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Numerical investigations on performance improvement mechanism of a high-power vertical centrifugal pump with special emphasis on hydraulic component matching

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Journal of Hydrodynamics 2023年第4期35卷 649-667页

作者： Gang Yang xi Shen De-sheng Zhang Wen-hua Luo Jia meng xu-tao Zhao Research Center of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang212013China Key Laboratory of Fluid Machinery and Engineering Xihua UniversityChengdu610039China

The purpose of this paper is to investigate the performance improvement mechanism of a high power vertical centrifugal pump by using numerical ***,a comparative study of energy losses and internal flow characteristics in the original and optimized models was carried out with special attention to the hydraulic component *** optimized model(model B)was obtained by optimizing the vaned diffuser and volute based on the original model(model A),mainly the diffuser inlet diameter,diffuser inlet vane angle,volute channel inlet width and volute throat area were ***,the comparative results on performance and energy losses of two models showed that the efficiency and head of model B was significantly increased under design and part-load *** is mainly due to the dramatic reduction of energy loss PL in the diffuser and ***,the comparisons of PL and flow patterns in the vaned diffuser showed that the matching optimization between the model B impeller outlet flow angle and diffuser inlet vane angle resulted in a better flow pattern in both the circumferential and axial directions of the diffuser,which leads to the PL3 *** meridian velocity Vm of model B was significantly increased at diffuser inlet regions and resulted in improvements of flow patterns at diffuser middle and outlet regions as well as pressure expansion ***,the comparisons of PL and flow characteristics in the volute showed that the turbulence loss reduction in the model B volute was due to the flow pattern improvement at diffuser outlet regions which provided better flow conditions at volute inlet *** matching optimization between the diffuser and volute significantly reduced the turbulence loss in volute sections 1–4 and enhanced the pressure expansion capacity in sections 8–10.

关键词： High-power vertical centrifugal pump performance improvement mechanism hydraulic component matching flow pattern energy balance equation

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Effect of ammonium sulfate on the formation of zinc sulfide species on hemimorphite surface and its role in sulfidation flotation

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International Journal of Minerals,Metallurgy and Materials 2023年第11期30卷 2147-2156页

作者： xi Zhang Yu Wang Jiushuai Deng Zhongyi Bai Hongxiang xu Qingfeng meng Da Jin Zhenwu Sun Key Laboratory of Separation and Processing of Symbiotic-Associated Mineral Resources in Non-ferrous Metal Industry School of Chemical and Environmental EngineeringChina University of Mining and Technology(Beijing)Beijing 100083China Inner Mongolia Research Institute China University of Mining and Technology(Beijing)Ordos 017001China State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Kunming 650093China Engineering Technology Research Centre for Comprehensive Utilization of Rare Earth Rare Metal and Rare-Scattered in Non-ferrous Metal IndustryChina University of Mining and Technology(Beijing)Beijing 100083China

Effectively strengthening the surface sulfidation is essential for recovering hemimorphite by froth *** this work,inductively coupled plasma optical emission spectrometer(ICP-OES)measurements,Visual MINTEQ calculation,X-ray photoelectron spectroscopy(XPS)analysis,time of flight secondary ion mass spectrometry(ToF-SIMS)analysis,and micro-flotation experiments were explored to systematically investigate the effect of ammonium sulfate((NH_(4))_(2)SO_(4))on the formation of zinc sulfide species on hemimorphite surface and its role in sulfidation *** results showed that(NH_(4))_(2)SO_(4)exhibited a positive influence on hemimorphite sulfidation *** was ascribed to the number of zinc components in the form of Zn^(2+)and[Zn(NH_(3))_(i)]^(2+)(i=1–4)increased in the flotation system after hemimorphite treatment with(NH_(4))_(2)SO_(4),which was beneficial to its interaction with sulfur species in solution,resulting in a dense and stable zinc sulfide layer generated on the hemimorphite surface.[Zn(NH_(3))_(i)]^(2+)participated in the sulfidation reaction of hemimorphite as a transition *** addition the sulfidation reaction of hemimorphite was accelerated by(NH_(4))_(2)SO_(4).Thus,(NH_(4))_(2)SO_(4)presents a vital role in promoting the sulfidation of hemimorphite.

