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A froth velocity measurement method based on improved U-Net++semantic segmentation in flotation process

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1816-1827页

作者： Yiwei chen Degang Xu Kun wan School of Automation Central South UniversityChangsha 410083China

During flotation,the features of the froth image are highly correlated with the concentrate grade and the corresponding working *** static features such as color and size of the bubbles and the dynamic features such as velocity have obvious differences between different working *** extraction of these features is typically relied on the outcomes of image segmentation at the froth edge,making the segmentation of froth image the basis for studying its visual ***,the absence of scientifically reliable training data with label and the necessity to manually construct dataset and label make the study difficult in the mineral *** solve this problem,this paper constructs a tungsten concentrate froth image dataset,and proposes a data augmentation network based on Conditional Generative Adversarial Nets(cGAN)and a U-Net++-based edge segmentation *** performance of this algorithm is also evaluated and contrasted with other algorithms in this *** the results of semantic segmentation,a phase-correlationbased velocity extraction method is finally suggested.

关键词： froth flotation froth segmentation froth image data augmentation velocity extraction image features

Large Deviations for a Critical Galton-Watson Branching Process

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Acta Mathematicae Applicatae Sinica 2024年

作者： dou-dou LI wan-lin SHI Mei ZHANG College of Statistics and Data Science Faculty of Science Beijing University of Technology Laboratory of Mathematics and Complex Systems (Ministry of Education) School of Mathematical SciencesBeijing Normal University Department of Mathematics and Physics North China Electric Power University

In this paper, a critical Galton-Watson branching process{Zn}is considered. Large deviation rates of SZn:=∑i=1ZnXiare obtained, where{Xi, i≥1}is a sequence of independent and identically distributed random variables and X1is in the domain of attraction of an α-stable law with α∈(0, 2). One shall see that the convergence rate is determined by the tail index of X1and the variance of Z1. Our results can be compared with those ones of the supercritical case.

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Intravascular photoacoustic and optical coherence tomography imaging dual-mode system for detecting spontaneous coronary artery dissection: A feasibility study

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Journal of Innovative Optical Health Sciences 2024年第1期17卷 77-86页

作者： Yongwei wang Yuyang wan Zhongjiang chen MOE Key Laboratory of Laser Life Science&Institute of Laser Life Science South China Normal University Guangzhou 510631P.R.China College of Biophotonics South China Normal University Guangzhou 510631 P.R.China School of Medical Technology and Engineering Fujian Medical University Fuzhou 350004 P.R.China

In this work,we present an intravascular dual-mode endoscopic system capable of both intravascular photoacoustic imaging(IVPAI)and intravascular optical coherence tomography(IVOCT)for recognizing spontaneous coronary artery dissection(SCAD)*** provides high-resolution and high-penetration images of intramural hematoma(IMH)at different depths,so it is especially useful for imaging deep blood clots associated with imaging *** can readily visualize the double-lumen morphology of blood vessel walls to identify intimal *** also demonstrate the capability of this dual-mode endoscopic system using mimicking phantoms and biological samples of blood clots in ex vivo porcine *** results of the experiments indicate that the combined IVPAI and IVOCT technique has the potential to provide a more accurate SCAD assessment method for clinical applications.

关键词： Spontaneous coronary artery dissection(SCAD) intravascular optical coherence tomography(IVOCT) intravascular photoacoustic imaging(IVPAI)

Cobalt-nanoparticle catalysts derived from zeolitic imidazolate framework@MXene composites for efficient oxidative self-coupling of benzylamines

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Frontiers of Chemical Science and Engineering 2024年第1期18卷 95-106页

作者： Jie chen Mingyuan Jian Deqiong Xie Kecan dou Deli chen Weidong Zhu Fumin Zhang Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Institute of Physical ChemistryZhejiang Normal UniversityJinhua 321004China

In this study,we synthesize a catalyst comprising cobalt nanoparticles supported on MXene by pyrolyzing a composite in a N2 ***,the composite comprises a bimetallic Zn/Co zeolitic imidazole framework grown in situ on the outer surface of *** catalytic efficiency of the catalyst is tested for the self-coupling of 4-methoxybenzylamine to produce value-added imine,where atmospheric oxygen(1 atm)is used as the *** on the results,the catalyst displayed impressive catalytic activity,achieving 95.4%yield of the desired imine at 383 K for 8 ***,the catalyst showed recyclability and tolerance toward benzylamine substrates with various functional *** outstanding performance of the catalyst is primarily attributed to the synergetic catalytic effect between the cobalt nanoparticles and MXene support,while also benefiting from the three-dimensional porous ***,a preliminary investigation of potential reaction mechanisms is conducted.

