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废气入射管道参数对缸内EGR分层的影响

重庆大学学报 2024年第1期47卷 21-30页

作者：杨川廖勇杜永波李元栋张力重庆大学机械与运载工程学院重庆400044 重庆招商局检测车辆技术研究院有限公司重庆401122

为了在某款摩托车汽油机缸内实现废气再循环(exhaust gas recirculation,EGR)分层以减少泵气损失,降低NOx排放,将原有的进气旁通系统改造为EGR系统,使用GT-POWER模型求解出3000 r/min、60 mg进气量工况下废气入射管道以及进排气道的边... 详细信息

为了在某款摩托车汽油机缸内实现废气再循环(exhaust gas recirculation,EGR)分层以减少泵气损失,降低NOx排放,将原有的进气旁通系统改造为EGR系统,使用GT-POWER模型求解出3000 r/min、60 mg进气量工况下废气入射管道以及进排气道的边界条件和初始条件,并将这些条件导入发动机的CONVERGE模型中进行计算,通过对比不同废气入射管径、不同安装角度、不同安装距离条件下的缸内流动特性、缸内速度场以及缸内废气质量分数分布,确定了最佳废气入射管道参数。结果表明:在3000 r/min、60 mg进气量工况下,当废气入射管径为5 mm,入射角度为17.5°,安装距离为22 mm时,气缸内能实现EGR分层。

关键词： EGR分层汽油机 CONVERGE仿真

Neural network-based fault diagnosis for spacecraft with single-gimbal control moment gyros

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Chinese Journal of Aeronautics 2022年第7期35卷 261-273页

作者： yuandong li Qinglei HU Xiaodong SHAO School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100083China Beihang Hangzhou Innovation Institute Yuhang Hangzhou 310023China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China

This paper proposes a neural network-based fault diagnosis scheme to address the problem of fault isolation and estimation for the Single-Gimbal Control Moment Gyroscopes(SGCMGs)of spacecraft in a periodic *** this end,a disturbance observer based on neural network is developed for active anti-disturbance,so as to improve the accuracy of fault *** periodic disturbance on orbit can be decoupled with fault by resorting to the fitting and memory ability of neural ***,the fault diagnosis scheme is established based on the idea of information *** data of spacecraft attitude and gimbals position are combined to implement fault isolation and estimation based on adaptive estimator and neural ***,an adaptive sliding mode controller incorporating the disturbance and fault estimation results is designed to achieve active fault-tolerant *** addition,the paper gives the proof of the stability of the proposed schemes,and the simulation results show that the proposed scheme achieves better diagnosis and control results than compared algorithm.

关键词： Control moment gyro Fault diagnosis Fault-tolerant control Neural networks Spacecraft attitude control

La元素对铸造Al-4.8Cu合金力学和导热性能的影响

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稀有金属 2024年第6期48卷 786-795页

作者：宋赵熙李元东刘文憬杨昊坤曹杨婧毕广利兰州理工大学材料科学与工程学院省部共建有色金属先进加工与再利用国家重点实验室甘肃兰州730050 兰州理工大学有色金属合金及加工教育部重点实验室甘肃兰州730050

以Al-4.8Cu合金为基体,通过加入稀土元素La,研究其对合金组织形貌、力学性能以及热导率的影响。采用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射(XRD)、万能拉伸试验机、热传导系数测量仪等分析手段,并结合第一性原理进行表征。结果表明... 详细信息

以Al-4.8Cu合金为基体,通过加入稀土元素La,研究其对合金组织形貌、力学性能以及热导率的影响。采用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射(XRD)、万能拉伸试验机、热传导系数测量仪等分析手段,并结合第一性原理进行表征。结果表明,随着La元素含量的增加,晶粒形貌由树枝晶向等轴晶转变,晶粒尺寸减小,当La元素的含量为0.38%时晶粒的细化现象较为明显,晶粒平均尺寸由不含La元素时的149μm降至69μm。随着La元素含量的增加,合金的抗拉强度、屈服强度、延伸率和热导率呈现先增大后减小的趋势,La元素含量为0.38%时,合金的抗拉强度、屈服强度达到最大,分别为175.69 MPa和115.20 MPa;La元素含量为0.29%时,合金的延伸率达到最大,为10.04%;La元素含量为0.78%时,合金的热导率达到最大,为210.70 W·m^(-1)·K^(-1),相比未添加La元素时分别提升了43.9%,43.5%,60.9%和10.3%。La元素加入过量后产生的Al4La,Cu5La相会对合金的力学性能和热导率产生较大危害。

