect  

NASA Astrophysics Data System (ADS)

We investigate the dynamic properties of the breakdown of integer quantum Hall states (QHSs). The critical field of QHS breakdown that occurs at a filling factor of ?˜2 is found to depend on the scan rate of the applied Hall field EH and to fluctuate stochastically; in contrast, a smooth breakdown is observed at ?˜4. The histogram of the critical values of EH can be used to derive the escape and relaxation time, ranging from a few seconds to 10 ?s between the low-dissipation QHS and the dissipation state. The increase of the escape rate between the low-dissipative QHS and the dissipative state is accompanied by a decrease of the relaxation rate and vice versa, indicating the bistable nature of the breakdown phenomena. The observed results agree well with the calculated results based on the basis of the bootstrap electron heating model. We conclude that the dynamic behaviors of QHS breakdown are governed by the transition probability that resides in the thermal bistable regime between the QHS and the dissipation states.

Li, Ming-Yang; Nakajima, T.; Lin, Kuan-Ting; Chi, C. C.; Chen, J. C.; Komiyama, S.

2012-06-01

201

Operational characteristics of a surface breakdown triggered vacuum switch with six gap rod electrode system  

Microsoft Academic Search

A triggered vacuum switch (TVS) is one of the important apparatuses in the field of pulsed power system. It has many advantages, such as wide working voltage range, high current capability, high transfer charge, flexible trigger system, high trigger reliability, rapid dielectric recovery, long life, compact fabric, low noise, etc. A small and compact sample of surface-breakdown TVS with six-gap

Zhengyang Zhou; Ling Dai; Jing Nan; Yanzhao Wang; Fuchang Lin

2011-01-01

202

The electrical characteristics of solid insulators for 154 kV class HTS transformer  

NASA Astrophysics Data System (ADS)

HTS transformer, without any loss of insulation lifetime due to the reduction in terms of size and weight, can increase the overload capacity, and have some benefits such as the improvement in efficiency, minimization of environmental pollution, and convenient spatial arrangement, which contribute a lot to electric power system operation. However, for practical insulation design of the HTS transformer, it is necessary to establish the research on electrical properties LN2 as well as solid insulators. These solid insulators have been used as main insulations for HTS transformer.In this paper, we discussed breakdown and V-t characteristics of glass fiber reinforced plastics (GFRP) and pressboard in LN2.

Cheon, H. G.; Choi, J. H.; Pang, M. S.; Kim, W. J.; Kim, S. H.

2011-11-01

203

Electric field changes generated by the preliminary breakdown for the negative cloud-to-ground lightning flashes in Malaysia and Sweden  

NASA Astrophysics Data System (ADS)

We present the study of the electric field changes generated by the preliminary breakdown for negative cloud-to-ground lightning flashes in Malaysia and Sweden concerning the association of slow field changes associated in preliminary breakdown process. We examined the total of 1685 negative cloud-to-ground lightning flashes from the total of 39 thunderstorms by recording the slow electric field, fast electric field and narrowband radiation field at 3 and 30 MHz signals simultaneously. Our results show that there is a pre-starting time, i.e. the duration between the first preliminary breakdown pulse and slow field changes starting point, which is found to be after the first preliminary breakdown pulse. The pre-starting time has the arithmetic and geometric mean range from 1.4-6.47 and 1-3.36 ms, respectively. The mean values of pre-starting time in Malaysia are greater than the values observed in Sweden by more than a factor of 3. From the two data sets it shows that the slow field changes never start before the preliminary breakdown. Furthermore, the use of single-station electric fields measurement with high resolutions of 12 bits transient recorder with several nanosecond accuracy allow one to distinguish the slow field changes generated by preliminary breakdown, which preceded the negative first return stroke, between tens to hundreds of milliseconds of pre-return stroke duration.

Baharudin, Z. A.; Fernando, M.; Ahmad, Noor Azlinda; Mäkelä, J. S.; Rahman, Mahbubur; Cooray, Vernon

2012-08-01

204

Electrical characteristics of silicon pixel detectors  

NASA Astrophysics Data System (ADS)

Prototype sensors for the ATLAS silicon pixel detector have been electrically characterized. The current and voltage characteristics, charge-collection efficiencies, and resolutions have been examined. Devices were fabricated on oxygenated and standard detector-grade silicon wafers. Results from prototypes which examine p-stop and standard and moderated p-spray isolation are presented for a variety of geometrical options. Some of the comparisons relate unirradiated sensors with those that have received fluences relevant to LHC operation.

Gorelov, I.; Gorfine, G.; Hoeferkamp, M.; Mata-Bruni, V.; Santistevan, G.; Seidel, S. C.; Ciocio, A.; Einsweiler, K.; Emes, J.; Gilchriese, M.; Joshi, A.; Kleinfelder, S.; Marchesini, R.; McCormack, F.; Milgrome, O.; Palaio, N.; Pengg, F.; Richardson, J.; Zizka, G.; Ackers, M.; Comes, G.; Fischer, P.; Keil, M.; Martinez, G.; Peric, I.; Runolfsson, O.; Stockmanns, T.; Treis, J.; Wermes, N.; Gößling, C.; Hügging, F.; Klaiber-Lodewigs, J.; Krasel, O.; Wüstenfeld, J.; Wunstorf, R.; Barberis, D.; Beccherle, R.; Caso, C.; Cervetto, M.; Darbo, G.; Gagliardi, G.; Gemme, C.; Morettini, P.; Netchaeva, P.; Osculati, B.; Rossi, L.; Charles, E.; Fasching, D.; Blanquart, L.; Breugnon, P.; Calvet, D.; Clemens, J.-C.; Delpierre, P.; Hallewell, G.; Laugier, D.; Mouthuy, T.; Rozanov, A.; Valin, I.; Andreazza, A.; Caccia, M.; Citterio, M.; Lari, T.; Meroni, C.; Ragusa, F.; Troncon, C.; Vegni, G.; Lutz, G.; Richter, R. H.; Rohe, T.; Boyd, G. R.; Skubic, P. L.; Šícho, P.; Tomasek, L.; Vrba, V.; Holder, M.; Ziolkowski, M.; Cauz, D.; Cobal-Grassmann, M.; D'Auria, S.; de Lotto, B.; del Papa, C.; Grassmann, H.; Santi, L.; Becks, K. H.; Lenzen, G.; Linder, C.

2002-08-01

205

Breakdown properties of epoxy nanodielectric  

SciTech Connect

Recent developments in polymeric dielectric nanocomposites have shown that these novel materials can improve design of high voltage (hv) components and systems. Some of the improvements can be listed as reduction in size (compact hv systems), better reliability, high energy density, voltage endurance, and multifunctionality. Nanodielectric systems demonstrated specific improvements that have been published in the literature by different groups working with electrical insulation materials. In this paper we focus on the influence of in-situ synthesized titanium dioxide (TiO{sub 2}) nanoparticles on the dielectric breakdown characteristics of an epoxy-based nanocomposite system. The in-situ synthesis of the particles creates small nanoparticles on the order of 10 nm with narrow size distribution and uniform particle dispersion in the matrix. The breakdown strength of the nanocomposite was studied as a function of TiO{sub 2} concentration at cryogenic temperatures. It was observed that between 2 and 6wt% yields high breakdown values for the nanodielectric.

Tuncer, Enis [ORNL; Cantoni, Claudia [ORNL; More, Karren Leslie [ORNL; James, David Randy [ORNL; Polyzos, Georgios [ORNL; Sauers, Isidor [ORNL; Ellis, Alvin R [ORNL

2010-01-01

206

Characteristics of solid aerosols produced by optical catapulting studied by laser-induced breakdown spectroscopy  

Microsoft Academic Search

Optical catapulting (OC) constitutes an effective method to transport small amounts of different materials in the form of a solid aerosol. In this report, laser-induced breakdown spectroscopy (LIBS) is used for the analysis of those aerosols produced by OC. For this purpose, materials were catapulted using a Q-switch Nd:YAG laser. A second Q-switch Nd:YAG laser was used for LIBS analysis

F. J. Fortes; J. J. Laserna

2010-01-01

207

Suppression of electrical breakdown in silicon nitride films deposited by catalytic chemical vapor deposition at temperatures below 200 degrees C.  

PubMed

Silicon nitride (SiN(x)) films for a gate dielectric layer of thin film transistors were deposited by catalytic chemical vapor deposition at a low temperature (< or = 200 degrees C). A mixture of SiH4, NH3 and H2 was used as a source gas. Metal-insulator-semiconductor (MIS) capacitor structures were fabricated for current-voltage (I-V) and capacitance-voltage (C-V) measurements. The breakdown voltage characteristics of the SiN(x) films were improved by the increase of NH3/SiH4 and H2/SiH4 mixing ratios and substrate temperatures. H2 treatment was attempted to improve the breakdown voltage further. A breakdown voltage as high as 6.6 MV/cm was obtained after H2 annealing at 180 degrees C. The defect states inside the SiN(x) films were analyzed by photoluminescence spectra. Silicon dangling bonds (2.5 eV) and nitrogen dangling bonds (3.1 eV) were observed. These defect states inside the SiN(x) films disappeared after H2 annealing. Flat band voltage shifts were observed in C-V curves, and their magnitudes decreased as the defect states inside the SiN(x) films decreased. PMID:21446552

Lee, Kyoung-Min; Hong, Wan-Shick

2011-01-01

208

On the calculation of breakdown voltages for uniform electric fields in compressed air and SF6  

Microsoft Academic Search

A novel method is described for calculating the breakdown voltage of uniform field gaps in compressed air and SF6 without the need for experiments. This method is based on the criterion of self-recurring single-electron avalanches developed in the gap. It is shown that the results computed by this method for pd values to the right of Paschen's minimum (up to

MAZEN ABDEL-SALAM; E. KEITH STANEK

1988-01-01

209

Self-healing breakdown of polyimide thin films in the cryogenic temperature region  

NASA Astrophysics Data System (ADS)

The breakdown characteristics of polyimide thin films were measured by taking advantage of self-healing breakdown in a wide temperature range. The electrical breakdown strength was nearly independent of temperature from 77 K to room temperature; it decreased with temperature in the high-temperature region. It showed little electrode-metal dependence at 77 K, but at room temperature, the A1 cathode indicated a lower breakdown strength than the Au cathode. From these results, the electronic breakdown process was considered as a possible breakdown mechanism in the cryogenic region, where only limited electronic-carrier injection from the electrode and thus little formation of space charges are expected. Although the breakdown strength retains nearly the same value after a polarity reversal at 77 K, in dry air at room temperature it fell just after the polarity reversal and gradually increased with the number of breakdowns.

Muramoto, Y.; Nagao, M.; Kosaki, M.

210

Characteristics of solid aerosols produced by optical catapulting studied by laser-induced breakdown spectroscopy  

NASA Astrophysics Data System (ADS)

Optical catapulting (OC) constitutes an effective method to transport small amounts of different materials in the form of a solid aerosol. In this report, laser-induced breakdown spectroscopy (LIBS) is used for the analysis of those aerosols produced by OC. For this purpose, materials were catapulted using a Q-switch Nd:YAG laser. A second Q-switch Nd:YAG laser was used for LIBS analysis of the ejected particles. Data processing of aerosols was conducted using conditional data analysis. Also, the standard deviation method was used for the qualitative identification of the ejected particles. Two modes of interaction in OC (OC with focused or defocused pulses) have been evaluated and discussed. LIBS demonstrates that the distribution (spreading) of the ejected particles along the propagation axis increased as a function of the interpulse delay time. The mass density and the thickness of the target also play an important role in OC-LIBS.

Fortes, F. J.; Laserna, J. J.

2010-08-01

211

Electrical Characteristics of Self-Biased Channel Diode  

NASA Astrophysics Data System (ADS)

A new low-loss diode, a self-biased channel diode, is described. In order to achieve a two-terminal operation by using a self-bias, the shunt electrode of the source and gate of the conventional DMOSFET with a floating body is adopted in this diode. By utilizing a DMOSFET, this proposed diode attains a high breakdown voltage compared with a lateral MOSFET. In this device, forward conduction is caused by the self-gate bias created by applying a positive voltage to the shunt electrode of the source and gate with respect to the drain. The direction of forward conduction is opposite to that of forward conduction in a conventional DMOSFET. In the reverse-bias state, the reverse current is very small without any bias owing to the shunt of the source and the gate electrode. In this report, the operational mechanism and electrical characteristics of the device fabricated for the proposed diode are discussed. From the experimental results, it is clear that at room temperature, the on-state voltage of the proposed diode is between that of the Ti-SBD and Cr-SBD. The simulated I-V characteristics are consistent with the measured values. From the simulation results, the proposed diode, in which a thin gate oxide layer and a high integration density of the DMOSFET cell are used, shows lower power loss in the temperature range 25-75°C than does the Cr-SBD. At high temperatures the power loss in the proposed diode is lower than that observed in the Ti-SBD and Cr-SBD which easily fall into thermal runaway.

Sugawara, Fumihiko; Yoshida, Tatsuya; Hoshi, Hideaki; Yamaguchi, Hideo; Ohnuma, Koichi

212

Polarization of the terahertz radiation of uniaxially compressed p germanium at the electrical breakdown of a shallow acceptor impurity  

SciTech Connect

The spectral and polarization investigations of spontaneous terahertz radiation under the conditions of the electrical breakdown of shallow acceptors (gallium) in germanium crystals have been reported. The radiation spectra of crystals uniaxially compressed in the [111] direction at a pressure of about 3 kbar, as well as undeformed crystals, have been measured at T = 5 K using a Fourier spectrometer with step scanning. The polarization of radiation has been estimated for transitions of holes between various states of a shallow acceptor in uniaxially compressed germanium. To identify the observed radiation lines, their experimental energies and polarizations have been compared to the respective calculated values. The spectral lines corresponding to the transitions of holes from the resonance state to the excited states of acceptors have been identified.

Andrianov, A. V., E-mail: alex.andrianov@mail.ioffe.ru; Zakhar'in, A. O.; Alekseev, P. S., E-mail: pavel.alekseev@mail.ioffe.ru [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Kagan, M. S. [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Russian Federation)

2012-12-15

213

Mesospheric electric breakdown and delayed sprite ignition caused by electron detachment  

Microsoft Academic Search

The electric discharge of a thundercloud in the troposphere is often accompanied by upper-atmospheric electric discharges such as sprites or halos. Present models assume that the net change in the density of free electrons during these discharges is determined by the competition between electron impact ionization and electron dissociative attachment to oxygen molecules, and that balance is achieved in an

F. J. Gordillo-Vázquez; A. Luque

2011-01-01

214

Electrical characteristics of thunderstorms in the Eastern part of India  

Microsoft Academic Search

Measurements of surface electric field made during the Pilot experiment to STORM at Kharagpur, India have been analyzed. During period of observations, i.e., from April 15 to May 31 2006, 14, thunderstorms were observed. Some electrical characteristic features of lighting associated with these thunderstorms are presented here. The electric field pattern shows that large number of negative electric field changes

V. Gopalakrishnan; S. D. Pawar; P. Murugavel; Kirankumar P. Johare

2011-01-01

215

Self-healing breakdown of polyimide thin films in the cryogenic temperature region  

Microsoft Academic Search

The breakdown characteristics of polyimide thin films were measured by taking advantage of self-healing breakdown in a wide temperature range. The electrical breakdown strength was nearly independent of temperature from 77 K to room temperature; it decreased with temperature in the high-temperature region. It showed little electrode-metal dependence at 77 K, but at room temperature, the A1 cathode indicated a

Y. Muramoto; M. Nagao; M. Kosaki

1995-01-01

216

Spark Discharge Characteristics of Vehicles Energized by AC Electric Fields.  

National Technical Information Service (NTIS)

This study examined certain characteristics of spark discharges from vehicles energized by an electric field. Vehicles were placed in an electric field produced by a 500-kv transmission line. Spark dischargers were delivered through a resistor to a driven...

J. P. Reilly

1980-01-01

217

Dielectric Breakdown and Molecular Orientation of Poly( 4,4'-Oxydiphenylene Pyromellitimide)  

Microsoft Academic Search

The electrical breakdown of polyimide (PI) thin films was investigated in the thickness range 0.8 2 µ m and in the temperature range -100 200° C, by taking advantage of self-healing. Two kinds of PI films were formed by vapor deposition polymerization (VDP) and coating of polyamic acid precursor in solution, VDP and S films, respectively. Breakdown characteristics of the

Kazuo Iida; Shuhei Nakamura; Goro Sawa

1994-01-01

218

Impact of thermal boundary conductances on power dissipation and electrical breakdown of carbon nanotube network transistors  

NASA Astrophysics Data System (ADS)

We study the impact of thermal boundary conductance (TBC) at carbon nanotube (CNT)-substrate interfaces and CNT junctions on power dissipation and breakdown in CNT network based thin film transistors (CN-TFTs). Comparison of our results from an electro-thermal transport model of CN-TFTs to experimental measurements of power dissipation and temperature profiles allows us to estimate the average CNT-SiO2 TBC as g ~ 0.16 Wm-1 K-1 and the TBC at CNT junctions as GC ~ 2.4 pWK-1. We find the peak power dissipation in CN-TFTs is more strongly correlated to the TBC of the CNT-substrate interface than to the TBC at CNT junctions. Molecular dynamics simulations of crossed CNT junctions also reveal that the top CNT is buckled over ~30 nm lengths, losing direct contact with the substrate and creating highly localized hot-spots. Our results provide new insights into CNT network properties which can be engineered to enhance performance of CN-TFTs for macro and flexible electronics applications.

Prakash Gupta, Man; Chen, Liang; Estrada, David; Behnam, Ashkan; Pop, Eric; Kumar, Satish

2012-12-01

219

VERY LOW FREQUENCY BREAKDOWN PROPERTIES OF ELECTRICAL INSULATION MATERIALS AT CRYOGENIC TEMPERATURES  

SciTech Connect

For long cables or equipment with large capacitance it is not always possible to conduct high voltage withstand at tests at 60 Hz due to limitations in charging currents of the power supply. Very low frequency (typically at a frequency of 0.1 Hz) has been used for conventional cables as a way of getting around the charging current limitation. For superconducting grid applications the same issues apply. However there is very little data at cryogenic temperatures on how materials perform at low frequency compared to 60 Hz and whether higher voltages should be applied when performing a high voltage acceptability test. Various materials including G10 (fiberglass reinforced plastic or FRP), Cryoflex (a tape insulation used in some high temperature superconducting cables), kapton (commonly used polyimide), polycarbonate, and polyetherimide, and in liquid nitrogen alone have been tested using a step method for frequencies of 60 Hz, 0.1 Hz, and dc. The dwell time at each step was chosen so that the aging factor would be the same in both the 60 Hz and 0.1 Hz tests. The data indicated that, while there is a small frequency dependence for liquid nitrogen, there are significant differences for the solid materials studied. Breakdown data for these materials and for model cables will be shown and discussed.

Sauers, Isidor [ORNL; Tuncer, Enis [ORNL; Polyzos, Georgios [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL; Pace, Marshall O [ORNL

2010-01-01

220

VERY LOW FREQUENCY BREAKDOWN PROPERTIES OF ELECTRICAL INSULATION MATERIALS AT CRYOGENIC TEMPERATURES  

SciTech Connect

For long cables or equipment with large capacitance it is not always possible to conduct high voltage withstand tests at 60 Hz due to limitations in charging currents of the power supply. Very low frequency (typically at a frequency of 0.1 Hz) has been used for conventional cables as a way of getting around the charging current limitation. For superconducting grid applications the same issues apply. However there is very little data at cryogenic temperatures on how materials perform at low frequency compared to 60 Hz and whether higher voltages should be applied when performing a high voltage acceptability test. Various materials including G10 (fiberglass reinforced plastic or FRP), Cryoflex (a tape insulation used in some high temperature superconducting cables), kapton (commonly used polyimide), polycarbonate, and polyetherimide, and in liquid nitrogen alone have been tested using a step method for frequencies of 60 Hz, 0.1 Hz, and dc. The dwell time at each step was chosen so that the aging factor would be the same in both the 60 Hz and 0.1 Hz tests. The data indicated that, while there is a small frequency dependence for liquid nitrogen, there are significant differences for the solid materials studied. Breakdown data for these materials and for model cables will be shown and discussed.

Sauers, I.; Tuncer, E.; Polizos, G.; James, D. R.; Ellis, A. R.; Pace, M. O. [Applied Superconductivity Group, Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2010-04-08

221

Resilience of gas-phase anharmonicity in the vibrational response of adsorbed carbon monoxide and breakdown under electrical conditions  

NASA Astrophysics Data System (ADS)

In surface catalysis, the adsorption of carbon monoxide on transition-metal electrodes represents the prototype of strong chemisorption. Notwithstanding significant changes in the molecular orbitals of adsorbed CO, spectroscopic experiments highlight a close correlation between the adsorbate stretching frequency and equilibrium bond length for a wide range of adsorption geometries and substrate compositions. In this work, we study the origins of this correlation, commonly known as Badger's rule, by deconvoluting and examining the contributions from the adsorption environment to the intramolecular potential using first-principles calculations. Noting that intramolecular anharmonicity is preserved upon CO chemisorption, we show that Badger's rule for adsorbed CO can be expressed solely in terms of the tabulated Herzberg spectroscopic constants of isolated CO. Moreover, although it had been previously established using finite-cluster models that Badger's rule is not affected by electrical conditions, we find here that Badger's rule breaks down when the electrified surface is represented as a periodic slab. Examination of this breakdown in terms of anharmonic contributions from the effective surface charge reveals limitations of conventional finite-cluster models in describing electrical conditions at metal electrodes.

Dabo, Ismaila

2012-07-01

222

Plasma characteristics determined by the Freja electric field instrument.  

National Technical Information Service (NTIS)

A new approach to the study of ionospheric plasma characteristics is presented using data from the Freja double probe electric field instrument. Plasma characteristics are derived from continuous measurements of the satellite potential and from intermitte...

P. A. Lindqvist G. T. Marklund L. G. Blomberg

1994-01-01

223

Electric field mediated breakdown of thin liquid films separating microscopic emulsion droplets  

NASA Astrophysics Data System (ADS)

The authors present a microfluidic technique for electrically induced breakup of thin films formed between microscopic emulsion droplets. The method involves creating a stationary film at the intersection of two microchannels etched onto a glass substrate. After stabilizing the film, a ramped potential is applied across it. The electrical stresses developed at the film interfaces lead to its rupture above a threshold potential. The potential difference at which the film ruptures assesses the film stability. This approach is employed to demonstrate how surfactant (lecithin) adsorption imparts stability to an ultrathin oil film formed between two water droplets.

Mostowfi, Farshid; Khristov, Khristo; Czarnecki, Jan; Masliyah, Jacob; Bhattacharjee, Subir

2007-04-01

224

Outages Investigation and Characterization of Saudi Electrical Cables using Laser Induced Breakdown Spectroscopy  

Microsoft Academic Search

Saudi electric Company (SEC), and Petrochemical industries in Saudi Arabia and other plants provide the utilizing location and testing, and also some of the raw insulation materials for cable industries. Major petrochemical producers are striving to improve the quality of the plastic raw materials. On the other hand, cable industry has also made noticeable progress in the production of distribution

M. H. Shwehdi; M. A. Gondal

2008-01-01

225

Forecasting of electrical breakdown in porous silicon using Flicker noise spectroscopy  

Microsoft Academic Search

Owing to the influence of environment and impact of energy fluxes (electric polarisation, heating, photon irradiation, etc.) physical and chemical properties of porous semiconductors (and other materials as well) experience changes which have to be monitored in order to distinguish the moment when the properties become out of a working range. There is a necessity of forecasting the development of

V. Parkhutik; E. Rayon; C. Ferrer; S. Timashev; G. Vstovsky

2003-01-01

226

Electrical breakdown strength of interfaces between solid insulation and transformer oil with variable water content  

Microsoft Academic Search

Pressure equalized cable terminals and high voltage connectors are bottlenecks in a subsea distribution system for electric power. Connectors known as wet mateable connectors must be able to operate in sea water at high hydrostatic pressure. The use of high viscosity liquid like grease, gel or oil being suggested in these terminations introduces a parallel liquid-solid interface. Assessment of the

M. Hasheminezhad; E. Ildstad; A. Nysveen

2008-01-01

227

Electrical characteristics of mammalian cells on porous supports  

Microsoft Academic Search

The quantification of epithelial barrier functions by measuring the trans-epithelial electrical resistance (TER) and using the Electric Cell-substrate Impedance Sensing (ECIS) has been complicated by the current flowing inside the narrow space underneath cells. This thesis work, by examining the electrical characteristics of epithelial cells on porous supports, is aimed to tackle this problem. A mathematical model has been constructed

Guo Chen

2003-01-01

228

Zipping it up: DEAs independent of the elastomer's electric breakdown field  

NASA Astrophysics Data System (ADS)

We demonstrate here an alternative dielectric elastomer actuator (DEA) structure, which relies on the compliant nature of elastomer membranes but does not require any electric field in the elastomer. Our elastomer zipping device is a macroscopic version of the electrostatic zipping actuators common in silicon MEMS. It consists of a cm-sized metallic bottom electrode, covered by a thin insulator, on which the elastomer membrane is bonded, enclosing a tapered air gap. A compliant electrode is patterned on the lower face of the elastomer membrane. Applying a voltage between solid bottom electrode and compliant electrode leads to controlled pull-in in movement, comparable to the closing of a zipper, thus giving large strokes and forces with no electrical requirements on the elastomer since no voltage is applied across the membrane. The compliant electrodes (20 mm diameter) are produced by metal ion-implantation into the elastomer membranes. The bottom metal electrodes are coated with 10 to 30 ?m of Al2O3. We report on our experimental study of membrane deflection and dynamics and discuss the effect of design parameters such as elastomer mechanical properties and actuator geometry. Membrane deflection of up to 1.4 mm was reached at only 200 V actuation voltage. The large membrane deformation achieved with this zipping actuation can be applied to applications such as pumps or tunable liquid lenses. The out-of plane movement of the membrane can be used for linear actuation.

