Study on stress testing of ferromagnetic materials based on magnetic anisotropy

The stress testing and evaluation of ferromagnetic materials that are widely applied in engineering has always been a focus of, and presented difficulties for, non-destructive testing. As there is still no effective method for detecting the stress of ferromagnetic materials, this paper puts forward the idea of applying the magnetic anisotropy method based on the inverse magnetostriction effect in stress testing of ferromagnetic materials. According to the principle of the magnetic anisotropy method, this paper discusses the development of Mn-Zn ferrite probes of three different structures, the construction of a magnetic anisotropy testing system comprising an excitation system, a signal collecting system and a signal processing system and the way in which a testing experiment was conducted on a 16MnR steel plate specimen under different conditions of stress, frequency and excitation voltage. All three types of probe can effectively determine the stress location of the specimen and present different phenomena and characteristics of the test. According to the experiment, significant correlation is seen between the stress and the magnetic signal, which provides a new idea for stress testing of ferromagnetic materials.

Nondestructive Detection of Ceramic Products Based on Tapping Sound Signal Feature Recogition

Recent studies on the test of ceramic non-destructive testing are mainly based on high cost technologies, image processing and so on, these method possesses some drawback of low efficiency, high cost and so on. What’s more, detecting whether the ceramic products by human through listening to sound of tapping is also effectless. This paper proposed a non-destructive method for ceramic products to solve this problem. This non-destructive method consists of a tapping device and a signal processing module. The tapping device will be applied to generate the tapping sound signal and the signal processing system will be applied to analysis signal. After the process of signal analysis, sample length and peak of spectrum 2 parameters is extracted, then use these parameters to train SVM, the results will be compared with BP neural network (BPNN). The result of experiment shows that SVM with different kernels of linear, poly, rbf, sigmoid respectively reach the accuracy of 96.29%, 96.29%, 46.29%, 93.82%, while BPNN reaches the accuracy of 93.21%. This result proves that SVM can effectively complete the task of identifying defective ceramics, and its performance is better than BPNN.

Sequential generation of self-starting diverse operations in all-fiber laser based on thulium-doped fiber saturable absorber

Self-starting Q-switching, Q-switched mode-locking and mode-locking operation modes are achieved sequentially in an all-fiber erbium-doped fiber laser with thulium-doped fiber saturable absorber for the first time. The central wavelengths of Q-switching, Q-switched mode-locking and mode-locking operation modes are 1569.7 nm, 1570.9 nm, and 1572 nm, respectively. The mode-locking operation of the proposed fiber laser generates stable dark soliton with a repetition rate of 0.99 MHz and signal-to-noise ratio of 65 dB. The results validate the capability of generating soliton pulse by doped fiber saturable absorber. Furthermore, the proposed fiber laser is beneficial to the applications of optical communication and signal processing system.

Development of Pulsar Digital Backend Based on RFSoC

Radio Frequency System on Chip (RFSoC) offers great potential for implementing a complete next generation signal processing system on a single board for radio astronomy. We designed a pulsar digital backend system based on ZCU111 board. The system uses RFSoC technology to implement digitization, channelization, correlation and high-speed data transmission in the Xilinx ZU28DR device. We have evaluated the performance of the 12-bit, 8 RF-ADCs, which are integrated in RFSoC, with the maximum sampling rate of 4.096 GSPS. The RF-ADC sampling frequency, channel bandwidth and the time resolution can be configured dynamically in our designed system. To verify the system performance, we deployed the RFSoC board on the Nanshan 26-meter radio telescope and observed the pulsar signal with a frequency resolution of 1 MHz and time resolution of 64 us. In the observation test, we obtained pulsar profiles with high signal-to-noise ratio and accurately searched the DM values. The experiment results show that, the performance of RF-ADCs, FPGA and CPU cores in RFSoC is sufficient for radio astronomy signal processing applications.

A LOW POWER AND HIGH SPEED APPROXIMATE ADDER FOR IMAGE PROCESSING APPLICATIONS

Low power is an essential requirement for suitable multimedia devices, image compression techniques utilizing several signal processing architectures and algorithms. In numerous multimedia applications, human beings are able to congregate practical information from somewhat erroneous outputs. Therefore, exact outputs are not necessary to produce. In Digital signal processing system, adders play a vital role as an arithmetic module in fixing the power and area utilization of the system. The trade off parameters such as area, time and power utilization also the fault tolerance environment of few applications have employed as a base for the adverse development and use of approximate adders. In this paper, various types of existing adders, approximate adders are analyzed based on the area, delay and power consumption. Also an approximate, high speed and power efficient adder is proposed which yields the better performance than the existing adders. It can be used in various image processing applications, data mining and where the accurate outputs are not needed. The existing and proposed approximate adders are simulated by using Xilinx ISE for time and area utilization. Power simulation has been done by using Microwind Software.