关键词：铝合金 La元素热导率力学性能第一性原理

含软弱土层场地地震动加速度反应谱特征周期调整方法

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地震学报 2024年第4期46卷 734-750页

作者：陈珍郝冰李远东周正华卞祝韩轶南京工业大学交通运输工程学院南京211816

在分析场地条件对地震震害影响及国内外关于软弱土层对场地地震反应影响的基础上,采用实际含淤泥质土层场地资料,建立了12个含软弱土层的场地模型,在不同输入地震动水平下进行了场地地震反应一维等效线性化分析,讨论了软弱土层厚度和埋... 详细信息

在分析场地条件对地震震害影响及国内外关于软弱土层对场地地震反应影响的基础上,采用实际含淤泥质土层场地资料,建立了12个含软弱土层的场地模型,在不同输入地震动水平下进行了场地地震反应一维等效线性化分析,讨论了软弱土层厚度和埋深对场地地震反应的影响。结果表明:随着软弱土层的埋深或厚度的增加,反应谱特征周期逐渐增大;输入地震动峰值增加,反应谱特征周期亦增大。继而依据软弱土层厚度、埋深及输入地震动强度对场地加速度反应谱特征周期的影响特征,提出了含软弱土层场地地震动加速度反应谱特征周期调整方法。

关键词：场地条件地震动特征周期等效线性化地震震害

补肾活血中药治疗膝骨性关节炎与骨质疏松症“共病”机制研究进展

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中草药 2024年第11期55卷 3898-3905页

作者：杨浩宇王世坤杨东元尹润宇邹远超李远栋天津中医药大学第一附属医院国家中医针灸临床医学研究中心天津300381

膝骨性关节炎(knee osteoarthritis,KOA)是一种以膝关节软骨退行性病变和继发性骨质增生为特征的慢性关节疾病。骨质疏松症(osteoporosis,OP)是一种代谢性骨病,主要由于骨量丢失与降低、骨组织微结构破坏、骨脆性增加,导致患者容易出现... 详细信息

膝骨性关节炎(knee osteoarthritis,KOA)是一种以膝关节软骨退行性病变和继发性骨质增生为特征的慢性关节疾病。骨质疏松症(osteoporosis,OP)是一种代谢性骨病,主要由于骨量丢失与降低、骨组织微结构破坏、骨脆性增加,导致患者容易出现骨折的全身代谢性骨病。KOA与OP在病因、发病机制方面有很多相似之处,2病病机特点均为以肾虚为本、血瘀为标。通过从促进骨修复、抑制骨破坏2方面对补肾活血类中药治疗KOA与OP“共病”作用机制进行归纳总结,为深入研究KOA与OP“共病”机制提供支持与参考。

关键词：膝骨性关节炎骨质疏松症补肾活血中药细胞自噬激素水平氧自由基

Microstructure characteristics and solidification behavior of wrought aluminum alloy 2024 rheo-diecast with self-inoculation method

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China Foundry 2012年第4期9卷 328-336页

作者： li Yanlei li yuandong li Chun Wu Huihui State Key Laboratory of Gansu Advanced Nonferrous Metal Materials Lanzhou University of TechnologyLanzhou 730050China Key Laboratory of Nonferrous Metal Alloys and Processing Ministry of EducationLanzhou University of TechnologyLanzhou 730050China

One important problem in casting wrought aluminum alloys is the high tendency to the formation of hot tears in the solidification *** using semi-solid metal(SSM) processing,the hot tearing tendency of alloys can be minimized during *** the present research,the semi-solid slurry of wrought aluminum alloy 2024 was firstly prepared with a novel self-inoculation method(SIM),and then the microstructure characteristics of the semi-solid slurry and the rheo-diecastings cast with the semi-solid slurry were *** results indicate that finer and more uniform globular primary α-Al particles can be obtained when the semi-solid slurry are isothermally held for a short period within the semi-solid temperature range,and the primary α-Al particles without entrapped liquid are uniformly fine,globular grains in the *** holding temperature and time affect the solid fraction,particle size,and shape *** the semi-solid slurry is held at 625 ℃ for 3 min and 5 min,the optimal values for the average equivalent diameter are 70.80 μm and 74.15 μm,and for the shape factor are 1.32 and 1.42,*** solidification process of the rheo-diecastings is composed of the following two distinct stages:primary solidification process and secondary solidification *** secondary solidification process consists further of the following three stages:(1) direct growth of secondary primary(α 2) phase from the surface of the primary α-Al phase particles without re-nucleation,(2) independent nucleation and growth of α 3 phase from the residual liquid,and(3) eutectic reaction at the end.

