scholarly journals Graphene Membrane as Suspended Mask for Lithography

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Giampiero Amato ◽  
Angelo Greco ◽  
Ettore Vittone
Keyword(s):  
Mechanical Properties ◽  
Ambient Air ◽  
Quality Requirements ◽  
Graphene Membrane ◽  
Mesoscopic Devices ◽  
Quantum Phenomena ◽  
Lithographic Masks ◽  
Shadow Evaporation

Thanks to its excellent mechanical properties, graphene is particularly suited for the realization of suspended membranes. The present paper deals with one possible application of such membranes that is the realization of suspended lithographic masks for shadow evaporation onto a substrate. This technique, which is largely used for realizing mesoscopic devices, where the quality requirements for the junctions prevent the exposure to ambient air and the occurrence of quantum phenomena requires highly defined structures, can be improved by the use of pure 2-dimensional masks, like graphene ones. Advantages and differences of this material with respect to commonly employed polymers are presented and discussed.

scholarly journals Fabrication and Quantum Phenomena of Superconducting Mesoscopic Devices.

Materia Japan ◽  
1999 ◽  
Vol 38 (11) ◽  
pp. 880-887
Author(s):  
Atsushi Saito ◽  
Katsuyoshi Hamasaki ◽  
Takashi Ishiguro
Keyword(s):  
Mesoscopic Devices ◽  
Quantum Phenomena

Environmental Effects on the Static and Fatigue Behaviours of Hemp Fibre under Tensile Loading

2015 ◽  
Vol 798 ◽  
pp. 410-418
Author(s):  
Anh Dung Ngo ◽  
Thu Nga Ho ◽  
Khalid Sefrioui Manar
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Failure Modes ◽  
Harmful Effect ◽  
Tensile Loading ◽  
Ambient Air ◽  
Absorption Mechanism ◽  
Hemp Fibre ◽  
Temperature And Humidity ◽  
Static Tensile

Environmental and loading mode effects on the tensile properties of Hemp fibre were investigated. At first, absorption of moisture into the fibre from ambient air and absorption of water into the fibre in immersion were studied. Then static and cyclic loadings tensile tests were conducted in various temperature and humidity conditions. It was found that, in ambient air (0% < RH < 80%) the moisture content of the studied fibre decreased with the increase of temperature conformed to the GAB model suggesting a multilayer absorption mechanism. On the contrary, for the fibre immersed in water, the moisture content increased with the increase of temperature. The activation of temperature on the diffusion of the water into the fibre by micro-pores and lumens jointly with the lack of possibility for the imprisoned water to evaporate might be the cause of this effect. Experimental results suggested that temperature and humidity could individually reduce the mechanical properties of Hemp fibre. Their interaction caused even a more harmful effect. Semi empirical and neural networks were used to predict the hygro-thermal effects on the mechanical properties under static tensile loading. Broken surfaces of the specimens were also examined showing different failure modes for static and cyclic tensile loadings. Finally, the value of the cellulose micro-fibrils angle (MFA) estimated using the static tensile stress-strain curve was 8.4o±1.9o.

Focused Ion Beam Induced Surface Damage Effect on the Mechanical Properties of Silicon Nanowires

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Tatsuya Fujii ◽  
Takahiro Namazu ◽  
Koichi Sudoh ◽  
Shouichi Sakakihara ◽  
Shozo Inoue
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Focused Ion Beam ◽  
Young's Modulus ◽  
Ion Beam ◽  
Surface Damage ◽  
Ambient Air ◽  
Film Deposition ◽  
Displacement Sensor ◽  
Uniaxial Tensile

In this paper, the effect of surface damage induced by focused ion beam (FIB) fabrication on the mechanical properties of silicon (Si) nanowires (NWs) was investigated. Uniaxial tensile testing of the NWs was performed using a reusable on-chip tensile test device with 1000 pairs of comb structures working as an electrostatic force actuator, a capacitive displacement sensor, and a force sensor. Si NWs were made from silicon-on-nothing (SON) membranes that were produced by deep reactive ion etching hole fabrication and ultrahigh vacuum annealing. Micro probe manipulation and film deposition functions in a FIB system were used to bond SON membranes to the device's sample stage and then to directly fabricate Si NWs on the device. All the NWs showed brittle fracture in ambient air. The Young's modulus of 57 nm-wide NW was 107.4 GPa, which was increased to 144.2 GPa with increasing the width to 221 nm. The fracture strength ranged from 3.9 GPa to 7.3 GPa. By assuming the thickness of FIB-induced damage layer, the Young's modulus of the layer was estimated to be 96.2 GPa, which was in good agreement with the literature value for amorphous Si.