Gebbers, Pit; Grätzel, Chauncey; Maffli, Luc; Stamm, Christoph; Shea, Herbert

2012-03-01

229

The Effect of Pre-Ionization Inhomogeneities on the Dynamics of a Subnanosecond Pulsed Electrical Breakdown in Gas Gaps1  

Microsoft Academic Search

The initiation and the development of a breakdown of highly overvoltaged gas gaps by voltage pulses having the rise time of 1 ns or shorter are studied experimentally and in theoreti- cal terms. The study revealed that ionization proc- esses leading to the breakdown start in the gas vol- ume and not from the surface of the electrodes. The gap

S. N. Ivanov; V. V. Lisenkov; V. G. Shpak

230

Simple models for electric gun operating characteristics  

Microsoft Academic Search

The electric gun, sometimes called a foil gun, uses the energy initially stored in a capacitor to electrically heat a thin conducting bridge in a transmission line connected to the capacitor. The deposited energy, typically several times the cohesive energy of the bridge material, is deposited in a time much less than the thermal time constant of the bridge, causing

1988-01-01

231

Radiation characteristics of electric furnace arcs  

Microsoft Academic Search

The electric arc furnace uses the energy radiated from high-power electric arcs to melt steel. A disadvantage of the process is that the intense radiation can erode the refractory lining of the furnace. Empirical work has shown that refractory erosion depends on arc power and voltage and their product has been used as an index of this erosion. However, no

Munroe

1982-01-01

232

Nanostructured Carbons and Their Electrical Transport Characteristics  

NASA Astrophysics Data System (ADS)

This thesis is about the fabrication, characterization, device preparation and electrical transport properties measurements of three types of nanostructured carbons. In particular, the foci are on the 4 Angstrom carbon nanotubes embedded in zeolite crystals, bundles of double-wall carbon nanotubes, and disordered graphene. The 4 Angstrom single-wall carbon nanotubes (SWCNTs) embedded in zeolite crystals are fabricated by a new heating process which introduces ethylene gas as the carbon source. Raman characterization indicates the sample quality to be improved compared to that fabricated by the original heating process that involved converting the precursor tripropylamine. Transport measurements carried out on these newly fabricated 4 Angstrom SWCNT samples show two types of superconducting resistive transitions. The first type is one-dimensional (1D) crossover to three-dimensional (3D) superconducting transition, which was observed to initiate at 15 K, followed by a sharp, order of magnitude resistance drop at 7.5 K. The sharp transition exhibits anisotropic magnetic field dependence. And differential resistance versus current curves indicate that the establishment of coherence proceeded in stages as the temperature is lowered below 15K. In particular, the sharp resistance drop and its attendant nonlinear IV characteristics are consistent with the manifestations of a Berezinskii-Kosterlitz-Thouless (BKT) transition that establishes a quasi-long range order in the plane transverse to the c-axis of the nanotubes. The second type is quasi 1D superconducting transition, which was also observed to initiate at 15 K. But the resistance drop exhibits a smooth feature and magnetic field independence up to 11 Tesla as temperature decreases. And differential resistance increases smoothly with bias current. Specific heat and new Meissner effect measurements carried out by Prof. Rolf Lortz's group provide strong support of the superconductivity in 4 Angstrom CNTs, with detailed features that are consistent with the transport results. The double-wall carbon nanotubes (DWCNTs) are characterized by HRTEM and Raman spectroscopy. The diameters of the outer and inner tubes are measured to be around 1.54 nm and 0.83 nm, respectively. The DWCNTs are packed closely together in each bundle, forming a nearly crystal-like structure. Resonant Raman measurements reveal the chirality information of the inner and outer tubes. By using the electron-beam lithography (EBL) techniques, both single DWCNT bundle and multiple DWCNT bundles were fabricated into devices for transport measurements. Clear evidences, comprising a resistance drop as a function of temperature, magnetoresistance and a differential resistance signature of the supercurrent, indicate a range of superconducting transition temperatures within 3-18K, with a peak in the occurrences around 5-7 K. Raman characterization for one of the selective samples shows the inner tube to be metallic and the outer tube to be semiconducting in character. A broad superconducting anomaly is also observed in specific heat data of a bulk DWCNT sample, which yields a Tc distribution that correlates well with the distribution obtained from the electrical data. Pristine graphene can have a high mobility that ensures ballistic transport on submicron distances. However, the presence of disorder would limit the carrier mean free path and prevent ballistic transport. Two types of disordered graphene were fabricated and studied. One is substitutionally boron-doped grapheme, and the other is nanostructured by plasma etching. They exhibit large negative magnetoresistance behavior that differs from the pristine graphene. The preliminary graphene work presented in this thesis is for the purpose of setting the stage for the experiments to be performed in the near future.

Shi, Wu

233

ELECTRIC TISSUE : RELATIONS BETWEEN THE STRUCTURE, ELECTRICAL CHARACTERISTICS, AND CHEMICAL PROCESSES OF ELECTRIC TISSUE.  

PubMed

In the main electric organs of the electric eel, the cross-sectional area, the thickness of the electroplaxes, and certain electrical characteristics of the tissue vary widely between the anterior and posterior ends. However, a transverse layer of the organs one electroplax thick has certain characteristics which are roughly uniform along the organs. These are its volume, its maximum voltage, its maximum current per unit area, and the resistance of unit area at the peak of the discharge. Measurements of the voltage developed by a segment of the organs across different external resistances at different instants during the discharge are all rather well described by representing the segment, with the adjacent non-electric tissue, as a simple combination of E.M.F. and ohmic resistance. The internal resistance of the tissue varies during the discharge. Its E.M.F. appears to be practically constant, at least during the greater part of the discharge. Estimates made of the total electric energy show it about equal to the energy supplied by the decrease of phosphocreatine and the formation of lactic acid. PMID:19873414

Cox, R T; Coates, C W; Brown, M V

1945-01-20

234

Correlation between field dependent electrical conduction and dielectric breakdown in a SiCOH based low-k (k = 2.0) dielectric  

NASA Astrophysics Data System (ADS)

The electrical conduction of a SiCOH based ultralow-k (k = 2.0) dielectric is investigated over an electric field range from 1.0 MV/cm to breakdown. Below 4.0 MV/cm, space-charge-limited current dominates the leakage. Above 5.0 MV/cm, a transition is found from trap-assisted Fowler-Nordheim (F-N) tunneling to F-N tunneling. It is hypothesized that under F-N tunneling stress, intrinsic material degradation causes positively charged defects generated in the dielectric. Moreover, this change of the dominant conduction path has a significant impact on the time dependent dielectric breakdown lifetime behavior.

Wu, C.; Li, Y.; Barbarin, Y.; Ciofi, I.; Croes, K.; Bömmels, J.; De Wolf, I.; To?kei, Zs.

2013-07-01

235

Radiation characteristics of electric furnace arcs  

SciTech Connect

The electric arc furnace uses the energy radiated from high-power electric arcs to melt steel. A disadvantage of the process is that the intense radiation can erode the refractory lining of the furnace. Empirical work has shown that refractory erosion depends on arc power and voltage and their product has been used as an index of this erosion. However, no theoretical basis has hitherto been presented for the refractory erosion index. This paper considers the electric arc as an ideal cylindrical radiator and proposes a theoretical basis for the observed empirical relationship. A similar index of arc energy into the furnace hearth is also derived. Computer simulation results are presented for a typical 80-ton electric arc furnace.

Munroe, M.M.

1982-08-01

236

Characteristics of AlGaN\\/GaN\\/AlGaN double heterojunction HEMTs with an improved breakdown voltage  

Microsoft Academic Search

We studied the performance of AlGaN\\/GaN double heterojunction high electron mobility transistors (DH-HEMTs) with an AlGaN buffer layer, which leads to a higher potential barrier at the backside of the two-dimensional electron gas channel and better carrier confinement. This, remarkably, reduces the drain leakage current and improves the device breakdown voltage. The breakdown voltage of AlGaN\\/GaN double heterojunction HEMTs (?100

Ma Juncai; Zhang Jincheng; Xue Junshuai; Lin Zhiyu; Liu Ziyang; Xue Xiaoyong; Ma Xiaohua; Hao Yue

2012-01-01

237

Barehand bonding arc electrical characteristics test  

Microsoft Academic Search

In July, 1991, the California Department of Occupational Safety and Health issued a variance to Pacific Gas and Electric Company to allow the use of barehand work procedures on 230 kV and 500 kV transmission lines. There were requirements and restrictions imposed upon PG&E for issuing and maintaining this variance permit. One such requirement was that PG&E institute a program

K. T. Cornish

1993-01-01

238

Electrical power generation characteristics of PZT piezoelectric ceramics  

Microsoft Academic Search

The electrical power generation characteristics of Mn-doped PZT ceramics responding to slow mechanical stress as well as to impact stress have been investigated. Although both the slow and impact stresses induce a reversible electrical response, the generation properties are distinctly different. Slow stress releases two output current peaks with opposite directions, responding to the increasing and decreasing part of the

Chao-Nan Xu; Morito Akiyama; Kazuhiro Nonaka; Tadahiko Watanabe

1998-01-01

239

Electrical Discharge Machining (EDM) Characteristics Associated with Electrical Discharge Energy on Machining of Cemented Tungsten Carbide  

Microsoft Academic Search

In this investigation, cemented tungsten carbides graded K10 and P10 were machined by electrical discharge machining (EDM) using an electrolytic copper electrode. The machining parameters of EDM were varied to explore the effects of electrical discharge energy on the machining characteristics, such as material removal rate (MRR), electrode wear rate (EWR), and surface roughness. Moreover, the effects of the electrical

Yan-Cherng Lin; Yuan-Feng Chen; Ching-Tien Lin; Hsinn-Jyh Tzeng

2008-01-01

240

49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.  

Code of Federal Regulations, 2010 CFR

...Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation...Operating characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the...

2010-10-01

241

49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.  

Code of Federal Regulations, 2010 CFR

...Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation...Operating characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the...

2009-10-01

242

Gas breakdown driven by L band short-pulse high-power microwave  

NASA Astrophysics Data System (ADS)

High power microwave (HPM) driven gas breakdown is a major factor in limiting the radiation and transmission of HPM. A method that HPM driven gas breakdown could be obtained by changing the aperture of horn antenna is studied in this paper. Changing the effective aperture of horn antenna can adjust the electric field in near field zone, leading to gas breakdown. With this method, measurements of air and SF6 breakdowns are carried out on a magnetically insulated transmission-line oscillators, which is capable of generating HPM with pulse duration of 30 ns, and frequency of 1.74 GHz. The typical breakdown waveforms of air and SF6 are presented. Besides, the breakdown field strengths of the two gases are derived at different pressures. It is found that the effects of air and SF6 breakdown on the transmission of HPM are different: air breakdown mainly shortens the pulse width of HPM while SF6 breakdown mainly reduces the peak output power of HPM. The electric field threshold of SF6 is about 2.4 times larger than that of air. These differences suggest that gas properties have a great effect on the transmission characteristic of HPM in gases.

Yang, Yi-Ming; Yuan, Cheng-Wei; Qian, Bao-Liang

2012-12-01

243

Electrical breakdown of the magnetic tunneling junction with an AlOx barrier formed by radical oxidation  

NASA Astrophysics Data System (ADS)

In this work, the dielectric breakdown in magnetic tunnel junctions (MTJs) was studied. The MTJ structure is Ta50/NiFe100/Co20/AlOx/Co30/RuRhMn100/Ta50 with the bottom lead of Ta50/Cu500/Ta50 and the top lead of Cu2000/Ta50 (in Å), where the tunneling barrier was formed by 2-20 min radical oxygen oxidation of a 10 Å-thick Al layer. The junctions with area from 2×2 to 20×20 ?m2 were patterned using the photolithography process, leading to tunneling magnetoresistance up to 17.2% and resistance-area product ranging from 350 ? ?m2 to 200 k? ?m2. The junctions studied show dc breakdown voltage from 0.7 to 1.3 V, depending on the junction area and the oxidation time. Long oxidation time up to 14 min and a small junction area results in a large dc breakdown voltage. The electrostatic discharge (ESD) of MTJs was tested by using a human body model. The ESD breakdown voltage increases with decreasing junction resistance. These results are discussed in terms of the E-model based on the field-induced distortion of atomic bonds in the oxide barrier.

Shimazawa, K.; Kasahara, N.; Sun, J. J.; Araki, S.; Morita, H.; Matsuzaki, M.

2000-05-01

244

Probing and modeling voltage breakdown in vacuum  

NASA Astrophysics Data System (ADS)

Voltage breakdown limits many technologies that rely on strong electric fields. Although many kinds of voltage breakdown have been well-explained, voltage breakdown in vacuum---the sudden transition from vacuum insulation to vacuum arc---remains relatively poorly understood. Despite the importance of vacuum insulation, technology has hardly improved breakdown voltages in the last ninety years. This work describes experiments in vacuum breakdown, as well as computer simulations of the initial stages of breakdown. A better understanding of voltage breakdown could particularly benefit particle accelerators used for high energy physics experiments and radiation sources, which require the highest attainable electric fields in the microwave resonators that accelerate particles. Despite some differences, voltage breakdown in microwave resonators shares some features with breakdown in DC vacuum gaps (diodes). In both cases, the localized adsorption of gas around an electron emission-source (e.g., field emission) could lead to breakdown. Analytical calculation shows that breakdown occurs when the product of the gas density and emission current exceed a critical value. Voltage breakdown in vacuum results from the interaction of the electric field and the electrodes. Using a scanning electron microscope, with energy dispersive x-ray spectroscopy (EDX) and Auger electron spectroscopy (AES) to identify surface constituents, we found that breakdown occurs often at the site of foreign particles on the cathode, usually leaving only a very small trace of the original material. At the breakdown site we frequently find small craters, surrounded by a large starburst-shaped pattern; surface analysis suggests that during breakdown, ions bombard the surface within the starburst region and sputter away surface contaminants and oxides. In general, particulate contamination on the cathode determines the breakdown voltage, independent of the cathode material or the thickness of the insulating surface oxide; however, the oxide thickness does change the nature of the starburst and the damage done to the surface during breakdown.

Werner, Gregory Richard

245

The influence of light from a nitrogen gas discharge lamp on the concentration of metastable species and on the time delay to electrical breakdown in nitrogen-filled diodes  

Microsoft Academic Search

The analysis of measurements of the overvoltage dependence of time delays to electrical breakdown in nitrogen-filled diodes under various illumination conditions confirms the role of long-lived metastable species. After long periods of afterglow the concentration of 0022-3727\\/31\\/22\\/012\\/img7 molecules significantly influences the breakdown probability as well as the magnitude of the glow-discharge current.

T. V. Jovanovic; Dj A. Bosan; Dj M. Krmpotic; M. K. Radovic

1998-01-01

246

A dynamic model for the electrical characteristics of fluorescent lamps  

Microsoft Academic Search

A model for the electrical behavior of fluorescent lamps at standard line frequency (50 Hz or 60 Hz) and at high frequency (20 kHz-50 kHz). The model is based on the following three relationships: the lamp's V-I characteristic at high frequency; the lamp's DC V-I characteristic; and the dynamic relationship between these two modes of operation. The first two are

U. Mader; P. Horn

1992-01-01

247

Electrical Energy Density and Discharge Characteristics of a Poly(vinylidene fluoride-chlorotrifluoroethylene)Copolymer  

Microsoft Academic Search

The high electric displacement (D>0.1 C\\/m2) and breakdown field (600 MV\\/m) in polyvinylidene fluoride based polymers suggest high electrical energy density in this class of polymers. By defect modifications which reduce or eliminate the remnant polarization in the polymer, a high electrical energy density can indeed be obtained. This paper shows that in properly prepared P(VDF-CTFE) copolymer film capacitors, an

Xin Zhou; Baojin Chu; Bret Neese; Minren Lin; Q. M. Zhang

2007-01-01

248

Electrical Characteristics of the Sparks Produced by Electrosurgical Devices  

Microsoft Academic Search

The electrical characteristics of the sparks produced between the active electrode and the biological tissue during electrosurgical procedures have been experimentally investigated. The results have shown that the minimum voltage required to initiate a spark depends on the applied voltage polarity resulting in electrosurgical voltage asymmetry. This voltage asymmetry is capable of producing DC levels that can result in tissue

Paulo JosÉ Abatti

2008-01-01

249

Electrical reliability of tunneling magnetoresistive read heads  

NASA Astrophysics Data System (ADS)

The electrical reliability of tunneling magnetoresistive (TMR) read heads has been studied in terms of dielectric breakdown characteristics of tunnel barrier and electrical failures under constant biasing current. The TMR read heads showed both ``intrinsic breakdown'' characteristics, which is caused by the high electric field, and ``extrinsic breakdown'' characteristics, which is caused by defects or pinhole-induced breakdown especially in a very thin dielectric layer. The dielectric breakdown voltage (Vbd) of real TMR read head is revealed to be strongly dependent on the duration of the applied voltage step (or applied voltage ramping speed), the initial junction resistance (R×A, A: Junction area) related to pinholes in a dielectric tunnel barrier, the tunnel barrier thickness, the ambient substrate temperature during breakdown test, and the applied voltage polarities. Different from typical metallic giant magnetoresistive spin-valve read heads, TMR read heads have a weaker reliability on sensing current density and exhibit two types of electrical failures: (1) Electrical short induced by tunnel barrier breakdown, and (2) electrical open induced by possible void formation in the metallic layers, which are used for free and pinned layers in exchange biased TMR read heads. The quasi-static transfer curves of head gimble assemble TMR read head was measured under various biasing currents. Transfer curve exhibited a strong dependence on the number of measurements above the threshold bias current, which is considered to be due to the current-induced voltage breakdown in the tunnel barrier.

Bae, Seongtae; Judy, Jack H.; Tsu, I.-Fei; Davis, Marshall

2003-12-01

250

Gas Breakdown of Radio Frequency Glow Discharges in Helium at near Atmospheric Pressure  

NASA Astrophysics Data System (ADS)

A one-dimensional self-consistent fluid model was developed for radio frequency glow discharge in helium at near atmospheric pressure, and was employed to study the gas breakdown characteristics in terms of breakdown voltage. The effective secondary electron emission coefficient and the effective electric field for ions were demonstrated to be important for determining the breakdown voltage of radio frequency glow discharge at near atmospheric pressure. The constant of A was estimated to be 64±4 cm-1Torr-1, which was proportional to the first Townsend coefficient and could be employed to evaluate the gas breakdown voltage. The reduction in the breakdown voltage of radio frequency glow discharge with excitation frequency was studied and attributed to the electron trapping effect in the discharge gap.

Liu, Xinkun; Xu, Jinzhou; Cui, Tongfei; Guo, Ying; Zhang, Jing; Shi, Jianjun

2013-07-01

251

Effects of activation by proton irradiation on silicon particle detector electric characteristics  

SciTech Connect

After irradiation with 7 and 9 MeV protons, activation-induced effects were encountered in measurements of current-voltage (IV) and capacitance-voltage (CV) characteristics for Czochralski and float-zone grown silicon particle detectors prepared on printed circuit boards with copper electrodes. With the present detector construction, the {sup 30}Si(p,n){sup 30}P and {sup 63}Cu(p,n){sup 63}Zn reactions induce dominant interference in such measurements. The daughter nuclides are positron emitters with half-lives of 2.5 and 38.5 min, respectively, and the slowing down of the emitted positrons generates a significantly large concentration of electron-hole pairs in the detector volume increasing the leakage current level and decreasing the breakdown voltage. The observed time-dependent characteristics were verified by modeling the activation of the detector structure and the resulting leakage current. As a result, the electrical measurements cannot be performed immediately after irradiation due to silicon activation, and, generally, materials becoming easily activated should be avoided in the detector concept.

Vaeyrynen, S.; Raeisaenen, J.; Tikkanen, P. [Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 University of Helsinki (Finland); Kassamakov, I. [Department of Micro and Nanosciences, Helsinki University of Technology, P.O. Box 3000, FI-02015 TKK (Finland); Tuominen, E. [Helsinki Institute of Physics, University of Helsinki, P.O. Box 64, FI-00014 University of Helsinki (Finland)

2009-07-15

252

Dielectric breakdown of polymer films containing metal clusters  

SciTech Connect

Thin films of gold-containing plasma-polymerized tetrafluoroethylene were prepared in an rf glow discharge. The films thus obtained showed a wide range of conductivities from insulating ( rho>10/sup 16/ ..cap omega.. cm) to metallic ( rhoapprox.3 x 10/sup -6/ ..cap omega.. cm), depending on plasma conditions during synthesis. The synthesis of the polymer is described in detail since it presents several new aspects. The structure and composition of the films were investigated by x-ray photoelectron spectroscopy and transmission electron microscopy. Studies of current-voltage characteristics in the dielectric regime, i.e., below electrical percolation, show that the conduction is volume limited (Poole--Frenkel effect) in non-gold-containing films, and characterized by a bistable switching behavior for gold-rich films. Dielectric breakdown measurements were realized on self-healing metal-insulator-metal structures. The Weibull analysis of breakdown voltages and a statistical treatment of times to breakdown under constant stress give, respectively, the nominal breakdown field E/sub 0/ and the specific breakdown field E/sub c/. These two sets of data follow similar functional behavior as a function of metallic volume fraction in the films. Surprisingly, the breakdown-field values remain relativity high up to the percolation concentration.

Laurent, C.; Kay, E.; Souag, N.

1988-07-01

253

Transition of a diffuse discharge to a spark at nanosecond breakdown of high-pressure nitrogen and air in a nonuniform electric field  

NASA Astrophysics Data System (ADS)

The transition of a runaway-electron-induced diffuse discharge initiated in a nonuniform electric field under a high pressure of air and nitrogen to a spark is studied. High-voltage pulses with a rise time of 0.5 ns are applied to a discharge gap with a tubular cathode having a small radius of curvature. It is shown that the leader of the spark discharge propagates toward the tubular cathode along preproduced tracks and may pass from one track to another. For a pulse rise time of about 0.5 ns and a gap length of 12 mm or more, it is found that spark leaders originating at the cathode (which has a small radius of curvature) do not reach the anode and accordingly, do not cause the spark breakdown of the gap. It is confirmed that the spark breakdown of the gap is associated with a spark leader that moves away from the plane electrode after the appearance of a bright spot on it.

Tarasenko, V. F.; Baksht, E. Kh.; Lomaev, M. I.; Rybka, D. V.; Sorokin, D. A.

2013-08-01

254

Electrical characteristics of interconnections for high-performance systems  

Microsoft Academic Search

A review is presented of the electrical characteristics of high-density, high-performance interconnections used in digital and communication applications. These interconnections behave as lossy transmission lines for the frequency range of interest. A brief theoretical explanation of the key properties of lossy, coupled transmission lines is given. A new short-pulse propagation technique used for characterizing a large category of wiring is

ALINA DEUTSCH

1998-01-01

255

Post-breakdown secondary discharges at the electrode/dielectric interface of a cylindrical barrier discharge  

NASA Astrophysics Data System (ADS)

The electrical breakdown characteristics of a double-walled cylindrical dielectric barrier discharge (DBD) lamp with a neon buffer gas under pulsed voltage excitation have been investigated. Following the formation of plasma in the main discharge gap, we have observed secondary breakdown phenomena at the inner and outer mesh electrode/dielectric interfaces under specific operating conditions. Plasma formation at these interfaces is investigated by monitoring the Ozone production rate in controlled flows of ultra high purity oxygen together with the overall electrical voltage-charge characteristics of the lamp. The results show that this secondary breakdown only occurs after the main discharge plasma has been established, and that significant electrical power may be dissipated in generating these spurious secondary plasmas. The results are important with regards to optimising the design and identifying efficient operating regimes of DBD based devices that employ mesh-type or wire/strip electrodes.

Carman, Robert; Ward, Barry; Kane, Deborah

2011-11-01

256

Electrical characteristics of mammalian cells on porous supports  

NASA Astrophysics Data System (ADS)

The quantification of epithelial barrier functions by measuring the trans-epithelial electrical resistance (TER) and using the Electric Cell-substrate Impedance Sensing (ECIS) has been complicated by the current flowing inside the narrow space underneath cells. This thesis work, by examining the electrical characteristics of epithelial cells on porous supports, is aimed to tackle this problem. A mathematical model has been constructed to quantify the impedance from the various sources within a cell/electrode system. This model presents three cell-related parameters, alpha, Rb and Cm: alpha stands for the impedance contribution from the above-mentioned current underneath cells, Rb is an equivalent representation of epithelial barrier functions and Cm denotes the capacitive impedance of cell membranes. Analysis of the three parameters as well as the electrode impedance (Z e) has revealed two experimental approaches to reduce or eliminate the complication of alpha to the deduction of Rb: lowering alpha down to zero or lowering both Ze and alpha. The experimental realization of the first approach has been studied by examining the electrical characteristics of the African green monkey kidney (BS-C-1) and Madin-Darby canine kidney (MDCK-II) cells on porous filters of mixed esters of cellulose or nitrocellulose. A unique setup featuring a plastic/filter/plastic triple-layer structure was constructed to measure the impedance of cells on filters. With the extremely low alpha, all the electrical characteristics can be explained by using an equivalent circuit and Rb can be directly obtained from the resistance difference in the low frequency range. The second approach has been experimentally investigated by examining the electrical characteristics of BS-C-1 cells on porous/rough electrodes, i.e. the gold ECIS electrodes electrochemically coated with conducting polypyrrole/heparin composites or platinum black. Ze and alpha, especially the former, were found to be significantly lowered, which greatly reduces the effect of alpha and yields many new impedance features. Rb can be also directly obtained in a different way from that for the solely lowered alpha on the non-conducting porous filters.

Chen, Guo

2003-10-01

257

The Effect of Nitrogen Sparging on the Long Term Stability of the Breakdown Electric Field Strength in a Repetitively Pulsed Oil Dielectric Switch  

Microsoft Academic Search

Summary form only given. Oil dielectrics, particularly hydrocarbon fluids, are often employed in applications involving dielectric breakdown. The reliability of the breakdown strength of the fluid, in its role as a switching medium, is frequently of great concern because unexpectedly low or high breakdown strength can produce timing errors, or worse yet, equipment failures. It is known from published investigations

P. Norgard; R. D. Curry; J. M. Turner

2007-01-01

258

Analysis of short pulse breakdown in water dielectric  

Microsoft Academic Search

The short pulse breakdown characteristic of water dielectric is the basis of its application in pulsed power filed. By the literature survey, the influencing factors on breakdown characteristics and the theoretical prediction of breakdown characteristic parameters in water dielectric is presented in this paper in order to provide some useful reference for the miniaturized design of high power microwave (HPM)

He-ming Ren; Jian-hua Yang; Jin-ming Gao; Jun Zhang

2011-01-01

259

Dielectric Breakdown of Cell Membranes  

PubMed Central

With human and bovine red blood cells and Escherichia coli B, dielectric breakdown of cell membranes could be demonstrated using a Coulter Counter (AEG-Telefunken, Ulm, West Germany) with a hydrodynamic focusing orifice. In making measurements of the size distributions of red blood cells and bacteria versus increasing electric field strength and plotting the pulse heights versus the electric field strength, a sharp bend in the otherwise linear curve is observed due to the dielectric breakdown of the membranes. Solution of Laplace's equation for the electric field generated yields a value of about 1.6 V for the membrane potential at which dielectric breakdown occurs with modal volumes of red blood cells and bacteria. The same value is also calculated for red blood cells by applying the capacitor spring model of Crowley (1973. Biophys. J. 13:711). The corresponding electric field strength generated in the membrane at breakdown is of the order of 4 · 106 V/cm and, therefore, comparable with the breakdown voltages for bilayers of most oils. The critical detector voltage for breakdown depends on the volume of the cells. The volume-dependence predicted by Laplace theory with the assumption that the potential generated across the membrane is independent of volume, could be verified experimentally. Due to dielectric breakdown the red blood cells lose hemoglobin completely. This phenomenon was used to study dielectric breakdown of red blood cells in a homogeneous electric field between two flat platinum electrodes. The electric field was applied by discharging a high voltage storage capacitor via a spark gap. The calculated value of the membrane potential generated to produce dielectric breakdown in the homogeneous field is of the same order as found by means of the Coulter Counter. This indicates that mechanical rupture of the red blood cells by the hydrodynamic forces in the orifice of the Coulter Counter could also be excluded as a hemolysing mechanism. The detector voltage (or the electric field strength in the orifice) depends on the membrane composition (or the intrinsic membrane potential) as revealed by measuring the critical voltage in E. coli B harvested from the logarithmic and stationary growth phases. The critical detector voltage increased by about 30% for a given volume on reaching the stationary growth phase.

Zimmermann, U.; Pilwat, G.; Riemann, F.

1974-01-01

260

Dielectric breakdown of cell membranes.  

