HIGH TEMPERATURE ULTRA HIGH VOLTAGE SIC THYRISTORS

2010 ◽  
Vol 2010 (HITEC) ◽  
pp. 000167-000173
Author(s):  
R. Singh ◽  
S. Creamer ◽  
E. Lieser ◽  
S. Jeliazkov ◽  
S. Sundaresan
Keyword(s):  
High Temperature ◽  
Voltage Drop ◽  
Carrier Lifetimes ◽  
Edge Termination ◽  
Minority Carrier Lifetimes ◽  
Stable Performance ◽  
Switching Characteristics ◽  
High Yields ◽  
Increasing Temperature ◽  
First Time

Through a systematic study, Silicon Carbide Gate Turn Off (GTO) Thyristors with record performance are demonstrated. Several Anode-Gate interdigitation schemes (raster, hex and involute) were explored to investigate their effect on the static as well as switching characteristics. An optimized edge-termination was employed that resulted in the achievement of near-theoretical forward blocking voltages (>8.1kV), and high yields (>60% on 8mm×8mm) on GTO Thyristors with 60μm/5×1014 cm−3 voltage-blocking epitaxial layers. A low differential specific on-resistance of 2.55 mΩ-cm2, and low on-state voltage drop were measured at 500 A/cm2. High Temperature forward I-V and reverse I-V characteristics show extremely stable performance with temperature, in contrast to state-of-the-art Si GTO Thyristors. Turn-on transient characteristics show a stable delay time of about 400 nano-seconds, and a rise-time that decreases with increasing temperature. Detailed high temperature turn-off measurements conducted using Anode-Switched mode was used to extract the value of minority carrier lifetimes as a function of temperature for the first time.

Radiation-Sensitized Thermal Cracking of n-Butane. II. Ionic Reactions

1975 ◽  
Vol 53 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Shingo Matsuoka ◽  
Takaaki Tamura ◽  
Keichi Oshima ◽  
Yunosuke Oshima
Keyword(s):  
Room Temperature ◽  
Material Balance ◽  
Thermal Cracking ◽  
Activation Energies ◽  
Chain Reactions ◽  
Ionic Reactions ◽  
Cracking Mechanism ◽  
High Yields ◽  
Increasing Temperature ◽  
First Time

Ionic reactions in the radiolysis of n-butane were studied at temperatures ranging from 17 to 548 °C. Ionic chain reactions were found for the first time to take part in the radiation-sensitized thermal cracking mechanism of hydrocarbon system.The isobutane and isobutene yields increased with increasing temperature and at 548 °C their G-values reached 31.2 and 12.1, respectively, though they were not formed by the thermal cracking of n-butane. The formation was completely suppressed by the addition of 0.15 mol% ammonia. They were produced with high yields irrespective of the kind of wall of the irradiation cells. It was concluded from these results that isobutane and isobutene were formed by homogeneous ionic chain reactions with activation energies. Part of the propane product was also found to have been formed by ionic chain reactions. From the effect of adding n-pentane on the yields of the ionic products, C4H9+ ion was inferred as the carrier ion.In the vicinity of room temperature, formation by ionic reactions of polymers with more than 14 carbon atoms was inferred from the material balance of the products from H2 to C14.

Multilayer ferrite inductors for the use at high temperatures

2020 ◽  
Vol 37 (2) ◽  
pp. 73-78 ◽  
Author(s):  
Heike Bartsch ◽  
Sebastian Thiele ◽  
Jens Mueller ◽  
Dirk Schabbel ◽  
Beate Capraro ◽  
...  
Keyword(s):  
High Temperature ◽  
High Performance ◽  
Content Type ◽  
Ferrite Material ◽  
Nickel Copper ◽  
Copper Zinc ◽  
Higher Temperature ◽  
Silver Palladium ◽  
Increasing Temperature ◽  
First Time