关键词： hemimorphite sulfidation ammonium sulfate zinc sulfide species adsorption flotation

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Rare nanoparticles shine colors with low-power STED

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Light(Science & Applications) 2022年第7期11卷 1324-1326页

作者： xinzhu xu Peng xi College of Future Technology Peking UniversityBeijingChina

The effect of cascade amplified depletion in lanthanide upconversion systems boosts their own emission bands inhibition,which facilitates multi-color nanoscopy with only one pair of low-power NIR CW lasers.

关键词： Rare lanthanide bands

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Multi-model ensemble learning for battery state-of-health estimation:Recent advances and perspectives

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Journal of Energy Chemistry 2025年第1期100卷 739-759页

作者： Chuanping Lin Jun xu Delong Jiang Jiayang Hou Ying Liang Zhongyue Zou xuesong Mei State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong University Shaanxi Key Laboratory of Intelligent Robots School of Mechanical Engineering Xi'an Jiaotong University Department of Electrical Engineering and Automation Luoyang Institute of Science and Technology School of Mechanical Engineering Hangzhou Dianzi University

The burgeoning market for lithium-ion batteries has stimulated a growing need for more reliable battery performance monitoring. Accurate state-of-health(SOH) estimation is critical for ensuring battery operational performance. Despite numerous data-driven methods reported in existing research for battery SOH estimation, these methods often exhibit inconsistent performance across different application scenarios. To address this issue and overcome the performance limitations of individual data-driven models,integrating multiple models for SOH estimation has received considerable attention. Ensemble learning(EL) typically leverages the strengths of multiple base models to achieve more robust and accurate outputs. However, the lack of a clear review of current research hinders the further development of ensemble methods in SOH estimation. Therefore, this paper comprehensively reviews multi-model ensemble learning methods for battery SOH estimation. First, existing ensemble methods are systematically categorized into 6 classes based on their combination strategies. Different realizations and underlying connections are meticulously analyzed for each category of EL methods, highlighting distinctions, innovations, and typical applications. Subsequently, these ensemble methods are comprehensively compared in terms of base models, combination strategies, and publication trends. Evaluations across 6 dimensions underscore the outstanding performance of stacking-based ensemble methods. Following this, these ensemble methods are further inspected from the perspectives of weighted ensemble and diversity, aiming to inspire potential approaches for enhancing ensemble performance. Moreover, addressing challenges such as base model selection, measuring model robustness and uncertainty, and interpretability of ensemble models in practical applications is emphasized. Finally, future research prospects are outlined, specifically noting that deep learning ensemble is poised to advance ens

关键词： Lithium-ion battery State-of-health estimation Data-driven Machine learning Ensemble learning Ensemble diversity

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Multiple scenario simulation and optimization of an urban green infrastructure network based on complex network theory:a case study in Harbin City,China

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Ecological Processes 2022年第1期11卷 439-454页

作者： Shuang Song Shao‑Han Wang meng‑xi Shi Shan‑Shan Hu Da‑Wei xu College of Landscape Architecture Northeast Forestry UniversityHarbin 150000China Key Lab for Garden Plant Germplasm Development&Landscape Eco‑Restoration in Cold Regions of Heilongjiang Province Harbin 150000China

Background:Urban green infrastructure(GI)networks play a significant role in ensuring regional ecological security;however,they are highly vulnerable to the influence of urban development,and the optimization of GI networks with better connectivity and resilience under different development scenarios has become a practical problem that urgently needs to be *** Harbin,a megacity in Northeast China,as the case study,we set five simulation scenarios by adjusting the economic growth rate and extracted the GI network in multiple scenarios by integrating the minimal cumulative resistance model and the gravity *** low‑degree‑first(LDF)strategy of complex network theory was introduced to optimize the GI network,and the optimization effect was verified by robustness ***:The results showed that in the 5%economic growth scenario,the GI network structure was more complex,and the connectivity of the network was better,while in the other scenarios,the network structure gradually degraded with economic *** optimization by the LDF strategy,the average degree of the GI network in multiple scenarios increased from 2.368,2.651,2.189,1.972,and 1.847 to 2.783,3.125,2.643,2.414,and 2.322,respectively,and the GI network structure connectivity and resilience were significantly enhanced in all ***:Economic growth did not necessarily lead to degradation of the GI network;there was still room for economic development in the study area,but it was limited under existing GI conditions,and the LDF strategy was an effective method to optimize the GI *** research results provide a new perspective for the study of GI network protection with urban economic growth and serve as a methodological reference for urban GI network optimization.

