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In this paper we presented the functional analysis of intelligent wheelchair, and proposed system configuration program. The working principle of the ultrasonic sensor system is expounded. We researched the method of path planning and random avoidance, and achieve environment modeling and path planning. Link Graph method is used for modeling whole environment and Dijkstra arithmetic is used to established...
We describe a design for an “audio display”, a loudspeaker that employs the bending vibrations of a panel, such as flat-panel television screen or projection surface, to render localized sound sources anywhere on the surface of the panel. The method employs a two-dimensional Fourier series reconstruction of the desired panel spatial vibration profile, and an array of force actuators affixed to the...
Intelligent Wheelchair Bed (IWB) is an important direction. And it is also one of the most active research direction in the robot field. In this work, the obstacle avoidance algorithm based on the Artificial Potential Field (APF) using ultrasonic sensors is proposed and realized in order to achieve the real-time and continuing obstacle avoidance for the IWB. The IWB can keep on detecting the environment...
Many high-end power machines demand greater bearing performance in terms of running speed, precision, reliability, longevity, noise reduction, etc. An ultrasonic bearing based on Near-Field Acoustic Levitation (NFAL) effect is a kind of emerging noncontact gas bearing. Due to its self-aligning capability, the ultrasonic bearing can steadily run at a high speed under high precision. Actuated by piezoelectric...
Cardiovascular disease, including atherosclerosis and critical limb ischemia, affects millions of people worldwide. There is a clinical need to base treatment decisions on quantitative analysis of the plaque composition. However, no reliable clinical methods to quantify the mechanical properties of plaque components and detect plaque vulnerability currently exist, particularly for coronary disease...
Elastic properties of the ocular tissues are significantly affected by intraocular pressure (IOP) in the eye. For example, the speed of the elastic wave in the cornea dramatically increases with IOP. In our previous studies using ultrasound shear wave imaging we demonstrated that, for the lens, the increase in IOP does not result significant changes in the wave velocity. Compared with ultrasound imaging,...
Piezoelectric ultrasonic motors (PUMs) are based on the concept of driving the runner by a mechanical vibration excited on the stator via the converse piezoelectric effect. They exhibit merits of small size, simple structure, quick response, high accuracy and resolution, self-locking when power off and a lack of electromagnetic radiation. The linear PUMs become the research focus in recent years as...
Blood clotting, a process to avoid bleeding, involves vasoconstriction, platelet plug build-up, coagulation, clot retraction and fibrinolysis. During coagulation, blood changes from liquid to gel, and the clot viscoelastic properties continue modifying until fibrinolysis. Tests to analyze bleeding disorders and anticoagulant therapy include clot-based assays, to detect the end-point of fibrin network...
Ultrasound-mediated drug delivery using microbubbles is a growing field with applications ranging from targeted chemotherapy to permeating the blood brain barrier. Despite the potential clinical impact of this technique, the precise parameters needed to reliably induce cell sonoporation, or increased cellular permeability, are not well understood. The goal of this work is to use high frame rate imaging...
A U-shaped linear piezoelectric ultrasonic motor (PUM) was proposed, designed and tested in this work, in which three longitudinal transducers were used together to achieve the linear driving by two feet synchronously. Longitudinal vibrations of the transducers were generated with certain temporal shift to form the desired elliptical movements on the two driving feet. Finite element method (FEM) was...
The acoustic microstreaming originating from microbubbles' linear oscillations can be used as a potential cell sonoporation tool for drug delivery and gene transfection. However, this bubble-based method suffers from bubble instability, non-uniform size, unreliable performance, and inconvenient trapping. In order to overcome the above drawbacks, in this study, we proposed a massive drug delivery method...
Flow cytometer plays an important role in cell sorting and analysis. Traditional flow cytometers adopt hydrodynamic focusing method which works well when the low flow velocity is relatively low. However, in order to have a higher analysis efficiency for clinical laboratories, a higher flow velocity is preferred, which sometimes will lead to cells siltation when using sheath flow. In this paper, an...
The 30MHz lithium niobate (LiNbO3) ultrasound transducer with a highly focused beam was used to generate gradient force which can pull a single leukemia cell to toward a focus to be a trapping situation. The transducer was sterilized by using 70% ethanol before the experiment. Five leukemia cells before treatment and five cells after treatment by a chemotherapy drug were trapped and measured their...
Myocardial elastance, derived from pressure-volume (PV) loops in the left ventricle (LV), can be used to assess LV function and myocardial performance. This method requires an invasive intracardiac pressure-volume catheter to be inserted in the LV, limiting the method's utility in clinical screening and monitoring. Strain echocardiography and cardiac acoustic radiation force impulse (ARFI) imaging...
A method for measurement of the bladder wall nonlinear elasticity is presented. The method is based on acoustoelasticity modeling of the bladder tissue modulus of elasticity changes at different volumetric loading levels. At each loading volume, tissue strain is obtained from the real-time images. Using acoustic radiation force, a transient Lamb wave is excited on the bladder wall and shear elasticity...
The pathological or physiological changes of the crystalline lens directly affect the eye accommodation and transmittance, and then increase the risk of the presbyopia and cataract for people in middle and old age groups. There is no universally accepted quantitative method to measure the lens' mechanical properties in vivo so far. This study aims to investigate the possibility of assessing the age-related...
A real-time ultrasound (US) coagulation monitoring for coagulation based on acoustic radiation force is described. US imaging to facilitate HIFU has advantages with respect to portability, cost effectiveness and spatiotemporal resolution. Localized motion imaging (LMI) is one of the techniques based on US to detect a change of tissue mechanical properties caused by its thermal coagulation. To achieve...
Cellular functions, for example proliferation, migration or gene expression, usually accompany a relationship with their mechanical properties. Three main methods, including atomic force microscopy (AFM), optical tweezer and magnetic tweezers, have been developed to measure cell's mechanics. However, AFM needs to contact cell resulting in prominent physical changes in elasticity and a pericellular...
The previously reported on-chip acoustic particle sorters mostly rely on high Q-value materials and elaborate geometry designs, which makes these devices not easy to build and unsuited for mass fabrication. In this work, we presented a novel two stage acoustic particle sorting approach with the advantages of operating on low-cost polymer-based microchips and using integrated micromachined ultrasound...
VisR ultrasound characterizes the viscoelastic properties of tissue by fitting acoustic radiation force (ARF)-induced displacements in the region of ARF excitation to a 1D mass-spring-damper (MSD) model. By so doing, viscosity and elasticity are found separately from each other but relative to the applied ARF amplitude. We refer to these parameters as ‘relative elasticity (RE)’ and ‘relative viscosity...
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