High-temperature mechanical properties of reduced NiO–8YSZ anode-supported bi-layer SOFC structures in ambient air and reducing environments

2013 ◽  
Vol 39 (3) ◽  
pp. 3103-3111 ◽  
Author(s):  
Somnath Biswas ◽  
Thangamani Nithyanantham ◽  
Saraswathi Nambiappan Thangavel ◽  
Sukumar Bandopadhyay
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Ambient Air ◽  
High Temperature Mechanical Properties

523 Effects of External Stresses on Oxidation in Ambient Air of Nuclear Graphites and Mechanical Properties of Oxidized Ones

2009 ◽  
Vol 2009.17 (0) ◽  
pp. _523-1_-_523-2_
Author(s):  
Yukihiro Sasajima ◽  
Yoshinobu Motohashi ◽  
Takaaki Sakuma ◽  
Taiju Shibata ◽  
Jun Aihara ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ambient Air ◽  
External Stresses

scholarly journals Elastic Modulus, Thermal Expansion, and Pyrolysis Shrinkage of Norway Spruce Under High Temperature

2021 ◽  
Author(s):  
Tito Adibaskoro ◽  
Michalina Makowska ◽  
Aleksi Rinta-Paavola ◽  
Stefania Fortino ◽  
Simo Hostikka
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Elastic Modulus ◽  
Norway Spruce ◽  
Elastic Moduli ◽  
Elevated Temperatures ◽  
Ambient Air ◽  
Time Dependent ◽  
Temperature History ◽  
Direction Parallel

AbstractThe orthotropic and temperature-dependent nature of the mechanical properties of wood is well recognized. However, past studies of mechanical properties at elevated temperatures are either limited to temperatures below 200 °C or focus only on the direction parallel to grain. The effect of time-dependent pyrolysis during measurement is often neglected. This paper presents a novel method for determining elastic modulus at high temperatures and thermal expansion coefficient in different orthotropic directions via Dynamic Mechanical-Thermal Analyser (DMTA). The method allows for drying, drying verification, and measurement in one chamber, eliminating the possibility of moisture reabsorption from ambient air. The repeatable measurements can be carried out in temperatures up to 325°C, adequate for observing time-dependent pyrolysis during measurement. Results of the measurements of Norway Spruce provide data of its mechanical response at temperature range previously not explored widely, as well as in the orthotropic direction. Time-dependent behaviour was observed in the thermal expansion and shrinkage experiment, where above 250°C the amount of shrinkage depends on heating rate. At such temperature, elastic moduli measurement also shows time dependence, where longer heating at certain temperature slightly increases the measured elastic modulus. Additionally, bilinear regression of the relationship between elastic moduli and temperature shows quantitatively good fit. Numerical simulation of the DMTA temperature history and wood chemical components mass losses show the onset of shrinkage and onset of hemicellulose mass loss occurring at around the same time, while decomposition of cellulose correlate with the sudden loss of elastic moduli.

Fracture behavior of Longmaxi shale with implications for subsurface applications

2020 ◽  
Vol 8 (4) ◽  
pp. SP205-SP213
Author(s):  
Zonghu Liao ◽  
Shunjie Deng ◽  
Xiaofeng Chen ◽  
Mengni Wu ◽  
Yongshang Kang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
System Development ◽  
Critical Role ◽  
Microstructural Analysis ◽  
Growth Index ◽  
Ambient Air ◽  
Natural Fractures ◽  
Rock Types ◽  
Longmaxi Shale ◽  
Cracking Mode

Fracture mechanical properties of shales have gained continued interest recently due to their critical role in many shale-related applications such as unconventional petroleum systems and subsurface carbon and waste disposal. However, due to their strong reactive nature to fluids, fracture mechanical properties of shales have not been extensively studied like other rock types. A more comprehensive understanding of fracture system development in shales under reactive fluids is needed for subsurface applications. We have measured fracture mechanical properties of Longmaxi shale outcrop samples in the Sichuan Basin, China, under different environments of ambient air, deionized water, saline fluids of NaCl and KCl at 0.5 M concentration, and acidic HCl fluid at pH of 5. All aqueous fluids tested show strong weakening effects on fracture propagation compared to the air environment, with the fracture toughness reduced by 75% and the subcritical fracture growth index reduced by 50%. Microstructural analysis reveals the predominantly grain boundary opening cracking mode for all tests, but the fracture traces branch more in reactive aqueous fluids. Natural fractures are comparable with artificial fractures in morphology. Bedding-perpendicular opening mode fractures with multiple-stage fracture fillings of calcite, quartz, and organic matters develop well in natural fractures. Our results suggest that clay mineral hydration and expansion are the main cause for the fluid weakening effect in Longmaxi shale, which has substantial implications for subsurface shale failure processes.

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