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This paper aims to investigate glass residual fiber length and fiber orientation of anisotropic injection molded glass fiber reinforced polyamide 66 composites (GF/PA66). A combined experimental and numerical study was carried out to investigate the effects of initial glass fiber length and fiber mass fraction on the finished samples. The model was validated with the experimental value. The glass fibers were oriented during the injection molding, and subsequently the composites exhibited anisotropic properties. Additionally, with the increase of fiber mass fraction, more fibers become oriented in the flow direction (Y direction). Moreover, the samples had a skin-core-skin structure and the residual fiber length in the skin layer was shorter than that in the core layer. Furthermore, with the increase of length-diameter ratio of initial fiber ranging from 50 to 90 and the increase of fiber mass fraction, the damage sustained by glass fiber during manufacturing aggravated and subsequently the loss rate of fiber length increased.

In order to better detect information about a mass in breast tissue, an ultrasound tomography algorithm based on adaptive time gain compensation (TGC) was designed. Field II was utilized to automatically evaluate the phantom attenuation coefficient and compensate for the attenuated image. The image reconstruction algorithm process is presented here. Furthermore, the experimental setup with the cylindrical motion of a piezoelectric micromachined ultrasonic transducer (PMUT) linear array was used to detect the mass in the breast model. The attenuation coefficient was evaluated by using the spectral cross-correlation method. According to the acquired attenuation coefficients, TGC compensates for the pulse-echo signal, and the horizontal slice image was reconstructed using the tomography algorithm. The experimental results show that this algorithm can evaluate the attenuation coefficient of the breast model and improve the ability to detect an internal mass. At the same time, the realization of attenuation compensation with software is beneficial to the development of portable medical equipment.

In recent years, short glass fiber reinforced PA66 composites (GF/PA) have been considered to be certain significant to promote the development of “automotive lightweight”. At current study, the mechanical properties of injection molded GF/PA were investigated both in axial and off-axis directions. In addition, the fiber volume fraction (vf ) and the residual length as well as the distribution of glass fiber (GF) after injection molding were investigated particularly to evaluate the interfacial property based on SEM observation and Kelly-Tyson model equation. It is found that the composites have a trend with a slight increase in the critical fiber length and decreased interfacial shear strength with an increase of vf.

In order to solve the problem of ultrasonic transmission attenuation in breast soft tissue, an ultrasound tomography algorithm based on time gain compensation (TGC) is presented. It is imaging of the breast with cylindrical motion of Piezoelectric Micromachined Ultrasonic Transducer (PMUT) linear array. The attenuation coefficients of the water, breast and mass were automatically evaluated by the spectral cross-correlation. Field II is used for simulation analysis, plus the detailed extraction process of attenuation coefficients and the influencing factors are provided. According to the acquired attenuation coefficients, and the pulse echo signal is compensated using TGC. The horizontal slice image is obtained. Experimental results show that this algorithm can effectively evaluate the attenuation coefficient of soft tissue. Besides, the size, location and boundary of breast masses can be detected. At the same time, using software to realize attenuation compensation is beneficial to the development of portable medical equipment.

The influence of vibration on the output of hydrophone having a serious disturbance on the measurement of sound. To suppress the output of hydrophone caused by vibration promoting its engineering application, a crafty piezoresistive eight beams vector hydrophone with thick thickness of mass block was designed. The models of presented hydrophone were established. Based on the models, a method optimizing the thickness of mass block to suppress the output caused by vibration, but hardly no influence on the output of hydrophone resulted by sound. The FEM simulation results demonstrate the practicality of this method. The output caused by vibration is minimum and output resulted by sound has hardly influence when the thickness of mass block is 230 μm for the designed hydrophone. This is beneficial to the engineering application of vector hydrophone.