关键词： GI network Simulation Complex network theory LDF strategy Robustness

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Single transition-metal atoms anchored on a novel Diracdispersiveπ-πconjugated holey graphitic carbon nitride substrate:computational screening toward efficient bifunctional OER/ORR electrocatalysts

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Rare Metals 2024年第8期43卷 3819-3832页

作者： Chun-Yao Fang xi-Hang Zhang Qiang Zhang Di Liu xiao-meng Cui Jing-Cheng xu Cheng-Long Shi meng-Yu Yang College of Science University of Shanghai for Science and TechnologyShanghai 200093China School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China

Nonprecious-metal-group single-metal-atom catalysts with bifunctional catalytic capabilities toward the oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)are highly sought after in energy-conversion and storage ***,producing renewable and sustainable energy sources remains ***,single-transition metal atoms anchored onπ-πconjugated two-dimensional(2D)graphitic carbon nitride substrates formπ-d conjugated conductive channels that enhance the overall electrocatalytic ***,firstprinciples calculations were carried out to design and demonstrate a novel macropore graphitic carbon nitride(gC_(10)N_(3))as a promising 2D electrocatalyst substrate to support single-transition metal(TM,from Sc to Au).The"donation-acceptance"charge interaction in the TM-N_(2)moiety effectively balances the adsorption strength of oxygenated intermediates in Ni@g-C_(10)N_(3)and Rh@gC_(10)N_3,making them effective bifunctional OER/ORR electrocatalysts with IrO_(2)/Pt-beyond overpotentials being as low as 0.39/0.38 V and 0.54/0.44 V,***,they possess high stability and conductivity and are less susceptible to oxidation and corrosion under working *** guarantees high activity under ambient ***,the origin of the OER/ORR activity of TM@g-C_(10)N_(3) is explained using multilevel descriptors:intrinsic(p,Bader charge,integral crystal orbital Hamilton population(ICOHP),bond length,and d-band center(εd).In particular,for optimal Ni@g-C_(10)N_(3),the clear hybridization between the Ni-d orbital and surface O-p orbital causes the paired electrons to occupy the bonding *** enables OH~*to be adsorbed on the Ni@g-C_(10)N_(3),thereby achieving the highest catalytic performance.

关键词： First-principles calculation Oxygen evolution reaction Oxygen reduction reaction Bifunctional electrocatalysts Single-metal-atom electrocatalysts

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Prospects for the application of transcranial magnetic stimulation in diabetic neuropathy

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Neural Regeneration Research 2021年第5期16卷 955-962页

作者： xi xu Dong-Sheng xu Department of Rehabilitation Medicine Affiliated Hospital of Nantong UniversityNantongJiangsu ProvinceChina Department of Rehabilitation Medicine Yueyang Hospital of Integrated Traditional Chinese and Western MedicineShanghaiChina School of Rehabilitation Science Shanghai University of Traditional Chinese MedicineShanghaiChina

Encouraging results have been reported for the use of transcranial magnetic stimulationbased nerve stimulation in studies of the mechanisms of neurological regulation,nerve injury repair,and nerve ***,to date,there are only a few reviews on the use of transcranial magnetic stimulation for diabetic *** with diabetic neuropathy vary in disease progression and show neuropathy in the early stage of the disease with mild symptoms,making it difficult to screen and *** the later stage of the disease,irreversible neurological damage occurs,resulting in treatment *** this review,we summarize the current state of diabetic neuropathy research and the prospects for the application of transcranial magnetic stimulation in diabetic *** review significant studies on the beneficial effects of transcranial magnetic stimulation in diabetic neuropathy treatment,based on the outcomes of its use to treat neurodegeneration,pain,blood flow change,autonomic nervous disorders,vascular endothelial injury,and ***,the studies suggest that transcranial magnetic stimulation can produce excitatory/inhibitory stimulation of the cerebral cortex or local areas,promote the remodeling of the nervous system,and that it has good application prospects for the localization of the injury,neuroprotection,and the promotion of nerve ***,transcranial magnetic stimulation is useful for the screening and early treatment of diabetic *** magnetic stimulation can also alleviate pain symptoms by changing the cortical threshold and inhibiting the conduction of sensory information in the thalamo-spinal pathway,and therefore it has therapeutic potential for the treatment of pain and pain-related depressive symptoms in patients with diabetic ***,based on the effect of transcranial magnetic stimulation on local blood flow and its ability to change heart rate and urine protein conten

