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Relation Between the Eventual Continuity and the E-property for Markov-Feller Semigroups

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 1-16页

作者： Yong liu Zi-yu liu LMAM School of Mathematical SciencePeking UniversityBeijing100871China

We investigate some relations between two kinds of semigroup regularities, namely the e-property and the eventual continuity, both of which contribute to the ergodicity for Markov processes on Polish *** precisely, we prove that for Markov-Feller semigroup in discrete time and stochastically continuous MarkovFeller semigroup in continuous time, if there exists an ergodic measure whose support has a nonempty interior,then the e-property is satisfied on the interior of the support. In particular, it implies that, restricted on the support of each ergodic measure, the e-property and the eventual continuity are equivalent for the discrete-time and the stochastically continuous continuous-time Markov-Feller semigroups.

关键词： Markov-Feller semigroup ergodicity e-property eventual continuity

低模数水玻璃对橡胶轻骨料混凝土力学性能的影响

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排灌机械工程学报 2021年第7期39卷 685-691页

作者：马快乐王海龙刘思盟杨虹张佳豪王辉内蒙古农业大学水利与土木工程学院内蒙古呼和浩特010018

为了了解不同掺量水玻璃对橡胶轻骨料混凝土(RLC)力学性能的影响,在RLC中加入水玻璃,并用20%粉煤灰代替水泥,制作水玻璃掺量分别为0,2%,4%,6%,8%的混凝土试块.通过核磁共振试验研究其微观孔隙变化及强度形成机理;进行对数函数曲线预测... 详细信息

为了了解不同掺量水玻璃对橡胶轻骨料混凝土(RLC)力学性能的影响,在RLC中加入水玻璃,并用20%粉煤灰代替水泥,制作水玻璃掺量分别为0,2%,4%,6%,8%的混凝土试块.通过核磁共振试验研究其微观孔隙变化及强度形成机理;进行对数函数曲线预测和BP神经网络强度预测,判断其可靠性并对比优劣.结果表明:水玻璃的掺入使RLC抗压强度呈现先增大后减小的趋势,其水玻璃最优掺量出现在2%;适量水玻璃的加入可提高0.180 mm的RLC力学性能,使其与最优组(0.850 mm的RLC组)28 d力学性能基本相同;水玻璃加入后混凝土孔隙度呈现出先减小后增大趋势,说明适量水玻璃的掺入可优化混凝土孔隙结构,提高混凝土强度;建立曲线拟合和BP神经网络预测模型,2种预测模型都可用于混凝土龄期强度预测,但BP神经网络预测模型的稳定性、可靠性及参数的全面性要优于曲线拟合模型.

关键词：橡胶水玻璃核磁共振 BP神经网络预测模型

Graph Signal Reconstruction from Low-Resolution Multi-Bit Observations

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Chinese Journal of Electronics 2024年第1期33卷 153-160页

作者： Zhaoting liu Chen YU Yafeng WANG Shuchen liu School of Communication Engineering Hangzhou Dianzi University

Low hardware cost and power consumption in information transmission, processing and storage is an urgent demand for many big data problems, in which the high-dimensional data often be modelled as graph *** paper considers the problem of recovering a smooth graph signal by using its low-resolution multi-bit quantized observations. The underlying problem is formulated as a regularized maximum-likelihood optimization and is solved via an expectation maximization scheme. With this scheme, the multi-bit graph signal recovery(MB-GSR) is efficiently implemented by using the quantized observations collected from random subsets of graph nodes. The simulation results show that increasing the sampling resolution to 2 or 3 bits per sample leads to a considerable performance improvement, while the energy consumption and implementation costs remain much lower compared to the implementation of high resolution sampling.

关键词： Quantization (signal) Costs Power demand Simulation Energy resolution Signal sampling Signal reconstruction

Synthesis of core-shell nanostructured SiO_(2)/TiO_(2)photocatalysts via atomic layer deposition in a fluidized bed with central tube

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Particuology 2024年第8期91卷 19-28页

作者： Wei liu Daoyin liu Zuyang Zhang Zhenkun Sun Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy&EnvironmentSoutheast UniversityNanjing 210096China

Fluidized bed atomic layer deposition is an efficient technique for particle coating with precise control over the film thickness and uniformity at the *** this study,a fluidized bed with a central tube is designed,where the central tube has two roles:improve fluidization and deliver precursors *** synthesis of core-shell structured SiO_(2)/TiO_(2)nanoparticle catalysts for photodegradation of tetracycline hydrochloride(TC)is carried out using TiCl_(4)and H_(2)O as precursors at 180℃under atmospheric *** the combination of vibration and central tube,the segregation of agglomerate size along the bed height is weakened,and the prepared SiO_(2)/TiO_(2)nanoparticles show excellent photocatalytic degradation performance:the degradation efficiency on TC is 96%under 300 W xenon lamp irradiation for 60 *** mechanism of enhanced photocatalytic activity is due to the Ti-O-Si bonds generated at the interface,which increase the ability to absorb sunlight and accelerate the separation of holes and electrons.