Purpose This paper aims to investigate the usability of the nickel copper zinc ferrite with the composition Ni0.4Cu0.2Zn0.4Fe1.98O3.99 for the realization of high-temperature multilayer coils as discrete components and integrated, buried function units in low temperature cofired ceramics (LTCC). Design/methodology/approach LTCC tapes were cast and test components were produced as multilayer coils and as embedded coils in a dielectric tape. Different metallization pastes are compared. The properties of the components were measured at room temperature and higher temperature up to 250°C. The results are compared with simulation data. Findings The silver palladium paste revealed the highest inductance values within the study. The measured characteristics over a frequency range from 1 MHz to 100 MHz agree qualitatively with the measurements obtained from toroidal test samples. The inductance increases with increasing temperature and this influence is lower than 10%. The characteristic of embedded coils is comparable with this of multilayer components. The effective permeability of the ferrite material reaches values around 130. Research limitations/implications The research results based on a limited number of experiments; therefore, the results should be verified considering higher sample sizes. Practical implications The results encourage the further investigation of the material Ni0.4Cu0.2Zn0.4Fe1.98O3.99 for the use as high-temperature ferrite for the design of multilayer coils with an operation frequency in the range of 5-10 MHz and operation temperatures up to 250°C. Originality/value It is demonstrated for the first time, that the material Ni0.4Cu0.2Zn0.4Fe1.98O3.99 is suitable for the realization of high-temperature multilayer coils and embedded coils in LTCC circuit carriers with high performance.

An Expeditious One-Pot Three-Component Synthesis of 4-Aryl-3,4-dihydrobenzo[g] quinoline-2,5,10(1H)-triones under Green Conditions

2020 ◽  
Vol 23 (23) ◽  
pp. 2626-2634
Author(s):  
Saiedeh Kamalifar ◽  
Hamzeh Kiyani
Keyword(s):  
Reaction Medium ◽  
Meldrum's Acid ◽  
Meldrum’S Acid ◽  
One Pot ◽  
One Pot Synthesis ◽  
Substituted Benzaldehydes ◽  
High Yields ◽  
First Time ◽  
Green Conditions

: An efficient and facial one-pot synthesis of 4-aryl-3,4-dihydrobenzo[g]quinoline- 2,5,10(1H)-triones was developed for the first time. The process proceeded via the three-component cyclocondensation of 2-amino-1,4-naphthoquinone with Meldrum’s acid and substituted benzaldehydes under green conditions. The fused 3,4-dihydropyridin-2(1H)- one-ring naphthoquinones have been synthesized with good to high yields in refluxing ethanol as a green reaction medium. This protocol is simple and effective as well as does not involve the assistance of the catalyst, additive, or hazardous solvents.

scholarly journals Investigation of the kinetics of spontaneous combustion of the major coal seam in Dahuangshan mining area of the Southern Junggar coalfield, Xinjiang, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li Shen ◽  
Qiang Zeng
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Coal Seam ◽  
Spontaneous Combustion ◽  
Heating Temperature ◽  
Characteristic Temperature ◽  
Mining Area ◽  
Particle Sizes ◽  
Coal Oxidation ◽  
Increasing Temperature

AbstractIn the present paper, with using diverse methods (including the SEM, the XRD, the TPO, the FTIR, and the TGA) , the authors analysed samples of the major coal seam in Dahuangshan Mining area with different particle sizes and with different heated temperatures (from 50 to 800 °C at regular intervals of 50 °C). The results from SEM and XRD showed that high temperature and high number of pores, fissures, and hierarchical structures in the coal samples could facilitate oxidation reactions and spontaneous combustion. A higher degree of graphitization and much greater number of aromatic microcrystalline structures facilitated spontaneous combustion. The results from TPO showed that the oxygen consumption rate of the coal samples increased exponentially with increasing temperature. The generation rates of different gases indicated that temperatures of 90 °C or 130 °C could accelerate coal oxidation. With increasing temperature, the coal oxidation rate increased, and the release of gaseous products was accelerated. The FTIR results showed that the amount of hydroxide radicals and oxygen-containing functional groups increased with the decline in particle size, indicating that a smaller particle size may facilitate the oxidation reaction and spontaneous combustion of coal. The absorbance and the functional group areas at different particle sizes were consistent with those of the heated coal samples, which decreased as the temperature rose. The results from TGA showed that the characteristic temperature T3 declined with decreasing particle size. After the sample with 0.15–0.18 mm particle size was heated, its carbon content decreased, and its mineral content increased, inhibiting coal oxidation. This result also shows that the activation energy of the heated samples tended to increase at the stage of high-temperature combustion with increasing heating temperature.

