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Enhancing High-Temperature Strength and Thermal Stability of Al2O3/Al Composites by High-Temperature Pre-treatment of Ultrafine Al Powders

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Acta Metallurgica Sinica(English Letters) 2020年第7期33卷 913-921页

作者： yu-ning zan Yang-Tao Zhou Xiao-Nan Li Guo-Nan Ma Zhen-yu Liu Quan-Zhao Wang Dong Wang Bo-Lv Xiao Zong-Yi Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of China72 Wenhua RoadShenyang 110016China

Amorphous Al2 O3-reinforced Al composite(am-Al2 O3/Al) compacted from ultrafine Al powders for high-temperature usages confronts with drawbacks because crystallization of am-Al2 O3 at high temperatures will result in serious strength *** at this unsolved problem,in this study,high-temperature Al materials with enhanced thermal stability were developed through introducing more thermally stable nano-sized particles via high-temperature pre-treatment of ultrafine A1 *** was found that the pre-treatment at ≤550℃ could introduce a few Al2 O3 in the Al matrix and increase the strength of the composites,but the strength was still below that of am-Al2 O3/Al because without being pinned firmly,grain boundaries(GBs) were softened at high temperature and intergranular fracture *** the pre-treatment was carried out at 600℃,nitridation and oxidation processes happened simultaneously,producing large numbers of intergranular(AlN+γ-Al2 O3) *** sliding and intergranular fracture were suppressed;therefore,higher strength than that of am-Al2 O3/Al was ***,the(AIN+γ-Al2 O3)/Al exhibited more superior thermal stability compared to amAl2 O3/Al for annealing treatment at 580℃ for 8 ***,an effective way to fabricate high-temperature Al composite with enhanced thermal stability was developed in this study.

关键词： composite composites treatment

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Cognitive Frequency Hopping Sequences

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Chinese Journal of Electronics 2016年第1期25卷 185-191页

作者： GUAN Lei LI zan HAO Benjian SI Jiangbo ning Ben State Key Laboratory of Integrated Service Networks School of Telecommunications EngineeringXidian University

Since the immutable conventional Frequency hopping(FH) sequence cannot keep high FH communication reliability in complex electromagnetic environment, we propose an algorithm that can generate high-performance Cognitive frequency hopping sequence(CFHS) for Cognitive frequency hopping(CFH) *** employing the pseudo-random perturbation mapping,the CFHS is generated by remapping the block cipher FH sequence with the adaptive frequency slot number and frequency gap. The CFHS inherits the great integrated performance and its parameters could change with the electromagnetic environment. The statistics properties of Markov and uniformity are analyzed based on the Markov process theory and probability theory. Simulation results show that CFHS outperforms the widely-used FH sequences on the performance of uniformity, randomness, Hamming correlation, complexity and sensitivity. The proposed CFHS could be extensively applied in high reliable CFH system.

关键词： Cognitive frequency hopping(CFH) Cognitive frequency hopping sequences(CFHS) Adaptive frequency slots number Adaptive wide gap

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Numerical simulation of solitary wave propagation based on MPS method

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Acta Oceanologica Sinica 2007年第3期26卷 121-128页

作者： LI Shaowu yu Zhi＇ an XIONG zan Department of Port and Coastal Engineering Tianjin University Tianjin 300072 China

The concept of candidate particle set is introduced in the MPS gridless numerical method to generate neighboring particle set ma- trix, which can reduce the CPU time to 1/11 of that before introduction. The Bi-CGSTAB （bi-conjugate gradient stabilized） algorithm is applied to solving the Poisson pressure equation, by which the solving speed is significantly accelerated. The process of solitary waves propagating over a numerical flume and interacting with a vertical wall is simulated. The simulated results of water surface elevation are in good agreement with the analytical solution as well as the measured data. The predicted maximum values of the run-up of solitary waves with various relative incident wave heights agree well with the measured results.