PubMed

With human and bovine red blood cells and Escherichia coli B, dielectric breakdown of cell membranes could be demonstrated using a Coulter Counter (AEG-Telefunken, Ulm, West Germany) with a hydrodynamic focusing orifice. In making measurements of the size distributions of red blood cells and bacteria versus increasing electric field strength and plotting the pulse heights versus the electric field strength, a sharp bend in the otherwise linear curve is observed due to the dielectric breakdown of the membranes. Solution of Laplace's equation for the electric field generated yields a value of about 1.6 V for the membrane potential at which dielectric breakdown occurs with modal volumes of red blood cells and bacteria. The same value is also calculated for red blood cells by applying the capacitor spring model of Crowley (1973. Biophys. J. 13:711). The corresponding electric field strength generated in the membrane at breakdown is of the order of 4 . 10(6) V/cm and, therefore, comparable with the breakdown voltages for bilayers of most oils. The critical detector voltage for breakdown depends on the volume of the cells. The volume-dependence predicted by Laplace theory with the assumption that the potential generated across the membrane is independent of volume, could be verified experimentally. Due to dielectric breakdown the red blood cells lose hemoglobin completely. This phenomenon was used to study dielectric breakdown of red blood cells in a homogeneous electric field between two flat platinum electrodes. The electric field was applied by discharging a high voltage storage capacitor via a spark gap. The calculated value of the membrane potential generated to produce dielectric breakdown in the homogeneous field is of the same order as found by means of the Coulter Counter. This indicates that mechanical rupture of the red blood cells by the hydrodynamic forces in the orifice of the Coulter Counter could also be excluded as a hemolysing mechanism. The detector voltage (or the electric field strength in the orifice) depends on the membrane composition (or the intrinsic membrane potential) as revealed by measuring the critical voltage in E. coli B harvested from the logarithmic and stationary growth phases. The critical detector voltage increased by about 30% for a given volume on reaching the stationary growth phase. PMID:4611517

Zimmermann, U; Pilwat, G; Riemann, F

1974-11-01

261

Proposed RF breakdown studies at the AWA.  

SciTech Connect

A study of breakdown mechanism has been initiated at the Argonne Wakefield Accelerator (AWA). Breakdown may include several factors such as local field enhancement, explosive electron emission, Ohmic heating, tensile stress produced by electric field, and others. The AWA is building a dedicated facility to test various models for breakdown mechanisms and to determine the roles of different factors in the breakdown. We plan to trigger breakdown events with a high-powered laser at various wavelengths (IR to UV) to determine the role of explosive electron emission in the breakdown process. Another experimental idea follows from the recent work on a Schottky-enabled photoemission in an RF photoinjector that allows us to determine in situ the field enhancement factor on a cathode surface. Monitoring the field enhancement factor before and after the breakdown can shed some light on a number of observations such as the crater formation process.

Conde, M.; Gai, W.; Power, J. G.; Yusof, Z.; Antipov, S.; Spentzouris, L.; Dolgashev, V.; High Energy Physics; IIT; Stanford Linear Accelerator Center

2006-01-01

262

Study of breakdown effects in silicon multiguard structures  

Microsoft Academic Search

The purpose of this work is to study layout solutions aimed at increasing the breakdown voltage in silicon micro-strip detectors. Several structures with multiple floating guards in different configurations have been designed and produced on high-resistivity silicon wafers. The main electrical characteristics of these devices have been measured before and after irradiation. Both radiation-induced surface and bulk damage effects were

M. Da Rold; N. Bacchetta; D. Bisello; A. Paccagnella; G.-F. Dalla Betta; G. Verzellesi; O. Militaru; R. Wheadon; P. G. Fuochi; C. Bozzi; R. Dell'Orso; A. Messineo; G. Tonelli; P. G. Verdini

1999-01-01

263

Spark discharge characteristics of vehicles energized by ac electric fields  

SciTech Connect

This study examined certain characteristics of spark discharges from vehicles energized by an electric field. Vehicles were placed in an electric field produced by a 500-kV transmission line. Spark discharges were delivered through a resistor to a driven ground rod. Discharge current and voltage were monitored. These data are analyzed to determine capacitance measured under transient spark conditions and are compared with capacitance determined from 60 Hz measurements. The importance of the vehicle tires is examined. Spark discharge waveforms were also studied using standard high voltage capacitors for comparison with those discharge waveforms obtained from measurements on the vehicles. The influence of the impedance of the earth return is discussed with reference to differences between waveforms from the vehicles and the laboratory capacitors.

Reilly, J.P.

1980-10-01

264

Surface breakdown and surface flashover characteristics of diamond and DLC thin films on dielectric substrates in vacuum  

Microsoft Academic Search

Summary form only given. Polycrystalline diamond and diamond-like carbon (DLC) thin films are becoming attractive candidates for protective coatings and as dielectric materials in the space environment because they are excellent electrical insulators, exceptional thermal conductor materials, and are also highly resistive to chemical attacks. Therefore, the design and development of high voltage devices using diamond in vacuum requires a

H. Kirkici; D. W. Noles

1997-01-01

265

The Electrical Characteristics of a Filamentary Dielectric Barrier Discharge  

SciTech Connect

The electrical characteristics of a filamentary dielectric barrier discharge using parallel-plate electrodes geometry were statistically studied. The DBD's system was powered by a 50 Hz power supply and operated at atmospheric pressure. The influence of the air gap and position of dielectric on the discharge had been investigated. It was found that the air gap distance and position of dielectric had significant influence on the discharge current pulse. The results showed that discharge with large distance between the high voltage electrode and the dielectric would generate higher current pulses during the positive cycle. The discharge energy of single pulse was also determined.

Tay, W. H.; Yap, S. L.; Wong, C. S. [Plasma Research Laboratory, Physics Department, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2010-07-07

266

The Electrical Characteristics of a Filamentary Dielectric Barrier Discharge  

NASA Astrophysics Data System (ADS)

The electrical characteristics of a filamentary dielectric barrier discharge using parallel-plate electrodes geometry were statistically studied. The DBD's system was powered by a 50 Hz power supply and operated at atmospheric pressure. The influence of the air gap and position of dielectric on the discharge had been investigated. It was found that the air gap distance and position of dielectric had significant influence on the discharge current pulse. The results showed that discharge with large distance between the high voltage electrode and the dielectric would generate higher current pulses during the positive cycle. The discharge energy of single pulse was also determined.

Tay, W. H.; Yap, S. L.; Wong, C. S.

2010-07-01

267

Phase formation, sintering behavior, and electrical characteristics of NASICON compounds  

Microsoft Academic Search

The dependence of phase formation, sintering behavior, and electrical characteristics of Sodium Superionic Conductor (NASICON) compounds on sintering temperature, time, and cooling process was investigated. In the von Alpen-type composition Na3.2Zr1.3Si2.2P0.8O10.5, ZrO2 second phase is in thermal equilibrium with crystalline NASICON and liquid phase above 1320°C, and when cooled through 1260–1320°C, the crystalline NASICON was formed by reaction between the

Hee-Bog Kang; N.-H. Cho

1999-01-01

268

Electrical discharge machining characteristics of metal matrix composites  

Microsoft Academic Search

This paper reports experimental investigations of the effect of machining parameters (discharge current, pulse-on time, pulse-off time, voltage) on the machining feed rate and surface roughness during wire electrical discharge machining (WEDM) of metal matrix composite AlSi7Mg\\/SiC and AlSi7Mg\\/Al2O3. Generally, the machining characteristics of WEDM metal matrix composites are similar to those which occur in the base material (AlSi7Mg aluminium

M. Rozenek; J. Kozak; L. D; K. ?ubkowski

2001-01-01

269

Breakdown Energy Of Gases And The Surface Law  

NASA Astrophysics Data System (ADS)

Energy of electrical breakdown of gases (breakdown energy) is a stochastic variable and its distribution is determined by the statistics of the breakdown time delay and the breakdown voltage. The surface law stating that voltage pulses applied to the gas diode cover a constant area in the voltage-time coordinates (U-t plane) can be derived as a linear approximation of the breakdown energy for the linear temporal current growth and it is not valid for electrical breakdowns by linearly rising (ramp) pulses.

Markovic, V. Lj.; Gocic, S. R.; Stamenkovic, S. N.

2010-07-01

270

Breakdown behavior of GaAs\\/AlGaAs HBT's  

Microsoft Academic Search

Avalanche breakdown behavior at the collector junction of the GaAs\\/AlGaAs HBT (heterojunction bipolar transistor) has been studied. Junction breakdown characteristics displaying hard breakdown, soft breakdown, and negative resistance breakdown behavior were observed and are interpreted by analysis of localized microplasma effects, uniform microplasma-free behavior, and associated current gain measurements. Light emission from the collector-base junction of the GaAs\\/AlGaAs HBT was

James J. Chen; Jen-Inn Chyi; Hadis Morkoc; Guang-Bo Gao

1989-01-01

271

Self heating in AlInN/AlN/GaN high power devices: Origin and impact on contact breakdown and IV characteristics  

NASA Astrophysics Data System (ADS)

It is observed experimentally that high electron mobility transistor devices with short channel length processed from nitride AlInN/AlN/GaN heterostructures containing 2D electron gases (2DEGs) with densities beyond 2 × 1013 cm-2 exhibit temperatures up to 1000 K if they are driven at high drain-source voltages. Corresponding current-voltage (IV) characteristics show a peaklike behavior with a maximum saturation current (IDS,max) up to 2 A/mm. The goal of this article is to describe device heating in the framework of LO phonon statistics and its dependence on channel length, carrier density, and applied voltage. The strong channel heating, on the other hand, affects the transport mobility and must be taken into account to correctly interpret IV characteristics and resolve the discrepancy with metal oxide semiconductor field effect transistor models. Furthermore, the breakdown of ohmic contacts can directly be related to the channel temperature, i.e., the channel reaches the melting point of the contact metallization. In addition, the model correctly predicts the behavior of IV curves versus 2DEG density and transistor initial ambient temperature. For 2DEGs confined in triangular potential wells formed at the heterointerface, a maximum IDS is found for 2DEG densities between 2 × 1013 and 3 × 1013 cm-2.

Gonschorek, M.; Carlin, J.-F.; Feltin, E.; Py, M. A.; Grandjean, N.

2011-03-01

272

Electrical characteristics of high-Tc superconducting mini-model cable under mechanical stresses in liquid nitrogen  

NASA Astrophysics Data System (ADS)

To develop 22.9 kV class high-Tc superconducting (HTS) cable in Korea, we have been studying electrical insulation properties of dielectric paper, such as breakdown voltage, partial discharge, which is one of the HTS cable structure elements. However, the research on the mechanical stress of dielectric paper compared to breakdown properties of dielectric paper is insufficient. A cracking and variation of the electrical insulation due to mechanical stresses during cooling and bending of HTS cables in cryogenic temperature is a serious problem. Thus, we investigated tensile stress and breakdown stress of dielectric paper under mechanical stress. Moreover, we manufactured mini-model cables investigated breakdown stress under bending stress to design a cable drum for conveyance. In the AC, impulse and partial discharge properties, all test results showed a similar tendency, and the suitable bending radius ratio R/r was decided to be more than 25.

Kim, H. J.; Kwag, D. S.; Kim, Y. S.; Kim, S. H.

2005-01-01

273

Ac and Impulse Breakdown of Liquid Nitrogen at 77 K for Quasi-Uniform Field Gaps  

NASA Astrophysics Data System (ADS)

Liquid nitrogen (LN2) is commonly used both as a coolant and electrical insulation in high temperature superconductor (HTS) equipment for power applications. Hence it is necessary to know the electrical breakdown characteristics of LN2 under a variety of practical conditions. The ac breakdown and positive and negative polarity breakdown results for lightning impulse (1.2 microsecond rise time/50 microsecond fall time) are presented for LN2 using sphere to plane electrode geometry for sphere diameters of 50.8 and 101.6 mm over a gap range of 1 to 15 mm. Voltages up to 110 kVrms were studied for ac breakdown and up to 500-kV peak for impulse. In this work both the ac and impulse breakdown voltages scale approximately with distance over the limited gaps studied which is indicative of a quasi-uniform (near-uniform) electric field between sphere and plane. These measurements were conducted in a dewar which could be pressurized from 1 to 2 bar absolute which greatly reduces the spontaneous formation of bubbles that can occur in open LN2 bath experiments and thus potentially reduce the breakdown strength. Results from the pressurized system and near atmospheric pressure similar to an open bath are compared.

James, D. R.; Sauers, I.; Ellis, A. R.; Schwenterly, S. W.; Tuncer, E.; Pleva, E.

2008-03-01

274

Optical-electrical simulation of organic solar cells: excitonic modeling parameter influence on electrical characteristics  

NASA Astrophysics Data System (ADS)

This paper deals with Organic Solar Cells (OSCs) simulation using finite element method. Optical modeling is performed via Finite Difference Time Domain method whereas the continuity and Poisson's equations are solved to obtain electrical characteristics of the OSC. In this work, simulation results point out the influence of physical parameters such as the exciton diffusion coefficient or the exciton lifetime on OSC performances. The comparison of modeling results and experimental measurement allows the exciton recombination, dissociation rate and lifetime to be determinated.

Vervisch, Wilfried; Biondo, Stéphane; Rivière, Guillaume; Duché, David; Escoubas, Ludovic; Torchio, Philippe; Simon, Jean-Jacques; Le Rouzo, Judikaël

2011-06-01

275

The Effect of Electrode Construction in Breakdown Time Lag of Impulse Breakdown in Mineral Oil  

NASA Astrophysics Data System (ADS)

A breakdown time lag of uniform and nonuniform electric fields using point-plane and sphere-sphere electrodes in mineral oil was measured. The stainless-steel spherical electrode was 12.5 mm in diameter. The needle electrode was made of iron and its tip was electrolytically polished. The copper plate electrode measured 10 mm×20 mm×1 mm. The effect on breakdown time lag wielded of differences in the distance between electrodes and applied impulse voltage revealed that the time lag was proportional to the applied voltage and the breakdown time lag of a nonuniform electric field was shorter than that of a uniform electric field. It was found that the breakdown phenomena in point-plane and sphere-sphere electrodes were respectively similar to a streamer-type breakdown and a streamer breakdown structure.

Hirai, Naoshi; Akumu, Aloys; Arii, Kiyomitsu

1998-09-01

276

Gate Oxide Wear-Out and Breakdown Effects on the Performance of Analog and Digital Circuits  

Microsoft Academic Search

To investigate the impact of gate oxide degradation and breakdown (BD) on complimentary metal-oxide-semiconductor circuit functionality, an accurate description of the electrical characteristics of the stressed devices, which can be included in circuit simulators, is needed. In this paper, a description of the stressed device performance that considers, on the one hand, the variation of the channel current and, on

Raul Fernandez; J. Martin-Martinez; R. Rodriguez; Montserrat Nafria; Xavier H. Aymerich

2008-01-01

277

Electrical characteristics of low temperature polysilicon TFT with a novel TEOS\\/oxynitride stack gate dielectric  

Microsoft Academic Search

This investigation is the first to demonstrate a novel tetraethylorthosilicate (TEOS)\\/oxynitride stack gate dielectric for low-temperature poly-Si (LTPS) thin film transistors (TFTs), composed of a plasma-enhanced chemical vapor deposition (PECVD) thick TEOS oxide\\/ultrathin oxynitride grown by PECVD N2O-plasma. The stack oxide shows a very high electrical breakdown field of 8.4 MV\\/cm, which is approximately 3 MV\\/cm larger than traditional PECVD

Kow-Ming Chang; Wen-Chih Yang; Chiu-Pao Tsai

2003-01-01

278

Dielectric Breakdown Lightning Model  

NSDL National Science Digital Library

The Dielectric Breakdown Lightning Model implements a common method for modeling lightning using a grid with regions of varying electric potential to simulate the electrical charge buildup during a lightning storm. To simulate the source of the lightning in the cloud, we set the potential to zero and place a small region of negative charge near the top of the grid. Along the bottom of the grid, we set the boundary potential to one to simulate the positive charge on the ground. All other grid points are given an initial electric potential equal to 0.5. After solving Laplace's equation, we examine all the grid points that are adjacent to a negative charge. We choose one adjacent point as the new growth site for the lightning, representing a point where the air is ionized and lightning will develop. The Dielectric Breakdown Lightning Model was developed as a final project in a sophomore-level Computational Physics course (Phy 200) using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.

Castle, Sam

2012-06-16

279

Breakdown phenomena in high power klystrons  

Microsoft Academic Search

In the course of developing new high peak power klystrons at SLAC, high electric fields in several regions of these devices have become an important source of vacuum breakdown phenomena. In addition, a renewed interest in breakdown phenomena for nanosecond pulse, multi-megavolt per centimeter fields has been sparked by recent R and D work in the area of gigawatt RF

A. E. Vlieks; M. A. Allen; R. S. Callin; W. R. Fowkes; E. W. Hoyt; J. V. Lebacqz; T. G. Lee

1988-01-01

280

Breakdown phenomena in high-power klystrons  

Microsoft Academic Search

In the course of developing new high-peak power klystrons at SLAC, high electric fields in several regions of these devices have become an important source of vacuum breakdown. In addition, a renewed interest in breakdown phenomena for ns pulse, MV\\/cm fields has been sparked by recent R and D work in the area of GW rf sources. The most important

A. E. Vlieks; M. A. Allen; R. S. Callin; W. R. Fowkes; E. W. Hoyt; J. V. Lebacqz; T. G. Lee

1989-01-01

281

Development of pulsed dielectric breakdown in liquids  

Microsoft Academic Search

A model is presented for the development of breakdown in liquids subjected to uniform high amplitude electric field stresses with duration of microseconds or less. In this model, breakdown proceeds in four stages: (i) formation of a low density site (nucleation) in the liquid near an electrode, (ii) growth and expansion of this site until the local density is reduced

H. M. Jones; E. E. Kunhardt

1995-01-01

282

Self-healing breakdown of metallized polypropylene  

Microsoft Academic Search

We have studied the self-healing breakdown of metallized PP films for different values of the PP film thickness and of the surface resistance of metal layer Rs. For each event, the breakdown voltage, the electrical current pulse, the emitted light and the cleared area have been measured. From the total charge flowing in the leads of the cell, the energy

P.-O. Sassoulas; B. Gosse; J.-P. Gosse

2001-01-01

283

Probabilistic description of traffic breakdowns.  

PubMed

We analyze the characteristic features of traffic breakdown. To describe this phenomenon we apply the probabilistic model regarding the jam emergence as the formation of a large car cluster on a highway. In these terms, the breakdown occurs through the formation of a certain critical nucleus in the metastable vehicle flow, which enables us to confine ourselves to one cluster model. We assume that, first, the growth of the car cluster is governed by attachment of cars to the cluster whose rate is mainly determined by the mean headway distance between the car in the vehicle flow and, maybe, also by the headway distance in the cluster. Second, the cluster dissolution is determined by the car escape from the cluster whose rate depends on the cluster size directly. The latter is justified using the available experimental data for the correlation properties of the synchronized mode. We write the appropriate master equation converted then into the Fokker-Planck equation for the cluster distribution function and analyze the formation of the critical car cluster due to the climb over a certain potential barrier. The further cluster growth irreversibly causes jam formation. Numerical estimates of the obtained characteristics and the experimental data of the traffic breakdown are compared. In particular, we draw a conclusion that the characteristic intrinsic time scale of the breakdown phenomenon should be about 1 min and explain the case why the traffic volume interval inside which traffic breakdown is observed is sufficiently wide. PMID:12188801

Kühne, Reinhart; Mahnke, Reinhard; Lubashevsky, Ihor; Kaupuzs, Jevgenijs

2002-06-26

284

Impulse breakdown of liquid water  

Microsoft Academic Search

Currently, studies of microsecond and sub-microsecond electrical breakdown in liquid water and water solutions are experiencing their renaissance period due to the development of advanced pulsed power systems and emerging technologies for environmental applications and plasma medicine. The present paper is focused on an investigation of polarity effects in sub-microsecond discharges in water. Distilled water, tap water and water based

I. V. Timoshkin; M. J. Given; M. P. Wilson; R. A. Fouracre; S. J. MacGregor

2010-01-01

285

Dielectric breakdown in liquid crystals  

NASA Astrophysics Data System (ADS)

Dielectric breakdown in insulators is a commonly observed phenomenon in gases, fluids and solids at large electric field amplitudes. The resulting discharge patterns generally exhibit a non-Euclidean, fractal dimension, representing breakdown channels in the insulating material. In this study dielectric breakdown is investigated for anisotropic fluids in Hele-Shaw cells, i.e. liquid crystals in a plate capacitor. The observed burn patterns are inscribed into the substrates, suggesting that they are the result of the surface degradation, due to the breakdown current at the electrode surface. They are the same on both substrate plates with an equal fractal dimension and of radial symmetry, even though the insulating material is anisotropic. Investigations were carried out as the electric field was varied from dc to ac conditions, for instant field application versus slow ramping, for materials with positive and negative dielectric anisotropy, for a variation of the alignment coating, in several different liquid crystal phases and as a function of cell gap, applied field amplitude, frequency and temperature. In all cases the fractal dimension of the burn pattern increases as the breakdown voltage increases.

Dierking, I.

2001-03-01

286

Electrical characteristics of printed Ag nanopaste on polyimide substrate.  

PubMed

We investigated the effects of sintering temperature on the microstructural evolution and electrical characteristics of screen-printed Ag patterns. A conducting paste containing 20 nm Ag nanoparticles (73 wt%) was screen printed onto a polyimide (PI) substrate and sintered at a temperature of 150, 200, 250 and 300 degrees C for 30 min. The microstructures of the sintered patterns were examined using field emission scanning electron microscopy (FESEM). The resistivity under the application of a DC signal decreased with increasing temperature. In the frequency range from 10 MHz to 20 GHz, the S-parameters of the sintered Ag conducting patterns were measured. The S-parameters indicated that the insertion losses at high frequency decreased with increasing sintering temperature due to the formation of interparticle necking after sintering. PMID:21456214

Lee, Young-Chul; Kim, Kwang-Seok; Kim, Jong-Woong; Kim, Jong-Min; Nah, Wansoo; Lee, Seong-Hee; Jung, Seung-Boo

2011-02-01

287

A new approach to analyze the degradation and breakdown of thin SiO 2 films under static and dynamic electrical stress  

Microsoft Academic Search

A test procedure, which provokes the oxide breakdown in two stages, is proposed to analyze the degradation and breakdown of thin SiO 2 films. This procedure can partially overcome the problems associated with dynamic tests and allows a direct comparison of static and dynamic stresses. The analysis of the data obtained using the proposed method has allowed us to conclude

R. Rodriguez; M. Nafria; E. Miranda; J. Sune; X. Aymerich

1999-01-01

288

Atmospheric Pressure RF Plasma Electrical and Optical Characteristics  

NASA Astrophysics Data System (ADS)

An atmospheric pressure 13.56 MHz RF source is used for plasma polymerization, nanocomposite deposition and for sterilization purposes. The air discharge electrical and optical characteristics are measured using monochromator and electrical probes. The addition of helium flow to the RF discharge system allows production of stable glow plasma discharge. The electron temperature and plasma densities are estimated using the emission lines of HeI and double probes. Emission of the He+air atmospheric pressure plasma is observed from the OH radical, several lines of the N2, N2^+ and atomic O, H and He lines. He flow rate and applied rf voltage affect on these emission spectra are investigated and the spectral lines are used for calculation of plasma parameters. Plasma electron temperature is calculated using HeI lines and compared with double probe data. The OI 777 and H? 656 lines are also investigated by varying the applied voltage and He flow rate. The calculated electron temperature was approximately 0.2 eV and dependent on the He flow rate and applied power.

Gulec, Ali; Oksuz, Lutfi; Hershkowitz, Noah

2009-10-01

289

Two-component structure of the current pulse of a ranaway electron beam generated during electric breakdown of elevated-pressure nitrogen  

NASA Astrophysics Data System (ADS)

Conditions are investigated at which two current pulses of ranaway electron beams are generated in elevated-pressure nitrogen during one voltage pulse. It is shown that the regime with two runaway electron beam current pulses takes place at decreased values of the electric field strength E in the gap (or decreased values of the parameter E/p, where p is the gas pressure). The regime with two runaway electron beam current pulses is observed both at high (1500-3000 Torr) and low (below 100 Torr) pressures. It is shown that, for the second runaway electron beam current pulse to form, the voltage across the gap should be partially reduced during the first pulse. At low nitrogen pressures (~10 Torr), the regime in which two runaway electron beams are generated can be implemented by increasing the breakdown strength of the gap and/or increasing the value of E/p. In experiments carried out in atmospheric-pressure air with a picosecond time resolution, a rather complicated structure of the beam current pulse is observed at a voltage rise time of ~300 ps.

Tarasenko, V. F.; Erofeev, M. V.; Lomaev, M. I.; Sorokin, D. A.; Rybka, D. V.

2012-11-01

290

Criteria for local myocardial electrical activation: effects of electrogram characteristics.  

PubMed

Detection of local electrical myocardial activation by means of extracellular recordings is often difficult in the presence of polyphasic electrograms. The purpose of this investigation was to compare the ability of several variables to distinguish unipolar deflections due to local activation from those due to nonlocal activity. A model of polyphasic deflections based on atrial recordings during reentrant tachycardia was used to facilitate distinction of local and distant activity by methods independent of the test variables. The performance of variables were assessed by comparing areas under receiver operating characteristic curves. Optimal thresholds of test variables were identified by maximizing statistics which corrected for the pretest probability of local activation. We found that the greatest negative first derivative of the unipolar potential discriminated between local and distant ventricular signals, but performed less well than the ratio of the first derivative to the potential for distinguishing between local atrial signals and distant ventricular signals. A linear combination of the potential and the ratio of the first derivative and the potential performed well for all groups of signals studied. We conclude that optimal criteria for detecting local activation depends on the characteristics of the population of signals and that a statistical approach can be used to identify optimal criteria for a given population. PMID:8319968

Anderson, K P; Walker, R; Fuller, M; Dustman, T; Ershler, P R; Lux, R L

1993-02-01

291

Experimental arrangement for the study of plasma breakdown  

Microsoft Academic Search

Plasma breakdown is the process that occurs when a voltage is applied across an electrode gap and the neutral gas in the gap becomes ionized and electrically conducting. The goal of our research is to study breakdown processes experimentally on a sub-nanosecond timescale, so that features of breakdown can be observed with adequate time and spatial resolution. In this paper,

E. Wagenaars; M. D. Bowden; G. M. W. Kroesen

2003-01-01

292

A theoretical approach to electric breakdown behaviour and effective secondary emission coefficient in gas discharge process between two parallel-plane disk electrodes  

SciTech Connect

The gas discharge characteristics are seriously influenced by the effective secondary electron-emission coefficient ({gamma}{sub eff}) originally defined by Townsend. A theoretical approach has been proposed for the determination of variation of this coefficient as a function of the geometrical parameter d/R (the ratio of inter-electrode distance to electrode radius) in the most practical range of 0.08{<=}d/R{<=}1.90. Two geometrical factors g{sub i} and g{sub p}, which are attributed to ion-induced and photon-induced terms, respectively, were introduced to the effective gamma in parallel-plane arrangement. The factors were theoretically derived and hence the effective gamma and the breakdown voltage for a specified geometrical parameter, such as d/R=0.16, were obtained. Then, the effective gamma and the Paschen curves for various geometrical parameters such as d/R=0.32, 0.63, 1.27, and 1.90 were theoretically reproduced. The obtained results showed quite a good agreement with those reported by other researchers and verified that the proposed g{sub i} and g{sub p} have properly been introduced and derived.

