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Numerical Investigation of the Fluid Flow Characteristics in the Hub Plate Crown of a Centrifugal Pump

Chinese Journal of Mechanical Engineering 2018年第4期31卷 182-191页

作者： Wei Dong wu-li chu School of Power and Energy Northwestern Polytechnical University Collaborative Innovation Center of Advanced AeroEngine

Due to the lack of understanding in the flow mechanism of the hub plate crown, the current calculation of the disc friction loss and the axial thrust in the centrifugal pump often uses empirical formulas. Research on the flow characteristics of the hub plate crown is of practical significance. The shroud and hub cavities are respectively studied with regard to tangential and radial velocities at the four different angular positions(0°, 90°, 180°, and 270°) at the four different operational points(0.6 Qsp, 0.8 Qsp, 1.0 Qsp, and 1.2 Qsp). Results indicate that at the same operational point, the smaller the volute chamber sectional area is, the higher the tangential velocity of the fluid core zone of the shroud cavity is. Radial leakage flow from the volute to the seal ring at the same operational point appears in 0° and 90° direction;when the flow is large, the tangential and radial velocities of the shroud and hub cavities with the same radius tend to be equal with axial symmetry. The axial leakage flow through the balance holes significantly affects the radial distribution of both tangential and radial velocities of fluid flow in the hub cavity. The numerical calculation results of fluid leakage through the clearance of back sealing ring are in good agreement with the test results. Accordingly, the magnitude of leakage is closely related to the fluid pressure and velocity distribution in the hub plate crown of the centrifugal pump. The analysis of the flow characteristics in the hub plate crown of the centrifugal pump could reveal the cause of the disc friction loss from the mechanism, providing a significant guidance for improving the accuracy of calculation and balancing the axial thrust in the centrifugal pump.

关键词： Centrifugal pump Shroud cavity Hub cavity Leakage of clearance Numerical simulation

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Phase field simulation of the 180°domain-switching process in PbTiO_3 single crystal under an antiparallel electric field

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International Journal of Minerals,Metallurgy and Materials 2010年第4期17卷 494-499页

作者： Ping-li liu wu-Yang chu li-Jie Qiao Corrosion and Protection Center Key Laboratory of Environmental Fracture University of Science and Technology Beijing Beijing 100083 China

The process of 180°domain switching in PbTiO_3 single crystal under an antiparallel electric field was investigated by the three-dimensional phase field simulation,especially the effect of electric field on the type and duration of domain *** is found that the polarization reversal of domains takes place under an antiparallel electric field in PbTiO_3 single *** results of the phase field simulation indicate that there is only 90°domain switching under a weak electric *** the rise of the electric field,180°domain switching *** the electric field is strengthened further,90°domain switching disappears and the duration of domain switching is shortened.

关键词： phase field simulation ferroelectric materials electric field domain switching

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Influences of the diameter of the balance hole on the flow characteristics in the hub cavity of the centrifugal pump

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Journal of Hydrodynamics 2019年第5期31卷 1060-1068页

作者： Wei Dong wu-li chu Zai-lun liu College of Water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100China School of Power and Energy Northwestern Polytechnical UniversityXi'an 710129China College of Energy and Power Engineering Lanzhou University of TechnologyLanzhou 730050China

The diameter of the impeller balance hole in a centrifugal pump is closely related to axial ***,to select the appropriate diameter of a balance hole is crucial for balancing the axial force of the centrifugal *** the validation of the CFD method and the grids independence study,the characteristics of flow in the hub cavity have been analyzed in 4 cases with different diameters of balance *** leakage rate of the liquid in the hub cavity of the centrifugal pump is calculated and compared with the test *** to the research,when no balance hole exists,the distribution of liquid velocity in the core area of the hub cavity exhibits axial symmetry,and the circumferential velocity component is approximately 0.4 times of the impeller's rotational *** the balance hole exists,the distribution of liquid velocity in the hub cavity does not exhibit axial symmetry,and the circumferential velocity component is larger than 0.4 times of the impeller's rotational *** radial leakage velocity on the turbulent boundary layer of the pump cover will increase with the increasing diameter of the balance hole.