关键词： MPS method candidate particle set Bi-CGSTAB algorithm solitary wave

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Interfacial microstructure and mechanical properties of Ti-6Al-4V/Al7050 joints fabricated using the insert molding method

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International Journal of Minerals,Metallurgy and Materials 2017年第12期24卷 1412-1423页

作者： Hong-xiang Li Xin-yu Nie zan-bing He Kang-ning Zhao Qiang Du Ji-shan Zhang Lin-zhong Zhuang State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China SINTEF Materials and Chemistry Pb.124 BlindernNO-0314 OsloNorway IJmuiden Technology Centre Tata Steel Research&Development1970 CA IJmuidenThe Netherlands

Ti-6Al-4V/Al7050 joints were fabricated by a method of insert molding and corresponding interfacial microstructure and mechanical properties were investigated. The interfacial thickness was sensitive to holding temperature during the first stage, and a good metallurgical bonding interface with a thickness of about 90 μm can be obtained at 750°C. X-ray diffraction, transmission electron microscopy, and thermodynamic analyses showed that the interface mainly contained intermetallic compound TiAl_3 and Al matrix. The joints featured good mechanical properties, i.e., shear strength of 154 MPa, tensile strength of 215 MPa, and compressive strength of 283 MPa, which are superior to those of joints fabricated by other methods. Coherent boundaries between Al/TiAl_3 and TiAl_3/Ti were confirmed to contribute to outstanding interfacial mechanical properties and also explained constant fracture occurrence in the Al matrix. Follow-up studies should focus on improving mechanical properties of the Al matrix by deformation and heat treatment.

关键词： interfacial microstructure interfacial bonding mechanism mechanical properties insert molding method coherent boundaries Ti/Al joints

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Kalman Filter-Based CNN-BiLSTM-ATT Model for Traffic Flow Prediction

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Computers, Materials & Continua 2023年第7期76卷 1047-1063页

作者： Hong Zhang Gang Yang Hailiang yu zan Zheng Institute of Transportation Inner Mongolia UniversityHohhot010020China Inner Mongolia Engineering Research Center for Urban Transportation Data Science and Applications Hohhot010020China

To accurately predict traffic flow on the highways,this paper proposes a Convolutional Neural Network-Bi-directional Long Short-Term Memory-Attention Mechanism(CNN-BiLSTM-Attention)traffic flow prediction model based on Kalman-filtered data ***,the original fluctuating data is processed by Kalman filtering,which can reduce the instability of short-term traffic flow prediction due to unexpected *** the local spatial features of the traffic data during different periods are extracted,dimensionality is reduced through a one-dimensional CNN,and the BiLSTM network is used to analyze the time series ***,the Attention Mechanism assigns feature weights and performs Soft-max *** experimental results show that the data processed by Kalman filter is more accurate in predicting the results on the CNN-BiLSTM-Attention *** with the CNN-BiLSTM model,the Root Mean Square Error(RMSE)of the Kal-CNN-BiLSTM-Attention model is reduced by 17.58 and Mean Absolute Error(MAE)by 12.38,and the accuracy of the improved model is almost free from non-working *** further verify the model’s applicability,the experiments were re-run using two other sets of fluctuating data,and the experimental results again demonstrated the stability of the ***,the Kal-CNN-BiLSTM-Attention traffic flow prediction model proposed in this paper is more applicable to a broader range of data and has higher accuracy.

关键词： Highway traffic flow prediction Kalman filter CNN-BiLSTM-Attention

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普伐他汀对大鼠坐骨神经压碎损伤功能恢复的影响

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中国组织工程研究 2025年第5期29卷 942-950页

作者：刘赞安冉李宝成内蒙古科技大学包头医学院内蒙古自治区包头市014000 内蒙古科技大学包头医学院第一附属医院手足踝外科内蒙古自治区包头市014010

背景:普伐他汀是临床上治疗高胆固醇血症的有效药物,目前发现其在中枢神经损伤的治疗上也能发挥有益作用,然而其机制仍未可知。目的:探究普伐他汀治疗能否加速坐骨神经压碎损伤的功能恢复及其潜在作用机制。方法:将雄性SD大鼠随机分为... 详细信息

