Formation and Characterization of Nanolayered Pd-Based Metal/p-4H SiC Systems with Ohmic Behaviour

2010 ◽  
Vol 10 ◽  
pp. 77-85 ◽  
Author(s):  
Lilyana Kolaklieva ◽  
Roumen Kakanakov ◽  
Efstathios K. Polychroniadis ◽  
Eleni Pavlidou ◽  
Ioannis Tsiaousis ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Surface Roughness ◽  
Thermal Properties ◽  
Structural Analysis ◽  
Surface Morphology ◽  
Barrier Height ◽  
Contact Resistivity ◽  
Excellent Thermal Stability

Three types of nanolayered Pd-based metal/p-4H SiC systems, Au/Pd, Au/Pd/Al and Au/Pd/Ti/Pd have been investigated and compared to Pd monolayered metallization regarding the electrical and thermal properties. The lowest contact resistivity of 2.8x10-5 .cm2 has been achieved with the Au/Pd/Ti/Pd contact. This contact exhibits excellent thermal stability during long-term heating at temperature of 700oC and at operating temperatures up to 450oC. The surface morphology investigation has shown that despite the observed decrease, the palladium agglomeration has been not avoided completely in the same contact. The dominated surface roughness was measured to be 75 nm. However, the formation of dendrites in certain places leads to increase the surface roughness to 125 nm. The structural analysis revealed that palladium silicides are formed at the interface metal/p-4H SiC which affects on decrease of the barrier height in more than two times and conversion of the contact from Schottky into ohmic.

Search for a Suitable Ohmic Metallization Scheme to GaN/AlGaN Heterostructures for Sub-Micron Devices

2010 ◽  
Vol 159 ◽  
pp. 81-86 ◽  
Author(s):  
Lilyana Kolaklieva ◽  
Roumen Kakanakov ◽  
V. Chitanov ◽  
Polina Dulgerova ◽  
Volker Cimalla
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Surface Morphology ◽  
Barrier Layer ◽  
Contact Structure ◽  
Annealing Temperature ◽  
Contact Resistivity ◽  
Initial Composition ◽  
Excellent Thermal Stability ◽  
Au Film

Ohmic properties, thermal stability and surface morphology of Al-based and non-aluminium metallizations are investigated in dependence on the annealing temperature and initial composition. Non-aluminium contacts show poor ohmic properties, while contact resistivity of 3.47x10-5 Ω.cm2 is achieved for Ti/Al/Ti/Au metallization with a former-Ti/Al ratio of (30 wt.% /70 wt.%). Thermal properties of the Al-based metallization are improved by application of Mo layer as a barrier under the upper Au film of the contact structure. These contacts show excellent thermal stability at operating temperatures as high as 400oC. The less Al amount in the contact composition and Mo barrier layer contribute to the smoother surface and better edge acuity.

Effect of polycyclosilane microstructure on thermal properties

2021 ◽  
Author(s):  
Qifeng Jiang ◽  
Sydnee Wong ◽  
Rebekka S Klausen
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Thermal Characterization ◽  
Side Chains ◽  
Phase Properties

Thermal characterization of polysilanes has focused on the influence of organic side chains, whereas little is understood about the influence of silane backbone microstructure on thermal stability, phase properties, and...

scholarly journals Identification and Characterization of a Novel Thermostable and Salt-Tolerant β-1,3 Xylanase from Flammeovirga pacifica Strain WPAGA1

Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1287
Author(s):  
Zhiwei Yi ◽  
Zhengwen Cai ◽  
Bo Zeng ◽  
Runying Zeng ◽  
Guangya Zhang
Keyword(s):  
Thermal Stability ◽  
Salt Tolerance ◽  
3D Structure ◽  
Catalytic Efficiency ◽  
Dynamics Simulation ◽  
Carbohydrate Binding ◽  
Salt Tolerant ◽  
Excellent Thermal Stability ◽  
Moderately Thermophilic

β-1,3 xylanase is an important enzyme in the biorefinery process for some algae. The discovery and characterization of new β-1,3 xylanase is a hot research topic. In this paper, a novel β-1,3 xylanase (Xyl88) is revealed from the annotated genome of Flammeovirga pacifica strain WPAGA1. Bioinformatic analysis shows that Xyl88 belongs to the glycoside hydrolase 26 (GH26) with a suspected CBM (carbohydrate-binding module) sequence. The activity of rXyl88 is 75% of the highest enzyme activity (1.5 mol/L NaCl) in 3 mol/L NaCl buffer, which suggests good salt tolerance of rXy188. The optimum reaction temperature in the buffer without NaCl and with 1.5 mol/L NaCl is 45 °C and 55 °C, respectively. Notably, the catalytic efficiency of rXyl88 (kcat/Km) is approximately 20 higher than that of the thermophilic β-1,3 xylanase that has the highest catalytic efficiency. Xyl88 in this study becomes the most efficient enzyme ever found, and it is also the first reported moderately thermophilic and salt-tolerant β-1,3 xylanase. Results of molecular dynamics simulation further prove the excellent thermal stability of Xyl88. Moreover, according to the predicted 3D structure of the Xyl88, the surface of the enzyme is distributed with more negative charges, which is related to its salt tolerance, and significantly more hydrogen bonds and Van der Waals force between the intramolecular residues, which is related to its thermal stability.