关键词： MXene sacrificial template oxidative self-coupling Co nanoparticles imine

Stepwise Ecological Restoration:A framework for improving restoration outcomes

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Geography and Sustainability 2024年第2期5卷 160-166页

作者： Junguo Liu Yuehan dou He chen Henan Provincial Key Laboratory of Hydrosphere and Watershed Water Security North China University of Water Resources and Electric PowerZhengzhou 450046China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Health and Environmental Sciences Xi’an Jiaotong-Liverpool UniversitySuzhou 215123China

Ecosystem degradation is one of the critical constraints for the sustainable development of our ***,recovering an ecosystem to a pre-impairment condition is often not *** International Restoration Standards provide the first framework for practical guidance on what constitutes the process of ecological repair and how this repair process can be influenced to improve net ecological *** these Standards,Restorative Continuum is highlighted and it recognises that many do not,yet there is still value in aspiring to improvements to the highest extent possible,with some sites potentially being able to be improved in a stepwise *** we elaborate on these Standards by providing a cross-ecosystem theoretical framework of Stepwise Ecological Restoration(STERE)for promoting higher environmental *** allows the selection of suitable restorative modes by considering the degree of degradation while encouraging a transition to a higher *** models include environmental remediation for completely modified and degraded ecosystems,ecological rehabilitation for highly modified and degraded ecosystems,and ecological restoration for degraded native *** requires selecting tailored restorative modes,setting clear restorative targets and reference ecosystems,applying a systematic-thinking approach,and implementing a continuous monitoring program at all process stages to achieve a resilient *** allows adaptive management in the context of climate change,and when the evidence is available,to“adapt to the future”to ensure climate *** STERE framework could assist in initiating and implementing restoration projects worldwide,especially in developing countries.

关键词： Ecological restoration Reference ecosystem Restorative modes Sustainable development

The breaking of spin symmetry in the single-particle resonances in deformed nuclei

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Nuclear Science and Techniques 2024年第3期35卷 237-245页

作者： Zhen-Yu Zheng Shou-wan chen Quan Liu School of Physics and Optoelectronic Engineering Anhui UniversityHefei 230601China

The exploration of spin symmetry (SS) in nuclear physics has been instrumental in identifying atomic nucleus *** this study,we solve the Dirac equation from the relativistic mean field (RMF) in complex momentum *** investigated SS and its breaking in single-particle resonant states within deformed nuclei,with a focus on the illustrative *** was the initial discovery of a resonant spin doublet in a deformed nucleus,with the expectation of the SS approaching the continuum *** increasing single-particle energy,the splitting of the resonant spin doublets widened *** escalating splitting implies diminishing adherence to the SS,indicating a departure from the expected behavior as the energy levels *** also analyzed the width of the resonant states,showing that lower orbital angular momentum resonances possess shorter decay times and that SS is preserved within broad resonant doublets,as opposed to narrow resonant *** the radial density of the upper components for the bound-state and resonant-state doublets,it becomes evident that while SS is well-preserved in the bound states,it deteriorates in the resonant *** impact of nuclear deformation (β_(2)) on SS was examined,demonstrating that an increase in β_(2) resulted in higher energy and width splitting in the resonant spin doublets,which is attributed to increased component ***,the sensitivity of spin doublets to various potential parameters such as surface diffuseness (a),radius (R),and depth (Σ0) is discussed,emphasizing the role of these parameters in *** study provides valuable insights into the behavior of spin doublets in deformed nuclei and their interplay with the nuclear structure,thereby advancing our understanding of SS in the resonance state.

关键词： Spin symmetry Resonant states Deformed nuclei Complex-momentum representation

Effect of slag composition on kinetic behavior of deep deoxidation of 5 wt.% Si high-silicon austenitic stainless steel

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Journal of Iron and Steel Research International 2024年第8期31卷 1873-1885页

作者： Guan-xiong dou Han-jie Guo Jing Guo Xue-cheng Peng Qing-yun chen School of Metallurgical and Ecological Engineering University of Science and Technology Beijing(USTB)Beijing 100083China Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials Beijing 100083China