Noori, H.; Ranjbar, A. H. [Faculty of Physics, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

2012-07-15

293

A theoretical approach to electric breakdown behaviour and effective secondary emission coefficient in gas discharge process between two parallel-plane disk electrodes  

NASA Astrophysics Data System (ADS)

The gas discharge characteristics are seriously influenced by the effective secondary electron-emission coefficient (?eff) originally defined by Townsend. A theoretical approach has been proposed for the determination of variation of this coefficient as a function of the geometrical parameter d/R (the ratio of inter-electrode distance to electrode radius) in the most practical range of 0.08<=d/R<=1.90. Two geometrical factors gi and gp, which are attributed to ion-induced and photon-induced terms, respectively, were introduced to the effective gamma in parallel-plane arrangement. The factors were theoretically derived and hence the effective gamma and the breakdown voltage for a specified geometrical parameter, such as d/R=0.16, were obtained. Then, the effective gamma and the Paschen curves for various geometrical parameters such as d/R=0.32, 0.63, 1.27, and 1.90 were theoretically reproduced. The obtained results showed quite a good agreement with those reported by other researchers and verified that the proposed gi and gp have properly been introduced and derived.

Noori, H.; Ranjbar, A. H.

2012-07-01

294

Modelling of time delay of electrical breakdown for nitrogen-filled tubes at pressures of 6.6 and 13.3 mbar in the increase region of the memory curve  

Microsoft Academic Search

Experimentally measured electrical breakdown time delay data versus the afterglow period (representing ‘memory curves’) for nitrogen-filled tubes at pressures of 6.6 and 13.3 mbar have been shown. The influence of N(4S) nitrogen atoms on secondary electron emission from the cathode (the SEE process) in late afterglow has been discussed. N(4S) atom concentration decay over relaxation time ?, N(4S)(?), has been

N T Nesic; G S Ristic; J P Karamarkovic; M M Pejovic

2008-01-01

295

Modelling of time delay of electrical breakdown for nitrogen-filled tubes at pressures of 6.6 and 13.3 mbar in the increase region of the memory curve  

Microsoft Academic Search

Experimentally measured electrical breakdown time delay data versus the afterglow period (representing 'memory curves') for nitrogen-filled tubes at pressures of 6.6 and 13.3 mbar have been shown. The influence of N(4S) nitrogen atoms on secondary electron emission from the cathode (the SEE process) in late afterglow has been discussed. N(4S) atom concentration decay over relaxation time tau, N(4S)(tau), has been

N. T. Nesic; G. S. Ristic; J. P. Karamarkovic; M. M. Pejovic

2008-01-01

296

Dielectric breakdown of MXB-71 phenolic and Sylgard 184\\/GMB silicone at high temperature  

Microsoft Academic Search

High temperature electrical breakdown characteristics have been determined for MXB-71 phenolic and Sylgard 184\\/GMB silicone in air and nitrogen environments. The phenolic material is used for electronic case housings whereas the silicone is an encapsulant. The experiments were performed with constant electric fields (values ranging from 3 x 10³ to 2.5 x 10⁴ V\\/cm) applied to the samples while the

R. T. Jr. Johnson; P. M. Beeson

1983-01-01

297

Dynamics of dielectric breakdown paths.  

PubMed

We investigate the dynamics and geometry of dielectric breakdown paths of needle defects of arbitrary residual resistivity in an otherwise homogeneous medium using a time-dependent electrical-circuit model. The circuit model consists of a semi-infinite lattice of capacitors in parallel with resistors that break down to a lower (residual) resistance. The breakdown occurs if the local field across a resistor exceeds a critical value for a breakdown delay time. We consider cases where the initial resistance is infinite or finite and where the residual resistance is finite or zero. We consider the model for the case where the applied field reaches the critical value adiabatically. We find that, as in the quasistatic case, the breakdown grows either one dimensionally or spreads with a fractal dimension (bifurcates) depending on the values of residual resistance and breakdown delay time. Also, we find that the propagation velocity of the needle oscillates spontaneously. We give the phase diagram for bifurcation and oscillations. We derive a simplified recursive map approximation to explain this behavior. PMID:16241371

Boksiner, Jeffrey; Leath, P L

2003-06-27

298

Electrical characteristics and comparison of two configurations of plasma needle  

NASA Astrophysics Data System (ADS)

Nonequilibrium plasmas is proved to be able to produce chemically reactive species at a low gas temperature while maintaining uniform reaction rates over relatively large areas. Plasma needle is one of the atmospheric pressure sources that can be used for treatment of living matter which is highly sensitive when it comes to low pressure or high temperatures (above 40 C). Before any application, it is necessary to examine the properties of such source as well as possible and define the optimum conditions for the specific treatment. For that purpose, it is particularly important to know electrical characteristics of the plasma needle, i.e., the power transmitted to the plasma. In order to achieve that, we have developed derivative probes previously used by Puac et al.[1] for measuring transmitted power in low pressure CCP RF discharge. In this paper we will make a comparison between two configurations of plasma needle that we have used in treatment of biological samples. Difference between these two configurations lays in additional copper ring that we have placed around glass tube at the tip of the needle. [1] Puac et. al, Plasma Processes and Polymers, Eds. R. d'Agostino, P. Favia, C. Oehr and M.R. Wertheimer, (Whiley: (2005) p 193-203

Malovic, Gordana; Puac, Nevena; Lazovic, Sasa; Djordjevic, Antonije; Petrovic, Zoran

2007-10-01

299

Investigation of the Electrical Short Circuit Characteristics of Tin Whiskers.  

National Technical Information Service (NTIS)

Existing risk simulations make the assumption that when a free tin whisker has bridged two adjacent exposed electrical conductors, the result is an electrical short circuit. This conservative assumption is made because shorting is a random event that has ...

K. J. Courey

2008-01-01

300

Dielectric Breakdown and Molecular Orientation of Poly( 4,4?-Oxydiphenylene Pyromellitimide)  

NASA Astrophysics Data System (ADS)

The electrical breakdown of polyimide (PI) thin films was investigated in the thickness range 0.8 2 µ m and in the temperature range -100 200° C, by taking advantage of self-healing. Two kinds of PI films were formed by vapor deposition polymerization (VDP) and coating of polyamic acid precursor in solution, VDP and S films, respectively. Breakdown characteristics of the films in the micron thickness range can be divided into two temperature regions. In the high-temperature region, the thermal process is operative and in the low-temperature region, the avalanche process seems to be predominant probable as compared with the thermal process. The breakdown characteristics were compared between VDP and S films. The results were explained with reference to the infrared reflection absorption spectroscopy of PI which indicates the crystallization and the molecular orientation of VDP film.

Iida, Kazuo; Nakamura, Shuhei; Sawa, Goro

1994-11-01

301

Physical and electrical characteristics of the high-k Ta2O5 (tantalum pentoxide) dielectric deposited on the polycrystalline silicon  

NASA Astrophysics Data System (ADS)

The high-k Ta2O5 films deposited on the polycrystalline silicon treated with different postrapid thermal annealing temperatures were formed as high-k interdielectrics. Physical and electrical characteristics of the Ta2O5 dielectrics were investigated with x-ray diffraction, x-ray photoelectron spectroscopy, atomic force microscopy, and electrical analysis. The annealing at 800 °C was found to be the optimal condition to reduce the defects and interface traps existed in the interface between the Ta2O5 dielectric and polysilicon to fabricate a well-crystallized film with higher breakdown field, lower leakage current and smaller charge trapping rate. This Ta2O5 dielectric shows promise for future generation of nonvolatile memory.

Kao, Chyuan-Haur; Chen, Hsiang; Chiu, Jing Sing; Chen, Kung Shao; Pan, Yu Tsung

2010-03-01

302

Rivaroxaban modulates electrical and mechanical characteristics of left atrium  

PubMed Central

Background Rivaroxaban reduces stroke in patients with atrial fibrillation (AF). Left atrium (LA) plays a critical role in the pathophysiology of AF. However, the electromechanical effects of rivaroxaban on LA are not clear. Results Conventional microelectrodes and a whole-cell patch-clamp were used to record the action potentials (APs) and ionic currents in rabbit LA preparations and isolated single LA cardiomyocytes before and after the administration of rivaroxaban. Rivaroxaban (10, 30, 100, and 300 nM) concentration-dependently reduced LA (n?=?7) AP durations at 90% repolarization (APD90) from 76?±?2 to 79?±?3, 67?±?4 (P?electrical and mechanical characteristics with direct ionic current effects.

2013-01-01

303

Electrical breakdown, electropermeabilization and electrofusion  

Microsoft Academic Search

The considerable amount of activity in the field of electrofusion and electropermeabilization is very promising from the point of view of new insights into biomembranes and new technologies in the future for the production of new compounds and modification of cell systems for nutrition, energy production and the removal of waste products. It is particularly gratifying to see how basic

Ulrich Zimmermann

304

Realization of high breakdown voltage (>700 V) in thin SOI devices  

Microsoft Academic Search

The avalanche breakdown voltage of silicon on insulator (SOI) lateral diodes is investigated theoretically and experimentally. Theoretically, a condition is derived for achieving a uniform lateral electric field and thus optimizing the breakdown voltage. Using this condition, it is shown that, for SOI thicknesses below about 1 ?m, diode breakdown voltage increases with decreasing SOI layer thickness. Experimentally, breakdown voltages

S. Merchant; E. Arnold; H. Baumgart; S. Mukherjee; H. Pein; R. Pinker

1991-01-01

305

Influence of thermal degradation of synthetic polymers (EPR, EPDM) on electrical characteristics  

Microsoft Academic Search

Electrical characteristics: dielectric constant, dielectric loss and volume resistivity were measured and correlated with structural changes induced by heating in water at three temperatures (40°, 60° and 80°C). IR and electrical determinations prove that oxygenated products decrease the material quality by worsening useful parameters. Degradation effects represent the contribution of products like alcohols and ketones to electrical behaviour of elastomers.

T. Zaharescu; M. Giurginca

1995-01-01

306

Wave propagation and dispersion characteristics in an electrically gyrotropic medium  

Microsoft Academic Search

The general dispersion relation for an electrically gyrotropic medium is derived in two different forms. It is shown that there exist two types of waves, type I and type II, in an electrically gyrotropic medium. The resonance and cut off conditions are obtained for the principle waves. Based on the results, the Clemmow-Mually-Allis (CMA) diagram is constructed. The CMA diagram

Abdullah Eroglu; Jay Kyoon Lee

2005-01-01

307

Surface breakdown igniter for mercury arc devices  

DOEpatents

Surface breakdown igniter comprises a semiconductor of medium resistivity which has the arc device cathode as one electrode and has an igniter anode electrode so that when voltage is applied between the electrodes a spark is generated when electrical breakdown occurs over the surface of the semiconductor. The geometry of the igniter anode and cathode electrodes causes the igniter discharge to be forced away from the semiconductor surface.

Bayless, John R. (Malibu, CA)

1977-01-01

308

Analysis and comparison of electrical characteristics for a single molecule wire with different electrode materials  

Microsoft Academic Search

In this paper, electrical characteristics of a phenyl dithiol molecule bridging between two electrodes of Pt are calculated and compared with a single molecule bridging between two electrodes of Au. The metal electrodes holding the same molecule have different transmission profiles, thereby leading to varying I-V characteristics. We use a simple model to analysis the I-V characteristic and investigate that

Shahram Mohammad Nejad; Parastoo Khademi; Ehsan Rahimi

2010-01-01

309

The breakdown phase in a coaxial plasma gun  

Microsoft Academic Search

The electrical breakdown in a coaxial plasma gun was investigated by means of optical and electrical measurements. The optimum start and operation conditions of the gun turned out to be strongly dependent on material and length of the cylindrical insulator.

A. Donges; G. Herziger; H. Krompholz; F. Rühl; K. Schönbach

1980-01-01

310

Voltage-dependent dielectric breakdown and voltage-controlled negative resistance in anodized Al-Al2O3-Au diodes  

NASA Astrophysics Data System (ADS)

Theories of dielectric breakdown in insulating films normally assume that dielectric breakdown depends on the electric field in the sample; that is, the thicker the film the higher the breakdown voltage. Contrary to theoretical expectations, voltage-dependent dielectric breakdown is observed in Al-Al2O3-Au diodes where Al2O3 is made by anodizing in different electrolytes. The breakdown voltage is ~4.5 V, independent of Al2O3 thickness and anodizing electrolyte. Voltage-controlled negative resistance (VCNR) develops in the current-voltage (I-V) characteristics of Al-Al2O3-Au diodes after voltage-dependent breakdown. Electron emission into vacuum accompanies the formation of VCNR in the I-V characteristics. Detailed studies of the development of VCNR show that the maximum current, the voltage for maximum current, and the voltage threshold for electron emission depend on the maximum voltage applied to the sample. A large current increase occurs for maximum applied voltage between 5 and 7 V. A fully developed VCNR characteristic has an ohmic contact suggesting that the development of an ohmic contact at a metal-insulator interface initiates breakdown.

Hickmott, T. W.

2000-09-01

311

ELECTRICAL AND MECHANICAL CHARACTERISTICS OF A VERY FAST LOBSTER MUSCLE  

PubMed Central

The remotor muscle of the second antenna of the American lobster is functionally divided into two parts. One part produces slow, powerful contractions and is used for postural control. The other part produces very brief twitches, can follow frequencies over 100/sec without fusion and is probably used for sound production. This great speed is due, in part, to synchronous arrival of nerve impulses at multiple terminals, a very brief membrane electrical response and electrical continuity throughout large volumes of sarcoplasm. Calculations indicate that the very extensive sarcoplasmic reticulum is probably responsible for the rapid decline of tension in this muscle.

Mendelson, Martin

1969-01-01

312

Comparison of the Microstructural Characteristics and Electrical Properties of Thermally Sprayed Al2O3 Coatings from Aqueous Suspensions and Feedstock Powders  

NASA Astrophysics Data System (ADS)

In this work the microstructural characteristics and electrical insulating properties of thermally sprayed alumina coatings produced by suspension-HVOF (S-HVOF) and conventional HVOF spray processes are presented. The electrical resistance at different relative air humidity (RH) levels (from 6 to 97% RH) and values of dielectric strength were investigated by direct current electrical resistance measurements, electrochemical impedance spectroscopy, and dielectric breakdown tests. Relationships between electrical properties and coating characteristics are discussed. At low humidity levels (up to 40% RH) the electrical resistivities of S-HVOF and HVOF coatings were on the same order of magnitude (1011 ?·m). At a very high humidity level (97% RH) the electrical resistivity values for the S-HVOF coatings were in the range 107-1011 ?·m, up to five orders of magnitude higher than those recorded for the HVOF coating (orders of magnitude of 106 ?·m). The better electrical resistance stability of the suspension-sprayed Al2O3 coatings can be explained by their specific microstructure and retention of a higher content of ?-Al2O3. The dielectric strength E d of suspension-sprayed coatings was found to be 19.5-26.8 kV·mm-1 for coating thicknesses ranging from 60 to 200 ?m. These values were slightly lower than those obtained for conventional HVOF coatings (up to 32 kV·mm-1). However, it seemed that the dielectric strength of conventionally sprayed coatings was more sensitive to the coating thickness (when compared with the values of E d determined for S-HVOF coatings) and varied to a greater extent (up to 10 kV·mm-1) when the coating thickness varied in the range 100-200 ?m.

Toma, Filofteia-Laura; Berger, Lutz-Michael; Scheitz, Stefan; Langner, Stefan; Rödel, Conny; Potthoff, Annegret; Sauchuk, Viktar; Kusnezoff, Mihails

2012-06-01

313

Investigation of the Electrical Short Circuit Characteristics of Tin Whiskers.  

National Technical Information Service (NTIS)

In this experiment, an empirical model to quantify the probability of occurrence of an electrical short circuit from tin whiskers as a function of voltage was developed. This model can be used to improve existing risk simulation models FIB and TEM images ...

K. J. Courey

2008-01-01

314

Machining Characteristics of Polycrystalline Silicon by Wire Electrical Discharge Machining  

Microsoft Academic Search

This study examines the use of wire electrical discharge machining (WEDM) in machining polycrystalline silicon with resistivity of 2–3 ?cm. The effects of different WEDM parameters on cutting speed, machining groove width, and surface roughness are explored. Experimental results indicate that open voltage is the critical parameter in breaking the insulation of polycrystalline silicon, and that pulse-on time has the

Po-Huai Yu; Hsiang-Kuo Lee; Yang-Xin Lin; Shi-Jie Qin; Biing-Hwa Yan; Fuang-Yuan Huang

2011-01-01

315

Modeling storage characteristics of electric vehicles in the grid  

Microsoft Academic Search

The modeling of complex systems always presents challenges when the intention is to predict the systems' future performance. The mounting number of electrical cars entails growing interest in grid integration and vehicle performance. Modeling will have to address aspects of personal mobility such as vehicle range and availability. A standardized model is needed, which is able to deliver the proper

K. Lipiec; P. Komarnicki

2010-01-01

316

An investigation of breakdown voltage in AMTECs  

NASA Astrophysics Data System (ADS)

Experiments are conducted to investigate the DC electrical breakdown voltage in cesium vapor between two planner molybdenum electrodes, 1.6 cm in diameter, separated by a 0.5 mm gap, and relate the results to the potential electrical breakdown on the cathode side of Alkali Metal Thermal-to-Electric Converters (AMTECs). In the first set of experiments, in which the electrodes are kept at 560 and 650 K, while varying the cesium pressure from 0.71 to 29 Pa, when the cooler electrode is positively biased, breakdown occurs at ~500 V, but at 700 V when the cooler electrode is negatively biased. In the second set of experiments, in which the electrodes are held at 625 and 1100 K and the cesium pressure varied from 1.7 to 235 Pa, when the cooler electrode is positively biased, breakdown voltage is <4 V, but in excess of 400 V when the cooler electrode is negatively biased. Since the first ionization potential and the ionization rate constant of cesium are lower and higher, respectively, than for the sodium (5.14 V) and potassium (4.34 V) vapors in AMTECs, the DC electrical breakdown voltage in an AMTEC is expected to be higher than measured in this work for cesium vapor. .

Momozaki, Yoichi; El-Genk, Mohamed S.

2002-01-01

317

The effect of electric field on the creep characteristics of low-density polyethylene (LDPE)  

Microsoft Academic Search

The effect of electric field on the creep characteristics and the corresponding parameters such as instantaneous strain, strain rate, activation energy, activation volume, stress-sensitivity parameter and viscosity was investigated.

M. Amin; H. M. Osman; S. S. Hamza; N. El-Nashar; S. F. Moghazy

1989-01-01

318

The Effect of Electrical Conductivity Variations on the Characteristics of Arc Discharges.  

National Technical Information Service (NTIS)

Algebraically calculated current-voltage characteristics of arc discharges are obtained with a canal model for planar and cylindrical arcs and electrical conductivity given as a power of the heat flux potential. For slower than linear variation, the curre...

A. M. Whitman I. M. Cohen

1973-01-01

319

Addressing the lower limit of breakdown delay time in vacuum  

NASA Astrophysics Data System (ADS)

Based on the Joule mechanism of vacuum breakdown initiation, the dependence of a pulsed electric strength on the high-voltage pulse duration at a finite rate of electric field buildup in the vacuum gap is calculated. The results of calculations are confirmed by experimental data available for subnanosecond pulses. It is shown that the breakdown delay time has no lower limit at an electric strength of up to ˜3 × 1010 V/m observed in experiment. The independence of the breakdown delay time of the electric field strength for pulse durations comparable with the pulse front width is explained by the finite rate of applied voltage buildup.

Emel'Yanov, A. A.; Emel'Yanova, E. A.

2006-11-01

320

Solid Breakdown Process from Viewpoint of Nature of Pre-Breakdown Current in Polymeric Insulating Materials  

NASA Astrophysics Data System (ADS)

Solid breakdown process was discussed on the basis of the experimental results on the electrical conduction just prior to breakdown for various polymeric insulating materials. For polyamideimide (PAI) and non-stretched polyvinylidene fluoride (PVDF), the pre-breakdown current sharply increased from an order of 1 ?s before breakdown. For polytheylene terephthalate (PET) and stretched PVDF, a sharp current increase could not be detected till about 100 ns, which was a limit of time resolution. Assuming that this sharp current increase is caused by the increase of filamentary current due to the temperature rise of a small spot, we discussed the maximum radius of the filament. It was concluded that for leading to filamentary thermal breakdown the radius of the filament should be less than about 3.5 ?m for PAI and non-stretched PVDF, and 1.3 ?m for stretched PVDF and 3000 Å for PET.

Hikita, Masayuki; Kanno, Ippei; Sawa, Goro; Ieda, Masayuki

1985-12-01

321

Magnetic field characteristics of electric bed-heating devices  

SciTech Connect

Measurements of the flux density and spectra of magnetic fields (MFs) generated by several types of electric bed heaters (EBH) were made in order to characterize the MFs to which the fetus may be exposed in utero from the mother`s use of these devices. Data on MFs were gathered from more than 1,300 in-home and laboratory spot measurements. In-home measurements taken at seven different positions 10 cm from the EBHs determined that the mean flux density at the estimated position of the fetus relative to the device was 0.45 {micro}T (4.5 mG) for electric blankets and 0.20 {micro}T (2.0 mG) for electrically heated water beds. A rate-of-change (RC) metric applied to the nighttime segment of 24 h EMDEX-C personal-dosimeter measurements, which were taken next to the bed of volunteers, yielded an approximate fourfold to sixfold higher value for electric blanket users compared to water-bed heater users. These same data records yielded an approximate twofold difference for the same measurements when evaluated by the time-weighted-average (TWA) MF exposure metric. Performance of exposure meters was checked against standard fields generated in the laboratory, and studies of sources of variance in the in-home measurement protocols were carried out. Spectral measurements showed that the EBHs measured produced no appreciable high-frequency MFs. Data gathered during this work will be used in interpreting results from a component of the California Pregnancy Outcome Study, which evaluates the use of EBHs as a possible risk factor in miscarriage.

Wilson, B.W.; Davis, K.C.; Heimbigner, T.; Buschbom, R.L. [Pacific Northwest National Lab., Richland, WA (United States); Lee, G.M. [California State Department of Health Services, Berkeley, CA (United States); Yost, M.G. [Univ. of Washington School of Public Health, Seattle, WA (United States)

1996-12-01

322

Magnetic field characteristics of electric bed-heating devices  

Microsoft Academic Search

Measurements of the flux density and spectra of magnetic fields (MFs) generated by several types of electric bed heaters (EBH) were made in order to characterize the MFs to which the fetus may be exposed in utero from the mother`s use of these devices. Data on MFs were gathered from more than 1,300 in-home and laboratory spot measurements. In-home measurements

B. W. Wilson; K. C. Davis; T. Heimbigner; R. L. Buschbom; G. M. Lee; M. G. Yost

1996-01-01

323

Effect of electrical discharge machining on the characteristics of carbon fiber reinforced carbon composites  

Microsoft Academic Search

This work investigated electrical discharge machining (EDM) of carbon fiber reinforced carbon composite material. The characteristics of composites machined by EDM were studied in terms of machining parameters. An empirical model of the composites was also proposed based on the experimental data. The composite material was produced by an electrical discharge sinker using a graphite electrode. The workpiece surface and

Y. H. Guu; H. Hocheng; N. H. Tai; S. Y. Liu

2001-01-01

324

A study of electrical characteristic changes in MOSFET by electron beam irradiation  

Microsoft Academic Search

Mechanisms for electrical characteristic changes in MOSFET caused by electron beam irradiation were studied using a SEM-based nano-probing system. A shift in Vth occurs when a hole is trapped in a defect (oxygen vacancy) in the gate dielectric layer. Holes are generated when the plasmon is excited by electron beam irradiation. Further, an electric field is created by the positive

Yasuhiro Mitsui; Takeshi Sunaoshi; Jon C. Lee

2009-01-01

325

Effect of the levels of intrinsic defects in the CdP{sub 2} band gap on electrical characteristics of corresponding structures with the Schottky barrier  

SciTech Connect

The electrical characteristics of Schottky barriers formed on n-type cadmium diphosphide are studied. It is established that the space-charge region at the metal-semiconductor interface represents in fact a Schottky layer formed owing to a high concentration of deep-level centers. The charge transport in the conducting direction for these structures is related to the above-barrier emission of electrons and is consistent with the diffusion theory for one or two types of charge carriers. The high concentration of ionized centers in the space-charge region gives rise to the tunneling mechanism of breakdown in the blocking direction. The frequency dependences of the complex conductance are governed by the exchange of charge carriers between the conduction band and donors that specify the conductivity type of the material and also by the recharing of the centers with a large depth of levels. Good agreement between the reported results and the theory is obtained.

Stamov, I. G., E-mail: istamov51@mail.ru; Tkachenko, D. V. [Dniester State University (Moldova, Republic of)

2006-10-15

326

A PSpice model for the electrical characteristics of fluorescent lamps  

Microsoft Academic Search

This paper presents a PSpice circuit model for the simulation of both static and dynamic characteristics of fluorescent lamps. The proposed model was developed from the combination and modifications of classical Cassie and Mayr equations. It is helpful for a preliminary design of high frequency electronic ballasts. Experimental results on fluorescent lamps at different conditions are presented and they appear

T. Liu; K. J. Tseng; D. M. Vilathgamuwa

1998-01-01

327

Avalanche breakdown in GaTa4Se8-xTex narrow-gap Mott insulators  

NASA Astrophysics Data System (ADS)

Mott transitions induced by strong electric fields are receiving growing interest. Recent theoretical proposals have focused on the Zener dielectric breakdown in Mott insulators. However, experimental studies are still too scarce to conclude about the mechanism. Here we report a study of the dielectric breakdown in the narrow-gap Mott insulators GaTa4Se8-xTex. We find that the I-V characteristics and the magnitude of the threshold electric field (Eth) do not correspond to a Zener breakdown, but rather to an avalanche breakdown. Eth increases as a power law of the Mott-Hubbard gap (Eg), in surprising agreement with the universal law EthEg2.5 reported for avalanche breakdown in semiconductors. However, the delay time for the avalanche that we observe in Mott insulators is over three orders of magnitude greater than in conventional semiconductors. Our results suggest that the electric field induces local insulator-to-metal Mott transitions that create conductive domains that grow to form filamentary paths across the sample.

Guiot, V.; Cario, L.; Janod, E.; Corraze, B.; Ta Phuoc, V.; Rozenberg, M.; Stoliar, P.; Cren, T.; Roditchev, D.

2013-04-01

328

High breakdown GaN HEMT with overlapping gate structure  

Microsoft Academic Search

GaN high electron mobility transistors (HEMTs) were fabricated using an overlapping-gate technique in which the drain-side edge of the metal gate overlaps on a high breakdown and high dielectric constant dielectric. The overlapping structure reduces the electric field at the drain-side gate edge, thus increasing the breakdown of the device. A record-high three-terminal breakdown figure of 570 V was achieved

N.-Q. Zhang; S. Keller; G. Parish; S. Heikman; S. P. DenBaars; U. K. Mishra

2000-01-01

329

Breakdown in high voltage, high energy density multilayer ceramic capacitors  

Microsoft Academic Search

Causes of breakdown, both mechanical and electrical, in high voltage, high energy density, BaTiO3 multilayer ceramic capacitors were studied. The flexural strength of the capacitors was 96 +\\/- 13 MPa. Failure was due to surface defects or pores close to the surfaces of the samples. The dielectric breakdown strength of the samples was 181 kV\\/cm. The causes of breakdown were

Amanda Young

2007-01-01

330

Electrical characteristics of highly reliable ultrathin hafnium oxide gate dielectric  

Microsoft Academic Search

Electrical and reliability properties of ultrathin HfO2 have been investigated. Pt electroded MOS capacitors with HfO2 gate dielectric (physical thickness ~45-135 Å and equivalent oxide thickness ~13.5-25 Å) were fabricated. HfO2 was deposited using reactive sputtering of a Hf target with O2 modulation technique. The leakage current of the 45 Å HfO2 sample was about 1×10-4 A\\/cm 2 at +1.0

Laegu Kang; Byoung Hun Lee; Wen-Jie Qi; Yongjoo Jeon; Renee Nieh; Sundar Gopalan; Katsunori Onishi; Jack C. Lee

2000-01-01

331

Role of the substrate in the electrical transport characteristics of focused ion beam fabricated nanogap electrode  

SciTech Connect

Precise metallic nanogap structure is fabricated on a glass substrate by using a 30 keV focused Ga ion beam. While investigating the I-V behavior of the nanogap structure, tunneling through the substrate has been found to play a vital role in the electrical transportation process. Substrate breakdown occurs at a certain applied voltage and a metal vapor state is initiated through intense heat generation at the nanogap region. The experimental observation confirms the role of the substrate in the explosion process. Metallic spherical particles are formed during cooling/condensation of the metal vapors or splashing of the liquid droplets showing a wide distribution of size from few tens of nanometers to few microns.