Effect of Long-Term Aging on Microstructure and Mechanical Properties of a Wrought Ni-Base Superalloy

2015 ◽  
Vol 816 ◽  
pp. 546-550
Author(s):  
Chao Yuan ◽  
Huan Wang ◽  
Jian Ting Guo ◽  
He Yong Qin
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Room Temperature ◽  
Excellent Thermal Stability ◽  
Good Thermal Stability ◽  
Increasing Trend ◽  
Size And Morphology ◽  
Strength And Plasticity ◽  
Base Superalloy

During long-term and high temperature service, microstructures of superalloys may change and then have an adverse impact on mechanical properties, so the stabilities of a wrought Ni-base superalloy aging without stress at 650°C were investigated in this paper. The results showed that the size and morphology of γ' precipitates in the alloy were not obviously influenced with the increase of exposure time, and primary MC carbides present excellent thermal stability. Moreover, almost no detrimental phase was found. Tensile strength and plasticity at room temperature after aging remained steady. Under the condition of 650°C/823MPa, the stress ruptures life presented increasing trend overall and plasticity decreases slightly. In conclusion, the experiment alloy presents a good thermal stability at 650°C.

scholarly journals Multi-wavelength excited white-emitting K2Gd(1−x)(PO4)(WO4):xDy3+ phosphors with satisfactory thermal properties for UV-LEDs

RSC Advances ◽  
2017 ◽  
Vol 7 (37) ◽  
pp. 23083-23092 ◽  
Author(s):  
Yue Guo ◽  
Byung Kee Moon ◽  
Byung Chun Choi ◽  
Jung Hyun Jeong ◽  
Jung Hwan Kim
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Excellent Thermal Stability ◽  
Multi Wavelength ◽  
Uv Leds

Luminescent multi-wavelength excited K2Gd(1−x)(PO4)(WO4):xDy3+ phosphors have excellent thermal stability and warm white emissions.

Study on the thermal stability of Controlled Permeability Formwork

2011 ◽  
Vol 374-377 ◽  
pp. 1426-1429
Author(s):  
Xiao Meng Guo ◽  
Jian Qiang Li ◽  
Xian Sen Zeng ◽  
De Dao Hong
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Dynamic Mechanical Analysis ◽  
Thermo Gravimetric Analysis ◽  
Mechanical Analysis ◽  
Gravimetric Analysis ◽  
Construction Work ◽  
Thermo Gravimetric ◽  
Excellent Thermal Stability ◽  
Thermal Stability Of

In this study, the thermal properties of a kind of new geotextile materials, so called controlled permeable formwork (CPF), were studied. Thermo-gravimetric analysis showed that the weight of CPF didn’t change much between 0~350 °C. Dynamic mechanical analysis showed that the storage modulus of CPF reduced from 25 MPa to around 10 MPa when the temperature rose to above 100 °C. The strength of sample decreased slightly with the increase of the temperature. The breaking elongation changed slightly with a maximum at 80 °C. The CPF showed excellent thermal stability and was suitable for general use in construction work.

Investigations on the Machinability of Titanium Alloy TC25

2014 ◽  
Vol 800-801 ◽  
pp. 92-96
Author(s):  
Hong Shan Zhang ◽  
Xing Ai ◽  
Zhan Qiang Liu ◽  
Ji Gang Liu ◽  
Zhao Lin Zhong
Keyword(s):  
Thermal Stability ◽  
Surface Roughness ◽  
Titanium Alloy ◽  
Service Life ◽  
Heat Resistance ◽  
Cutting Forces ◽  
Cutting Parameters ◽  
Aircraft Industry ◽  
Excellent Thermal Stability ◽  
Cemented Carbide Tools

Titanium alloy TC25 has been widely used in aircraft industry due to its excellent thermal stability, heat resistance and longer service life. In this paper, cemented carbide tools were applied to carry out orthogonal milling experiments for both titanium alloy TC25 and TC4 with identical cutting conditions. Cutting forces, cutting temperatures and surface roughness were measured to assess the machinability for TC25 and TC4. From the experimental results, the cutting parameters can be optimized to guide efficient machining processing of TC25.

Clay modification with silane compounds and characterization of the silicone rubber/clay composites

2012 ◽  
Vol 32 (8-9) ◽  
pp. 493-502 ◽  
Author(s):  
Kyeong Hoon Jang ◽  
Eung-Soo Kim ◽  
Young Ho Jeon ◽  
Jin-San Yoon
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Silicone Rubber ◽  
Cross Linking ◽  
Mechanical And Thermal Properties ◽  
Curing Agent ◽  
Thiol Groups ◽  
Rubber Composites ◽  
Clay Modification

Abstract Na+ montmorillonite (MMT) was modified with benzyldimethyltetradecylammonium chloride (B13) and further with (3-mercaptopropyl)triethoxysilane and vinyltrimethoxysilane to prepare B13-MMT, mercaptomethylorthosilicate modified MMT (MTMO), and vinyltrimethoxysilane modified MMT (VTMO), respectively. The pristine and modified clays were compounded with an HTV-type silicone rubber (GP-30®), and the physical properties and morphology of the resulting rubber composites were examined. Both HTV/MTMO and HTV/VTMO exhibited an intercalated/exfoliated coexisting morphology, but the degree of exfoliation of the former composite was higher than that of the latter. Moreover, the thermal stability, as assessed by the onset temperature of thermal degradation, as well as the tensile stress, elongation at the break, and tear strength of HTV/MTMO was higher than those of HTV/B13-MMT and HTV/VTMO. However, the cross-linking density of HTV/MTMO was the lowest among the composites examined because the thiol groups of MTMO extinguished and abstracted the radicals formed by the curing agent. Accordingly, the improved mechanical and thermal properties of HTV/MTMO were attributed to the enhanced interactions between HTV and MTMO due to the chemical reaction between the thiol groups of MTMO and the vinyl groups of HTV.

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