With use of photon techniques including visible light, soft and hard x-rays, precise fundamental laser welding processes in the repair and maintenance of nuclear plant engineering were reviewed mechanistically. We mak...
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Background: Protein-lipid interactions play essential roles in the conformational stability and biological functions of membrane proteins. However, few of the previous computational studies have taken into account the...
The octopus arm is a unique tool that combines strength and flexibility. It can shorten, elongate and bend at any point along its length. To model this behavior, a hyper-redundant manipulator composed of multiple segm...
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The octopus arm is a unique tool that combines strength and flexibility. It can shorten, elongate and bend at any point along its length. To model this behavior, a hyper-redundant manipulator composed of multiple segments is proposed. Each segment is a parallel robotic mechanism with redundant actuation. The kinematics and dynamics of this manipulator are analyzed and simulated utilizing a modular computational modeling method. Simulation results for some primitive movements are presented, and the effect of hydrodynamic forces is included.
The infrared (IR) absorption spectra and resonant Raman spectra of ABC-stacked tri- and tetra-layer graphene are studied using the density functional theory. It is found that they exhibit very different characteristic...
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The infrared (IR) absorption spectra and resonant Raman spectra of ABC-stacked tri- and tetra-layer graphene are studied using the density functional theory. It is found that they exhibit very different characteristic peaks in their IR spectra and G-band resonant Raman spectra, compared with those of AB-stacked ones, caused by the different stacking sequence and interlayer coupling. The anisotropy of the IR spectra with respect to the direction of the light electric field is significant. The IR spectra are more sensitive to the stacking number when the electric field is perpendicular to the graphene plane due to the interlayer polarization. On the other hand, the calculated first-order G-band resonant Raman spectra are also found to be sensitive to the different stacking sequence and stacking number, though the sensitivity will decay as the stacking number increases. The high sensitivities make both IR and Raman spectra possible to identify the stacking sequence and number of few-layer graphene by comparing theory and experiment.
The need for large-scale electronic structure calculations arises recently in the field of material physics, and efficient and accurate algebraic methods for large simultaneous linear equations become greatly importan...
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The need for large-scale electronic structure calculations arises recently in the field of material physics, and efficient and accurate algebraic methods for large simultaneous linear equations become greatly important. We investigate the generalized shifted conjugate orthogonal conjugate gradient method, the generalized Lanczos method, and the generalized Arnoldi method. They are the solver methods of large simultaneous linear equations of the one-electron Schrödinger equation and map the whole Hilbert space to a small subspace called the Krylov subspace. These methods are applied to systems of fcc Au with the NRL tight-binding Hamiltonian [F. Kirchhoff et al., Phys. Rev. B 63, 195101 (2001)]. We compare results by these methods and the exact calculation and show them to be equally accurate. The system size dependence of the CPU time is also discussed. The generalized Lanczos method and the generalized Arnoldi method are the most suitable for the large-scale molecular dynamics simulations from the viewpoint of CPU time and memory size.
Repetitive Transcranial Magnetic Stimulation (rTMS) is effective for intractable diseases of the nervous system. As the effects of rTMS last only several hours, rTMS therapies need to be continued daily. Under present...
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Repetitive Transcranial Magnetic Stimulation (rTMS) is effective for intractable diseases of the nervous system. As the effects of rTMS last only several hours, rTMS therapies need to be continued daily. Under present circumstances, it is difficult to use rTMS in patients' home, because only experienced physicians in limited hospitals can use the expensive and complicated rTMS system. Therefore, we developed a magnetic navigation system for home use of rTMS. The proposed system uses inexpensive and small magnetic sensors;hence it is suitable for home use. By using the proposed method, even people who have no medical knowledge and technique can easily navigate the coil to the optimal position preliminarily specified by expert physicians. Our system needs to collect some dataset which consists of magnetic field and the corresponding position of the coil at the patients' initial visit. Since it is bothersome to collect a large number of dataset, we reduced the dataset by approximation using multi-regression analysis.
The electric field dependence and anisotropy of the impact ionization coefficients of 4H-SiC are investigated by means of the avalanche breakdown behavior of p+n diodes. The breakdown voltages as a function of doping ...
The electric field dependence and anisotropy of the impact ionization coefficients of 4H-SiC are investigated by means of the avalanche breakdown behavior of p+n diodes. The breakdown voltages as a function of doping density and the multiplication factors of a leakage current are obtained using p+n diode fabricated on (0001) and (1120) 4H-SiC epitaxial wafers. The obtained impact ionization coefficients show large anisotropy; the breakdown voltage of a p+n diode on (1120) wafer is 60% of that on (0001) wafer. We have shown that anisotropy of the impact ionization coefficients is attributable to the anisotropy of saturation velocity originated from the electronic structure of 4H-SiC.
Vacancy-type defects in plasma immersion B-implanted Si were probed by a monoenergetic positron beam. A positron annihilates with an electron and emits two 511 keV γ-quanta. Doppler broadening spectra of the annihila...
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Silicon (Si) is currently the basis of most of our nanodevice technology and ultrathin materials based on Si would have the great advantage of easy integration into existing circuitry. Recently, it has been demonstrat...
Silicon (Si) is currently the basis of most of our nanodevice technology and ultrathin materials based on Si would have the great advantage of easy integration into existing circuitry. Recently, it has been demonstrated using molecular-dynamics calculations that two-dimensional ultrathin layered Si can be formed by cooling fluid Si confined in a slit pore [T. Morishita et al., Phys. Rev. B 77, 081401(R) (2008)]. Here we investigate, using ab initio density-functional theory, the structural and electronic properties of ultrathin double layer Si with and without hydrogenation or substitutional doping. We show that such materials have very desirable electronic properties, being able to be changed from metallic to semiconducting. They may also act as p-type or n-type semiconductors upon partial hydrogenation or substitutional doping of phosphorus. We suggest that these materials may be of great importance to production of nanoelectronic devices and sensors.
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