Based on a thermodynamic study of 5 wt.%Si high-silicon austenitic stainless steel(SS-5Si)smelting using CaF_(2)-CaO-Al_(2)0_(3)-Mg-Si0_(2) slag to obtain a low oxygen content of less than 10×10^(-4) wt.%,a kinetic mass transfer model for deep deoxidation was established through laboratory studies,and the effects of slag components and temperature on deoxidation during the slag-steel reaction process of sS-5Si were systematically *** experimental data verified the accuracy of the model *** results showed that the final oxygen content in the steel at 1873 K was mainly controlled by the oxygen content derived from the activity of SiO_(2) regulated by the[Si]-[O]equilibrium reaction in the slag system;in particular,when the slag basicity R(R=w(CaO)/w(SiO2),where w(CaO)and w(SiO_(2))are the contents of CaO and SiO_(2) in the slag,respectively)is 3,the Al2O3 content in the slag needs to be less than 2.7%.The mass transfer rate equation for the kinetics of the deoxidation reaction revealed that the mass transfer of oxygen in the liquid metal is the rate-controlling step under different slag conditions at 1873 K,and the oxygen transfer coefficient ko.m increases with increasing the slag basicity from 4.0×10^(-6)m s^(-1)(R=1)to 4.3×10^(-5) m s^(-1)(R=3).ko.m values at R=2 and R=3 are almost the same,indicating that high slag basicity has little *** integral of the mass transfer rate equation for the deoxidation reaction of SS-5Si under different slag conditions is *** total oxygen content of the molten steel decreases with increasing basicity from an initial content of 22×10^(-4) to 3.2×10^(-4) wt.%(R=3),consistent with the change in ko.m with slag *** R=2,the slag-steel reaction takes 15 min to reach equilibrium(w[O]=5.5×10^(-4) wt.%),whereas at R=3,the slag-steel reaction takes 30 min to reach equilibrium(w[0]=3.2×10^(-4) wt.%).Considering the depth of deoxidation and reaction time of SS-5Si smelting,it is recommended the slag b

关键词： Slag-steel reaction Kinetics Rate-controlling step Deep deoxidation Transfer coefficient

Unraveling the mechanism of potassium metal capacitor for highly efficient charge storage

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Science China Chemistry 2024年第5期67卷 1578-1588页

作者： Qianqian Yao Pei Tang Kunyao Peng Zhenyuan Miao Yuecong chen Qingyun dou Xingbin Yan Department of Materials Science and Engineering Sun Yat-sen UniversityGuangzhou 510275China South China Academy of Advanced Optoelectronics South China Normal UniversityGuangzhou 510006China

Although hybrid metal ion capacitors(MICs) are highly desired to achieve both high power density of supercapacitors and high energy density of rechargeable batteries, the mismatch problem of electrochemical kinetics of negative and positive electrodes in MICs hampers the realization of this goal. Here, a new hybrid capacitor concept-potassium metal capacitor(PMC) is proposed for the first time, where potassium metal and commercial activated carbon(AC) without any modification are applied as negative and positive electrodes, respectively, and the electrolyte is the same as that of non-aqueous potassium ion batteries. The simplest PMC prototype exhibits a good combination of high energy density(184.9 Wh kg^(-1)) and power density(12.4 kW kg^(-1)), which benefits from the synergistic effect of potassium metal and AC electrode. The former experiences fast potassium plating/striping during charging and discharging, and the later possesses complex multiple charge behaviors driven by low potential of potassium metal. Specifically, below open-circuit voltage, transportation of solvated cations in AC pores plays an important role;beyond this voltage, synergy actions of cations and anions, including adsorption/desorption of solvated cations and anions, and ions exchange between them, dominate the capacitance contribution. This work enriches the types of MICs, and deepens the understanding of the energy storage mechanism of non-aqueous hybrid metal capacitors.

关键词： hybrid capacitor potassium metal activated carbon charge storage mechanism

NIR-IIb-triggered photodynamic therapy combined with chemotherapy platform based on rare-earth-doped nanoparticles

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Rare Metals 2024年第7期43卷 3220-3231页

作者： Zhuo Tu Yong wan Juan Ge chen-chen Li Tao Liang Zhen Li Chemistry and Chemical Engineering Hubei UniversityWuhan 430062China

Photodynamic therapy(PDT),with high spatiotemporal selectivity,minimal side effects and less drug resistance,has emerged as a promising approach for the treatment of ***,inadequate penetration depth and poor efficacy seriously restrict its practical *** address these challenges,we developed a combined therapy platform(RENP@C/D-FA)based on rare-earth-doped nanoparticles(RENPs)with a structure of NaErF_(4):Tm(0.5%)@NaYF_(4),on which photosensitizer Ce6(chlorin e6)and chemo-therapeutic drug(DOX)(doxorubicin)were loaded by encapsulating with an amphiphilic polymer distearoyl phosphatidylethanolamine-polyethylene glycol-folic acid(DSPE-PEG-FA).RENPs with NaErF_(4) as the matrix possess multiple excitation/emission peaks,enabling activation of PDT under near-infrared-Ⅱb(NIR-Ⅱb,1500-1700 nm)excitation and luminescence imaging in NIR-Ⅱb region by absorbing 808 nm near-infrared ***,DOX can be selectively released in the acidic microenvironment of *** from the tumor targeting capability of folic acid,this platform can successfully ablate tumor cells and inhibit tumor growth by combining PDT and *** innovative approach holds great promise as a powerful tool for cancer treatment,showing the potential to revolutionize PDT.

关键词： Photodynamic therapy Rare-earth-doped nanoparticles NIR-IIb Chemotherapy Combined therapy