关键词： autonomic neuropathy central nervous system depression inflammation oxidative stress pain peripheral nerve plasticity recovery regeneration vascular

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Review of organic and inorganic pollutants removal by biochar and biochar-based composites

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Biochar 2021年第3期3卷 255-281页

作者： Liping Liang Fenfen xi Weishou Tan xu meng Baowei Hu xiangke Wang College of Life Science Shaoxing UniversityShaoxing 312000People’s Republic of China College of Textile and Garment Shaoxing UniversityShaoxing 312000People’s Republic of China

Biochar(BC)has exhibited a great potential to remove water contaminants due to its wide availability of raw materials,high surface area,developed pore structure,and low ***,the application of BC for water remediation has many *** by the intense desire of overcoming unfavorable factors,a growing number of researchers have carried out to produce BC-based composite materials,which not only improved the physicochemical properties of BC,but also obtained a new composite material which combined the advantages of BC and other *** article reviewed previous researches on BC and BC-based composite materials,and discussed in terms of the preparation methods,the physicochemical properties,the performance of contaminant removal,and underlying adsorption *** the recent research progress in the removal of inorganic and organic contaminants by BC and BC-based materials was also systematically *** BC-based composite materials have shown high performance in inorganic or organic pollutants removal,the potential risks(such as stability and biological toxicity)still need to be noticed and further *** the end of this review,future prospects for the synthesis and application of BC and BC-based materials were *** review will help the new researchers systematically understand the research progress of BC and BC-based composite materials in environmental remediation.

关键词： Biochar magnetic composites Nanometallic oxide/hydroxide biochar composites Biochar based 2D membrane 3D biochar-based macrostructures Biological toxicity

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Do medullary thyroid carcinoma patients with high calcitonin require bilateral neck lymph node clearance?A case report

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World Journal of Clinical Cases 2021年第6期9卷 1343-1352页

作者： Feng-Jiao Gan Tie Zhou Shun Wu meng-xi xu Su-Hong Sun Department of Thyroid and Breast Surgery Affiliated Hospital of Zunyi Medical UniversityZunyi 563000Guizhou ProvinceChina

BACKGROUND In clinical work,85%-90%of malignant thyroid diseases are papillary thyroid cancer(PTC);thus,clinicians neglect other types of thyroid cancer,such as medullary thyroid carcinoma(MTC).CASE SUMMARY We report a 53-year-old female patient with a preoperative calcitonin level of 345 pg/*** was no definitive diagnosis of MTC by preoperative fine-needle aspiration cytology or intraoperative frozen pathology,but the presence of PTC and MTC was confirmed by postoperative paraffin *** patient underwent total thyroidectomy and bilateral central lymph node *** follow-up at 1.5 years after surgery revealed no signs of recurrence or *** The issue in clinical work-up regarding types of thyroid cancer provides a novel and challenging idea for the surgical treatment of *** the absence of central lymph node metastasis,it is worth addressing whether patients with high calcitonin can undergo total thyroidectomy and bilateral central lymph node dissection without bilateral lateral neck lymph node dissection.

关键词： Medullary thyroid carcinoma Papillary thyroid carcinoma Simultaneous different types of thyroid cancer Calcitonin Fine needle aspiration cytology Surgery Case report

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Multiscale stochastic finite element method on random field modeling of geotechnical problems- a fast computing procedure

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Frontiers of Structural and Civil Engineering 2015年第2期9卷 107-113页

作者： xi F. xu School of Civil Engineering Beo'ing Jiaotong University Beijing 100044 China

The Green-function-based multiscale stochastic finite element method (MSFEM) has been formulated based on the stochastic variational principle. In this study a fast computing procedure based on the MSFEM is developed to solve random field geotechnical problems with a typical coefficient of variance less than 1. A unique fast computing advantage of the procedure enables computation performed only on those locations of interest, therefore saving a lot of computation. The numerical example on soil settlement shows that the procedure achieves significant computing efficiency compared with Monte Carlo method.

关键词： multiscale finite element settlement perturbation random field geotechnical

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