作者机构:
[Zhang, Cong; Miao, Qing; Zhang, C; Liu, Ke; Zheng, Ziang; Chen, Dachang] Wuhan Polytech Univ, Sch Elect & Elect Engn, Wuhan 430023, Peoples R China.;[Luo, Yi] Chinese Acad Sci, Inst Elect Engn, Beijing Int S&T Cooperat Base Plasma Sci & Energy, Beijing 100190, Peoples R China.;[Xiao, Song] Wuhan Univ, Sch Elect Engn & Automat, Wuhan, Peoples R China.;[Xiao, Beibei] Jiangsu Univ Sci & Technol, Sch Energy & Power Engn, Zhenjiang, Peoples R China.
通讯机构:
[Luo, Y ] C;[Zhang, C ] W;Wuhan Polytech Univ, Sch Elect & Elect Engn, Wuhan 430023, Peoples R China.;Chinese Acad Sci, Inst Elect Engn, Beijing Int S&T Cooperat Base Plasma Sci & Energy, Beijing 100190, Peoples R China.
摘要:
Abstract Heptafluoroisobutyronitrile (C4F7N) is being considered as a promising alternative to the greenhouse gas SF6 in the electrical industry. However, its biotoxicity necessitates the development of gas sensing technology to detect leaked C4F7N. A combination of density functional theory and experiments was employed to evaluate the adsorption and sensing performance of different metal‐phthalocyanines as potential sensing materials for C4F7N detection. The study included exploring adsorption configurations with adsorption energies, electron transfer, and adsorption distance, as well as comparisons of electronic properties, electron distribution, and density of states (DOS) among the MPcs. Furthermore, gas sensing experiments were conducted using different MPcs to detect 25–100 ppm C4F7N. The results revealed that Mn‐Pc, Fe‐Pc, Co‐Pc, and Zn‐Pc exhibited considerable chemical interactions, while Ni‐Pc and Cu‐Pc showed weaker adsorption strength. These findings were further elucidated based on the electron density and DOS of atomic orbitals. Moreover, gas sensing experiments indicated that Co‐Pc demonstrated a higher response compared to Fe‐Pc at the same concentration of C4F7N. Overall, the theoretical and experimental insights offer valuable guidance for C4F7N detection and provide a systematic approach to screen and explore organometallic polymer‐based gas sensors applicable in various fields.
关键词:
Density functional theory;Surface oxygen;Kinetics analysis;Sensing mechanism;SnO2(110)
摘要:
Surface oxygen species play a key role in determining the chemi-resistive gas sensing performance of SnO2. 2 . Through surface modification, the type of oxygen species at different working temperatures can be modulated, leading to changes in carrier concentration and surface activity. Single atom structures (SAS) hold enormous potential in the gas sensing domain; however, the impact of different SAS on surface oxygen species on SnO2 2 remains unclear, resulting in inconsistent improvements in sensing properties. This study conducted a theoretical investigation of different 4d noble metal SAS (Ru, Rh, and Pd) modified SnO2(1 2 (1 10) surface, encompassing both electronic and chemical sensitization. All three SAS, when substituting penta-coordinated Sn atom (Sn5c), 5 c ), can inject holes and create a thicker depletion layer to varying degrees. Ru and Rh SAS can accelerate the decomposition of adsorbed O2 2 and O3. 3 . More importantly, Ru and Rh can hinder the combination of adsorbed O* species with adjacent two-coordinated lattice oxygen (O2c), 2 c ), enhancing the chemical stability of O*, which plays a decisive role in detecting reducing gases, with Ru exhibiting a better effect. This theoretical work not only enhances methods and mechanisms for adjusting surface oxygen species and improving the sensing performance of SnO2-based 2-based gas sensors, but also provides useful guidance for screening and designing SAS in experimental procedures on different semiconductor metal oxide surfaces.