关键词： Centrifugal pump balance hole hub cavity circumferential velocity component radial velocity component

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Sn-1.5Ag-2Zn低银无铅焊料与取向铜界面研究

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表面技术 2023年第8期52卷 406-412页

作者：肖金屈福康程伟李武初广州华立学院广州511300

目的高密度封装技术能减少焊盘尺寸和焊盘里面所含晶粒的数量,当多晶焊盘转为单晶焊盘时,晶粒的取向会对界面处金属间化合物的形成产生重要影响。选取具有发展前景的Sn-1.5Ag-2Zn作为焊料合金,研究焊料与单晶(111)铜基板界面反应,得到... 详细信息

目的高密度封装技术能减少焊盘尺寸和焊盘里面所含晶粒的数量,当多晶焊盘转为单晶焊盘时,晶粒的取向会对界面处金属间化合物的形成产生重要影响。选取具有发展前景的Sn-1.5Ag-2Zn作为焊料合金,研究焊料与单晶(111)铜基板界面反应,得到金属间化合物的生长动力学规律。方法将Sn-1.5Ag-2Zn无铅焊料分别与单晶(111)铜基板及多晶紫铜基板在250℃下进行回流焊接5 min,将焊接后的样品在160℃下分别进行20 h,100 h,300 h,600 h热处理。用扫描电子显微镜背散射电子成像和二次电子成像、X射线衍射仪(XRD)、能谱仪等研究焊接界面处的显微组织、金属间化合物成分以及性能。结果合金焊料与铜基板接触迅速生长出凹凸不平类似扇贝状Cu_(6)Sn_(5)金属间化合物层,与单晶铜表面形成的Cu_(6)Sn_(5)晶粒尺寸比多晶铜的大,单晶铜无晶界阻挡原子扩散,影响晶粒形核与长大。合金焊料与单晶(111)铜焊点在160℃下热处理20 h快速形成的Cu_(6)Sn_(5)生长速度是多晶铜上焊点的2倍左右。而后随热处理时间增加增长缓慢,热处理600 h后厚层Cu_(6)Sn_(5)由于裂纹扩散出现溃断,金属间化合物的厚度维持在3.5μm。焊料与多晶铜焊点在热处理过程中生成的Cu_(5)Zn_(8)起到阻挡层的作用,阻挡焊料与铜基板接触,抑制Cu_(6)Sn_(5)生成,热处理300 h后Cu_(5)Zn_(8)破碎分解,Cu_(6)Sn_(5)在阻挡层消失后快速生长,厚度约为2.8μm。结论单晶铜上焊点金属间化合物的厚度比多晶铜上金属间化合物的厚度多0.7μm,热处理后合金焊料与单晶铜界面形成的金属间化合物致密性更好,基本没有孔隙,而合金焊料与多晶铜界面上金属间化合物晶粒间存在明显孔隙,可以预测合金焊料与单晶铜界面的焊接质量更好。

关键词： Sn-1.5Ag-2Zn 单晶铜合金焊料焊接扩散

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Treadmill exercise in combination with acousto-optic and olfactory stimulation improves cognitive function in APP/PS1 mice through the brain-derived neurotrophic factor-and Cygb-associated signaling pathways

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Neural Regeneration Research 2025年第9期20卷 2706-2726页

作者： Biao Xiao Chaoyang chu Zhicheng lin Tianyuan Fang Yuyu Zhou chuxia Zhang Jianghui Shan Shiyu Chen liping li Department of Physiology and Pharmacology Health Science CenterNingbo UniversityNingboZhejiang ProvinceChina Ningbo Key Laboratory of Behavioral Neuroscience Health Science CenterNingbo UniversityNingboZhejiang ProvinceChina Key Laboratory of Addiction Research of Zhejiang Province NingboZhejiang ProvinceChina

A reduction in adult neurogenesis is associated with behavioral abnormalities in patients with Alzheimer's ***,enhancing adult neurogenesis represents a promising therapeutic approach for mitigating disease symptoms and ***,nonpharmacological interventions aimed at inducing adult neurogenesis are currently *** individual non-pharmacological interventions,such as aerobic exercise,acousto-optic stimulation,and olfactory stimulation,have shown limited capacity to improve neurogenesis and cognitive function in patients with Alzheimer's disease,the therapeutic effect of a strategy that combines these interventions has not been fully *** this study,we observed an age-dependent decrease in adult neurogenesis and a concurrent increase in amyloid-beta accumulation in the hippocampus of amyloid precursor protein/presenilin 1 mice aged 2-8 *** deposition became evident at 4 months,while neurogenesis declined by 6 months,further deteriorating as the disease ***,following a 4-week multifactor stimulation protocol,which encompassed treadmill running(46 min/d,10 m/min,6 days per week),40 Hz acousto-optic stimulation(1 hour/day,6 days/week),and olfactory stimulation(1 hour/day,6 days/week),we found a significant increase in the number of newborn cells(5'-bromo-2'-deoxyuridine-positive cells),immature neurons(doublecortin-positive cells),newborn immature neurons(5'-bromo-2'-deoxyuridine-positive/doublecortin-positive cells),and newborn astrocytes(5'-bromo-2'-deoxyuridine-positive/glial fibrillary acidic protein-positive cells).Additionally,the amyloid-beta load in the hippocampus *** findings suggest that multifactor stimulation can enhance adult hippocampal neurogenesis and mitigate amyloid-beta neuropathology in amyloid precursor protein/presenilin 1 ***,cognitive abilities were improved,and depressive symptoms were alleviated in amyloid precursor protein/presenilin 1 mice