Purification of Eucalyptus globulus water prehydrolyzates using the HiTAC process (high-temperature adsorption on activated charcoal)

Holzforschung ◽  
2011 ◽  
Vol 65 (4) ◽  
Author(s):  
Jenny Sabrina Gütsch ◽  
Herbert Sixta
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Adsorption Process ◽  
Value Added ◽  
Sustainable Utilization ◽  
Pulp And Paper Mills ◽  
Paper Mills ◽  
Charcoal Adsorption ◽  
Increasing Temperature ◽  
Value Added Products

Abstract The implementation of biorefinery concepts into existing pulp and paper mills is a key step for a sustainable utilization of the natural resource wood. Water prehydrolysis of wood is an interesting process for the recovery of xylo-oligosaccharides and derivatives thereof, while at the same time cellulose is preserved to a large extent for subsequent dissolving pulp production. The recovery of value-added products out of autohydrolyzates is frequently hindered by extensive lignin precipitation, especially at high temperatures. In this study, a new high-temperature adsorption process (HiTAC process) was developed, where lignin is removed directly after the autohydrolysis, which enables further processing of the autohydrolyzates. The suitability of activated charcoals as a selective adsorbent for lignin under process-relevant conditions (150 and 170°C) has not been considered up to now, because former experiments showed decreasing efficiency of charcoal adsorption of lignin with increasing temperature in the range 20–80°C. In contrast to these results, we demonstrated that the adsorption of lignin at 170°C directly after autohydrolysis is even more efficient than after cooling the hydrolyzate to room temperature. The formation of lignin precipitation and incrustations can thus be efficiently prevented by the HiTAC process. The carbohydrates in the autohydrolysis liquor remain unaffected over a wide charcoal concentration range and can be further processed to yield valuable products.

scholarly journals Experimental Investigation of Wave Velocity-Permeability Model for Granite Subjected to Different Temperature Processing

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Guanghui Jiang ◽  
Jianping Zuo ◽  
Teng Ma ◽  
Xu Wei
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Wave Velocity ◽  
Pore Fluid ◽  
Rock Matrix ◽  
Permeability Model ◽  
Wave Velocities ◽  
Before And After ◽  
Different Temperatures ◽  
Increasing Temperature

Understanding the change of permeability of rocks before and after heating is of great significance for exploitation of hydrocarbon resources and disposal of nuclear waste. The rock permeability under high temperature cannot be measured with most of the existing methods. In this paper, quality, wave velocity, and permeability of granite specimen from Maluanshan tunnel are measured after high temperature processing. Quality and wave velocity of granite decrease and permeability of granite increases with increasing temperature. Using porosity as the medium, a new wave velocity-permeability model is established with modified wave velocity-porosity formula and Kozeny-Carman formula. Under some given wave velocities and corresponding permeabilities through experiment, the permeabilities at different temperatures and wave velocities can be obtained. By comparing the experimental and the theoretical results, the proposed formulas are verified. In addition, a sensitivity analysis is performed to examine the effect of particle size, wave velocities in rock matrix, and pore fluid on permeability: permeability increases with increasing particle size, wave velocities in rock matrix, and pore fluid; the higher the rock wave velocity, the lower the effect of wave velocities in rock matrix and pore fluid on permeability.

A Brief Overview on High Temperature Friction and Wear

2010 ◽  
Author(s):  
Mustafa Bulut Coskun ◽  
Mahmut Faruk Aksit
Keyword(s):  
High Temperature ◽  
Gas Turbines ◽  
Friction And Wear ◽  
Oxidation Behavior ◽  
Elevated Temperatures ◽  
Wear Performance ◽  
Large Pressure ◽  
Higher Power ◽  
Vibratory Motion ◽  
Increasing Temperature

With the race for higher power and efficiency new gas turbines operate at ever increasing pressures and temperatures. Increased compression ratios and firing temperatures require many engine parts to survive extended service hours under large pressure loads and thermal distortions while sustaining relative vibratory motion. On the other hand, wear at elevated temperatures limits part life. Combined with rapid oxidation for most materials wear resistance reduces rapidly with increasing temperature. In order to achieve improved wear performance at elevated temperatures better understanding of combined wear and oxidation behavior of high temperature super alloys and coatings needed. In an attempt to aid designers for high temperature applications, this work provides a quick reference for the high temperature friction and wear research available in open literature. High temperature friction and wear data have been collected, grouped and summarized in tables.