关键词： SiO_(2)/TiO_(2)nanoparticles Fluidization Atomic layer deposition Photocatalysts Photocatalytic mechanism

基于分层解码和渐进融合的快速显著性目标检测

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天津大学学报（自然科学与工程技术版） 2024年第7期57卷 721-728页

作者：杨爱萍王子麒程思萌刘彦天津大学电气自动化与信息工程学院天津300072

现有显著性目标检测方法大多只关心模型的检测精度,容易忽略模型的编解码效率,导致网络运行速度较慢.针对上述问题,本文提出一种基于分层解码和渐进融合的快速显著性目标检测网络,并分别设计语义提取模块、空间增强模块和边界提取模块,... 详细信息

现有显著性目标检测方法大多只关心模型的检测精度,容易忽略模型的编解码效率,导致网络运行速度较慢.针对上述问题,本文提出一种基于分层解码和渐进融合的快速显著性目标检测网络,并分别设计语义提取模块、空间增强模块和边界提取模块,对编码器提取到的多尺度特征进行分层筛选和高效解码.其中,语义提取模块可准确定位显著性目标的整体区域,空间增强模块可完整保留显著性目标的空域信息,边界提取模块可增强显著性目标的边界轮廓.由于不同层级特征的感受野和分辨率不同,本文设计了邻间聚合模块和边界细化模块,对筛选后的特征进行渐进式融合并逐步细化得到最后的显著性预测图.实验结果表明,所提方法不仅能够得到边界清晰、区域完整的显著性预测图,还能显著提升模型的编解码效率,快速检测显著性目标,在ECSSD和HKU-IS数据集上的最大值F max分别为0.947和0.936,优于其他方法.

关键词：显著性目标检测分层解码渐进融合邻间聚合边界细化

Optimized the vanadium electrolyte with sulfate-phosphoric mixed acids to enhance the stable operation at high-temperature

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Frontiers of Chemical Science and Engineering 2024年第2期18卷 13-26页

作者： Ling Ge Tao liu Yimin Zhang Hong liu School of Resource and Environmental Engineering Wuhan University of Science and TechnologyWuhan 430081China State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control Wuhan University of Science and TechnologyWuhan 430081China Hubei Collaborative Innovation Center for High Efficient Utilization of Vanadium Resources Wuhan University of Science and TechnologyWuhan 430081China Hubei Provincial Engineering Technology Research Center of High Efficient Cleaning Utilization for Shale Vanadium Resource Wuhan University of Science and TechnologyWuhan 430081China School of Resource and Environmental Engineering Wuhan University of TechnologyWuhan 430070China

Herein, the influence of the concentration design and comprehensive performance of the sulfate-phosphoric mixed acid system electrolyte is investigated to realize an electrolyte that maintains high energy density and stable operation at high temperatures. Static stability tests have shown that VOPO4 precipitation occurs only with vanadium(V) electrolyte. The concentration of vanadium ion of 2.0–2.2 mol·L^(–1), phosphoric acid of 0.10–0.15 mol·L^(–1), and sulfuric acid of 2.5–3.0 mol·L^(–1) are suitable for a vanadium redox flow battery in the temperature range from –20 to 50 ℃. The equations for predicting the viscosity and conductivity of electrolytes are obtained by the response surface method. The optimized electrolyte overcomes precipitation generation. It has 2.8 times higher energy density than the non-phosphate electrolyte, and a coulomb efficiency of 94.0% at 50 ℃. The sulfate-phosphoric mixed acid system electrolyte promotes the electrode reaction process, increases the current density, and reduces the resistance. This work systematically optimizes the concentrations of composition of positive and negative vanadium electrolytes with mixed sulfate-phosphoric acid. It provides a basis for the different valence states and comprehensive properties of sulfate-phosphoric mixed acid system vanadium electrolytes under extreme environments, guiding engineering applications.