Rajput, Nitul S.; Verma, H. C. [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Singh, Abhishek K. [Materials Science Programme, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

2012-07-15

332

Aging effect on electrical characteristics of insulating oil in field transformer  

Microsoft Academic Search

To ensure long-term reliability of transformers, it is important to identify the degradation characteristics of insulating oil in long-term operations, which are the dominant factors of the transformer dielectric strengths. Analysis on aged field insulating oil was conducted to identify how insulating oil in transformers changes and deteriorates with increasing age and what are the impacts on the electrical characteristics

Masanori Kohtoh; Shuhei Kaneko; Shigemitsu Okabe; Tsuyoshi Amimoto

2009-01-01

333

Partial discharge activity in electrical insulation for high temperature superconducting (HTS) cables  

Microsoft Academic Search

This paper discusses electrical insulation characteristics of liquid nitrogen (LN2) \\/ polypropylene (PP) laminated paper composite insulation system for the practical electrical insulation design of high temperature superconducting (HTS) cables. Partial discharge (PD) inception, propagation and breakdown (BD) characteristics under ac voltage application were obtained and discussed at atmospheric and pressurized conditions. Experimental results were analyzed quantitatively and revealed that

H. Okubo; H. Kojima; F. Endo; K. Sahara; R. Yamaguchi; N. Hayakawa

2008-01-01

334

Influence of Pore Size on Dielectric Breakdown in Plasma-polymerized Films  

NASA Astrophysics Data System (ADS)

For solid materials with gas-filled pores, dielectric breakdown is preceded by gas-phase partial discharge. As pore size shrinks, there is a limiting pore diameter where the number of gas molecules is insufficient to support phenomena depending on multiple gas phase events. Pores are an integral part of most plasma-polymerized materials. We are investigating dielectric breakdown in three plasma-polymerized organic films: acetylene, aniline and tetrathiafulvalene (TTF). Motivation for selecting these precursor molecules includes 1) obtaining very small pore sizes, 2) presence of pi bonds in a thoroughly studied material and 3) unique light emitting molecules, respectively. Preliminary results show that dielectric breakdown voltage follows a Weibull distribution. Electrical characterization of the films includes 1) low voltage (5-50 mV) ac impedance spectroscopy, 2) high voltage (1-1,000 V) variable frequency ac measurements of partial discharge and dielectric breakdown thresholds and 3) current-voltage characteristics for voltages below dielectric breakdown. Prospective applications include organic light emitting devices, organic insulators for electronic circuits, piezoelectric copolymer films and polymer-based sensors.

Pedrow, Patrick; Chang, Jen-Ho

2004-11-01

335

An Assessment of Wind Turbine Characteristics and Wind Energy Characteristics for Electricity Production  

Microsoft Academic Search

This work is an analysis of wind turbine characteristics and wind energy characteristics of four regions around Elazig, Turkey, namely Maden, Agin Elazig and Keban. Wind speed data and wind direction in measured hourly time-series format is statistically analyzed based on 6 years between 1998 and 2003. The probability density distributions are derived from time-series data and distributional parameters are

E. Kavak Akpinar; S. Akpinar

2006-01-01

336

Dielectric breakdown in silica-amorphous polymer nanocomposite films: the role of the polymer matrix.  

PubMed

The ultimate energy storage performance of an electrostatic capacitor is determined by the dielectric characteristics of the material separating its conductive electrodes. Polymers are commonly employed due to their processability and high breakdown strength; however, demands for higher energy storage have encouraged investigations of ceramic-polymer composites. Maintaining dielectric strength, and thus minimizing flaw size and heterogeneities, has focused development toward nanocomposite (NC) films; but results lack consistency, potentially due to variations in polymer purity, nanoparticle surface treatments, nanoparticle size, and film morphology. To experimentally establish the dominant factors in broad structure-performance relationships, we compare the dielectric properties for four high-purity amorphous polymer films (polymethyl methacrylate, polystyrene, polyimide, and poly-4-vinylpyridine) incorporating uniformly dispersed silica colloids (up to 45% v/v). Factors known to contribute to premature breakdown-field exclusion and agglomeration-have been mitigated in this experiment to focus on what impact the polymer and polymer-nanoparticle interactions have on breakdown. Our findings indicate that adding colloidal silica to higher breakdown strength amorphous polymers (polymethyl methacrylate and polyimide) causes a reduction in dielectric strength as compared to the neat polymer. Alternatively, low breakdown strength amorphous polymers (poly-4-vinylpyridine and especially polystyrene) with comparable silica dispersion show similar or even improved breakdown strength for 7.5-15% v/v silica. At ?15% v/v or greater silica content, all the polymer NC films exhibit breakdown at similar electric fields, implying that at these loadings failure becomes independent of polymer matrix and is dominated by silica. PMID:23639183

Grabowski, Christopher A; Fillery, Scott P; Westing, Nicholas M; Chi, Changzai; Meth, Jeffrey S; Durstock, Michael F; Vaia, Richard A

2013-05-02

337

Breakdown and Transmission of High Power Microwave Beam  

Microsoft Academic Search

Considering the pondermotive force, the transmission of high power microwave beam after air breakdown is studied. It is put forward that for long pulse beam, high-repetition pulses beam and continuous wave beam, the process of air breakdown and transmission is different compared with uniform plane wave. The uneven electric-field distribution will lead to redistribution of electron concentration and will finally

Rao Yu-ping; Lin Jing-yu

2006-01-01

338

Model for dielectric breakdown in metal-insulator composites  

Microsoft Academic Search

We consider continuum and lattice models for dielectric breakdown in random metal-insulator composites. The continuum model consists of a random composite below the metallic percolation threshold pc. The dielectric is assumed to break down and become metallic when the local electric field exceeds a certain critical value. For fixed external boundary conditions and sample size, if the initial breakdown field

D. R. Bowman; D. Stroud

1989-01-01

339

Frequency-Dependent Dielectric Breakdown in Thin Polyvinylcarbazole Films  

Microsoft Academic Search

Dielectric breakdown in thin polyvinylcarbazole (PVK) films prepared by vapor deposition polymerization has been investigated at various ac voltages. Real-time measurements were carried out automatically with a system composed of a digital oscilloscope, a controllable signal generator and a microcomputer. Self-healing breakdown takes place at the peak applied voltage. AC electric strength decreases with temperature, and increases with frequency in

Keiichi Miyairi

2003-01-01

340

Structural, optical and electrical characteristics of a new NLO crystal  

NASA Astrophysics Data System (ADS)

A new nonlinear optical (NLO) organic crystal 1-[4-({(E)-[4-(methylsulfanyl)phenyl]methylidene}amino)phenyl]ethanone (MMP) has been grown by slow evaporation technique at ambient temperature. The crystal structure of MMP was determined by single crystal X-ray diffraction. MMP crystallizes in non-centrosymmetric monoclinic system with space group P21. The FT-IR spectrum recorded for new crystal confirmed the presence of various functional groups in the material. MMP was found to be thermally stable up to 300 °C. The grown crystal was optically transparent in the wavelength range of 400-1100 nm. The second harmonic generation (SHG) efficiency of the crystal was measured by the classical powder technique using Nd:YAG laser and was found to be 4.13 times more efficient than reference material, urea. Third order nonlinear parameters were measured by employing the Z-scan technique. The laser damage threshold for MMP crystal was determined to be 4.26 GW/cm2. The Brewster angle technique was employed to measure the refractive index of the crystal and the values for green and red wavelengths were found to be 1.35 and 1.33, respectively. The dielectric and electrical measurements were carried out to study the different polarization mechanisms and conductivity of the crystal.

D'silva, E. D.; Krishna Podagatlapalli, G.; Venugopal Rao, S.; Dharmaprakash, S. M.

2012-09-01

341

Basic study of transient breakdown voltage in solid dielectric cables. Final report  

SciTech Connect

A comprehensive review of the technical and scientific publications relating to crosslinked polyethylene (XLPE) and ethylene propylene rubber (EPR) insulated cables revealed that there is very little known with respect to the life expectancy, the final factory voltage test background and the mechanism of voltage breakdown of these cables. In this study a new methodology for the investigation of breakdown voltages of XLPE and EPR insulated cables was developed which is based on the investigation of breakdown voltages at various voltage transients such as unipolarity pulses and dual-polarity pulses, and a.c. voltage at power and high frequency. Also, a new approach to statistical testing was developed which allows one to establish a correlation among the breakdown voltages obtained with various voltage transients. Finally, a method for the determination of threshold voltage regardless of the magnitude of apparent charge was developed. Extensive statistical testing of breakdown voltages was conducted using: impulses with front durations from approximately 1.5 to 1000 ..mu..s and times to half-values from 40 to 3000 ..mu..s; dual-polarity pulses consisting of d.c. voltage and standard impulse of opposite polarity; combined a.c. and d.c. voltages; and a.c. voltages at power and high frequencies. Based on the results of this testing, a model of breakdown and electrical aging of XLPE and EPR insulated cables was developed as well as life expectancy characteristics for high voltage stress XLPE insulated cables operated in a dry environment at room temperature and at 90/sup 0/C. Life expectancy characteristics for EPR insulated cables are approximated. A test procedure including requirements for full-reel factory voltage withstand and partial discharge testing of finished XLPE and EPR insulated cables is proposed. Cables that pass the proposed tests will exhibit a smaller rate of failure in service than cables tested in accordance with present practices.

Bahder, G.; Sosnowski, M.; Katz, C.

1980-09-01

342

A Numerical Model for Thermal Second Breakdown.  

National Technical Information Service (NTIS)

A computer model is developed for simulating reverse bias thermal second breakdown (TSB) transients in thin film diodes. The model performs a one-dimensional electrical and a two-dimensional thermal simulation. Simulations are performed up to the onset of...

W. H. Causey

1978-01-01

343

Dielectric Breakdown and its Influence on Ignition.  

National Technical Information Service (NTIS)

Electrical conduction, dielectric breakdown and the consequent ignition of small pellets, 0.2 to 5 mm in thickness and 5 to 7 mm in diameter, of MTV compositions SR886B, SR886E and SR886E have been investigated. The investigations were made using d.c fiel...

M. M. Chaudhri F. A. Al-Ramadhan I. U. Haq

1993-01-01

344

Kinetic theory of runaway air breakdown  

Microsoft Academic Search

The kinetic theory for an air breakdown mechanism advanced in a previous paper [Phys. Lett. A 165, 463 (1992)] is developed. The relevant form of the Boltzmann equation is derived and the particle orbits in both velocity space and configuration space are computed. A numerical solution of the Boltzmann equation, assuming a spatially uniform electric field, is obtained and the

R. A. Roussel-Dupre; A. V. Gurevich; T. Tunnell; G. M. Milikh

1994-01-01

345

Microwave Multipactor Breakdown Between Two Cylinders  

Microsoft Academic Search

An analysis has been made of the microwave breakdown threshold for multipactor in an open structure comprising two parallel cylinders, approximating, e.g., parts of a helix antenna. The electron motion in the corresponding electromagnetic field is analyzed by separating the motion into a slowly varying drift velocity (driven by the ponderomotive force due to the electric field inhomogeneity) and a

J. Rasch; D. Anderson; Joakim F. Johansson; M. Lisak; J. Puech; Elena Rakova; V. E. Semenov

2010-01-01

346

The Exact Distribution of Breakdown Time Delay  

Microsoft Academic Search

Following up from the recent work of Maluckov (IEEE Trans. Plasma Sci., vol. 31, p. 1344, 2003), Maluckov (IEEE Trans. Plasma Sci., vol. 34, p. 2, 2006), we derive explicit expressions for the probability density function, cumulative distribution function, and the means of the electrical breakdown time delay (tD). We provide a five-line computer program for computing the associated percentile

Saralees Nadarajah; Samuel Kotz

2007-01-01

347

Protonic Theory of Dielectric Breakdown of Water  

Microsoft Academic Search

We are investigating how electric sparks form in heavy water (D2O) in order to test our model of dielectric breakdown in regular water (H20). The precursors to these sparks are called leaders, which are charged plasma filaments with densities greater than liquid water. Our model is a one dimensional plasma wave that relies on a concomitant increase in dissociation rates

James Espinosa

2005-01-01

348

Diffusion barrier and electrical characteristics of a self-aligned MgO layer obtained from a Cu(Mg) alloy film  

NASA Astrophysics Data System (ADS)

Diffusion barrier characteristics and electrical properties of self-aligned MgO layers obtained from a Cu(Mg) alloy film have been investigated. Self-aligned surface and interfacial MgO layers were formed upon annealing a Cu(Mg) film in an oxygen ambient and prevented interdiffusion of Cu in SiO2 up to 700 °C. The thermal stability of a pure Cu/TiN/Si multilayer system has been significantly enhanced up to 800 °C by the MgO layers by forming a MgO/Cu/MgO/TiN/Si multilayer system. A combined structure of Si3N4(500 Å)/MgO(100 Å) increased the breakdown voltage up to 20 V from 15 V and reduced the leakage current density down to 3×10-9 A/cm2 from 1×10-8 A/cm2 compared to a pure copper system. Consequently, the deposition of Cu(Mg) alloy followed by annealing in an oxygen ambient gives rise to the formation of a self-aligned MgO layer with excellent diffusion barrier and electrical characteristics and the film can be applied as a gate electrode in thin-film transistor/liquid-crystal displays, resulting in a reduction of process steps.

Lee, W. H.; Cho, H. L.; Cho, B. S.; Kim, J. Y.; Nam, W. J.; Kim, Y.-S.; Jung, W. G.; Kwon, H.; Lee, J. H.; Lee, J. G.; Reucroft, P. J.; Lee, C. M.; Lee, E. G.

2000-10-01

349

Non-Uniform Field Breakdown and Surface Flashover in Liquid Nitrogen Gaps for HTS Applications  

SciTech Connect

Abstract: Liquid nitrogen (LN2) is used as a coolant and electrical insulation in many High Temperature Superconducting (HTS) applications. Hence a good understanding of the breakdown characteristics of this medium under a variety of practical electrode geometries and conditions is needed for design of high voltage equipment. While there is considerable literature on breakdown of LN2 gaps for uniform (plane-plane) or quasi-uniform electric fields (sphere-plane), there is much less data available for highly non-uniform field gaps and for surface flashover along insulators. In this paper we present results on sphere-plane and cylindrical rod-plane gaps in LN2 as a function of sphere and rod diameters and radius of the rod edge at 1 bar pressure. In addition the surface flashover voltages of Fiber-Reinforced Plastic (FRP) in LN2 with these electrode arrangements will also be reported.

James, David Randy [ORNL; Sauers, Isidor [ORNL; Tuncer, Enis [ORNL; Ellis, Alvin R [ORNL; Tekletsadik, Kasegn [Consultant, SuperPower, Inc.; Hazelton, Drew [SuperPower Incorporated, Schenectady, New York

2006-01-01

350

Breakdown voltage characteristics in the SF6\\/N2 gas mixtures for DS\\/ES compartment of a 245kV gas insulated switchgear  

Microsoft Academic Search

The SF6 gas insulated switchgear (GIS) is the electric power equipment for transmission and distribution line which reduced the size of the electric power equipments by installing in a sealed tank. Since the size of the GIS is about 1\\/10 of the air insulated switchgear, high quality insulation gas should be used. However this gas is a source of global

Wang-Byuck Suh; Jae-Yun Yim; Ki-Dong Song; Yong-Moo Chang; Dong-Ho Bae

2011-01-01

351

Work Breakdown Structure Guide.  

National Technical Information Service (NTIS)

Utilization of the work breakdown structure (WBS) technique is an effective aid in managing Department of Energy (DOE) programs and projects. The technique provides a framework for project management by focusing on the products that are being developed or...

1987-01-01

352

Product Work Breakdown Structure.  

National Technical Information Service (NTIS)

The work required for any large construction project must be subdivided in order to be readily analyzed and managed. Any such subdivision scheme is a work breakdown structure. Traditional shipbuilders employ work subdivisions by ships functional systems w...

Y. Okayama L. D. Chirillo

1980-01-01

353

A mesh reflecting surface with electrical characteristics independent on direction of electric field of incident wave  

Microsoft Academic Search

For large deployable antennas on board satellites, a knitted wire mesh is used as reflecting surface because it is lightweight and elastic due to its knitted structure. The mesh reflecting surface has high reflectivity for the electric field parallel to the wire running direction (Takano, T. et al., 1992). This nature of the mesh, the dependence of reflectivity on the

Amane Miura; Masato Tanaka

2004-01-01

354

Impact of Si substrate nitridation on electrical characteristics of Ta2O5 stack capacitors  

Microsoft Academic Search

A comparison of the effect of rapid thermal nitridation (RTN) of the Si surface in N2O and NH3 ambient at different temperatures (700-850 °C) on the dielectric and electrical characteristics of thin (~20 nm) Ta2O5 stacks has been made. The electrical parameters of capacitors (film permittivity, oxide charge, densities of bulk traps, interface and slow states, leakage current) are discussed

A. Paskaleva; D. Spassov; E. Atanassova

2007-01-01

355

Physical characteristics of GE (General Electric) BWR (boiling-water reactor) fuel assemblies  

SciTech Connect

The physical characteristics of fuel assemblies manufactured by the General Electric Company for boiling-water reactors are classified and described. The classification into assembly types is based on the GE reactor product line, the Characteristics Data Base (CDB) assembly class, and the GE fuel design. Thirty production assembly types are identified. Detailed physical data are presented for each assembly type in an appendix. Descriptions of special (nonstandard) fuels are also reported. 52 refs., 1 fig., 6 tabs.

Moore, R.S.; Notz, K.J.

1989-06-01

356

Torque characteristics analysis of an eddy current electric machine for automotive braking applications  

Microsoft Academic Search

We introduce an enhanced parametric model for a copper-layered eddy current electric machine (retarder) for automotive braking applications. The modeled torque characteristics of the copper-layered electromagnetic retarders are based on the results from a detailed electromagnetic finite element analysis (FEA) of these eddy current machines. The model uses a parameterized double-exponential function to model the steady state speed-torque characteristics of

Sohel Anwar; Randy C. Stevenson

2006-01-01

357

Inherent time delay for dielectric breakdown in shock-loaded x-cut quartz  

Microsoft Academic Search

Dielectric breakdown in shock-loaded x-cut quartz is examined under conditions of both impact loading and Q-switched laser-irradiation loading. It is observed that breakdown is characterized by an inherent time delay which depends on the magnitude of the electric field. For pulse duration less than about 30 ns, dielectric breakdown is not observed.

R. A. Graham; L. C. Yang

1975-01-01

358

Modeling for electrical characteristics of solid oxide fuel cell based on fractional calculus  

Microsoft Academic Search

It's vital for the research of electrochemical reaction in solid oxide fuel cell (SOFC) to establish accurate dynamic model of its electrical characteristics. The inherent potential polarization of SOFC is analyzed, and integer order dynamic model is established by equivalent circuit. Experimental data is studied by electrochemical impedance spectroscopy (EIS), and its novel fractional order dynamic model is proposed exploringly

HongLiang Cao; Li Xi; ZhongHua Deng; Qin Yi

2009-01-01

359

Electric assisted bicycles and measurement of real-time performance characteristics for power management strategies  

Microsoft Academic Search

Electric assisted bicycles can offer a cost effective alternative for commuter applications. However there is limited knowledge about the operating characteristics of such bicycles, which is necessary to optimize the rating of energy storage as it can significantly affect their range and weight. This study examines and realises an alternative design for a wheel hub direct drive. The paper also

Stuart Brand; S. Bakhri; N. Ertugrul

2007-01-01

360

Characteristics and prediction of magnetic noise due to DC electric railcars for biomagnetic measurements  

Microsoft Academic Search

A magnetically shielded room for biomagnetism should be designed taking account of the S\\/N ratio of the biomagnetic signal to the environmental magnetic noise generated mainly by dc electric railcars at an installed location. This paper describes the characteristics of the fluctuation of magnetic noise and a method of prediction of its amplitude. The distance dependence of the magnetic noise

Keita Yamazaki; Kazuo Kato; Koichiro Kobayashi; Yoshinori Uchikawa; Yoji Kumagai; Akira Haga; Koji Fujiwara

2001-01-01

361

Electrical Characteristics and Testing Considerations for Gate Oxide Shorts in CMOS ICs  

Microsoft Academic Search

This paper examines the electrical characteristics and testing considerations of gate oxide shorts. Gate oxide shorts will cause increased IDD and in the majority of cases will degrade logic voltage levels and propagation delay times, but may not affect functionality. Stuck-at and functional models are therefore inadequate for testing gate oxide shorts in CMOS ICs unless they are used in

Jerry M. Soden; Charles F. Hawkins

1985-01-01

362

The influence of surface treatments on the electrical characteristics of polysilicon emitter bipolar transistors  

Microsoft Academic Search

Silicon bipolar transistors have been made with arsenic-implanted or phosphorus-diffused polysilicon emitters. The effects of different surface treatments, prior to polysilicon deposition, are investigated by comparing results obtained for a dip etch in hydrofluoric acid with those for an RCA clean. Detailed electrical results are presented for these two types of device, including transistor characteristics as a function of temperature.

B. Soerowirdjo; P. Ashburn; A. Cuthbertson

1982-01-01

363

Land-ocean contrast on electrical characteristics of lightning discharge derived from satellite optical measurements  

Microsoft Academic Search

Comparative studies on the electrical properties of oceanic and continental lightning are crucial to elucidate air discharge processes occurring under different conditions. Past studies however have primarily focused on continental lightning because of the limited coverage of ground-based instruments. Recent satellite measurements by FORMOSAT-2\\/ISUAL provided a new way to survey the global characteristics of lightning and transient luminous events regardless

T. Adachi; R. Said; S. A. Cummer; J. Li; Y. Takahashi; R. Hsu; H. Su; A. B. Chen; S. B. Mende; H. U. Frey

2010-01-01

364

Investigation of the electrical characteristics of low-temperature thermionic power generators  

Microsoft Academic Search

The effectiveness of improving the output characteristics of thermionic electrical power generators by injecting oxygen into the electrode gap was studied at emitter temperatures between 1200 and 1400 C. The electrodes were of plane geometry. Tungsten (110) single crystals were used as the emitter material, and polycrystalline molybdenum or nickel (110) single crystals for the collectors. It is shown that

N. E. Menabde; V. K. Tskhakaia; L. M. Tsakadze; V. A. Iurev; V. N. Lebedev

1978-01-01

365

Experimental Investigation of the Electrical and Optical Characteristics of an Inductively Coupled Discharge in Neon  

Microsoft Academic Search

An experimental investigation of the electrical and optical characteristics of an inductively coupled discharge in neon is performed in a wide range of conditions of discharge burning, namely, discharge tube diameters of 20, 34, and 58 mm, neon pressures of 10 to 600 Pa, discharge currents of 1 to 30 A, and current frequencies of 25 and 250 kHz. The

M. V. Isupov; I. M. Ulanov; A. Yu. Litvintsev

2004-01-01

366

Simulation study of electrical dynamic characteristics of lithium-ion battery  

Microsoft Academic Search

The electrical dynamic characteristics of a lithium-ion battery have been simulated by an equivalent circuit, which is derived from the measured impedance. The transient voltage response to the various kinds of applied current waves such as single pulse, single rectangular, triangle, and sawtooth waves is experimentally examined and calculated by using the numerical Laplace transform with the equivalent circuit. The

Kiyonami Takano; Ken Nozaki; Yoshiyasu Saito; Akira Negishi; Ken Kato; Yoshio Yamaguchi

2000-01-01

367

Electric Characteristics of Hybrid Polymer Membranes Composed of Two Lipid Species  

NASA Astrophysics Data System (ADS)

Electric characteristics of hybrid polymer membranes composed of two lipid species were studied, where one lipid species is positively charged in aqueous solution and the other is negatively charged. As a result, it was found that the hybrid membranes responded to taste substances in different ways according to the molar mixing ratio of these two kinds of lipids, and also showed different response characteristics from those of the single-lipid membranes. The membranes with the mixing ratio around 50% exhibited the largest responses to HCl (sourness) and monosodium glutamate (umami). Moreover, good quantitative agreements with the observed data on the response electric potential were obtained using a theory describing both the changes in surface electric potential and surface charge density with taste substances.

Oohira, Koji; Toko, Kiyoshi; Akiyama, Hideyuki; Yoshihara, Hiroshi; Yamafuji, Kaoru

1995-09-01

368

Breakdown and partial discharges in magnetic liquids.  

PubMed

The dielectric properties (permittivity, loss factor, dielectric breakdown strength) of magnetic liquids were investigated. The magnetic liquids were composed of magnetite particles coated with oleic acid as surfactant and dispersed in transformer oil. To determine their dielectric properties they were subjected to a uniform magnetic field at high alternating electric fields up to 14 MV m(-1). Nearly constant permittivity of magnetic liquid with particle volume concentration ? = 0.0019 as a function of electric field was observed. Magnetic liquids with concentrations ? = 0.019 and 0.032 showed significant changes of permittivity and loss factor dependent on electric and magnetic fields. The best concentration of magnetic fluid was found at which partial current impulse magnitudes were the lowest. The breakdown strength distribution of the magnetic liquid with ? = 0.0025 was fitted with the Duxbury-Leath, Weibull and Gauss distribution functions. PMID:21694240

Herchl, F; Marton, K; Tom?o, L; Kop?anský, P; Timko, M; Koneracká, M; Kolcunová, I

2008-05-01

369

Breakdown and partial discharges in magnetic liquids  

NASA Astrophysics Data System (ADS)

The dielectric properties (permittivity, loss factor, dielectric breakdown strength) of magnetic liquids were investigated. The magnetic liquids were composed of magnetite particles coated with oleic acid as surfactant and dispersed in transformer oil. To determine their dielectric properties they were subjected to a uniform magnetic field at high alternating electric fields up to 14 MV m-1. Nearly constant permittivity of magnetic liquid with particle volume concentration ? = 0.0019 as a function of electric field was observed. Magnetic liquids with concentrations ? = 0.019 and 0.032 showed significant changes of permittivity and loss factor dependent on electric and magnetic fields. The best concentration of magnetic fluid was found at which partial current impulse magnitudes were the lowest. The breakdown strength distribution of the magnetic liquid with ? = 0.0025 was fitted with the Duxbury-Leath, Weibull and Gauss distribution functions.

Herchl, F.; Marton, K.; Tom?o, L.; Kop?anský, P.; Timko, M.; Koneracká, M.; Kolcunová, I.

