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Study of the Dynamic Processes of Multi-point Initiation of Co-axial Explosively Formed Projectiles with Tail Wings Using High Speed Image Processing Technologies

Zhao Chang-Xiao, Cheng Yangfan, Li Dan-Yi, Zhang Bei-Bei, Wang Xin, Ji Chong

Central European Journal of Energetic Materials

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2024

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Vol. 21, no. 3

255--281

EN

In order to study the dynamic processes of co-axial explosively formed projectiles (CEFP) with tail wings formed by multi-point initiation, a novel image processing technique based on a high-speed camera was designed. The temperature field distribution and formation process of a CEFP with tail wings, formed by multipoint initiation, can be measured using the colorimetric temperature measurement method, the binary image processing technique, and contour detection technologies. The experimental results were verified using LS-DYNA software. The experimental results showed that a projectile with a regular shape and four symmetrical tail wings was formed by initiating the shaped charge with a double-layer liner at four points. The explosion temperature of the detonation products was in the range of 2000-2600 K, and the explosion pressure at the detonation center was 6.92 GPa. The morphology, flight velocity, and draw ratio of the CEFP obtained using the high-speed image processing technology were in good agreement with numerical simulation results, which demonstrates a promising application prospect for measuring the explosion temperature, flight velocity, and motion attitude of shells, rockets, and other kinds of weapons.

2

Evaluation on safety and efficacy of ultrasound assisted thrombolysis in a sheep artificial heart pump

Cui Yongchun, Zheng Xiaobing, Wang Shuo, Zhou Jianye, Yue Guangxin, Peng Peng, Li Qiuju, Li Jubo, Li Yue, Luo Jiafei, Zhang Qi, Zhang Xue, Li Yongjian, Wang Xin

Biocybernetics and Biomedical Engineering

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2024

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Vol. 44, no. 2

277--285

EN

Thrombosis is a major and serious complication in patients with artificial heart pump assist device (HPAD). There is an urgent need for an efficient and safe method to solve the clinical challenge. We have developed a new type of ultrasound integrated heart pump assist device (uHPAD) with a pair of ultrasonic transducer rings installed around the pump. Based on the in-vitro experiments, the sonothrombolysis protocol was determined. Then, in-vivo experiments were performed on sheep to evaluate the efficacy and safety of the novel uHPAD. It is found that the ultrasound assisted thrombolysis with the drug-loaded microbubbles can accelerate the dissolution of the thrombus in the pump, while have no significant negative effect on blood cell components, coagulation-hemolysis system, and the structure and function of main organs. The ultrasound assisted thrombolysis is demonstrated to be a promising method to solve the clinical problem of thrombosis in the HPAD.

3

Adaptive trans-dimensional inversion of multimode dispersion curve based on slime mold algorithm

Wang Xin, Feng Xuan, Liu Qian, Bai Han, Dong Xuri, Wang TaiHan

Acta Geophysica

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2024

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Vol. 72, no. 1

233--245

EN

With the rise of low-cost and high-density observation system Distributed Acoustic Sensing (DAS), the effective utilization of high-mode surface wave becomes extremely important due to unique measuring method of DAS. To solve the interference of mode identification of dispersion curve and model dimension division on inversion results, we introduced the fitting degree of the dispersion curve, the model dimension, and the uncertainty estimation of the picked dispersion curve to construct a new objective function, and developed a strategy of adaptive trans-dimensional inversion of multimode dispersion curve based on slime mold algorithm (SMA). The research results show that our objective function can not only satisfy the fitting degree of dispersion curve, but also adaptively select the best model dimension, and does not depend on the mode identification of dispersion curve. Inversion strategy based on SMA algorithm has high flexibility, accuracy, stability, and practicality. Our method develops a new technology for dispersion curve inversion and provides a new idea for DAS system to realize low-cost and high-resolution city underground structure detection.

4

COVID-RDNet: A novel coronavirus pneumonia classification model using the mixed dataset by CT and X-rays images

Fang Lingling, Wang Xin

Biocybernetics and Biomedical Engineering

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2022

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Vol. 42, no. 3

977--994

EN

Corona virus disease 2019 (COVID-19) testing relies on traditional screening methods, which require a lot of manpower and material resources. Recently, to effectively reduce the damage caused by radiation and enhance effectiveness, deep learning of classifying COVID-19 negative and positive using the mixed dataset by CT and X-rays images have achieved remarkable research results. However, the details presented on CT and X-ray images have pathological diversity and similarity features, thus increasing the difficulty for physicians to judge specific cases. On this basis, this paper proposes a novel coronavirus pneumonia classification model using the mixed dataset by CT and X-rays images. To solve the problem of feature similarity between lung diseases and COVID-19, the extracted features are enhanced by an adaptive region enhancement algorithm. Besides, the depth network based on the residual blocks and the dense blocks is trained and tested. On the one hand, the residual blocks effectively improve the accuracy of the model and the non-linear COVID-19 features are obtained by cross-layer link. On the other hand, the dense blocks effectively improve the robustness of the model by connecting local and abstract information. On mixed X-ray and CT datasets, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), area under curve (AUC), and accuracy can all reach 0.99. On the basis of respecting patient privacy and ethics, the proposed algorithm using the mixed dataset from real cases can effectively assist doctors in performing the accurate COVID-19 negative and positive classification to determine the infection status of patients.