关键词： all vanadium redox flow battery mixed-acid vanadium electrolyte concentration optimization response surface methodology high-temperature stability

Performance analysis and multi-objective optimization based on a modified irreversible Stirling cycle

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Science China(Technological Sciences) 2024年第6期67卷 1668-1684页

作者： XU Lei YU MinJie liu ZhiChun liu Wei School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan430074China

The efficiency of the actual Stirling engine is much lower than the ideal Carnot cycle *** obtain more precise efficiency for Stirling engines,this paper proposes a modified Stirling cycle with a more accurate heat transfer process in Stirling engines based on a thermodynamic function called available *** finite-time thermodynamic method is used to analyze the model performance under constant heat source temperature,finite temperature difference heat transfer,and incomplete regenerative processes.A new polytropic process is introduced to model the heat transfer between the working fluid and external heat sources in which only heat above ambient temperature is converted into technical *** regenerator is divided into numerous smaller heat reservoirs with individual temperature to analyze the incomplete regenerative *** expressions of the output power and thermal efficiency are obtained based on the modified irreversible Stirling cycle,and the effects of irreversible losses are analyzed to evaluate the performance of the proposed *** indicate that the efficiency of the modified cycle is much lower than that of the ideal Stirling cycle with an isothermal *** the increase of the average heat transfer temperature difference,there exists an optimum value for the power of the irreversible *** optimum power of the model was obtained for varying thermodynamic parameters by optimizing the average heat transfer temperature difference between the hot and cold *** optimize the irreversible model,the multi-objective optimization analysis is carried out based on NSGA-Ⅱ,which results in an optimized output power of 40.87 kW and an optimized thermal efficiency of 44%.

关键词： stirling cycle regenerative processes isopotential processes multi-objective optimization finite time thermodynamics

Lanthanide-based microlasers:Synthesis,structures,and biomedical applications

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Nano Research 2024年第1期17卷 97-111页

作者： Qian Zhang Yawei liu Kai liu Hongjie Zhang Engineering Research Center of Advanced Rare Earth Materials(Ministry of Education) Department of ChemistryTsinghua UniversityBeijing 100084China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Xiangfu Laboratory Jiaxing 314102China

The large size of lasers limits their applications in confined spaces,such as in biosensing and in vivo brain tissue *** this regard,micron-sized lasers have been *** exhibit great potential for biological detecting,remote sensing,and depth tracking due to their small sizes,sensitive properties of their spectral fingerprints,and flexible positional modulation in the ***-based luminescent materials that possess long excited-state lifetime,narrow emission bandwidth,and upconversion behaviors are promising as gain mediums for novel *** addition,lanthanide-based microlasers could be generated under natural ambient conditions with pumped or continuous light sources,which significantly promotes the practical applications of *** progress in the design,synthesis,and biomedical applications of lanthanide-based microlasers has been outlined in this *** ions doped and upconverted lanthanide-based microlasers are highlighted,which exhibit advantageous structures,miniaturized dimensions,and high lasing *** applications of lanthanide-based microlasers are further discussed,the upconverted microlasers show great advantages for biological applications owing to their tunable excitation and emission characteristics and excellent environmental ***,perspectives and challenges in the field of lanthanide-based microlasers are presented.

关键词： microlasers lanthanide-based luminescent materials upconversion nanoparticles biological applications

Modulation mechanism of electron energy dissipation on superlubricity based on fluorinated 2D ZIFs

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Nano Research 2024年第4期17卷 3198-3209页

作者： Yuxin Li Lei liu Kunpeng Wang Yuhong liu State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China School of Mechatronic Engineering Shanghai UniversityShanghai 200444China

Electron energy dissipation is an important energy dissipation pathway that cannot be ignored in friction ***-dimensional zeolite imidazole frameworks(2D ZIFs)and fluorine doping strategies give 2D Zn-ZIF and 2D Co-ZIF unique electrical properties,making them ideal materials for studying electron energy dissipation *** this paper,based on the superlubricity modulation of 2D fluoridated ZIFs,the optimal tribological properties are obtained on the 2D F-Co-ZIF surface,with the friction coefficient as low as *** experiments,density functional theory(DFT)simulation,and fluorescence detection are used to explain the mechanism of fluorine doping regulation of tribological properties from the two stages,namely energy transfer and energy ***,the energy will transfer into the friction system through the generation of electron–hole pairs under an external excitation,and release by radiation and non-radiation energy dissipation *** reduces energy transfer by altering the electronic properties and band structures of ZIFs,and slows down the charge transfer by enhancing the shielding efficiency,thus slowing the non-radiative energy dissipation rate during the energy release *** insights not only help us better understand the role of fluorine doping in improving tribological properties,but also provide a new way to further explore the electron energy dissipation pathway during friction.

关键词： superlubricity electron energy dissipation modulation two-dimensional zeolite imidazole frameworks(2D ZIFs) fluorination