نتایج جستجو برای: composite propeller
تعداد نتایج: 125326 فیلتر نتایج به سال:
This paper numerically discusses how the performance of a NACA marine propeller is affected by the number of blades, which is one of the most crucial geometrical parameters determining the performance of a propeller. Results are presented in terms of the hydrodynamic and structural parameters. The results show that changing the number of blades changes the hydrodynamic efficiency, torque, thrus...
The modular structure of many protein families, such as β-propeller proteins, strongly implies that duplication played an important role in their evolution, leading to highly symmetrical intermediate forms. Previous attempts to create perfectly symmetrical propeller proteins have failed, however. We have therefore developed a new and rapid computational approach to design such proteins. As a te...
The aim of this paper is to present a hybrid electrical air-cushion tracked vehicle (HETAV) for the operation on swamp peat. Mathematical models are incorporated with accounting kinematics and dynamics behaviors of the vehicle. Sinkage of the HETAV is sensed by an ultrasonic displacement (UD) sensor, in order to operate the air-cushion system. The air-cushion of HETAV is protected with a novel-...
Quantitative abdominal T(2) measurements may be useful for lesion differentiation and functional tissue characterization. However, T(2) mapping of the abdomen with conventional spin-echo (SE) and turbo-spin-echo (TSE) approaches can be challenging due to physiologic motion artifacts. Multishot TSE-based PROPELLER (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction) can...
The form of a real AT-body fermion wave function when expanded in Slater determinants of natural orbitals is investigated using a computer. I t is found that in the case when the number of natural orbitals is N f 2 there is a considerable reduction in the number of Slater determinants required. This offers the possibility of calculating atomic wave functions which are significantly more accurat...
Periodically rotated overlapping parallel lines with enhanced reconstruction-echo-planar imaging (PROPELLER-EPI) is a multishot technique that samples k-space by acquisition of narrow blades, which are subsequently rotated until the entire k-space is filled. It has the unique advantage that the center of k-space, and thus the area containing the majority of functional MRI signal changes, is sam...
PROPELLER technique is widely used in MRI examinations for being motion insensitive, but it prolongs scan time and is restricted mainly to T2 contrast. Parallel imaging can accelerate PROPELLER and enable more flexible contrasts. Here, we propose a multi-step joint-blade (MJB) SENSE reconstruction to reduce the noise amplification in parallel imaging accelerated PROPELLER. MJB SENSE utilizes th...
In AE Aqr, magnetic fields transfer energy and angular momentum from a rapidly spinning white dwarf to material in the gas stream from the companion star, with the effect of spinning down the white dwarf while flinging the gas stream material out of the binary system. This magnetic propeller produces a host of observable signatures, chief among which are broad single-peaked flaring emission lin...
Polyethylene glycol binding alters human telomere G-quadruplex structure by conformational selection
Polyethylene glycols (PEGs) are widely used to perturb the conformations of nucleic acids, including G-quadruplexes. The mechanism by which PEG alters G-quadruplex conformation is poorly understood. We describe here studies designed to determine how PEG and other co-solutes affect the conformation of the human telomeric quadruplex. Osmotic stress studies using acetonitrile and ethylene glycol s...
Quiet PROPELLER MRI techniques match the quality of conventional PROPELLER brain imaging techniques.
BACKGROUND AND PURPOSE Switching of magnetic field gradients is the primary source of acoustic noise in MR imaging. Sound pressure levels can run as high as 120 dB, capable of producing physical discomfort and at least temporary hearing loss, mandating hearing protection. New technology has made quieter techniques feasible, which range from as low as 80 dB to nearly silent. The purpose of this ...
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