Design and use of an Efficient Plasma Jet Reactor for High Temperature Gas/Solid Reactions

1983 ◽  
Vol 30 ◽  
Author(s):  
F. W. Giacobbe ◽  
D. W. Schmerling
Keyword(s):  
Carbon Monoxide ◽  
High Temperature ◽  
Arc Discharge ◽  
Plasma Jet ◽  
Direct Result ◽  
Discharge Region ◽  
Plasma Flame ◽  
Powdered Carbon ◽  
High Yields ◽  
Experimental Trials

ABSTRACTA unique and efficient plasma jet reactor has been developed and used to study the high temperature production of carbon monoxide from a reaction between powdered carbon and a pure carbon dioxide plasma. The plasma jet reactor was designed to allow the injection of powdered carbon above the arc discharge region rather than into the plasma flame below the arc discharge region. High yields of carbon monoxide, produced at relatively high efficiencies, were a direct result of this technique. The plasma jet was also designed to enable rapid changing and testing of various anode insertsAverage yields of carbon monoxide in the product gases were as high as 80–87% in selected experimental trials. Carbon monoxide was produced at rates exceeding 15,000 1/hr (at STP) with a power expenditure of 52 Kw.

Gold(I) Complexes Bearing P∩N-Ligands: An Unprecedented Twelve-membered Ring Structure Stabilized by Aurophilic Interactions

2009 ◽  
Vol 64 (11-12) ◽  
pp. 1513-1524 ◽  
Author(s):  
Uwe Monkowius ◽  
Manfred Zabel ◽  
Michel Fleck ◽  
Hartmut Yersin
Keyword(s):  
Solid State ◽  
Ring Structure ◽  
Phosphine Ligands ◽  
X Ray Crystallography ◽  
Aggregation Pattern ◽  
Elemental Analyses ◽  
High Yields ◽  
First Time ◽  
Solid State Structures ◽  
Aurophilic Interactions

The P∩N-ligands Ph2Pqn, 1, Ph2 Piqn, 2, Ph2 Ppym, 3, and the As∩N-ligands Ph2Asqn, 4, Ph2Asiqn, 5, (Ph = phenyl, qn = 8-quinoline, iqn = 1-isoquinoline, pym = 2-pyrimidine) have been synthesized, the ligands 2 and 5 for the first time. Their ligand properties were probed by the synthesis of gold(I) complexes. Reaction with (tht)AuCl (tht = tetrahydrothiophene) yielded the chlorogold complexes Ph2RP-Au-Cl (R = qn, 6; iqn, 7; pym, 8) and Ph2RAs-Au-Cl (R = qn, 9; iqn, 10) in high yields. Further treatment of 7 and 8 with one equivalent of AgBF4 provided the complexes [(Ph2Piqn)Au]BF4, 11, [(Ph2Ppym)Au]BF4, 12, and [(Ph2Piqn)Au(tht)]BF4, 14. For comparison, the previously reported complex [(Ph2Ppy)Au]BF4 (py = pyridine), 13, was re-investigated. The compounds were characterized by elemental analyses, mass spectrometry and NMR spectroscopy. In addition, the solid-state structures of 2, 3, 6, 7, 9 - 14 have been determined by X-ray crystallography. The chloro-gold compounds crystallize in the common rod-like structure known from R3EAuCl (R = aryl, E = P, As) complexes without further aggregation via aurophilic interactions. In all cases the phosphine acts as a monodentate ligand. In the solid state compounds 11 - 13 feature an unprecedented cyclic trinuclear aggregation pattern, in which the Au(I) atoms are linearly coordinated by the bridging phosphine ligands forming a cyclic (P-Au-N)3 arrangement. The resulting twelvemembered ring is further stabilized by Au · · · Au interactions. Due to the presence of these Au · · · Au contacts, 11 - 13 are emissive in the solid state but not in solution

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