摘要:
<jats:p>
<p>The advancement of Internet of Things technology has made continuous environmental monitoring a crucial requirement for various applications. To address the issue of the network life cycle, Wireless Rechargeable Sensor Networks (WRSNs) have emerged as a promising solution. This research is focused on WRSN applications in indoor settings such as the Industrial Internet of Things and indoor greenhouses. In such scenarios, rechargeable wireless sensing devices can gather the required information, reducing equipment costs and eliminating the inconvenience of wired sensors. This study proposes the utilization of a genetic algorithm to optimize the deployment of chargers in indoor environments. Compared to greedy algorithms, this approach can determine the best solution for charger deployment and minimize deployment expenses.</p>
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通讯机构:
[Zhang, C ] W;Wuhan Polytech Univ, Sch Elect & Elect Engn, Wuhan 430048, Peoples R China.
关键词:
personal audio system;sound field control;acoustic contrast;reconstruction error;array effort
摘要:
<jats:p>A personal audio system has a wide application prospect in people’s lives, which can be implemented by sound field control technology. However, the current sound field control technology is mainly based on sound pressure or its improvement, ignoring another physical property of sound: particle velocity, which is not conducive to the stability of the entire reconstruction system. To address the problem, a sound field method is constructed in this paper, which minimizes the reconstruction error in the bright zone, minimizes the loudspeaker array effort in the reconstruction system, and at the same time controls the particle velocity and sound pressure of the dark zone. Five unevenly placed loudspeakers were used as the initial setup for the computer simulation experiment. Simulation results suggest that the proposed method is better than the PM (pressure matching) and EDPM (eigen decomposition pseudoinverse method) methods in the bright zone in an acoustic contrast index, the ACC (acoustic contrast control) method in a reconstruction error index, and the ACC, PM, and EDPM methods in the bright zone in a loudspeaker array effort index. The average array effort of the proposed method is the smallest, which is about 9.4790, 8.0712, and 4.8176 dB less than that of the ACC method, the PM method in the bright zone, and the EDPM method in the bright zone, respectively, so the proposed method can produce the most stable reconstruction system when the loudspeaker system is not evenly placed. The results of computer experiments demonstrate the performance of the proposed method, and suggest that compared with traditional methods, the proposed method can achieve more balanced results in the three indexes of acoustic contrast, reconstruction error, and loudspeaker array effort on the whole.</jats:p>
摘要:
Urban sound event detection can automatically preload relevant information for a robot to ensure that it can be applied to various scene-activity tasks. To address the limitations of timbre similarity and scene recognition by audio collection devices, a fusion model based on the self-attention mechanism is proposed in this paper. The model consists of scattering transform and self-attention model. The scattering transform computes modulation spectrum coefficients of multiple orders through cascades of wavelet convolutions and modulus operators. It is learnable compared with Mel-scale Frequency Cepstral Coefficients (MFCC), and can be used to better restore the semantic features of some sound scenes with similar timbres. The transformer has an outstanding effect on Natural Language Processing (NLP) owing to its self-attention mechanism. In this paper, the self-attention mechanism in its encoder was used in the model, mainly to make the feature granularity consistent to refine the features. In addition, Focal Loss function was adopted in the model to curb the sample distribution imbalance. The Google Command and ESC-50 were used to supplement the scene categories of dataset UrbanSound8K. The model parameters of the learnable filters that performed well on the dataset UrbanSound8K were preserved to fine-tune the other two datasets with insufficient data volume and more target categories. The length of slice duration was further explored the in the model. The experimental results show that the model can achieve better performance in a large range of scene models.
摘要:
This paper mainly introduces the basic principles of BCH code, which is a type of error control codes. The error control system is an important method to improve the communication transmission system. Communication system that containing BPSK modulation is built by MATLAB and through simulating and analyzing the performance of BCH communication systems, it was discovered that the BCH code transmission characteristic has significant gain. This paper provides the theory basis for the projects that contain BCH code.
期刊:
Lecture Notes in Electrical Engineering,2013年227(1):679-686 ISSN:1876-1100
通讯作者:
Chen, X.(xfangchen@126.com)
作者机构:
[Xiufang Chen] College of Electrical and Electronic Engineering, Wuhan Polytechnic University, Wuhan, China;[Chaoping Zhang] Department of Physical and Electronic Engineering, Leshan Normal University, Leshan, China