关键词： acousto-optic stimulation adult neurogenesis Alzheimer's disease amyloid precursor protein/presenilin 1 mice amyloid-beta deposition brain cell apoptosis cognitive impairment depression-like behavior involuntary treadmill exercise olfactory stimulation serum metabolites

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Multilevel analysis of the central-peripheral-target organ pathway:contributing to recovery after peripheral nerve injury

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Neural Regeneration Research 2025年第10期20卷 2807-2822页

作者： Xizi Song Ruixin li Xiaolei chu Qi li Ruihua li Qingwen li Kai-Yu Tong Xiaosong Gu Dong Ming Academy of Medical Engineering and Translational Medicine Tianjin UniversityTianjinChina Haihe Laboratory of Brain-Machine Interface and Human-Machine Fusion TianjinChina Department of Rehabilitation Tianjin University Tianjin HospitalTianjinChina Department of Hand Microsurgery Tianjin University Tianjin HospitalTianjinChina School of Exercise and Health Tianjin University of SportTianjinChina Department of Biomedical Engineering the Chinese University of Hong KongHong Kong Special Administrative RegionChina

Peripheral nerve injury is a common neurological condition that often leads to severe functional limitations and *** on the pathogenesis of peripheral nerve injury has focused on pathological changes at individual injury sites,neglecting multilevel pathological analysis of the overall nervous system and target *** has led to restrictions on current therapeutic *** this paper,we first summarize the potential mechanisms of peripheral nerve injury from a holistic perspective,covering the central nervous system,peripheral nervous system,and target *** peripheral nerve injury,the cortical plasticity of the brain is altered due to damage to and regeneration of peripheral nerves;changes such as neuronal apoptosis and axonal demyelination occur in the spinal *** nerve will undergo axonal regeneration,activation of Schwann cells,inflammatory response,and vascular system regeneration at the injury *** damage to target organs can occur,including skeletal muscle atrophy and sensory receptor *** then provide a brief review of the research advances in therapeutic approaches to peripheral nerve *** main current treatments are conducted passively and include physical factor rehabilitation,pharmacological treatments,cell-based therapies,and physical ***,most treatments only partially address the problem and cannot complete the systematic recovery of the entire central nervous system-peripheral nervous system-target organ ***,we should further explore multilevel treatment options that produce effective,long-lasting results,perhaps requiring a combination of passive(traditional)and active(novel)treatment methods to stimulate rehabilitation at the central-peripheral-target organ levels to achieve better functional recovery.

关键词： central nervous system central peripheral target organ multilevel pathological analysis nerve regeneration peripheral nerve injury peripheral nervous system target organs therapeutic approach

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新型车载式物探钻机的开发与应用

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探矿工程（岩土钻掘工程） 2009年第5期36卷 44-46页

作者：李武初中国地质大学〈武汉〉计算机学院湖北武汉430074 长沙探矿机械厂湖南长沙410100

分析了目前市场上车载式物探钻机的优缺点,并提出新型车载式物探钻机主要应解决的问题;介绍了TW 100型拖拉机物探钻机的主要组成部分、特点、技术参数以及试机情况。

关键词：物探钻机车载液压

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Smart Cellulose‑Based Janus Fabrics with Switchable liquid Transportation for Personal Moisture and Thermal Management

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Nano-Micro Letters 2025年第1期17卷 333-347页

作者： Jianfeng Xi Yanling Lou liucheng Meng Chao Deng Youlu chu Zhaoyang Xu Huining Xiao Weibing wu Jiangsu Co‑Innovation Center of Efficient Processing and Utilization of Forest Resources International Innovation Center for Forest Chemicals and MaterialsJiangsu Provincial Key Lab of Sustainable Pulp and Paper Technology and Biomass MaterialsNanjing Forestry UniversityNanjing 210037People’s Republic of China College of Materials Science and Engineering Nanjing Forestry UniversityNanjing 210037People’s Republic of China Department of Chemical Engineering University of New BrunswickFrederictonNB E3B 5A3Canada Macromolecular Chemistry and Bavarian Polymer Institute University of BayreuthBayreuth 95440Germany

