scholarly journals Critical Output Torque of a GHz CNT-Based Rotation Transmission System Via Axial Interface Friction at Low Temperature

2019 ◽  
Vol 20 (16) ◽  
pp. 3851
Author(s):  
Puwei Wu ◽  
Jiao Shi ◽  
Jinbao Wang ◽  
Jianhu Shen ◽  
Kun Cai
Keyword(s):  
Low Temperature ◽  
Rotational Frequency ◽  
Interface Friction ◽  
Output Torque ◽  
Torque Moment ◽  
System Temperature ◽  
Lower Temperature ◽  
Dynamics Simulations ◽  
Driving Torque ◽  
Sudden Jump

It was discovered that a sudden jump of the output torque moment from a rotation transmission nanosystem made from carbon nanotubes (CNTs) occurred when decreasing the system temperature. In the nanosystem from coaxial-layout CNTs, the motor with specified rotational frequency (ωM) can drive the inner tube (rotor) to rotate in the outer tubes. When the axial gap between the motor and the rotor was fixed, the friction between their neighbor edges was stronger at a lower temperature. Especially at temperatures below 100 K, the friction-induced driving torque increases with ωM. When the rotor was subjected to an external resistant torque moment (Mr), it could not rotate opposite to the motor even if it deformed heavily. Combining molecular dynamics simulations with the bi-sectioning algorithm, the critical value of Mr was obtained. Under the critical torque moment, the rotor stopped rotating. Accordingly, a transmission nanosystem can be designed to provide a strong torque moment via interface friction at low temperature.

scholarly journals Fast oxygen ion migration in Cu–In–oxide bulk and its utilization for effective CO2 conversion at lower temperature

2021 ◽  
Author(s):  
Jun-Ichiro Makiura ◽  
Takuma Higo ◽  
Yutaro Kurosawa ◽  
Kota Murakami ◽  
Shuhei Ogo ◽  
...  
Keyword(s):  
Low Temperature ◽  
Water Gas Shift ◽  
Chemical Looping ◽  
Co2 Conversion ◽  
Ion Migration ◽  
Oxygen Ion ◽  
Reverse Water Gas Shift ◽  
Oxygen Ion Migration ◽  
Lower Temperature ◽  
Water Gas

Efficient activation of CO2 at low temperature was achieved by reverse water–gas shift via chemical looping (RWGS-CL) by virtue of fast oxygen ion migration in a Cu–In structured oxide, even at lower temperatures.

Rotation-induced axial oscillation of a composite nanoconvertor at low temperature

2020 ◽  
pp. 107754632093711
Author(s):  
Bo Song ◽  
Kun Cai ◽  
Jiao Shi ◽  
Qing-Hua Qin
Keyword(s):  
Molecular Dynamics ◽  
Low Temperature ◽  
Large Amplitude ◽  
Oscillation Amplitude ◽  
Axial Direction ◽  
Axial Vibration ◽  
Axial Oscillation ◽  
Axial Translation ◽  
Vibration Responses ◽  
Dynamics Simulations

We propose a model of a nanostructure which can transform an input rotation into an output oscillation. In the model, the rotor has two identical internally hydrogenated deformable parts. The mechanism is that the rotation-induced centrifugal force and van der Waals force drive the recoverable deformation of the hydrogenated deformable parts, which gives rise to the axial translation of the free end of the rotor. Once the two hydrogenated deformable parts deform periodically, the free end of the rotor oscillates periodically in the axial direction. Molecular dynamics simulations are conducted to reveal the dynamic response of the system at low temperature. Four main types of deformation and the first three orders of vibration responses of the hydrogenated deformable parts are analyzed. Synchronous breathing vibration of the two hydrogenated deformable parts produces ideal oscillation with large amplitude. Asynchronous axial vibration of the hydrogenated deformable parts reduces the oscillation amplitude or produces beat vibration. The way to control the amplitude of the axial oscillation/vibration is given.

scholarly journals Crystallization Behavior of the Low-Temperature Mineralization Sintering Process for Glass Nanoparticles

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3281
Author(s):  
Yeongjun Seo ◽  
Tomoyo Goto ◽  
Sunghun Cho ◽  
Tohru Sekino
Keyword(s):  
Low Temperature ◽  
Crystallization Behavior ◽  
Sol Gel ◽  
Hydrothermal Condition ◽  
Uniaxial Pressure ◽  
Sintering Process ◽  
Bioactive Glasses ◽  
Sol Gel Process ◽  
Sbf Solution ◽  
Lower Temperature