2008-05-01

370

The electrical and photoconductivity characteristics of donor-acceptor alternating copolymer using solution process  

NASA Astrophysics Data System (ADS)

The authors report on the electrical and photoconductivity characteristics of donor-acceptor alternating copolymer, poly(dioctyloxinapthalenediketopyrrolopyrrole) (PONDPP) with Al/PONDPP/p-Si/Al hybrid organic/inorganic Schottky diode for optoelectronic applications. The fabricated device shows ideality factor value of 2.6 and barrier height of 0.68 eV obtained from current-voltage characteristics. The high rectification ratio of 1.86 × 104 and photo-responsivity of 55 mA/W at 650 nm is achieved. From results, we found that the fine photo-response and electrical characteristics are attributed to the modified band-gap structure to have Schottky barrier at highest occupied molecular orbital to valence band of silicon and high hole mobility of PONDPP.

Woo Jeong, Shin; Back Lee, Gi; Ha, Hyeon-Jun; Kwon, Soon-Ki; Kim, Yun-Hi; Kwon Ju, Byeong

2012-12-01

371

Interfacial and Breakdown Characteristics of MOS (Metal-Oxide-Semiconductor) Devices with Rapidly Grown Ultrathin SiO2 Gate Insulators.  

National Technical Information Service (NTIS)

Metal-oxide-semiconductor devices fabricated with tungsten/n+ polysilicon composite gates and subhundred-angstrom SiO2 gate insulators grown by rapid thermal oxidation were characterized by various electrical measurements. The as-fabricated devices with u...

M. M. Moslehi S. C. Shatas K. C. Saraswat J. D. Meindl

1986-01-01

372

Analysis of Laser Breakdown Data  

NASA Astrophysics Data System (ADS)

Experiments on laser breakdown for ns pulses of 532 nm or 1064 nm light in water and dozens of simple hydrocarbon liquids are analyzed and compared to widely-used models and other laser breakdown experiments reported in the literature. Particular attention is given to the curve for the probability of breakdown as a function of the laser fluence at the beam focus. Criticism is made of the na"ive forms of both ``avalanche'' breakdown and multi-photon breakdown. It appears that the process is complex and is intimately tied to the chemical group of the material. Difficulties with developing an accurate model of laser breakdown in liquids are outlined.

Becker, Roger

2009-03-01

373

Effects of barium on the nonlinear electrical characteristics and dielectric properties of SnO2-based varistors  

NASA Astrophysics Data System (ADS)

The effects of barium on electrical and dielectric properties of the SnO2.Co2O3.Ta2O5 varistor system sintered at 1250oC for 60min were investigated. It is found that barium significantly improves the nonlinear properties. The breakdown electrical field increases from 378.0 to 2834.5V/mm, relative dielectric constant (at 1kHz) falls from 1206 to 161 and the resistivity (at 1kHz) rises from 60.3 to 1146.5k?.cm with an increase of BaCO3 concentration from 0mol% to 1.00mol%. The sample with 1.00mol% barium has the best nonlinear electrical property and the highest nonlinear coefficient (?=29.2). A modified defect barrier model is introduced to illustrate the grain-boundary barrier formation of barium-doped SnO2-based varistors.

Wang, Chun-Ming; Wang, Jin-Feng; Wang, Chun-Lei; Chen, Hong-Cun; Su, Wen-Bin; Zang, Guo-Zhong; Qi, Peng; Zhao, Ming-Lei; Ming, Bao-Quan

2004-11-01

374

A theoretical estimation of the pre-breakdown-heating time in the underwater discharge acoustic source  

Microsoft Academic Search

One of the common characteristics of the electrothermal breakdown in an underwater discharge acoustic source (UDAS) is the existence of a pre-breakdown-heating phase. In our experiment, two phenomena were observed: (1) the breakdown time that takes on high randomicity and obeys a “double-peak\\

Wang Yi-Bo; Wang Shang-Wu; Zeng Xin-Wu

2012-01-01

375

Effect of ambient gas on self-healing breakdown of polyimide thin films  

Microsoft Academic Search

The purpose of this study is to clarify the effect of ambient gas (in dry air and SF6) on self-healing breakdown characteristics of polyimide thin films. The effect of polarity reversal after breakdown was also studied and the breakdown mechanism at the polarity reversal was discussed

Y. Muramoto; K. Fujino; M. Nagao; M. Kosaki

1995-01-01

376

Electrical characteristic analysis using low-frequency noise in low-temperature polysilicon thin film transistors.  

PubMed

This study carried out an electrical characteristic analysis using low-frequency noise (LFN) in top gate p-type low-temperature polysilicon thin film transistors (LTPS TFTs) with different active layer thicknesses between 40 nm and 80 nm. The transfer characteristic curves show that the 40-nm device has better electrical characteristics compared with the 80-nm device. The carrier number fluctuation, with and without correlated mobility fluctuation model in both devices, has modeled well the measured noise. On the other hand, the trap density and coulomb scattering in the 40-nm device are smaller compared with the 80-nm device. To confirm the effectiveness of the LFN noise analysis, the trap densities at a grain boundary are extracted using in both devices the similar methods of Proano et al. and Levinson et al. That is, coulomb scattering, caused by the trapped charges at or near the interface, has a greater effect on the device with inferior electrical properties. Based on the LFN and the quantitative analysis of the trap density at a grain boundary, the interface traps between the active layer and the gate insulator can explain the devices' electrical degradation. PMID:22966605

Kim, Y M; Jeong, K S; Yun, H J; Yang, S D; Lee, S Y; Kim, M J; Kwon, O S; Jeong, C W; Kim, J Y; Kim, S C; Lee, G W

2012-07-01

377

Understanding junction breakdown in multicrystalline solar cells  

NASA Astrophysics Data System (ADS)

Extensive investigations on industrial multicrystalline silicon solar cells have shown that, for standard 1 ? cm material, acid-etched texturization, and in absence of strong ohmic shunts, there are three different types of breakdown appearing in different reverse bias ranges. Between -4 and -9 V there is early breakdown (type 1), which is due to Al contamination of the surface. Between -9 and -13 V defect-induced breakdown (type 2) dominates, which is due to metal-containing precipitates lying within recombination-active grain boundaries. Beyond -13 V we may find in addition avalanche breakdown (type 3) at etch pits, which is characterized by a steep slope of the I-V characteristic, avalanche carrier multiplication by impact ionization, and a negative temperature coefficient of the reverse current. If instead of acid-etching alkaline-etching is used, all these breakdown classes also appear, but their onset voltage is enlarged by several volts. Also for cells made from upgraded metallurgical grade material these classes can be distinguished. However, due to the higher net doping concentration of this material, their onset voltage is considerably reduced here.

Breitenstein, Otwin; Bauer, Jan; Bothe, Karsten; Kwapil, Wolfram; Lausch, Dominik; Rau, Uwe; Schmidt, Jan; Schneemann, Matthias; Schubert, Martin C.; Wagner, Jan-Martin; Warta, Wilhelm

2011-04-01

378

Batteries for electric drive vehicles: Evaluation of future characteristics and costs through a Delphi study  

SciTech Connect

Uncertainty about future costs and operating attributes of electric drive vehicles (EVs and HEVs) has contributed to considerable debate regarding the market viability of such vehicles. One way to deal with such uncertainty, common to most emerging technologies, is to pool the judgments of experts in the field. Data from a two-stage Delphi study are used to project the future costs and operating characteristics of electric drive vehicles. The experts projected basic vehicle characteristics for EVs and HEVs for the period 2000-2020. They projected the mean EV range at 179 km in 2000, 270 km in 2010, and 358 km in 2020. The mean HEV range on battery power was projected as 145 km in 2000, 212 km in 2010, and 244 km in 2020. Experts` opinions on 10 battery technologies are analyzed and characteristics of initial battery packs for the mean power requirements are presented. A procedure to compute the cost of replacement battery packs is described, and the resulting replacement costs are presented. Projected vehicle purchase prices and fuel and maintenance costs are also presented. The vehicle purchase price and curb weight predictions would be difficult to achieve with the mean battery characteristics. With the battery replacement costs added to the fuel and maintenance costs, the conventional ICE vehicle is projected to have a clear advantage over electric drive vehicles through the projection period.

Vyas, A.D.; Ng, H.K.; Anderson, J.L.; Santini, D.J.

1997-07-01

379

Vacuum breakdown of carbon-nanotube field emitters on a silicon tip  

NASA Astrophysics Data System (ADS)

Findings are given from the experimental observation of the vacuum breakdown of carbon-nanotube (CNT) field emitters on a Si tip. The CNTs were grown on the apex of a Si microtip by microwave plasma-enhanced chemical vapor deposition. The electrical contact of the CNT-Si junction was shown to be of ohmic type. A fine tungsten microprobe in combination with a scanning electron microscopy (SEM) system was employed for both the field emission and the contact conductivity measurements. This arrangement allows to precisely measure the characteristics of individual CNT and to in situ inspect the morphology of the CNT emitters on Si tips before and after vacuum breakdown events. An upper limit in emission current density of ~103 A/m2 from the CNT emitters was recorded before a vacuum breakdown event is initiated. Clear evidence was found to show that the vacuum breakdown of the CNTs results in melting of the Si tip. These findings enhance the understanding of the failure mechanism of CNT emitters. It also has important technical implication to the development of ultrabright electron source.

She, J. C.; Xu, N. S.; Deng, S. Z.; Chen, Jun; Bishop, H.; Huq, S. E.; Wang, L.; Zhong, D. Y.; Wang, E. G.

2003-09-01

380

Ragone characteristics of aqueous mobile batteries and their application in projecting ranges of electric vehicles  

SciTech Connect

A Ragone characteristic is defined as the specific energy available from a battery as a function of the specific power level at which it is discharged. Ragone plots obtained at the National Battery Test Laboratory (NBTL) are given for the following electric-vehicle propulsion batteries: Ni/Zn, Ni/Fe, improved state-of-the-art lead-acid, a lead-acid designed for hybrid vehicle application, and a standard golf cart battery. The NBTL test results are compared with results from Jet Propulsion Laboratory results. The Ragone plots can be used to project the range of an electric vehicle with a particular battery. (LEW)

Hornstra, F.; Christianson, C.; Corp, D.; Fredrickson, D.; Gay, E.; Hayes, E.; Webster, C.; Yao, N.P.

1983-01-01

381

Work Breakdown Structure.  

National Technical Information Service (NTIS)

This is one of a series of reports designed for use in a guidebook for life-cycle cost analysis in the US Army Materiel Command (USAMC). The report is predicated on the fact that the practical application of the detailed work breakdown structure is largel...

J. O'Flaherty

1971-01-01

382

Beauty in the Breakdown  

ERIC Educational Resources Information Center

|Most human beings look at erosion as the destruction of a surface, but artists can see that erosion often creates indefinable beauty. Where do you see beauty in the breakdown? In this article, the author presents an innovative lesson that would allow students to observe both human and physical nature. In this activity students will create a work…

Brisco, Nicole

2008-01-01

383

Dielectric breakdown of water  

Microsoft Academic Search

A critical review of past theories on dielectric breakdown of water is presented. It is shown that past models do not agree qualitatively with empirical experiments. A new model based on protonic conduction and on dipole ordering is presented and found to agree with experiments both qualitatively and quantitatively.

James Charles Espinosa

2000-01-01

384

Modeling of current and thermal mode second breakdown phenomena  

NASA Astrophysics Data System (ADS)

A computer code which solves the transport equations for electrons and holes in conjunction with the heat transfer equation, to investigate current mode and thermal second breakdown (CSB and TSB) was used. For an epitaxial transistor, we have calculated the average failure threshold power and the average failure threshold energy, as a function of the delay time to failure for different external resistances. We show that, because of the existence of two types of breakdown phenomena, the threshold power and threshold energy curves are not a continuous function of the delay times. We have calculated the evolution of the electric fields and the densities of holes and electrons as a function of space and time during current mode second breakdown. And, we have investigated the temporal behavior of the temperature during second breakdown. Finally, we present some preliminary experimental results concerning the threshold power for breakdown.

Yee, J. H.; Orvis, W. J.; Martin, L. C.; Peterson, J. C.

1982-09-01

385

The Effect of Mechanical Hardness on RF Breakdown  

SciTech Connect

Preliminary high-energy tests have been performed on the next linear collider test accelerator and the traveling wave structures have been examined with a scanning electron microscope. This has yielded the locations of radio frequency breakdowns, characterized by surface craters, occurring on the oxygen-free electric copper traveling wave structure. It has been proposed that the occurrence of high voltage breakdown may be related to material hardness. We have examined this possibility by measuring the hardness of various crystal grains within the copper structure and searching for any correlations to the breakdown events. The hardness of various copper crystals grains has been measured with a nano-indenter and the crystal grains have subsequently been analyzed for breakdown damage. This preliminary analysis does not show any explicit indications that mechanical hardness may be related on the occurrence of RF breakdown. Further research is suggested to verify these initial results.

Adamson, Kristi

2003-09-05

386

Breakdown Patterns in Branly's Coheror  

NASA Astrophysics Data System (ADS)

We use thermal imaging of Joule heating to see for the first time electrical conducting paths created by the so-called Branly effect in a two-dimensional metallic granular medium (aluminium). Multiple breakdowns are shown to occur when the medium is submitted to high voltage increases (more than 500V) with rise times close to one hundred of microseconds. Nous présentons une visualisation directe des chemins de conduction créés par l'effet Branly dans une couche de grains d'aluminium. Cette visualisation est réalisée par imagerie infrarouge en tirant partie du fait que les grains participant à la conduction du courant sont chauffés par effet Joule. Nous montrons qu'il apparaît de multiples “chemins de Branly” lorsque le système est soumis à des rampes de tension de temps de montée de l'ordre de 100 ?m et de tension maximale supérieure à 500 V.

Vandembroucq, D.; Boccara, A. C.; Roux, S.

1997-02-01

387

Influence of the degradation on the surface states and electrical characteristics of EOS structures  

NASA Astrophysics Data System (ADS)

The application of ion sensitive field effect transistors (ISFET's) to the measurements of the pH of chemical solutions is one of the most important fields of microelectronic sensors. However, ISFET's still present some problems, such as shifts and drifts of electrical characteristics. In this work a systematic study of the evolution of electrical characteristics of EOS (electrolyte-oxide-semiconductor) and ENOS (electrolyte-nitride-oxide-semiconductor) structures, equivalent to ISFET gates, using the quasi-static C-V method is presented. Results show that the total drift in the flat band voltage can be separated in two terms, one due to immersion in an aqueous ambient and other due to the ionic strength.

Cabruja, E.; Merlos, A.; Cané, C.; Lozano, M.; Bausells, J.; Esteve, J.

1991-07-01

388

Optical and electrical characteristics of pure and doped potassium hydrogen tartrate single crystals  

NASA Astrophysics Data System (ADS)

The optical and electrical characteristics of pure, sodium- and lithium-doped potassium hydrogen tartrate crystals grown by the gel technique are reported. An optical absorption study conducted in the UV-Vis range of 200-800 nm reveals the transparency of these crystals in the entire visible range but not in the ultraviolet range. The optical band gap of pure potassium hydrogen tartrate crystals is found to be dependent on doping by Na or Li ions. The non-linear optical behaviour of these crystals is reported and explained. The electrical properties of pure and doped potassium hydrogen tartrate crystals are studied by measuring electrical resistivity from 80 to 300 K. It is shown that while pure potassium hydrogen tartrate crystal is an insulator at room temperature (300 K), doping by Na or Li ions makes it a semiconductor. The results have been explained in terms of the variable range hopping model.

Quasim, I.; Firdous, A.; Khosa, S. K.; Kotru, P. N.

2009-08-01

389

Injected charges in partial SOI LDMOSFETs: A new technique for improving the breakdown voltage  

NASA Astrophysics Data System (ADS)

High breakdown voltage and reduced on-resistance are desired characteristics in power MOSFETs. In order to obtain an excellent performance of lateral double-diffused MOSFET (LDMOS) devices, we have proposed a new technique in which at the surface of buried oxide, negative and positive charges are incorporated, periodically. This strategy modulates the electric field and causes high breakdown voltage. Also, by considering the charges at interface of the buried oxide, depletion islands form in the drift region that the current density increases on the top of the drift region and the on-resistance decreases. Our simulation with two-dimensional ATLAS simulator shows that an Injected Charge in Buried Oxide of Partial SOI LDMOSFET (ICBO-PSOI) has considerable improvement in high frequency with reduced switching delay.

Mehrad, Mahsa; Orouji, Ali A.

2013-05-01

390

Physical and electrical characteristics of silicon oxynitride films with various refractive indices  

Microsoft Academic Search

This study explores the relationship between both the physical and the electrical characteristics of silicon oxynitride (SiON) films and the refractive index. The single wafer rapid thermal process modules were used for low pressure chemical vapour deposition of SiON films. A series of SiON films with refractive index between 1.50 and 1.83 were fabricated. Fourier transform infrared absorption spectroscopy and

Jeng-Hwa Liao; Jung-Yu Hsieh; Hsing-Ju Lin; Wei-Yao Tang; Chun-Ling Chiang; Yun-Shan Lo; Tai-Bor Wu; Ling-Wu Yang; Tahone Yang; Kuang-Chao Chen; Chih-Yuan Lu

2009-01-01

391

Analysis of the sensitivity and frequency characteristics of coplanar electrical cell–substrate impedance sensors  

Microsoft Academic Search

A PDMS-glass based micro-device was designed and fabricated with 12 coplanar impedance sensors integrated for electrical cell–substrate impedance sensing (ECIS). The sensitivity and frequency characteristics of the sensors were investigated both theoretically (equivalent circuit model) and experimentally for the commonly used micro-electrode dimension scale (20–80?m). The experimental results matched well with the theoretical model analysis and revealed that, within this

Lei Wang; He Wang; Keith Mitchelson; Zhongyao Yu; Jing Cheng

2008-01-01

392

In vivo electrical characteristics of human skin, including at biological active points  

Microsoft Academic Search

The aim is to compare the mean values of the in vivo electrical characteristics of bioiogical active points (BAPs) with those\\u000a of the surrounding human skin. The impedance measurements at BAPs and on the surrounding skin are carried out in vivo on ten\\u000a young, healthy people. The results of the measurements show that the BAP resistance RP is smaller, and

E. F. Prokhorov; J. González-Hernández; Y. V. Vorobiev; E. Morales-Sánchez; T. E. Prokhorova; G. Zaldivar Lelo de Larrea

2000-01-01

393

Chemical and Physical Characteristics of Pulsed Electrical Discharge Within Gas Bubbles in Aqueous Solutions  

Microsoft Academic Search

The chemical and physical characteristics of pulsed electrical discharge within gas bubbles immersed in an aqueous solution\\u000a were investigated using a reactor with long protrusion length high voltage needle electrodes. Argon gas was introduced at\\u000a the base of the needle electrode causing gas bubbles to flow upwards in contact with the needle. The effects of needle protrusion\\u000a length were evaluated

Kai-Yuan Shih; Bruce R. Locke

2010-01-01

394

Electrical characteristics of fully superconducting synchronous generator in persistent excitation mode  

SciTech Connect

A brushless excitation system would be useful so as to enhance features of superconducting generators further. Based on such a concept, the authors have fabricated a brushless-excited superconducting generators with a superconducting dynamo i.e. Magnetic flux pump. Concurrently, a fully superconducting generator in which both of armature and fled coils are made of superconductors has been investigated. The paper describes the experimental machine model and the test results about electrical characteristics.

Muta, I.; Tsukiji, H.; Hoshino, T.; Mukai, E. (Saga Univ. (Japan). Faculty of Science and Engineering)

1992-01-01

395

Dynamical scaling behavior of current-electric field characteristics in two-dimensional disordered superconductors  

Microsoft Academic Search

We study the dynamics of magnetic vortices driven by transport current in two-dimensional disordered type-II superconductors, using the Langevin dynamics simulation of the vortex model developed. Exploring the electric field induced by the vortex motion as a function of the transport current (E-J characteristics), we find that the combined effect of random impurities and the current induced vortex-antivortex pair creation

Yoshihisa Enomoto; Sadamichi Maekawa

1997-01-01

396

Electrical properties and distortion characteristics of MLCCs with composite dielectric material  

Microsoft Academic Search

The electrical properties and distortion characteristics of multilayer ceramic capacitors (MLCCs) with composite dielectric material, which consisted of ferroelectric and paraelectric phases were studied. In composite dielectrics, BaTiO3 (BTO) was used for the ferroelectric phase, while SrTiO3 (STO) and CaTiO3 CTO were used for the paraelectric phases. The dielectric ceramics with composite structure of MLCC were prepared with these perovskite

M. Miyauchi; K. Takano; A. Sato; Y. Nakano

2007-01-01

397

Tuning the Electrical Conductivity of Polyaniline by Controlling the Molecular Characteristics of the Polymer Acid Template  

Microsoft Academic Search

We have investigated the electrical conductivity of polyaniline (PANI) that is template synthesized with a polymer acid as a function of the polymer acid molecular characteristics. The polymer acid of choice is poly(2-acrylamino-2-methyl-1-propanesulfonic acid) and it was synthesized by both conventional free-radical polymerization (PAAMPSA) and atom transfer radical polymerization (ATRP); aPAAMPSA. The synthesis of aPAAMPSA is kinetically controlled and thus

Joung Eun Yoo; Tracy Bucholz; Yueh-Lin Loo

2007-01-01

398

Electrical characteristics of metal\\/semiconductor nanocontacts using light emission in a scanning tunneling microscope  

Microsoft Academic Search

Light emission from the tunneling junction of a scanning tunneling microscope (STM) has been used to obtain the electrical characteristics of small three-dimensional gold islands deposited on flat MoS2 surfaces. It is shown that these nanocontacts behave as poor rectifying junctions whose properties are altered by leakage currents. These properties are similar to those generally observed on point contacts where

C. Maurel; R. Coratger; F. Ajustron; J. Beauvillain; P. Gerard

2003-01-01

399

Electrical characteristics of metal/semiconductor nanocontacts using light emission in a scanning tunneling microscope  

NASA Astrophysics Data System (ADS)

Light emission from the tunneling junction of a scanning tunneling microscope (STM) has been used to obtain the electrical characteristics of small three-dimensional gold islands deposited on flat MoS2 surfaces. It is shown that these nanocontacts behave as poor rectifying junctions whose properties are altered by leakage currents. These properties are similar to those generally observed on point contacts where a sharp STM tip is brought in contact with a semiconductor.

Maurel, C.; Coratger, R.; Ajustron, F.; Beauvillain, J.; Gerard, P.

2003-08-01

400

LETTER: Breakdown and preionization experiments in the SINP tokamak  

NASA Astrophysics Data System (ADS)

Breakdown phenomena in the SINP tokamak are studied experimentally for different values of filling pressure (p), toroidal electric field (E), toroidal magnetic field and vertical magnetic field by using a hot filament preionization system. Breakdown had been achieved for a wide range of E/p, starting from 100 up to 4000 V.cm-1.torr-1. In the present experiment it has been observed for the first time that there exists an optimum value of the electric field on either side of which the breakdown time increases. The experimental results have been explained in terms of a model by Hutchinson and Strachan (1974), invoking particle drift compensation by runaway electrons during the breakdown phase in the tokamak. Previously, in this kind of runaway electron dominated breakdown a monotonic increase of the breakdown time: with E was observed. The effect of the preionization strength has also been studied with the help of a radio frequency (RF) system. The breakdown time could be shortened to within a few ionization times ( approximately=15 mu s) by RF preionization

Chattopadhyay, P. K.; Pal, R.; Ray, N. R.; Gupta, P. K.

1996-09-01

401

Frequency-Dependent Dielectric Breakdown in Thin Polyvinylcarbazole Films  

NASA Astrophysics Data System (ADS)

Dielectric breakdown in thin polyvinylcarbazole (PVK) films prepared by vapor deposition polymerization has been investigated at various ac voltages. Real-time measurements were carried out automatically with a system composed of a digital oscilloscope, a controllable signal generator and a microcomputer. Self-healing breakdown takes place at the peak applied voltage. AC electric strength decreases with temperature, and increases with frequency in the range of 10 Hz-3 kHz. A gold electrode has a lower electric strength than an aluminum electrode. The frequency-dependent breakdown has been explained tentatively in terms of the field enhancement due to the hole space charge leading to carrier injection and resulting in the breakdown.

Miyairi, Keiichi

2003-08-01

402

Electrical characteristics of thin Ta2O5 films deposited by reactive pulsed direct-current magnetron sputtering  

NASA Astrophysics Data System (ADS)

Room temperature deposition of tantalum oxide films on metallized silicon substrates was investigated by reactive pulsed magnetron sputtering of Ta in an Ar/O2 ambient. The dielectric constant of the tantalum oxide ranged from 19 to 31 depending on the oxygen percentage [P(%)=PO2/(PO2+PAr)] used during sputtering. The leakage current density was less than 10 nA/cm2 at 0.5 MV/cm electric field and the dielectric breakdown field was greater than 3.8 MV/cm for P=60%. A charge storage as high as 3.3 ?F/cm2 was achieved for 70-Å-thick film. Pulse frequency variation (from 20 to 200 kHz) did not give a significant effect in the electrical properties (dielectric constant or leakage current density) of the Ta2O5 films.

Kim, J.-Y.; Nielsen, M. C.; Rymaszewski, E. J.; Lu, T.-M.

2000-02-01

403

TiO2 breakdown under pulsed conditions  

NASA Astrophysics Data System (ADS)

Model studies of current conduction and breakdown in TiO2 were carried out. Our simulation results indicate that electrical breakdown of TiO2 under multiple-pulsed conditions can occur at lower voltages as compared to quasi-dc biasing. This is in agreement with recent experimental data and is indicative of a cumulative phenomena. We demonstrate that the lower breakdown voltages observed in TiO2 under pulsed conditions is a direct rise-time effect, coupled with successive detrapping at the grain boundaries.

Zhao, G.; Joshi, R. P.; Lakdawala, V. K.; Schamiloglu, E.; Hjalmarson, H.

2007-01-01

404

Generalized dielectric breakdown model  

NASA Astrophysics Data System (ADS)

We propose a generalized version of the dielectric breakdown model (DBM) for generic breakdown processes. It interpolates between the standard DBM and its analog with quenched disorder (QDBM), as a temperaturelike parameter is varied. The physics of other well-known fractal growth phenomena such as invasion percolation and the Eden model are also recovered for some particular parameter values. Competition between different growing mechanisms leads to nontrivial effects and allows us to better describe real growth phenomena. Numerical and theoretical analyses are performed to study the interplay between the elementary mechanisms. In particular, we observe a continuously changing fractal dimension as temperature is varied, and report evidence of a phase transition at zero temperature in the absence of an external driving field; the temperature acts as a relevant parameter for the ``self-organized'' invasion percolation fixed point. This permits us to obtain insight into the connections between self-organization and standard phase transitions.

Cafiero, R.; Gabrielli, A.; Marsili, M.; Muñoz, M. A.; Pietronero, L.

1999-07-01

405

Modelling of time delay of electrical breakdown for nitrogen-filled tubes at pressures of 6.6 and 13.3 mbar in the increase region of the memory curve  

NASA Astrophysics Data System (ADS)

Experimentally measured electrical breakdown time delay data versus the afterglow period (representing 'memory curves') for nitrogen-filled tubes at pressures of 6.6 and 13.3 mbar have been shown. The influence of N(4S) nitrogen atoms on secondary electron emission from the cathode (the SEE process) in late afterglow has been discussed. N(4S) atom concentration decay over relaxation time ?, N(4S)(?), has been analysed by a numerical model and two analytical models. N(4S) decay analytical models are combined with different yield models that describe the SEE process by N(4S) and these combinations are employed to fit the experimental data. It has been shown that in late afterglow solving of very simple analytical equations instead of numerical solving of partial differential equations for N(4S)(?) fitting can be used and that the combination of the first and the second order of the SEE process by N(4S) in yield modelling should be used in the case of 13.3 mbar pressure.