In this paper, we propose a multi-perspective ultrasound imaging technology with the cylindrical motion of four piezoelectric micromachined ultrasonic transducer (PMUT) rotatable linear arrays. The transducer is configured in a cross shape vertically on the circle with the length of the arrays parallel to the z axis, roughly perpendicular to the chest wall. The transducers surrounded the breast, which achieves non-invasive detection. The electric rotary table drives the PMUT to perform cylindrical scanning. A breast model with a 2 cm mass in the center and six 1-cm superficial masses were used for the experimental analysis. The detection was carried out in a water tank and the working temperature was constant at 32 &deg, C. The breast volume data were acquired by rotating the probe 90&deg, with a 2&deg, interval, which were 256 &times, 180 A-scan lines. The optimized segmented dynamic focusing technology was used to improve the image quality and data reconstruction was performed. A total of 256 A-scan lines at a constant angle were recombined and 180 A-scan lines were recombined according to the nth element as a dataset, respectively. Combined with ultrasound imaging algorithms, multi-perspective ultrasound imaging was realized including vertical slices, horizontal slices and 3D imaging. The seven masses were detected and the absolute error of the size was approximately 1 mm where even the image of the injection pinhole could be seen. Furthermore, the breast boundary could be seen clearly from the chest wall to the nipple, so the location of the masses was easier to confirm. Therefore, the validity and feasibility of the data reconstruction method and imaging algorithm were verified. It will be beneficial for doctors to be able to comprehensively observe the pathological tissue.

A bionic fish cilia median-low frequency three-dimensional MEMS vector hydrophone is reported in this paper. The piezoresistive reasonable position was obtained through finite element analysis by ANSYS and the structure was formed by MEMS processes including lithography, ion implantation, PECVD and etching, etc. The standing wave barrel results show that the lowest sensitivity of the hydrophone is −200 dB and reach up to −160 dB (in which the voltage amplification factor is 300). It has a good frequency response characteristics in 25 Hz ∼ 1500 Hz band. Directivity tests displayed that the hydrophone has a good “8”-shaped directivity, in which the resolution is not less than 30 dB, and asymmetry of the maximum axial sensitivity value is less than 1.2 dB.

Optical micro-ring resonator prepared on Silicon-On-Insulator (SOI) has high sensitivity, small size and low mode volume. Its high sensitivity has been widely applied to the optical information transmission and inertial navigation devices field, while it is rarely applied in the testing of Mechanics. This paper presents a cantilever stress/strain gauge with an optical microring resonator. It is proposed the using of radius change of ring waveguide for the sensing element. When external stress is put on the structure, the radius of the SOI ring waveguide will be subjected to variation, which causes the optical resonant parameters to change. This ultimately leads to a red-shift of resonant spectrum, and shows the excellent characteristics of the structure's stress/strain sensitivity. Designed a bicyclic cascade embedded optical micro-cavity structure, which was prepared by employing MEMS lithography and ICP etching process. The characteristic of stress/strain sensitivity was calculated theoretically. Two values of 0.185 pm x kPa(-1) and 18.04 pm x microstrain(-1) were obtained experimentally, which also was verified by theoretical simulations. Comparing with the single-loop micro-cavity structure, its measuring range and stress sensitivity increased by nearly 50.3%, 10.6%, respectively. This paper provides a new method to develop micro-opto-electromechanical system (MOEMS) sensors.

Because traditional method for tunable grating fabrication has harsh process condition, complex fabrication process, high costs and long cycle. Proposed a low-cost, simple process, can be prepared in large quantities gradient grating process method, based on self-assembly process using the rigid film/flexible substrate and oxygen plasma method prepared a micron scale gradient grating. Use of plasma free time controllability and excellent elastic of PDMS obtained the desired grating. First, polyethylene terephthalate (PET) was spin-coated layer of polydimethylsiloxane (PDMS) film on the thin film, two-layer film to be cured PDMS film after bending and treated with an oxygen plasma (plasma), in generating a rigid surface oxide layer, With flexible PET rigid layer applied uniform stress, when the stress exceeds the critical value, the PDMS substrate to form a self-assembled structure grating fold. Due to changes in prestressed bending, so the PDMS film formation period and height of the grating stepped fold, which is graded grating. Using visible light as the performance test light source for graded grating and selecting first-order diffracted as the detection target. The authors can see the grating has a good diffraction effects and achieves good spectral effect. Experiments show that graded grating has obvious diffraction grating, and the diffraction angle varies significantly, and can be widely used for stress measurement, the flexible gradient grating prepared by this method can also be used to detect changes in the stress strain as a miniature device, the future is expected for miniature spectrometer, scanners, optical communications and other fields.