Wyniki wyszukiwania - BazTech

1

An arbitrary waveform synthesis structure with high sampling rate and low spurious

Zhao Wenhao, Tian Shulin, Guo Guangkun, You Jiajing, Wu Qiong, Liu Ke

Metrology and Measurement Systems

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2022

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Vol. 29, nr 1

159--173

EN

The arbitrary waveform generator is characterised by its flexible signal generation, high frequency resolution and rapid frequency switching speed and is wildly used in fields like communication, radar systems, quantum control, astronautics and biomedicine. With continuous development of technology, higher requirements are placed on to the arbitrary waveform generator. Sampling rate determines the bandwidth of the output signal, spurious-free dynamic range determines the quality of generated signal. Due to above, these two indicators’ improvement is vital. However, the existing waveform generation methods cannot generate signals with quality good enough due to their technical limitations, and in order to realize a high system sampling rate, to accomplish waveform generation process in FPGA, multipath parallel structure is needed. Therefore, we proposed a parallel waveform synthesis structure based on digital resampling, which fixed the problems existing in the current methods effectively and achieved a high sampling rate as well as high quality arbitrary waveform synthesis. We also built up an experimental test bench to validate the proposed structure.

2

Research on the impacts of information capacity on farmers’ green prevention and control technology adoption

Wu Qiong, Gao Shujie, Wang Xulong, Zhao Yushuai

Ecological Chemistry and Engineering. S

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2022

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Vol. 29, nr 3

305--317

EN

This study was carried out to reveal the key factors affecting farmers’ green prevention and control technology adoption and to deeply analyse the influence of different generations of farmers’ information capacity on green prevention and control technology adoption. Based on the survey data of 509 farmers in Liaoning Province and the probit model and logit model, this paper conducted an empirical analysis of the farmers’ green prevention and control technology adoption, and analysed the differences in farmers’ adoption of green prevention and control technology from the perspective of intergenerational difference. The research results show as follows: First, information capacity has a significant positive impact on farmers’ green prevention and control technology adoption; Second, the influence of information capacity on the green prevention and control technology adoption of different generations of farmers is different. Information consciousness has more significant influences on farmers in the new and middle-generations; information needs have more significant influences on farmers in the new and old generations; information use only has significant influences on farmers in the middle-generation. Therefore, in order to increase the probability of farmers’ green prevention and control technology adoption, it is necessary to not only pay attention to the influence of farmers’ information capacity, but also fully consider the different stages of the life cycle of different generations of farmers and their own endowment differences.

3

Electrical energy conversion characteristics based on underwater high-voltage pulse discharge

Yan Dong, Chen Songbai, Wu Qiong, Zhang Fengxiang, Lai Lipeng, Chen Inchen

Journal of Power Technologies

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2021

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Vol. 101, nr 4

190--201

EN

Underwater high-voltage (HV) pulse discharge mainly involves the process of HV discharge, breaking down water and releasing huge amounts of electrical energy, which is then rapidly converted into plasma. The plasma expands and creates shock waves and bubble pulsation effects. These effects are the main ways in which electrical energy transfers into mechanical energy. A breakdown process analysis model and an experimental method are proposed with a view to revealing the energy conversion characteristics during underwater pulse discharge and to understand the basic physical process. A plasma channel model was established in combination with the existing fundamentals of electricity and theoretical analysis. In addition, the discharge process was analyzed, along with shock wave and bubble pulsation action characteristics, on the basis of an underwater pulse discharge experiment. Meanwhile, theoretical analysis revealed the basic physical process involved in the electrical energy conversion effect. The results demonstrate the following: (1) The vaporization-ionization" breakdown model divides the breakdown process into three stages (i.e., heating effect, breakdown detonation and mechanical energy effect stages); (2) the heating effect stage is a phase prior to breakdown, which possesses significant heating characteristics and generates initial plasma; (3) a large electric current (104A) during the breakdown process heats the plasma channel to a high-temperature, where it becomes dense; this condition is followed by an instant decrease in channel resistance; the breakdown current peak depends on the residual voltage at the moment of breakdown; (4) during the breakdown detonation stage, discharge breakdown occurs, along with electric arc detonation. After the heating gasification process, when the electrical field intensity is suficient, the high-temperature HV plasma rapidly expands outward, resulting in a rapid conversion from electrical energy to mechanical energy. Thus, shock waves are formed, followed by bubble pulsation. The proposed method provides a good prospect for the application of underwater HV pulse discharge technology in the field of engineering.

4

Need for cognitive closure, information acquisition and adoption of green prevention and control technology

Wu Qiong, Zhou Jing

Ecological Chemistry and Engineering. S

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2021

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Vol. 28, nr 1

129--143

EN

In this paper, we use the OLS regression method to analyse the influencing mechanism of the NFCC on farmers’ adoption of green prevention and control technology and further verify the mediating effect of information acquisition. The results show that the NFCC has a direct effect on the adoption of green prevention and control technology, and information acquisition has a mediating effect. The first stage of cognitive closure has a more significant effect on farmers’ adoption of green prevention and control technology, information acquisition ability has a significant positive impact on farmers’ adoption of green prevention and control technology, and information acquisition has an incomplete mediating effect on the impact of cognitive closure on the adoption of green prevention and control technologies. This paper further studies and verifies the action path of two dimensions of the NFCC on farmers’ adoption of green prevention and control technology. The results have certain theoretical significance for expanding the knowledge of farmers’ green prevention and control technology behaviour and further enriching the research on farmers’ cognition.