The Janus fabrics designed for personal moisture/thermal regulation have garnered significant attention for their potential to enhance human ***,the development of smart and dynamic fabrics capable of managing personal moisture/thermal comfort in response to changing external environments remains a ***,a smart cellulose-based Janus fabric was designed to dynamically manage personal moisture/*** cotton fabric was grafted with N-isopropylacrylamide to construct a temperature-stimulated transport ***,hydrophobic ethyl cellulose and hydrophilic cellulose nanofiber were sprayed on the bottom and top sides of the fabric to obtain wettability *** fabric exhibits anti-gravity directional liquid transportation from hydrophobic side to hydrophilic side,and can dynamically and continuously control the transportation time in a wide range of 3–66 s as the temperature increases from 10 to 40℃.This smart fabric can quickly dissipate heat at high temperatures,while at low temperatures,it can slow down the heat dissipation rate and prevent the human from becoming too *** addition,the fabric has UV shielding and photodynamic antibacterial properties through depositing graphitic carbon nitride nanosheets on the hydrophilic *** smart fabric offers an innovative approach to maximizing personal comfort in environments with significant temperature variations.

关键词： Directional water transport Cotton fabric Anti-gravity directional liquid transportation Janus wettability

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互联网背景下高校思想政治教育载体创新研究

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湖北师范大学学报（哲学社会科学版） 2022年第1期42卷 111-116页

作者：熊霖李悟初安徽大学江淮学院合肥230031

互联网,特别是以智能手机为核心的移动互联网技术深刻地改变了青年群体的物质及精神生活方式。互联网信息的传播特性使得青年人在精神生活中更加渴望一种平等友好的交往关系,同时族群化的网络生态环境导致青年群体形成了僵化刻板的世界... 详细信息

互联网,特别是以智能手机为核心的移动互联网技术深刻地改变了青年群体的物质及精神生活方式。互联网信息的传播特性使得青年人在精神生活中更加渴望一种平等友好的交往关系,同时族群化的网络生态环境导致青年群体形成了僵化刻板的世界观,更加热衷感官刺激的文化生活。前述情况对思政教育无疑产生了极大的冲击,也必将成为推进思政教学改革的外在动力。基于载体在思政教学中所发挥的作用,可以认为载体是思政教学目的得以实现的保障。思政教师应当积极开拓创新,促成载体种类形式的创新,从而推动思政教学的改革,打造金课,为实现立德树人的根本任务贡献力量。

关键词：思政教学改革载体创新互联网大学生

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基于铜铟微纳米层常温超声辅助瞬态固相键合技术

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表面技术 2022年第12期51卷 312-319页

作者：肖金翟倩周艳琼李武初陈基松王超超广州华立学院广州511300

目的采用针状形貌铜铟微纳米层和超声能量,在常温下实现键合互连,保证互连的可靠性,从而解决传统回流焊工艺因高温引发的高热应力、信号延迟加剧等问题。方法将镀有铜铟微纳米层的基板表面作为键合偶,对键合接触区域施加超声能量和一定... 详细信息

目的采用针状形貌铜铟微纳米层和超声能量,在常温下实现键合互连,保证互连的可靠性,从而解决传统回流焊工艺因高温引发的高热应力、信号延迟加剧等问题。方法将镀有铜铟微纳米层的基板表面作为键合偶,对键合接触区域施加超声能量和一定压力,实现2块铜铟基板的瞬态固相键合。用扫描电子显微镜、透射电子显微镜、X射线衍射(XRD)、焊接强度测试仪等分析键合界面处的显微组织、金属间化合物及剪切强度,并对键合界面进行热处理。结果在超声作用和较小的压力下,铜铟微锥阵列结构相互插入,形成了稳定的物理阻挡结构。键合界面处的薄铟层在超声能量作用下,其原子快速扩散转变为金属间化合物Cu2In。Cu2In是一种优质相,具有良好的塑性,有利于提高互连强度。当键合界面铟层的厚度为250 nm,键合压力为7 MPa,键合时间为1 s时,获得了相对最佳的键合质量,同时键合界面孔洞消失。热处理实验结果表明,这种固相键合技术无需额外进行热处理,就能获得良好的键合强度。结论铜铟微纳米针锥的特殊形貌及超声波能量的引入,使键合在室温条件下即可瞬间完成,键合质量良好,可以获得较小的键合尺寸。

关键词：金属材料固相键合铜−铟微纳米键合强度扩散

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