背景:普伐他汀是临床上治疗高胆固醇血症的有效药物,目前发现其在中枢神经损伤的治疗上也能发挥有益作用,然而其机制仍未可知。目的:探究普伐他汀治疗能否加速坐骨神经压碎损伤的功能恢复及其潜在作用机制。方法:将雄性SD大鼠随机分为假手术组(坐骨神经暴露但不损伤+生理盐水灌胃)、阴性对照组(坐骨神经压碎损伤+生理盐水灌胃)、普伐他汀组(坐骨神经压碎损伤+普伐他汀灌胃)。普伐他汀组大鼠术后普伐他汀(5 mg/kg)灌胃治疗1周,其余两组大鼠给予等量生理盐水灌胃。术后观察各组大鼠一般情况;术后第2,4,6,8周末测量各组大鼠的坐骨功能指数;术后8周末测量腓肠肌湿质量比;ELISA法检测血清中炎症细胞因子的水平;组织形态计量学分析坐骨神经有髓神经纤维数目、纤维直径、轴突直径、髓鞘厚度;RT-qPCR检测神经生长因子、脑源性神经营养因子的mRNA表达量,Western blot法检测生长相关蛋白43的蛋白表达量。结果与结论:与阴性对照组相比,普伐他汀组坐骨神经功能指数恢复更快(P<0.05),更接近于假手术组水平,血清中炎症细胞因子肿瘤坏死因子α及白细胞介素6表达更低(P<0.05)且接近假手术组,坐骨神经中神经生长因子、脑源性神经营养因子的mRNA相对表达量增加(P<0.05或P<0.01),坐骨神经中生长相关蛋白43的蛋白相对表达量也明显增加(P<0.05),有髓神经纤维数目增加更多,纤维直径、轴突直径及髓鞘厚度数值更大(P<0.01)且与假手术组更接近。结果说明,普伐他汀的治疗加速了坐骨神经压碎损伤的功能恢复,其可能机制是抑制炎症细胞因子肿瘤坏死因子α及白细胞介素6的表达及促进神经营养因子神经生长因子、脑源性神经营养因子的分泌。

关键词：周围神经损伤普伐他汀功能恢复神经营养因子坐骨神经功能指数

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Organocatalytic stereoselective cationic polymerization of vinyl ethers by employing a confined BrΦnsted acid as the catalyst

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Science China Chemistry 2022年第2期65卷 304-308页

作者： zan Yang Xun Zhang yu Jiang Qiang Ma Saihu Liao Key Laboratory of Molecule Synthesis and Function Discovery(Fujian Province University) State Key Laboratory of Photocatalysis on Energy and EnvironmentCollege of ChemistryFuzhou UniversityFuzhou 350108China Beijing National Laboratory for Molecular Sciences Beijing 100190China

The properties of poly(vinyl ether)s(PVEs)are highly dependent on their tacticity,and the appealing thermoplastics features of isotactic PVEs have drawn considerable efforts to develop stereoselective cationic polymerization methods to access this class of ***,reported methods that could achieve a high degree of tacticity control are limited to process employing metal-based Lewis acids,and with various limitations on catalyst loading,monomer scope,***,we introduce a metal-free stereoselective cationic polymerization of vinyl ethers by employing a class of chiral confined Br?nsted acids,imidodiphosphorimidates(IDPis),as the *** organocatalytic approach features its metal-free conditions,high efficiency,high stereoselectivity,single catalyst system,operation simplicity,etc.

关键词： organocatalysis stereoselective polymerization tacticity vinyl ethers BrΦnsted acids

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Resveratrol, an activator of SIRT1, restores erectile function in streptozotocin-induced diabetic rats

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Asian Journal of Andrology 2013年第5期15卷 646-651页

作者： Wen yu zan Wan Xue-Feng Qiu yun Chen yu-Tian Dai Department of Urology Affiliated Drum Tower Hospital School of Medicine Nanjing University Nanjing 210008 China