Nesic, N. T.; Ristic, G. S.; Karamarkovic, J. P.; Pejovic, M. M.

2008-11-01

406

Dielectric breakdown distributions of large dielectric constant liquids  

Microsoft Academic Search

This paper reports area and time dependent dielectric breakdown distributions of ethylene glycol and water solutions cooled to -23°C. Electrode areas of 80, 400, 2000, and 10,000 cm² spaced 1 cm apart were repeatedly stressed with voltage pulses exponentially decaying in 5 to 20 ms. Approximately 80,000 measurements concentrated at electric field strengths near the 1% breakdown probability region of

F. J. Zutavern; M. T. Buttram; M. W. OMalley

1984-01-01

407

Fabrication of Floating-Gate-Type Fin-Channel Double- and Tri-Gate Flash Memories and Comparative Study of Their Electrical Characteristics  

NASA Astrophysics Data System (ADS)

Floating-gate (FG)-type fin-channel double-gate (DG) and tri-gate (TG) flash memories with different control-gate (CG) lengths (LCG) from 76 to 256 nm have successfully been fabricated by using (110)-oriented silicon on insulator (SOI) wafers, and their electrical characteristics have been comparatively investigated. It was experimentally found that better short channel effect (SCE) immunity, smaller threshold voltage (Vt) variations, and a higher program speed are obtained in the TG-type flash memories than in the DG-type memories. The higher performance of the TG-type flash memory is partly due to the additional top gate and recessed buried oxide (BOX) region, which strengthen the controllability of the channel potential and increase the coupling ratio of the FG to CG. Moreover, it was also found that the measured source--drain (SD) breakdown voltage (\\mathit{BV}DS) is higher than 3.2 V even when LCG was reduced to 76 nm. Therefore, the developed fin-channel TG structure is expected to be very useful for the fabrication of scaled NOR-type flash memory.

Liu, Yongxun; Kamei, Takahiro; Matsukawa, Takashi; Endo, Kazuhiko; O'uchi, Shinichi; Tsukada, Junichi; Yamauchi, Hiromi; Ishikawa, Yuki; Hayashida, Tetsuro; Sakamoto, Kunihiro; Ogura, Atsushi; Masahara, Meishoku

2012-04-01

408

Electric properties and related physical characteristics of the atmosphere and surface of Titan  

NASA Astrophysics Data System (ADS)

The permittivity, waves and altimetry (PWA) instrument was designed for the investigation of the electric properties and other related physical characteristics of the atmosphere of Titan, from an altitude around 140 km down to the surface. PWA carried sensors to measure the atmospheric conductivity, and record electromagnetic and acoustic waves up to frequencies of 11.5 and 6.7 kHz, respectively. PWA also measured the relief roughness during the descent and the permittivity of the surface after touchdown. The measurements and the results of the preliminary analysis are presented. An ionized layer is detected at altitudes above 50 km, using two independent techniques, and the presence of free electrons in the upper atmosphere is confirmed. An electric signal at around 36 Hz is observed throughout the descent, but it is not yet confirmed that this emission is unambiguously related to a resonance of the ionospheric cavity. The relative dielectric constant of Titan's surface material is nearly 2 and the electric conductivity 4×10 -10 S m -1. The electric properties of the surface seem to evolve after touch-down, possibly due to a local warming of the landing site by the Huygens Probe body.

Grard, R.; Hamelin, M.; López-Moreno, J. J.; Schwingenschuh, K.; Jernej, I.; Molina-Cuberos, G. J.; Simões, F.; Trautner, R.; Falkner, P.; Ferri, F.; Fulchignoni, M.; Rodrigo, R.; Svedhem, H.; Béghin, C.; Berthelier, J.-J.; Brown, V. J. G.; Chabassière, M.; Jeronimo, J. M.; Lara, L. M.; Tokano, T.

2006-10-01

409

Characteristics of the initial rising portion of near and far lightning return stroke electric field waveforms  

NASA Astrophysics Data System (ADS)

We examine initial rising portions of electric field waveforms of negative first return strokes in natural cloud-to-ground lightning recorded simultaneously at near and far distances from the lightning channel. The near and far field-measuring stations are located at Camp Blanding and in Gainesville, Florida, respectively, separated by a distance of about 45 km. A total of five return strokes had been recorded in 2007-2008, four of which were analyzed in detail (one was not suitable for analysis due to saturation of electric field waveform at the far station). Field waveform characteristics, including overall zero-to-peak and 10-to-90% risetimes, duration of slow front, fast transition 10-to-90% risetime, and magnitude of slow front relative to the peak, were found to be similar to those reported from other studies, in which the field propagation path was over ground (as opposed to sea water). It is shown, via modeling, that the slow front in electric field waveforms at far distances is primarily due to the radiation field component, while at near distances it is composed of comparable contributions from all three components of electric field. For both measured and model-predicted waveforms, the durations of the slow front appear to be similar at near and far distances from the lightning channel.

Nag, A.; Rakov, V. A.; Tsalikis, D.; Howard, J. S.; Biagi, C. J.; Hill, J. D.; Uman, M. A.; Jordan, D. M.

2012-11-01

410

Electrical characteristics and doping mechanism of DNA molecules doped with iodine solutions.  

PubMed

This study examined the electrical characteristics of deoxyribonucleic acid (DNA) molecules doped with iodine solution and their chemical state changes before and after doping. The experiments were progressed in each lambda (A), poly(dA)-poly(dT) and poly(dG)-poly(dC) DNA under the same conditions. The authors prepared 20 nm gap Au/Ti electrodes fabricated by e-beam lithography. DNA solutions were dropped on the nano gap of the electrodes and DNA films were formed by drying in a vacuum. DNA films were doped with an iodine solution dissolved in methanol. The authors measured the electrical conductivity of DNA molecules as the number of iodine doping times in 10(-2) torr vacuum. As increase of the iodine solution doping number, the electrical conductivity of three sorts of DNA molecules was remarkably improved respectively. X-ray photoelectron spectroscopy (XPS) was performed to inspect the electrical conduction mechanism that holes on DNA nitrogen region were generated by transferring electrons to iodine molecules. PMID:20358983

Kim, Nam-Hoon; Lee, Woo Cheol; Roh, Yonghan

2010-05-01

411

Electrical and Electrochemical Performance Characteristics of Large Capacity Li-Ion Cells  

SciTech Connect

We are currently evaluating large capacity (20 - 40 Ah) Bluestar (cylindrical) and Yardney (prismatic) Li-ion cells for their electrical and electrochemical performance characteristics at different temperatures. The cell resistance was nearly constant from room temperature to -20{degrees}C but increased by over 10 times at -40{degrees}C. The specific energy and power as well as the energy density and power density are high and didn't reach a plateau even at the highest discharge rates tested. For example, the prismatic Li-ion cells gave close to 280 Wh l{sup -1} at 4-amp discharge and 249 Wh l{sup -1} at 20-amp discharge at room temperature. For the same current range the specific power values are 102 Wh kg{sup -1} and 91 Wh kg{sup -1}. Cycle life and other electrical and electrochemical properties of the cells will be presented.

Doughty, I.D.; Hill, C.; Ingersoll, D.; Marsh, C.; Nagasubramanian, G.; Radzykewycz, D

1998-12-01

412

Neutron, gamma ray, and temperature effects on the electrical characteristics of thyristors  

NASA Astrophysics Data System (ADS)

Experimental data showing the effects of neutrons, gamma rays, and temperature on the electrical and switching characteristics of phase-control and inverter-type SCR's are presented. The special test fixture built for mounting, heating, and instrumenting the test devices is described. Four SCR's were neutron irradiated at 300 K and four at 365 K for fluences up to 3.2 x 10 exp 13 pn/sq. cm, and eight were gamma irradiated at 300 K only for gamma doses up to 5.1 Mrads. The electrical measurements were made during irradiation and the switching measurements were made only before and after irradiation. Radiation induced crystal defects, resulting primarily from fast neutrons, caused the reduction of minority carrier lifetime through the generation of R-G centers. The reduction in lifetime caused increases in the on-state voltage drop and in the reverse and forward leakage currents, and decreases in the turn-off time.

Frasca, A. J.; Schwarze, G. E.

413

Neutron, gamma ray, and temperature effects on the electrical characteristics of thyristors  

NASA Astrophysics Data System (ADS)

Experimental data showing the effects of neutrons, gamma rays, and temperature on the electrical and switching characteristics of phase-control and inverter-type SCR's are presented. The special test fixture built for mounting, heating, and instrumenting the test devices is described. Four SCR's were neutron irradiated at 300 K and four at 365 K for fluences up to 3.2 x 10 exp 13 n/sq. cm, and eight were gamma irradiated at 300 K only for gamma doses up to 5.1 Mrads. The electrical measurements were made during irradiation and the switching measurements were made only before and after irradiation. Radiation induced crystal defects, resulting primarily from fast neutrons, caused the reduction of minority carrier lifetime through the generation of R-G centers. The reduction in lifetime caused increases in the on-state voltage drop and in the reverse and forward leakage currents, and decreases in the turn-off time.

Frasca, A. J.; Schwarze, G. E.

1992-05-01

414

Electrical and dielectric characteristics of Al/Dy2O3/p-Si heterostructure  

NASA Astrophysics Data System (ADS)

In this work we report the electrical characteristics of high-k Dy2O3 dielectric deposited on p-Si substrate by electron beam deposition under ultra vacuum. The surface morphology of Dy2O3 is investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface topography analysis reveals that the Dy2O3 film is nanograined and contains numerous contacts between columnar grains. The electrical properties of Al/Dy2O3/p-Si heterostructure are further analyzed by current-voltage (I-V), capacitance-voltage (C-V), capacitance-frequency (C-f) and conductance-frequency (G-f) measurements. The dominant conduction mechanisms which governed the Al/Dy2O3/p-Si heterostrucure are determined. The hetrostructure induces a significant value of leakage current: 1.1×10-5 A at flat-band voltage -1 V which is linked to the structural properties of the elaborated structure. The effects of grain boundaries and oxygen vacancies within the dielectric are observed in term of leakage current. Indeed, the C(V) characteristics measured at different applied voltage show a large frequency-dispersion, indicative of the presence of a continuous distribution of interface states. So, the interface state densities are determined from the C(V) characteristics to be around 1013 eV-1 cm-2. C(f) measurements elucidate that the capacitance behavior is typical of material with traps. From G(f) and C(f) measurement the trap density and relaxation time are also determined. It is suggested that the interface states series resistance are important parameters that strongly influence the electrical properties of Al/Dy2O3/p-Si heterostrucure.

Cherif, Ahlem; Jomni, Sami; Mliki, Najeh; Beji, Lotfi

2013-11-01

415

Electrical Characteristics of Ultrasonic Nozzle Using Multilayer Ring-Type Piezoelectric Ceramics for Light Oil Spray  

Microsoft Academic Search

In this paper, ultrasonic nozzle and its driving circuit were manufactured. And then, their electrical properties were investigated. Ultrasonic nozzle using multilayer ring-type piezoelectric ceramics was fabricated by Pb[(Mn1\\/3Nb2\\/3)0.02(Ni1\\/3Nb2\\/3)0.12(Zr0.50Ti0.50)0.86]O3 (abbreviated as PMN-PNN-PZT) composition which have excellent piezoelectric characteristics. The multilayer ring-type piezoelectric ceramics using pure Ag inner electrode was sintered at 900°C low temperatures. In order to drive ultrasonic nozzle,

Jinhee Kang; Yuhyong Lee; Larkhoon Hwang; Juhyun Yoo; Jaeil Hong

2010-01-01

416

Effect of vacuum annealing cleaning on electrical characteristics of GaAs\\/1-x\\/P\\/x\\/Mo Schottky diodes  

Microsoft Academic Search

A vacuum annealing procedure for surface cleaning prior to barrier metal evaporation is proposed. The reported method is suitable for III-V compounds and has been checked for GaAs\\/1-x\\/P\\/x\\/-Mo Schottky diodes. Electrical characteristics of the junctions seem to be best at around 550 C, but for higher temperatures the electrical characteristics degenerate, indicating the incorporation of a surface layer with a

E. Calleja; J. Piqueras

1981-01-01

417

Land-ocean contrast on electrical characteristics of lightning discharge derived from satellite optical measurements  

NASA Astrophysics Data System (ADS)

Comparative studies on the electrical properties of oceanic and continental lightning are crucial to elucidate air discharge processes occurring under different conditions. Past studies however have primarily focused on continental lightning because of the limited coverage of ground-based instruments. Recent satellite measurements by FORMOSAT-2/ISUAL provided a new way to survey the global characteristics of lightning and transient luminous events regardless of land and ocean. In this study, we analyze ISUAL/spectrophotometer data to clarify the electrical properties of lightning on a global level. Based on the results obtained by Cummer et al. [2006] and Adachi et al. [2009], the OI-777.4nm emission intensity is used to infer lightning electrical parameters. Results show a clear land-ocean contrast on the parameters of lightning discharge: in oceanic lightning, peak luminosity is 60 % higher and the time scale of return stroke is 30 % shorter. These results suggest higher peak current in oceanic lightning, which is consistent with the fact that elves, EMP-driven phenomena, also tend to occur over the ocean [Chen et al., 2008]. Further analysis of lightning events occurring around the Caribbean Sea shows that the transition-line of lightning electrical properties is precisely located along the coastline. We suggest that the differences in these electrical properties may be due to the boundary conditions (conductivity, surface terrain, etc). In this talk, based on the calibration with NLDN and Duke magnetometer data, current moment change and charge moment change will be globally evaluated using a complete set of the ISUAL-observed lightning events.

Adachi, T.; Said, R.; Cummer, S. A.; Li, J.; Takahashi, Y.; Hsu, R.; Su, H.; Chen, A. B.; Mende, S. B.; Frey, H. U.

2010-12-01

418

Low sidelobe characteristics of a dual-frequency base station antenna in the case of electrical beam tilt use  

Microsoft Academic Search

To accommodate the remarkable increase in the numbers of mobile phone subscribers, plural systems and multi-frequency bands are being employed. In Japan, PDC (Personal Digital Cellular) systems use the frequency bands of 800 MHz and 1500 MHz. Typical electrical characteristics of base station antennas are low sidelobe levels and electrical beam tilt capabilities. In case of frequency sharing the 800

Y. Yamada; Y. Ebine; M. Kijima

1999-01-01

419

Analysis of Machining Characteristics in Additive Mixed Electric Discharge Machining of Nickel-Based Super Alloy Inconel 718  

Microsoft Academic Search

Additive mixed electric discharge machining (AEDM) is a recent innovation for enhancing the capabilities of electrical discharge machining process. The objective of present research work is to study the influence of operating process input parameters on machining characteristics of nickel-based super alloy (Inconel 718) in aluminium AEDM with copper electrode. The effectiveness of AEDM process on Inconel is evaluated in

Anil Kumar; Sachin Maheshwari; Chitra Sharma; Naveen Beri

2011-01-01

420

Analysis of Machining Characteristics in Additive Mixed Electric Discharge Machining of Nickel Based Super Alloy Inconel 718  

Microsoft Academic Search

Additive mixed electric discharge machining (AEDM) is a novel innovation for enhancing the capabilities of electrical discharge machining process. The objective of present research work is to study the influence of operating process input parameters on machining characteristics of nickel based super alloy (Inconel 718) in aluminium additive mixed EDM of with copper electrode. The effectiveness of AEDM process on

Anil Kumar; Sachin Maheshwari; Chitra Sharma; Naveen Beri

2011-01-01

421

Effects of channel stoichiometry and processing temperature on the electrical characteristics of zinc tin oxide thin-film transistors  

Microsoft Academic Search

Thin-film transistor (TFT) structures with zinc tin oxide channel layer are fabricated and electrically characterized; zinc tin oxide composition (Zn:Sn ratio) and post-deposition anneal temperature are varied so as to explore their effects on electrical performance. Channel mobility and turn-on voltage are extracted from measured electrical characteristics, thus mapping TFT performance (for the process and structure used here) across the

R. L. Hoffman

2006-01-01

422

On the dielectric breakdown of water; An electrochemical approach  

SciTech Connect

The dielectric breakdown of water under static fields has been studied by current-potential relation for six metals. The relations are quasi-linear up to a current density of a few A-cm{sup {minus} 2}. The limiting current continues for a few volts to a few hundred volts, depending on the metal. A glow develops at the electrode and becomes continuous at the end of the plateau, where the current density increases irregularly (breakdown). The breakdown potential does not depend on the field in the water. It occurs at about the same current density for most of the metals. When electrolytes are added, the cell potential at the breakdown is decreased. Adsorbed layers and organic coatings increase the breakdown potential. Electrical energy storage in water is increased by {approximately} 10 times by coatings. The breakdown potential decreases with increase of log of rate constant for hydrogen evolution on the various electrodes and with the corresponding work function. The cell potentials for breakdown correspond to fields in the dielectric below that needed to dissociate it.

Szklarczyk, M.; Kainthla, R.C.; Bockris, J.O.M. (Surface Electrochemistry Lab. Dept of Chemistry, Texas A and M Univ., College Station, TX (US))

1989-09-01

423

Electrical insulation design and withstand test of model coils for 6.6 kV class HTSFCL  

Microsoft Academic Search

Electrical design and withstand test of mini-model coils for high temperature superconducting fault current limiter (HTSFCL) have been studied. Electrical insulating factors of the HTS coil for HTSFCL are turn-to-turn and layer-to-layer. The electrical insulation of turn-to-turn depends on surface length, and the electrical insulation of layer-to-layer depends on surface length and breakdown strength of LN2. Therefore, two basic characteristics

Seung-Myeong Baek; Jong-Man Joung; Sang-Hyun Kim

2004-01-01

424

Characteristics of gas and residues produced from electric arc pyrolysis of waste lubricating oil.  

PubMed

An attempt has been made to recover high-calorific fuel gas and useful carbonaceous residue by the electric arc pyrolysis of waste lubricating oil. The characteristics of gas and residues produced from electric arc pyrolysis of waste lubricating oil were investigated in this study. The produced gas was mainly composed of hydrogen (35-40%), acetylene (13-20%), ethylene (3-4%) and other hydrocarbons, whereas the concentration of CO was very low. Calorific values of gas ranged from 11,000 to 13,000 kcal kg(-1) and the concentrations of toxic gases, such as NO(x), HCl and HF, were below the regulatory emissions limit. Gas chromatography-mass spectrometry (GC/MS) analysis of liquid-phase residues showed that high molecular-weight hydrocarbons in waste lubricating oil were pyrolyzed into low molecular-weight hydrocarbons and hydrogen. Dehydrogenation was found to be the main pyrolysis mechanism due to the high reaction temperature induced by electric arc. The average particle size of soot as carbonaceous residue was about 10 microm. The carbon content and heavy metals in soot were above 60% and below 0.01 ppm, respectively. The utilization of soot as industrial material resources such as carbon black seems to be feasible after refining and grinding. PMID:19897349

Song, Geum-Ju; Seo, Yong-Chil; Pudasainee, Deepak; Kim, In-Tae

2009-11-07

425

An Analysis of the Initial Breakdown Pulses for Positive Cloud-to-Ground Flashes  

NASA Astrophysics Data System (ADS)

In order to further understand the initiating mechanism of positive cloud-to-ground (PCG) flashes, the characteristics of initial breakdown pulse trains are investigated by using electric field data of Guangdong province. Considering the difference in initial polarity between the initial breakdown pulses and the first return stoke (RS), three types of bipolar pulse trains, including the same polarity (type I), the opposite polarity (type II) and the composite polarity (type III), are identified. The percentages of type I, type II and type III are about 84%, 10% and 6%, respectively. The statistical results show that PCG flashes including initial breakdown pulse trains, which occur frequently when PCG flashes are not active, are about 12% of all the PCG flashes. The width of individual pulse (Tpw) and the interval of adjacent pulses (Tpi) are about 25?s and 271?s, respectively. The mean values of pulse train duration (Td) and the interval (Tp-ri) between initial breakdown pulse train and RS are 8.88ms and 98.48ms, respectively. The average value of the ratio (Rp-rr) between the maximum amplitude of pulse train and the amplitude of the first stroke pulse is 0.16. The ratio is smaller in Guangzhou province than in Japan and in Brazil. Comparing of the parameters of type I and type II, it can be found that Tpw, Td and Tpi of type II are less than those of type I, however, the values of Tp-ri and Rp-rr of type II are larger than those of type I. The possible causes of the observating several types of pulse trains and the significantly diversified pulse characteristics are discussed.

Zhang, Yang; Zhang, Yijun; Lu, Weitao; Zheng, Dong

426

A breakdown model for the bipolar transistor to be used with circuit simulators  

NASA Astrophysics Data System (ADS)

A breakdown model for the output characteristics of the bipolar transistor (bjt) has been developed. The behavioral modeling capability of PSPICE, a popular SPICE program (with emphasis on integrated circuits) was used to implement the macromodel. The model predicts bjt output characteristics under breakdown conditions. Experimental data was obtained to verify the macromodel. Good agreement exists between the measured and the simulated results.

Keshavarz, A. A.; Raney, C. W.; Campbell, D. C.

427

Modelling of time-dependent dielectric barrier breakdown mechanisms in MgO-based magnetic tunnel junctions  

NASA Astrophysics Data System (ADS)

An investigation of barrier endurance till electrical breakdown in MgO-based magnetic tunnel junctions (MTJs) is presented. Samples were tested under pulsed electrical stress. By studying the effect of delay between successive pulses, an optimum endurance of MTJs is observed for an intermediate value of delay between pulses corresponding to an optimum trade-off between the average density of charge trapped in the barrier and the amplitude of its time-modulation at each voltage pulse. A charge trapping-detrapping model was developed which shows good coherence with experimental results. The influence of the delay between pulses on the trapped charge density in the tunnel barrier and on its time-modulation is discussed. The average density of trapped charges and its time-modulation are, respectively, responsible for a static and dynamic stress within the tunnel barrier, both leading to breakdown. The probability of breakdown of the MTJ for different applied pulse conditions has been evaluated. The expected endurance of the MTJs was deduced depending on the characteristics of the electrical stress in terms of delay, and unipolarity versus bipolarity. The study emphasizes the role of electron trapping/detrapping mechanisms on the tunnel barrier reliability. It also shows that extremely long endurance could be obtained in MTJs by reducing the density of electron trapping sites in the tunnel barrier.

Amara-Dababi, S.; Bea, H.; Sousa, R.; Mackay, K.; Dieny, B.

2012-07-01

428

Analysis and Regularization of the TD-EFIE Low-Frequency Breakdown  

Microsoft Academic Search

Low-frequency breakdown phenomenon plaguing marching-on-in-time solutions of time domain electric field integral equations is analyzed and cured. A theoretical analysis of the breakdown identifies deficiencies in the treatments proposed to date. A scheme for eliminating low frequency breakdown phenomena that leverages hierarchical regularization is presented. It applies to arbitrary meshes and gives rise to linear systems that are better conditioned

Francesco P. Andriulli; Hakan Bagci; Francesca Vipiana; Giuseppe Vecchi; Eric Michielssen

2009-01-01

429

Visualization on the behavior of nanoparticles in magnetic fluids under the electric field  

NASA Astrophysics Data System (ADS)

The dielectric breakdown characteristics of magnetic fluids can be influenced by the magnetic nanoparticles included because their properties should be affected by the applied electric field. Based on measuring the dielectric breakdown voltage of magnetic fluids, we found that it is higher than that of the pure transformer oil in the case of the specific volume concentrations of magnetic nanoparticles. It is known from a numerical simulation that the conductive nanoparticles might behavior as electron scavengers in the electrically stressed magnetic fluids and change fast electrons into slowly negative charged nanoparticles for the electrical breakdown. In this study, we focus on the motion of magnetic nanoparticles in the fluids under the electric field applied by the visualization using a microchannel and an optical microscope.

Lee, W.-H.; Lee, J.-C.

2013-02-01

430

Solar PV electricity and market characteristics: two Canadian case-studies  

Microsoft Academic Search

To determine whether solar electricity (that is, electricity generated by photovoltaics) is, on an average, more valuable—in market terms—than the electricity generated in power systems as a whole, this article investigates the extent to which solar resource availability in two Canadian locations is associated with peak electricity market demand and peak electricity market price. More specifically, solar radiation and electricity

Ian H. Rowlands

2005-01-01

431

The structure of vortex breakdown  

Microsoft Academic Search

The term 'vortex breakdown', as used in the reported investigation, refers to a disturbance characterized by the formation of an internal stagnation point on the vortex axis, followed by reversed flow in a region of limited axial extent. Two forms of vortex breakdown, which predominate, are shown in photographs. One form is called 'near-axisymmetric' (sometimes 'axisymmetric'), and the other is

S. Leibovich

1978-01-01

432

Electrical characteristics and photocurrent spectral response of Si nanowires p-i-n junctions.  

PubMed

P-i-n junctions were fabricated along Si nanowires (SiNWs) via the conventional top-down approach using optical lithography. Each device comprises 500 identical SiNWs connected in parallel, and each SiNW has triangular cross-section with dimensions of ~6 nm (base) by ~8 nm (height). The photodiodes exhibit very good rectifying electrical characteristics with a low reverse bias current of ~0.2 fA per SiNW. The photocurrent spectral response exhibits three peaks between 400 nm to 700 nm, which arise due to local optical field enhancement associated with diffraction by the periodic SiNW array and interference in an air/SiO2/Si cavity. PMID:21560445

Sun, Yongshun; Rusli; Yu, Mingbin; Salfi, Joe; Souza, Christina; Ruda, Harry E; Singh, Navab; Lin, Foo Kai; Lo, Patrick; Kwong, Dim Lee

2011-03-14

433

Electrical and optical characteristics of a low-frequency atmospheric plasma discharge  

NASA Astrophysics Data System (ADS)

The electrical and optical characteristics of a capacitive discharge operated at atmospheric pressure were studied. The discharge was operated with and without dielectric barriers to investigate how the discharge behaved using a low frequency power source. Plasma formation was found at three main harmonics; 30 kHz, 80 kHz, and 150 kHz. In addition, other higher frequency components approaching the MHz regime were found to contribute to plasma generation. The presence of the dielectric barriers significantly effected discharge properties. With the electrodes covered by dielectric barriers, the alpha-gamma transition occurs with increasing power. Without dielectric barriers, the discharge was constricted and operated only in the abnormal mode of operation. Spatial results from the He I (706 nm) emission profile along with gas temperature measurements from the N2+ rotational band will be presented.

Oldham, Christopher J.; King, Matthew R.; Guarnieri, C. Richard; Cuomo, Jerome J.

2008-10-01

434

Dynamical scaling behavior of current-electric field characteristics in two-dimensional disordered superconductors  

NASA Astrophysics Data System (ADS)

We study the dynamics of magnetic vortices driven by transport current in two-dimensional disordered type-II superconductors, using the Langevin dynamics simulation of the vortex model developed. Exploring the electric field induced by the vortex motion as a function of the transport current (E-J characteristics), we find that the combined effect of random impurities and the current induced vortex-antivortex pair creation yields the dynamical scaling behavior of E-J curves near a certain critical temperature. Critical scaling exponents are found to be z ~= 2, ? ~= 2 and ? ~= 0.5, for the dynamical exponent, the static exponent and the resistivity decay exponent, respectively, which are almost independent of the magnetic induction. On the other hand, the critical temperature, Tcr, depends on the magnetic induction, B, as Tcr/Tc0 = 1 - B0.68 with superconducting transition temperature Tc0 at zero field.

Enomoto, Y.; Maekawa, S.