关键词： self-inoculation method wrought aluminum alloy 2024 solidification behavior secondary solidification

Effects of Reheating Duration on the Microstructures and Tensile Properties of Thixoforged In Situ Mg_2Si_p/AM60B Composites

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Acta Metallurgica Sinica(English Letters) 2014年第5期27卷 957-967页

作者： Tijun Chen Suqing Zhang Yushi Chen yuandong li Ying Ma Yuan Hao Key laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of Technology

The influences of reheating duration on microstructures and tensile properties of thixoforged in situ Mg2Sip/ AM60B composites have been investigated. The results indicate that the reheating time affects the volume fraction, composition and distribution of the liquid phase, the evolution of the liquid pools within the primary particles, and the morphology and distribution of the Mg2Si particles of the semisolid feedstock. These changes then affect the subsequent solidification behavior and deformation mechanism during thixoforging, which are responsible for the resulting micro- structure and tensile properties. Mg2Si particles play a strengthening role for the matrix through the load transfer mechanism. The appropriate reheating time is 60 min at 600 ℃ when the mold preheating temperature is at 300 ℃. The ultimate tensile strength and elongation of the resulting composite are up to 209 MPa and 11.9%, respectively.

关键词： In situ synthesis Magnesium matrix composites Semisolid Mechanical properties

Analytical study of seashell using laser-induced breakdown spectroscopy

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Plasma Science and Technology 2017年第2期19卷 52-55页

作者： Ying li Yanhong GU Ying ZHANG yuandong li Yuan LU Optics and Optoelectronics Laboratory Ocean University of ChinaQingdao 266100People's Republic of China

Seashell has been applied as an indicator for ocean research and element analysis of the seashell is used to track biological or environmental evolution. In this work, laser-induced breakdown spectroscopy （liBS） was applied for elementary analysis of an ezo scallop-shell, and a graphite enrichment method was used as the assistance. It was found that liBS signal intensity of Ca fluctuated less than 5%, in spite of the sampling positions, and Sr/Ca was related to the shell growth. A similar variation was also found when using a direct liBS analysis on the shell surface, and it might be more practicable to track shell growth by investigating Sr/Ca ratio with Sr ionic line at 421.6 nm. The obtained results prove that calcium （Ca） is qualified as an internal reference for shell analysis, and liBS is a potential analytical method for seashell study.

关键词： seashell analysis liBS graphite enriched process Sr/Ca shell growth

Effects of novel self-inoculation method on microstructure of AM60 alloy

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China Foundry 2011年第1期8卷 121-126页

作者： Xing Bo li yuandong Ma Ying Hao Yuan State Key Lab. of Gansu Advanced Non-ferrous Metal Materials Lanzhou University of Technology Lanzhou 730050 China Key Lab. of Non-ferrous Metal Alloys and Processing Ministry of Education Lanzhou University of Technology Lanzhou 730050 China

A novel cast processing method,self-inoculation method (SIM),was *** process involves the addition of self-inoculant to melt,then pouring the melt to a mould through a multi-stream mixing cooling *** this paper,the process parameters were *** indicate that the melt treatment temperature,the amount of self-inoculant added,and the slope angle of the cooling channel are the key factors for SIM *** optimized parameters are that the melt treatment temperature is between 680 and 700°C;the addition of self-inoculant is between 5wt.% and 7wt.%;and the slope angle of the cooling channel is between 30° and 45°.Further analysis reveals that SIM changes the solidification microstructure of slurry by controlling the nucleation and growth of the primary phase in the melt.

关键词： AM60 alloy self-inoculation method multi-stream mixing cooling channel nucleation and growth