Bioactive glasses are promising materials for various applications, such as bone grafts and implants. The development of sintering techniques for bioactive glasses is one of the most important ways to expand the application to biomaterials. In this paper, we demonstrate the low-temperature mineralization sintering process (LMSP) of glass nanoparticles and their crystallization behavior. LMSP is a novel process employed to densify glass nanoparticles at an extremely low temperature of 120 °C. For this new approach, the hydrothermal condition, mineralization, and the nanosize effect are integrated into LMSP. To induce mineralization in LMSP, bioactive glass nanoparticles (BGNPs, 55SiO2-40CaO-5P2O5, mol%), prepared by the sol-gel process, were mixed with a small amount of simulated body fluid (SBF) solution. As a result, 93% dense BGNPs were realized under a temperature of 120 °C and a uniaxial pressure of 300 MPa. Due to the effect of mineralization, crystalline hydroxyapatite (HAp) was clearly formed at the boundaries of BGNPs, filling particles and interstitials. As a result, the relative density was remarkably close to that of the BGNPs conventionally sintered at 1050 °C. Additionally, the Vickers hardness value of LMSP samples varied from 2.10 ± 0.12 GPa to 4.28 ± 0.11 GPa, and was higher than that of the BGNPs conventionally sintered at 850 °C (2.02 ± 0.11 GPa). These results suggest that, in addition to LMSP being an efficient densification method for obtaining bulk bioactive glasses at a significantly lower temperature level, this process has great potential for tissue engineering applications, such as scaffolds and implants.

Effects of Neutron Irradiation on Tensile Properties of V-Ti-Cr-Si Type Alloys with Pre-Existing Helium

1998 ◽  
Vol 540 ◽  
Author(s):  
M. Satou ◽  
T. Chuto ◽  
H. Koide ◽  
A. Hasegawa ◽  
K. Abe
Keyword(s):  
Low Temperature ◽  
Ambient Temperature ◽  
Tensile Properties ◽  
Yield Stress ◽  
Neutron Irradiation ◽  
Uniform Elongation ◽  
Temperature Range ◽  
Temperature Irradiation ◽  
Helium Implantation ◽  
Lower Temperature

AbstractHelium effect on loss of uniform elongation after low-temperature neutron irradiation of the V-Ti-Cr-Si-Al-Y alloy was studied. Helium implantation to about 30 atomic ppm was carried out before neutron irradiation to 50 dpa at 406°C. The yield stress of the irradiated specimen with helium pre-implantation was slightly smaller than that of irradiated specimens without helium. The uniform elongation and the increase in yield stress of the irradiated specimens were not affected by helium pre-implantation at ambient temperature. It might be possible that the helium effect appears after lower temperature irradiation such as 300°C or lower, which corresponds to the temperature range where the loss of uniform elongation of the alloy is particularly pronounced.

Low Temperature Growth Mechanisms for Rheed Oscillations

1993 ◽  
Vol 312 ◽  
Author(s):  
R. Biswas ◽  
K. Roos ◽  
M. C. Tringides
Keyword(s):  
Low Temperature ◽  
Thermal Diffusion ◽  
Ultrathin Films ◽  
Surface Display ◽  
Landing Site ◽  
Lateral Motion ◽  
Temperature Growth ◽  
Dynamics Simulations ◽  
Three Body ◽  
Open Question

AbstractLow temperature (T<150 K) RHEED oscillations during the growth of ultrathin films suggest the presence of substantial adatom mobility. In most systems thermal diffusion can not account for the observed oscillations, and the origin of the oscillations is an open question. Experiments on Ag/Si(111) at 150 K demonstrate the absence of thermal diffusion due to the observed scaling in the RHEED intensity for different flux rates. We have performed molecular dynamics simulations to understand the mechanisms of RHEED oscillations at low temperature. Classical two- and three-body Si potentials were used together with an adatom mass that is 3.84 times the Si mass to account for the Ag/Si mass ratio. Results indicate that the landing site for the adatom is very important to predict whether a particular adatom will display lateral motion or not. A fraction of the adatoms incident near a maximum of the potential energy surface display significant lateral motion. The substrate stiffness for Ag/Si results in an energy transfer process which is much slower than that in fcc/fcc systems.