The high incidence of erectile dysfunction （ED） in diabetes highlights a need for effective treatment strategies. Resveratrol, an activator of silent information regulator 2-related enzymes 1 （sirtuinl, SIRT1）, has received attention for its valuable effects in cancer, neurodegenerative diseases, longevity and cardiovascular disease. To explore the effects of resveratrol in diabetes-induced ED, resveratrol was administered to rats with streptozocin （65 mg kg-1）-induced diabetes. Erectile function, cavernous structure, tissue protein expression of silent information regulator 2-related enzymes 1 （sirtuinl, SIRT1）, p53 and forkhead transcription factor 0 3a （FOXO3a）, superoxide dismutase （SOD） activity and malondialdehyde （MDA） levels in the corpora cavernosa were studied. We found that SIRT1 was expressed in cavernosal tissue, and it was downregulated in the corpora of diabetic rats. The administration of resveratrol upregulated the expression of SI RT1 and restored erectile function. In contrast, resveratrol downregulated the expression of p53 and FOXO3a, which regulate apoptosis and oxidative stress. Furthermore, the resveratrol-treated group showed an improvement in smooth muscle content, SOD activity and MDA levels when compared with the diabetic group. Therefore, the ability of resveratrol to improve diabetes-induced ED is likely related to its activation of SIRT1 expression, thus causing the suppression of apoptosis and resistance towards oxidative stress.

关键词： apoptosis erectile dysfunction oxidative stress resveratrol

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The improved element-free Galerkin method forthree-dimensional wave equation

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Acta Mechanica Sinica 2012年第3期28卷 808-818页

作者： zan Zhang Dong-Ming Li yu-Min Cheng Kim Moew Liew Shanghai Institute of Applied Mathematics and Mechanics Shanghai University200072 ShanghaiChina Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University200072 ShanghaiChina Department of Civil and Architectural Engineering City University of Hong KongTat Chee AvenueKowloonHong Kong SARChina

The paper presents the improved element-free Galerkin （IEFG） method for three-dimensional wave propa- gation. The improved moving least-squares （IMLS） approx- imation is employed to construct the shape function, which uses an orthogonal function system with a weight function as the basis function. Compared with the conventional moving least-squares （MLS） approximation, the algebraic equation system in the IMLS approximation is not ill-conditioned, and can be solved directly without deriving the inverse matrix. Because there are fewer coefficients in the IMLS than in the MLS approximation, fewer nodes are selected in the IEFG method than in the element-free Galerkin method. Thus, the IEFG method has a higher computing speed. In the IEFG method, the Galerkin weak form is employed to obtain a dis- cretized system equation, and the penalty method is applied to impose the essential boundary condition. The traditional difference method for two-point boundary value problems is selected for the time discretization. As the wave equations and the boundary-initial conditions depend on time, the scal- ing parameter, number of nodes and the time step length are considered for the convergence study.

关键词： Weighted orthogonal function Improved mov-ing least squares (IMLS) approximation. Improved element-free Galerkin (IEFG) method Penalty method Temporaldiscretization Wave equation

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Stability analysis of complex terrain slope based on multi-source point cloud fusion

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Journal of Mountain Science 2022年第9期19卷 2703-2714页

作者： zan Wen-bo ZHANG Wen-jie WANG ning ZHAO Chun-chen YANG Qian LI Hao School of Highway Chang’an UniversityXi’an 710064China Research and Development Center for Loess Mechanics and Engineering Test Technology Shaanxi Polytechnic InstituteXianyang 712000China School of Automobile Chang’an UniversityXi’an 710064China

Numerical modelling is a common routine for slope stability analysis in the complex terrain,and the accuracy of topographic survey has a great impact on the *** this study,a combination of unmanned aerial vehicle(UAV)photogrammetry and 3D laser scanning technique was first proposed to establish a high-precision digital elevation model(DEM),which could be accurate to 0.2 m,fulfilling the engineering ***,a series of 3D/2D finite element models(FEM)were constituted on the basis of DEM to investigate the slope stability in the complex *** results indicate that the deformation of complex terrain slope is chiefly triggered by compression-shear failure and the failure zones are mostly distributed on the middle-upper part and the ***,the complex terrain slope is divided into concave,convex,concave-convex and convex-concave slope according to the topographical curvature,and the factor of safety(FOS)is as follows:the maximum value 1.8504 for the concave-convex slope,the minimum value 1.1129 for the convexconcave slope,and the median for either concave or convex *** inflection points and curvature of the slope jointly determine the shape of nonlinear slope,dominating the morphological effect on the slope stability,so the rational use of section morphological effect will be conducive to the overall stability of the *** four representative slopes,the plastic deformation first emerges into the middle,then progressively develops to the upper,and finally forms the connected failure zones.

关键词： Slope stability Complex terrain DEM Numerical simulation Plastic zone Factor of Safety

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