5

Effects of Yttrium (Y) Substitution by Cerium (Ce) on Microstructure and Corrosion Behavior of Near-Equiatomic Alniy Medium-Entropy Amorphous Alloy Ribbons

Zhang Shuyan, Zhang Zhibin, Wang Xin, Gao Yangyang, Liang Xiubing

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

637--643

EN

Through partially replacing Y element, Ce was added into near-equiatomic AlNiY medium-entropy amorphous alloy (denoted as MEAA) ribbons by the melt spinning process in this study. The differences of microstructure, thermal stability, hardness and corrosion resistance of Al33.3Ni33.3Y33.4-xCex(x = 0, 2, 5, 8, 13) alloy ribbons were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimeter (DSC) and Vickers-type hardness tester. The anti-corrosion performance in 3.5 wt.% NaCl solution of alloy ribbons was investigated elaborately through the general potentiodynamic polarization curves (Tafel) and electrochemical impedance spectroscopy (EIS). Results suggested that all ribbon samples could remain amorphous structure and the hardness are all above 510 HV0.1. With the increase of Ce content, the thermal stability begins to be gradually lower. However, according to the analysis of crystallization kinetics, all types of MEAA ribbons presents the relatively prominent thermal stability compared with traditional Al-based amorphous alloys. The corrosion current density raises firstly, then shows a decreasing trend, and has a slight increase at last. Therefore, appropriate content of Ce element can improve the corrosion protection performance of alloy ribbons and the 5 at.% Ce MEAA ribbons exhibited the excellent corrosion resistance in this study.

6

Strengthening the rough selection effect of n-ethyl o-isopropyl thionocarbamate (Dow: Z-200) on chalcopyrite by ultrasonic pretreatment

Wang Yan, Wang Yubin, Yu Bo, Wang Xin, Ma Xiaoxiao

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 1

64--74

EN

In this study, the properties of (CH3)2CHOC(S)NHC2H5(Dow: Z-200) after the ultrasonic pretreatment was characterized by employing surface tension, viscosity, and Fourier transform infrared (FTIR) spectroscopy, and its influence on chalcopyrite rough selecting was investigated. The results indicate that the pretreated Z-200 can improve the index of chalcopyrite roughing. And, under the same reagent system, the recovery of copper reached 82.84% which was an increase of 24.44% compared with the untreated when Z-200 after ultrasonic pretreatment was applied to the rough separation of chalcopyrite. The reason why ultrasonic can strengthen the flotation effect of Z-200 on chalcopyrite is that ultrasonic pretreatment can decrease the surface tension and viscosity of Z-200 and enhance its foaming performance. Meanwhile, the ultrasonic cavitation destroys the molecular structure of Z-200, so that the relative proportion of methyl absorption peak and amine absorption peak in Z-200 increases. This also further improves the collection performance and foaming performance of Z-200 and strengthens its separation effect on chalcopyrite. The research provides a new idea for Z-200 to act on chalcopyrite and improve its flotation efficiency, reduce the amount of flotation reagent, and its pollution to the environment. It also provides a theoretical basis for expanding the application of ultrasonic technology in the field of flotation.

7

Tissue coefficient as a novel index in bioelectric impedance analysis researches and applications

Li Ying, Ma Ren, Wang Xin, Jin Jingna, Wang He, Liu Zhipeng, Yin Tao

Biocybernetics and Biomedical Engineering

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2020

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Vol. 40, no. 3

950--964

EN

Background: Bioimpedance is of great importance in both basic and clinical researches. Though several parameters have been used in detection and analyzing the condition of the tissues and human body epidemically and clinically, we hypothesize that the ratio of resistive and capacitive components of tissues could be discriminative in bioelectric impedance analysis (BIA) related researches. Materials and methods: In this article, we introduced a newly coined parameter, tissue coefficient, to the open data from an online database. Results: The 54 kinds of tissues can be classified into 4 categories: (1) liquid, (2) nail, (3) stomach & muscle, (4) fat & brain. The related time coefficient is especially useful to characterize the liquid-like tissues. Conclusion: The results suggest that the tissue coefficient is promising in distinguishing different tissues, and other BIA-related (bioelectric impedance analysis) scenarios.

8

Tissue coefficient of bioimpedance spectrometry as an index to discriminate different tissues in vivo

Li Ying, Ma Ren, Wang Xin, Jin Jingna, Wang He, Liu Zhipeng, Yin Tao

Biocybernetics and Biomedical Engineering

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2019

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Vol. 39, no. 3

923--936

EN

Bioimpedance indicating cell and tissue condition of the living things is of great importance in impedance spectrum analysis and other related researches, in which measurement of the skin impedance is a tricky problem due to the peculiarity of the stratum corneum. The aim of the study is to develop a method to elucidate the skin impedance in a large frequency range and to find out a biomarker to estimate it. In this article, we introduce a non-destructive method of using both surface and needle electrodes to investigate the electrical properties of the skin including stratum corneum of sixteen anesthetized C57BL/6 mice in vivo. A capacitance model was introduced to bridge the complex Debye's model and the practical three-element model. A new biomarker (tissue coefficient) was introduced to compare the whole skin with the viable skin. The contribution of the viable skin to the impedance of the whole skin can be ignored unless the concerned frequency is much higher than 10 kHz. The CG plot show direct link with the e-s plot, and the tissue coefficient shows significant difference between the whole skin and viable skin and reflects the alpha and beta dispersions. The results suggest that the method of using both surface and needle electrodes to investigate the impedance the whole skin including stratum corneum is practical, and the tissue coefficient is especially suitable for in vivo study, and has great potentials in estimation and discrimination of living tissues, cancer detection, bioelectrical impedance analysis (BIA) and other related fields.