1997-02-01

435

Effect of Annealing on Microstructure and Electrical Characteristics of Doped Poly (3-Hexylthiophene) Films  

NASA Astrophysics Data System (ADS)

The effect of annealing on the microstructure and electrical characteristics of poly (3-hexylthiophene) (P3HT) films doped with very small amounts of the electron acceptor 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) is studied. X-ray diffraction and UV-vis spectrum studies show that unlike the pure P3HT film, the thermal treatment on the doped films under an Ar atmosphere can effectively enhance the crystalline order of P3HT films, as well as successfully facilitate the orientation of the polymer chains. This improvement is attributed to the electrostatic force between P3HT and F4-TCNQ molecules. This force induces the polymer chains to crystallize and orient during the annealing process. As a result, annealing significantly improves performance, especially for the Ion/Ioff ratio of the TFTs based on the doped P3HT films.

Ma, Liang

2010-12-01

436

Electrical characteristics and interface structure of magnetic tunnel junctions with hafnium oxyfluoride barrier  

SciTech Connect

We have studied the effects of fluorine inclusion on the electrical transport characteristics and interface structure of the hafnium oxide barrier in a magnetic tunnel junction. The tunneling magnetoresistance (TMR) and resistance-area (RA) as a function of oxidation time show that the TMR ratio of the hafnium oxyfluoride barrier is higher (8.3%) than that of the hafnium oxide barrier (5.7%) at their optimum conditions, and the oxyfluoride barrier junctions maintain a high TMR ratio even when the RA product increases by three orders of magnitude. X-ray photoelectron spectroscopy analysis shows that the fluorine atoms in the oxyfluoride barrier play an important role in the formation of a barrier with uniform composition. We believe that the initial fluoride layer is causing the subsequent oxygen diffusion to slow down, resulting in the formation of a defect-free hafnium oxide layer. These results are consistent with what we have found for aluminum oxyfluoride barriers.

Yu, Y.Y.; Kim, D.S.; Char, K. [Center for Strongly Correlated Materials Research and School of Physics, Seoul National University, Seoul 151-742 (Korea, Republic of)

2004-12-01

437

Ionization and drift characteristics of electrons in copper vapor in electric field  

NASA Astrophysics Data System (ADS)

The ionization and drift characteristics (Townsend coefficient, drift velocity, mean energy) of electrons in copper vapor occurring in a homogeneous electric field have been numerically simulated. Copper is of interest by offering an example of element with the peak excitation cross section being significantly greater than the ionization cross section. A two-branch curve of electron loss is constructed, which separates the region of effective electron multiplication and the region of significant runaway (from which electrons leave the discharge gap without multiplication). Owing to the large excitation cross section of copper, the upper and lower branches of the electron leaving curve are closer to each other for this metal vapor than for usual gases.

Tkachev, A. N.; Fedenev, A. A.; Yakovlenko, S. I.

2007-01-01

438

Kinetic theory of runaway air-breakdown  

SciTech Connect

The kinetic theory for a new air breakdown mechanism advanced in a previous paper is developed. The relevant form of the Boltzmann equation is derived and the particle orbits in both velocity space and configuration space are computed. A numerical solution of the Boltzmann equation, assuming a spatially uniform electric field, is obtained and the temporal evolution of the electron velocity distribution function is described. The results of our analysis are used to estimate the magnitude of potential x-ray emissions from discharges in thunderstorms.

Roussel-Dupre, R.A. [Los Alamos National Lab., NM (United States); Gurevich, A.V. [AN SSSR, Moscow (Russian Federation). Fizicheskij Inst.; Tunnell, T. [EG and G Energy Measurements, Inc., Los Alamos, NM (United States); Milikh, G.M. [Maryland Univ., College Park, MD (United States). Dept. of Astronomy

1993-09-01

439

An integrated measurement system for LED thermal, optical and electrical characteristics  

NASA Astrophysics Data System (ADS)

Thermal, optical and electrical parameters are main characterization of light-emitting diodes (LEDs). Consumers are often concerned about the explicit properties such as luminous intensity, luminous flux and color. But Manufacturers may pay more attention to the thermal characteristic. Excess heat at the junction directly affects the LED performance in terms of color shit, light output and life. To measure all these parameters of LED accurately and simultaneously, we designed an integrated system, product number SSP8112, which was based on a new developed thermal, optical and electrical measurement instrument and a specially-made integrating sphere with temperature controller. The thermal measurement segment of the instrument was developed in accordance with JESD51-1 standard; it can automatically record the transient response curve of heat with a 50?s time resolution and a 0.5mV voltage resolution. And the integrating sphere, which has high light reflectivity, good thermal insulation and tolerance to high temperature, was used to achieve the optical response during the experiment. The principle and structure of this system were introduced and discussed, and at the end an application example was presented.

Zou, Xiyong; Zheng, Xiaoming; Jin, Shangzhong; Ni, Kai; Zhou, Huaming; He, Xianqi

2008-03-01

440

Electrical and morphological characteristics of anteroventral periventricular nucleus kisspeptin and other neurons in the female mouse.  

PubMed

Neurons in the rodent anteroventral periventricular nucleus (AVPV) play a key role in integrating circadian and gonadal steroid hormone information in the control of fertility. In particular, estradiol-sensitive kisspeptin neurons located in the AVPV, and adjacent structures [together termed the rostral periventricular area of the third ventricle (RP3V)], are critical for puberty onset and the preovulatory LH surge. The present study aimed to establish the morphological and electrical firing characteristics of RP3V neurons, including kisspeptin neurons, in the adult female mouse. Cell-attached electrical recordings, followed by juxtacellular dye filling, of 129 RP3V neurons in the acute brain slice preparation revealed these cells to exhibit multipolar (53%), bipolar (43%), or unipolar (4%) dendritic morphologies along with silent (16%), irregular (41%), bursting (25%), or tonic (34%) firing patterns. Postrecording immunocytochemistry identified 17 of 100 filled RP3V cells as being kisspeptin neurons, all of which exhibited complex multipolar dendritic trees and significantly (P < 0.05) higher bursting or high tonic firing rates compared with nonkisspeptin neurons. The firing pattern of RP3V neurons fluctuated across the estrous cycle with a significant (P < 0.05) switch from irregular to tonic firing patterns found on proestrus. A similar nonsignificant trend was found for kisspeptin neurons. All RP3V neurons responded to gamma-aminobutyric acid and glutamate, about 10% to RFamide-related peptide-3, about 5% to vasopressin, 0% to vasoactive intestinal peptide, and 0% to kisspeptin. These studies provide a morphological and electrical description of AVPV/RP3V neurons and demonstrate their cycle-dependent firing patterns along with an unexpected lack of acute response to the circadian neuropeptides. PMID:20211970

Ducret, Eric; Gaidamaka, Galina; Herbison, Allan E

2010-03-08

441

Formative Time Lag to Breakdown in Micro Gap at Low Atmospheric Pressure  

Microsoft Academic Search

This paper studies the discharge development in a micro gap between metal materials in air experimentally and analytically. As a high voltage side electrode is stressed by different voltages at a fixed gap length with UV irradiation, the electrical breakdown voltage is measured as a function of the time lag. The measured time lag until the spark breakdown ranges from

K. Nitta; S. Matsuoka; M. Chiba; K. Hidaka

2006-01-01

442

Distribution regularity of breakdown field strength of high voltage ceramic capacitor  

Microsoft Academic Search

Electrical breakdown tests on high voltage ceramic capacitors, whose ceramic disks were in two kind of geometry, were carried out under various rates of voltage rise. It was shown that the breakdown field strength of samples in the same form displayed a Weibull distribution for the same rate of voltage rise. With increasing rate, the slope and character strength of

Liu Bin; Chen Wei; Zhang Yajie; Chen Shoutian

2000-01-01

443

Evolution of cathode initiated pulsed dielectric breakdown in polar and nonpolar liquids  

Microsoft Academic Search

A model is presented for the development of breakdown in liquids subjected to uniform high amplitude electric field stresses with ⩽?s duration. In this model, breakdown proceeds in four stages: (a) formation of a nucleation site near the cathode, (b) growth and expansion of this site until the local density is sufficiently reduced for electron impact ionization to take place,

H. M. Jones; E. E. Kunhardt

1996-01-01

444

Frequency Dependent Dielectric Breakdown of Thin Polyimide Films Prepared by Vapor Deposition Polymerization  

Microsoft Academic Search

Dielectric breakdown of thin polyimide films prepared by vapor deposition polymerization has been investigated for various ac voltages. Real time measurements were made automatically with a system composed of a digital oscilloscope, controllable signal generator and microcomputer. The self-healing breakdown takes place at the peak of the applied voltage. The ac electric strength decreases with temperature, and it increases with

Keiichi Miyairi

2001-01-01

445

A quantitative physical model for time-dependent breakdown in SiO2  

Microsoft Academic Search

A quantitative physical breakdown model for thin SiO2 is developed. The physical mechanism responsible fcor oxide breakdown has been reexamined and found to be hole trapping at localized areas. A quantitative model is built on this physical understanding of the wearout mechanism. Using this model, which considers electron injection, hole generation and charge trapping during electrical stresses and their effects

I. C. Chen; S. Holland; C. Hut

1985-01-01

446

Electricity  

NSDL National Science Digital Library

5th Grade Electricity Try this Using Electricity Activity. Don't forget to follow the directions! Use this to learn more about electricity: Blobz Guide to Electricity Follow the directions closely! Learn more about Electricity with Electricity Tech-Topics. ...

Lerdahl, Miss

2010-02-23

447

Studies on the Electrical Characteristics of a DC Glow Discharge by Using Langmuir Probe  

SciTech Connect

Electrical characteristics of a DC glow discharge are studied with the aim of determining the suitable parameters for stable operation of the dusty plasma system. The presence of dust particles in plasma significantly alters the charged particle equilibrium in the plasma and leads to various phenomena. Argon plasma produced by DC glow discharge is investigated with a further goal of studying dusty plasma phenomena. The discharge system has two disc-shaped parallel plate electrodes. The electrodes are enclosed in a large cylindrical stainless steel chamber filled with argon gas. Two important physical parameters affecting the condition of the discharge are the gas pressure and the inter-electrode distance. A single Langmuir probe based on the Keithley source meter is used to determine the electron temperature of the positive column. A custom designed probe is employed to determine the potential distribution between the electrodes during the discharge. The I-V characteristic curve and the Langmuir probe measurement are then used to determine the electron energy distribution of the glow discharge plasma.

Safaai, S. S.; Yap, S. L.; Wong, C. S.; Muniandy, S. V. [Plasma Research Laboratory, Physics Department, Faculty of Science, University of Malaya, 50603 KualaLumpur (Malaysia); Smith, P. W. [University of Oxford (United Kingdom)

2010-07-07

448

Analysis of the sensitivity and frequency characteristics of coplanar electrical cell-substrate impedance sensors.  

PubMed

A PDMS-glass based micro-device was designed and fabricated with 12 coplanar impedance sensors integrated for electrical cell-substrate impedance sensing (ECIS). The sensitivity and frequency characteristics of the sensors were investigated both theoretically (equivalent circuit model) and experimentally for the commonly used micro-electrode dimension scale (20-80 microm). The experimental results matched well with the theoretical model analysis and revealed that, within this micro-electrode dimension scale, as the electrode width decreased or as the total electrode length decreased the sensitivity of sensor increased over the whole sensing frequency range, whilst electrode to electrode distance had no influence on sensitivity. Through our frequency characteristics analysis, the whole frequency range could be divided into four parts. New functions describing the dominant components in each frequency range were defined and validated experimentally, and could be used to explain the phenomenon of an ECIS sensing frequency window. The contribution to the impedance measurement of cells growing on the edges of the electrodes was determined for the first time. Finally, novel proposals for ECIS sensor design and ECIS measurements were presented. PMID:18511255

Wang, Lei; Wang, He; Wang, Lei; Mitchelson, Keith; Yu, Zhongyao; Cheng, Jing

2008-03-29

449

Electrical characteristics of floating-gate memory devices with titanium nanoparticles embedded in gate oxides.  

PubMed

The electrical characteristics of titanium (Ti) nanoparticle-embedded metal-oxide-semiconductor (MOS) capacitors and metal-oxide-semiconductor field effect transistors (MOSFETs) with blocking Al2O3 layers are studied in this work. Ti nanoparticles were synthesized by a thermal deposition of Ti and by a subsequent thermal annealing procedure. The capacitance versus voltage (C-V) curves obtained for a representative MOS capacitor embedded with Ti nanoparticles exhibit large flat-band voltage shifts, demonstrating the presence of charge storages in the Ti nanoparticles. The counterclockwise hysteresis and flat-band voltage shift observed from the C-V curves imply that electrons are stored in a floating gate layer consisting of the Ti nanoparticles present between the tunneling oxide and control oxide layers in the MOS capacitor and that these stored electrons originate from the p-type Si substrate in inversion condition. Moreover, the source/drain current versus gate voltage curves for the Ti nanoparticle-embedded MOSFETs and the threshold voltage shift characteristics of program/erase time, endurance and retention are analyzed in this paper. PMID:19435057

Park, Byoungjun; Cho, Kyoungah; Yun, Junggwon; Koo, Yong-Seo; Lee, Jong-Ho; Kim, Sangsig

2009-03-01

450

Optical breakdown threshold investigation of 1064 nm laser induced air plasmas  

SciTech Connect

We present the theoretical and experimental measurements and analysis of the optical breakdown threshold for dry air by 1064 nm infrared laser radiation and the significance of the multiphoton and collisional cascade ionization process on the breakdown threshold measurements over pressures range from 10 to 2000 Torr. Theoretical estimates of the breakdown threshold laser intensities and electric fields are obtained using two distinct theories namely multiphoton and collisional cascade ionization theories. The theoretical estimates are validated by experimental measurements and analysis of laser induced breakdown processes in dry air at a wavelength of 1064 nm by focusing 450 mJ max, 6 ns, 75 MW max high-power 1064 nm IR laser radiation onto a 20 {mu}m radius spot size that produces laser intensities up to 3 - 6 TW/cm{sup 2}, sufficient for air ionization over the pressures of interest ranging from 10 to 2000 Torr. Analysis of the measured breakdown threshold laser intensities and electric fields are carried out in relation with classical and quantum theoretical ionization processes, operating pressures. Comparative analysis of the laser air breakdown results at 1064 nm with corresponding results of a shorter laser wavelength (193 nm) [M. Thiyagarajan and J. E. Scharer, IEEE Trans. Plasma Sci. 36, 2512 (2008)] and a longer microwave wavelength (10{sup 8} nm) [A. D. MacDonald, Microwave Breakdown in Gases (Wiley, New York, 1966)]. A universal scaling analysis of the breakdown threshold measurements provided a direct comparison of breakdown threshold values over a wide range of frequencies ranging from microwave to ultraviolet frequencies. Comparison of 1064 nm laser induced effective field intensities for air breakdown measurements with data calculated based on the collisional cascade and multiphoton breakdown theories is used successfully to determine the scaled collisional microwave portion. The measured breakdown threshold of 1064 nm laser intensities are then scaled to classical microwave breakdown theory after correcting for the multiphoton ionization process for different pressures and good agreement, regarding both pressure dependence and breakdown threshold electric fields, is obtained. The effect of the presence of submicron particles on the 1064 nm breakdown threshold was also investigated. The measurements show that higher breakdown field is required, especially at lower pressures, and in close agreement with classical microwave breakdown theory and measurements in air.

Thiyagarajan, Magesh; Thompson, Shane [Plasma Engineering Research Lab (PERL), College of Science and Engineering, Texas A and M University-Corpus Christi, Texas 78412 (United States)

2012-04-01

451

Optical breakdown threshold investigation of 1064 nm laser induced air plasmas  

NASA Astrophysics Data System (ADS)

We present the theoretical and experimental measurements and analysis of the optical breakdown threshold for dry air by 1064 nm infrared laser radiation and the significance of the multiphoton and collisional cascade ionization process on the breakdown threshold measurements over pressures range from 10 to 2000 Torr. Theoretical estimates of the breakdown threshold laser intensities and electric fields are obtained using two distinct theories namely multiphoton and collisional cascade ionization theories. The theoretical estimates are validated by experimental measurements and analysis of laser induced breakdown processes in dry air at a wavelength of 1064 nm by focusing 450 mJ max, 6 ns, 75 MW max high-power 1064 nm IR laser radiation onto a 20 ?m radius spot size that produces laser intensities up to 3 - 6 TW/cm2, sufficient for air ionization over the pressures of interest ranging from 10 to 2000 Torr. Analysis of the measured breakdown threshold laser intensities and electric fields are carried out in relation with classical and quantum theoretical ionization processes, operating pressures. Comparative analysis of the laser air breakdown results at 1064 nm with corresponding results of a shorter laser wavelength (193 nm) [M. Thiyagarajan and J. E. Scharer, IEEE Trans. Plasma Sci. 36, 2512 (2008)] and a longer microwave wavelength (108 nm) [A. D. MacDonald, Microwave Breakdown in Gases (Wiley, New York, 1966)]. A universal scaling analysis of the breakdown threshold measurements provided a direct comparison of breakdown threshold values over a wide range of frequencies ranging from microwave to ultraviolet frequencies. Comparison of 1064 nm laser induced effective field intensities for air breakdown measurements with data calculated based on the collisional cascade and multiphoton breakdown theories is used successfully to determine the scaled collisional microwave portion. The measured breakdown threshold of 1064 nm laser intensities are then scaled to classical microwave breakdown theory after correcting for the multiphoton ionization process for different pressures and good agreement, regarding both pressure dependence and breakdown threshold electric fields, is obtained. The effect of the presence of submicron particles on the 1064 nm breakdown threshold was also investigated. The measurements show that higher breakdown field is required, especially at lower pressures, and in close agreement with classical microwave breakdown theory and measurements in air.

Thiyagarajan, Magesh; Thompson, Shane

2012-04-01

452

Validity of the Space-Time Enlargement Law for vacuum breakdown  

Microsoft Academic Search

This paper investigates, theoretically and experimentally, the applicability of the Space-Time Enlargement Law to vacuum-insulated systems. A discussion on how characteristics of possible vacuum breakdown mechanisms determine the distribution function of the breakdown voltage random variable is presented. By superimposing effects of electrode surface enlargement and inter-electrode gap enlargement, expressions for the mean value and standard deviation of the breakdown

P. Osmokrovi?; R. Mari?; K. Stankovi?; D. Ili?; M. Vujisi?

2010-01-01

453

Frequency Dependent Dielectric Breakdown of Thin Polyimide Films Prepared by Vapor Deposition Polymerization  

NASA Astrophysics Data System (ADS)

Dielectric breakdown of thin polyimide films prepared by vapor deposition polymerization has been investigated for various ac voltages. Real time measurements were made automatically with a system composed of a digital oscilloscope, controllable signal generator and microcomputer. The self-healing breakdown takes place at the peak of the applied voltage. The ac electric strength decreases with temperature, and it increases with frequency in the range of 10 Hz-3 kHz. The frequency dependent breakdown has been explained tentatively in terms of the establishment of a conductive path leading to the breakdown.

Miyairi, Keiichi

2001-03-01

454

Laser-initiated channels for ion transport: breakdown and channel evolution  

SciTech Connect

The electrical breakdown and discharge evolution in CO/sub 2/ laser-heated molecular gases has been studied. With the laser tuned to a vibrational mode of NH/sub 3/, C/sub 2/H/sub 4/, CH/sub 2/CHCN, or CH/sub 3/OH the breakdown potential decreases as much as 10-fold for laser pulse energies up to 35 J/cm/sup 2/. The subsequent 50--142-cm discharges are straight, stable, and reproducible. Analogous tests in D/sub 2/ and air yield only a small alteration of breakdown potential and do not cause a straight discharge. The expansion of the initial laser-heated gas has been modeled by the CHARTB hydrocode with the addition of the NH/sub 3/ equation of state in tabular and analytic form to that code. The breakdown characteristics and initial expansion stage confirm the earlier calculation of laser heating to 1900--2100 /sup 0/K. Experimental observations of the discharge evolution in NH/sub 3/ have measured (1) the radial expansion velocity by streak-camera photography of the H/sub ..beta../ emission zone, (2) the plasma temperature by the Niv/Niii line-ratio method, and (3) the electron-density profile by holographic interferometry. The central zone of the channel is heated to 5.5 eV and expands with a radial velocity of 1.0--1.2 mm/..mu..s for the case of a 27-kA discharge in 20 Torr of NH/sub 3/. Preliminary hydrocode simulations of the discharge show qualitative agreement with observations.

Olsen, J.N.; Baker, L.

1981-05-01

455

Barrier breakdown mechanisms in MgO-based magnetic tunnel junctions under pulsed conditions and correlation with low-frequency noise  

NASA Astrophysics Data System (ADS)

An investigation of barrier breakdown in MgO based Magnetic Tunnel Junctions submitted to pulsed electrical stress is presented. By studying the effect of delay between successive pulses, we observed that a very pronounced optimum in endurance of MTJs is obtained for an intermediate value of the delay between pulses corresponding to the characteristic time for a trapped electron in the barrier to escape from its trap. A charge trapping-detrapping model was proposed which consistently explains our experimental data. The delay between successive pulses affects the density of electrons trapped in the barrier. The average value in time and the time-modulation of the density of trapped charge give rise to distinct breakdown mechanisms. Our model allows evaluating the MTJ probability of breakdown for different applied pulse conditions. An expected endurance of the MTJs is then derived depending on the characteristics of the electrical stress in terms of delay, amplitude, unipolarity versus bipolarity. In a second part, low-frequency (0-12 kHz) noise measurements were performed in order to correlate the electrical noise with the defect density in the barrier.

Amara-Dababi, S.; Bea, H.; Sousa, R. C.; Baraduc, C.; MacKay, K.; Dieny, B.

2012-10-01

456

High-Power Microwave Breakdown of Dielectric Interfaces.  

National Technical Information Service (NTIS)

This is the final technical report for AFOSR Grant No. 91-0260, that began in May, 1991 and concluded two years later on May 15, 1993. The first objective of this project was to study the electrical breakdown, due to microwaves, which occurs on the surfac...

M. Kristiansen L. Hatfield M. Crawford

1993-01-01

457

Simulation of root development based on the dielectric breakdown model  

Microsoft Academic Search

Knowing the root distribution in soil is essential for estimating water uptake by plant roots. It is difficult, however, to characterize and model undisturbed root systems. Root development in a two-dimensional potential field is simulated with the dielectric breakdown model (DBM), which implies a similarity between electric discharge and root distribution. A weighted potential gradient with an exponent rj was

O. HIROTA

1999-01-01

458

Simulation of root development based on the dielectric breakdown model  

Microsoft Academic Search

Knowing the root distribution in soil is essential for estimating water uptake by plant roots. It is difficult, however, to characterize and model undisturbed root systems. Root development in a two-dimensional potential field is simulated with the dielectric breakdown model (DBM), which implies a similarity between electric discharge and root distribution. A weighted potential gradient with an exponent ? was

J. CHIKUSHI; O. HIROTA

1998-01-01

459

An empirical formula for gas switch breakdown delay  

SciTech Connect

An empirical scaling relationship between the mean electric field and the breakdown time has been found. Many divergent sets of data were used from breakdown experiments on power lines, laser-triggered switches, trigatrons, e-beam triggered gaps, sharp-point electrode to plane gaps, and uniform field gaps. This relationship builds on the Felsenthal and Proud data and extends their breakdown time delay (formative time) data by three orders of magnitude and into the region of interest for triggered gas switching. The data indicates that electrically triggered gaps, laser-triggered gaps, and untriggered gaps are governed by the same time-delay processes. Predictions can be made of trigger gap geometry, trigger delays, and trigger polarity effects. Breakdown delays of sub-centimeter-long to at least 8-meter-long gaps in air with either high or low field-enhanced electrodes are described by this equation. In addition, this relationship appears to be valid for a variety of gases and even accurately predicts the breakdown delay of mixtures of air and SF/sub 6/. 13 refs., 12 figs., 1 tab.

Martin, T.H.

1989-01-01

460

Feedback and breakdown in parallel-plate chambers  

NASA Astrophysics Data System (ADS)

The existence of a strong connection between the photon feedback and the breakdown phenomena in parallel plate avalanche chambers (PPACs) is generally accepted. In this work we made a detailed study of these processes in mixtures of Ar and He with CH4, C2H6 and triethylamine (TEA) vapors. Two breakdown modes (fast and slow) were identified, active for different levels of photon feedback. The breakdown limit (as against the photon feedback) is found to be quite independent of the nature of the filling gas, depending mainly on the total charge in the avalanche. Analytical expressions, based on our measurements, are proposed for the first Townsend coefficient and for the VUV light production coefficient as a function of the electric field and quencher partial pressure. These expressions allow to justify the constant fast breakdown limit on the basis of a space-charge induced electric field distortion. Some results of other authors, concerning a counting rate dependence of the breakdown limit, can also be explained in the framework of this model.

Fonte, P.; Peskov, V.; Sauli, F.

1991-07-01

461

Direct current breakdown in gases for complex geometries from high vacuum to atmospheric pressure  

NASA Astrophysics Data System (ADS)

The demand for improved performances of power transmission devices requires ever smaller dimensions and higher working voltages which lead to increased risk of breakdown, for example, in satellite slip rings. Previous works are mostly limited to breakdown in simple geometries such as parallel plates or pin to plate. Here we discuss the effect of more complex geometries for dc breakdown in gases over a large pressure range (2 × 10?5 to 103 mbar). Experimental measurements of dc gas discharge breakdown in a ring assembly geometry are compared with a numerical simulation model for gas breakdown using a fluid model. Starting with parallel plates (1 and 100 mm gap width representing approximately the shortest and longest electric field path lengths in the ring assembly geometry) and extending to double gap and multi-gap geometries, an understanding of the overall shape of the breakdown voltage versus pressure curve is established. The high (low) pressure thresholds of gas discharge are determined by the shortest (longest) electric field path length in a complex geometry. Moreover, the availability of multiple path lengths leads to a breakdown voltage minimum over a wide range of intermediate pressure because breakdown can occur in the most favourable gap. Finally, the numerical simulation in the ring assembly shows the importance of parameters such as the secondary electron emission coefficient which play a major role in determining the breakdown voltage value.

Schnyder, R.; Howling, A. A.; Bommottet, D.; Hollenstein, Ch

2013-07-01

462

Mobile charge, soft breakdown, and self-healing in hydrogen silsesquioxane based intermetal dielectric  

NASA Astrophysics Data System (ADS)

The electrical characteristics of hydrogen silsesquioxane based flowable oxide (FOxregistered) films proposed for interconnect isolation applications have been studied. It is demonstrated that negative and positive charges exist in the as-made, cured films with densities of 0.95 x1012 and 1.5 x1012 cm-2, respectively for thicknesses of 114 nm. The negative charges can be removed from the films by application of modest electric fields (positive or negative, approx1.75 MV cm-1). The positive charge can be similarly displaced but not removed from the film; this results in time dependent relaxation and redistribution of the positive charge if the films are left unbiased. Time dependent irreversible evolution of the leakage current under positive and negative bias (approx3 MV cm-1) shows a slow breakdown phenomena. An unusual self-healing effect is evidenced in these films.

Devine, R. A. B.

2002-09-01

463

A method to investigate the electron scattering characteristics of ultrathin metallic films by in situ electrical resistance measurements.  

PubMed

In this article, a method to measure the electrical resistivity/conductivity of metallic thin films during layer growth on specific underlayers is described. The in situ monitoring of an underlayer electrical resistance, its change upon the incoming of new material atoms/molecules, and the growth of a new layer are presented. The method is easy to implement and allows obtaining in situ experimental curves of electrical resistivity dependence upon film thickness with a subatomic resolution, providing insight in film growth microstruc