scholarly journals The Low-Temperature Crystallization and Interface Characteristics of ZnInSnO/In Films Using a Bias-Crystallization Mechanism

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
K. J. Chen ◽  
F. Y. Hung ◽  
T. S. Lui ◽  
S. J. Chang ◽  
Z. S. Hu
Keyword(s):  
Low Temperature ◽  
Transparent Conductive Oxide ◽  
Crystallization Mechanism ◽  
Critical Factors ◽  
Interface Characteristics ◽  
Short Period ◽  
Higher Temperature ◽  
Low Temperature Crystallization ◽  
Lower Temperature ◽  
Temperature Crystallization

This study presents a successful bias crystallization mechanism (BCM) based on an indium/glass substrate and applies it to fabrication of ZnInSnO (ZITO) transparent conductive oxide (TCO) films. The effects of bias-crystallization on electrical and structural properties of ZITO/In structure indicate that the current-induced Joule heating and interface diffusion were critical factors for low-temperature crystallization. With biases of 4 V and 0.1 A, the resistivity of the ZITO film was reduced from3.08×10−4 Ω∗cm to6.3×10−5 Ω∗cm. This reduction was attributed to the bias-induced energy, which caused indium atoms to diffuse into the ZITO matrix. This effectuated crystallizing the amorphous ZITO (a-ZITO) matrix at a lower temperature (approximately170∘C) for a short period (≤20 min) during a bias test. The low-temperature BCM developed for this study obtained an efficient conventional annealed treatment (higher temperature), possessed energy-saving and speed advantages, and can be considered a candidate for application in photoelectric industries.

Interface Conditions for Coupled Atomistic and Continuum Models of Solids for Dynamics Problems at Finite Temperature

2006 ◽  
Vol 978 ◽  
Author(s):  
Xiantao Li ◽  
Weinan E
Keyword(s):  
Molecular Dynamics ◽  
Boundary Conditions ◽  
Finite Temperature ◽  
Langevin Equations ◽  
Continuum Models ◽  
Interface Conditions ◽  
System Temperature ◽  
Dynamics Simulations ◽  
Dynamics Problems ◽  
Generalized Langevin Equations

AbstractWe will present a general formalism for deriving boundary conditions for molecular dynamics simulations of crystalline solids in the context of atomistic/continuum coupling. These boundary conditions are modeled by generalized Langevin equations, derived from Mori-Zwanzig's formalism. Such boundary conditions are useful in suppressing phonon reflections, and maintaining the system temperature.

Thermal Adaptation of Pennisetum: Leaf Structure and Composition

1977 ◽  
Vol 4 (4) ◽  
pp. 541 ◽  
Author(s):  
CJ Pearson ◽  
DG Bishop ◽  
M Vesk
Keyword(s):  
Low Temperature ◽  
Temperature Sensitivity ◽  
Thermal Adaptation ◽  
Chloroplast Ultrastructure ◽  
Lipid Phase ◽  
Genotypic Differences ◽  
Lipid Phase Transitions ◽  
Chlorophyll Accumulation ◽  
Chlorophyll Distribution ◽  
Lower Temperature

Studies were made of the effects of growth temperatures and transition to colder temperature on chloroplast ultrastructure, chlorophyll accumulation, lipids and protein of two Pennisetum americanum cultivars and a P. americanum × P. purpureum biotype which differed in temperature sensitivity. All genotypes had structure and chlorophyll distribution consistent with NADP-malic enzyme C4 systems and lipid phase transitions at temperatures similar to those of other 'chilling-sensitive' plants. All accumulated less starch at low temperature and there was mobilization of starch, aggregation of thylakoids in mesophyll chloroplasts and swelling of loculi on transition from 24/19 to 18/13°C. Intolerance of Pennisetum to low temperature was clearly not due to accumulation of starch, nor were genotypic differences in temperature sensitivity related to starch. The cold susceptibility of cv. Ingrid Pearl, in contrast with the tolerance of the intraspecific and interspecific hybrids, was associated with inability to accumulate chlorophyll in the mesophyll of some leaves; fluctuations in chlorophyll a/b ratios within 5 days of transition to lower temperature; and inability to accumulate higher concentrations of soluble proteins in apparently normal leaves grown at 18/13°C. Genotypic differences in temperature sensitivity did not appear related to the physical properties of membranes, which did not change within 5 days of transition to 18/13°C.

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