摘要:
Device for focusing pulses comprising at least emitting means comprising a network (5) of transducers (6), these emitting means being adapted to make the network of transducers emit, into a reflective cavity (7), at least one wave focused onto at least one target point (4) of a target medium (2). The reflective cavity comprises a multi—scattering medium (8) adapted to cause multiple scattering of said wave.
摘要:
A device (10) for receiving and/or emitting an electromagnetic wave, comprising a medium (11) of dielectric material, a plurality of passive resonant elements (12) incorporated inside said medium, the plurality of passive resonant elements (12) comprising a frequency band-gap, two neighbor passive resonant elements belonging to the plurality being spaced apart from each other of a first distance lower than λ/4, and at least one active resonant element (13) incorporated inside said plurality, said active resonant element (13) having a second structure different from a first structure of the passive resonant elements (12), so that said active resonant element (13) has at least a second resonance frequency comprised inside the frequency band-gap of said plurality of passive elements (12).
摘要:
Method of high-resolution ultrasound imaging, in which transducers (T 1 -T n ) are made to emit ultrasound waves in a field of observations containing micro bubbles, by making the micro bubbles burst one by one in tandem with the emissions of ultrasound waves. At each shot j of an ultrasound wave, raw reverberated signals S j (i,t) picked up by each transducer i are recorded, and then differential signals V j (i,t) representative of variations between successive raw signals are determined, a parabolic function P j (x) is fitted to the differential signals corresponding to each shot j, and then a crest A j (x 0 ,y 0 ) of this function P j , corresponding to the position of the micro bubble destroyed between shots j-1 and j, is determined.
摘要:
Method for rheological characterization of a viscoelastic medium, comprising the following steps: (a) an excitation step during which a vibratory excitation is generated in the viscoelastic medium leading to a deformation of the medium, (b) a deformation measurement step during which the deformation of the medium caused by the excitation is observed, (c) and a characterization step during which at least one non-zero power parameter y is determined such that a rheological parameter of the medium x is equal to x(f ) = a + b.fy, where f is the frequency, a is a real number and b a non-zero scale parameter. It is thus possible to obtain mapping of the power parameter y.
摘要翻译:粘弹性介质的流变学表征方法,具有以下步骤:(a)在粘弹性介质中产生振动激发导致介质变形的激发步骤,(b)变形测量步骤,其中变形 观察到由激励引起的介质,(c)和表征步骤,其中确定至少一个非零功率参数y,使得介质x的流变参数等于x(f)= a + b ·fy,其中f是频率,a是实数和ba非零比例参数。 因此可以获得功率参数y的映射。
摘要:
The inventive imaging method consists in generating a mechanical wave having shearing and compressional components in a viscoelastic medium and in determining the movement parameter of said viscoelectic medium at different points during the propagation of said mechanical wave. Said method comprises a correction stage when the movement parameter is processed for eliminating errors caused by the compressional component of the mechanical wave.