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| 1 | Microstructure and Mechanical Properties of 7005 Aluminum Alloy Components Formed by Thixoforming显示文摘In the present research, semisolid billet of 7005 aluminum alloy was fabricated by using recrystallization and partial remelting(RAP), then thixoformed at different isothermal temperatures, preheating temperatures and load routes. Mechanical properties and microstructure of the thixoformed product were investigated. The results showed that microstructure achieved by three-step induction heating warm extruded 7005 aluminum alloy consists of a uniform and spheroidal microstructure suitable for thixoforming.Preheating temperature of the die affected signi?cantly the ?lling status of semisolid billet of 7005 aluminum alloy. Complete ?lling status with good surface quality was obtained at a preheating temperature of 365 °C. Thixoformed microstructures consisting of relatively spheroidal grains illustrate the dependence of ?lling process on the sliding and rotating of solid grains rather than plastic deformation of solid grains. A non-uniform distribution of liquid phase was found in the different regions of the thixoformed product due to the slower adjustable velocity of solid grains as compared with liquid phase. Increase of isothermal temperatures led to a slight decrease of mechanical properties of the thixoformed product due to coarsening of solid grains. The highest yield strength, ultimate tensile strength and elongation of thixoformed components with T6 heat treatment are 237 MPa, 361 MPa and 16.8%, respectively, which were achieved at the isothermal temperature of 605 °C. Load route has a signi?cant effect on mechanical properties and microstructure of the thixoformed product. Defects, such as crack and microporosity occurred in the microstructure of the thixoformed product obtained under load route 2. It led to an obvious reduction of mechanical properties as compared with route 1. A better compatibility of deformation caused by more liquid fraction at the isothermal temperature of 612 °C is bene?cial to reducing nonuniformity of liquid phase in the different regions of the thixoformed product. | Jufu Jiang H.V.Atkinson Ying Wang | 2017 | Journal of Materials Science & Technology2017，33，4： | 7 |
| 2 | Compression Mechanical Behaviour of 7075 Aluminium Matrix Composite Reinforced with Nano-sized SiC Particles in Semisolid State显示文摘The 7075 aluminium matrix composite reinforced with nano-sized Si C particles was fabricated by ultrasonic assisted semisolid stirring method. The compression mechanical behaviour of the fabricated composite in semisolid state was investigated. The results show that the microstructure of the composite before semisolid compression consists of fine and spheroidal solid grains surrounded by liquid phase.Semisolid compression led to a nonuniform plastic deformation of solid grains. A slight plastic deformation occurred in the locations near the free surface due to the dependence of deformation on liquid flow and flow of liquid incorporating solid grains. However, obvious plastic deformation occurred in the central location and location contacting to die due to the contribution of plastic deformation of solid grains.The true stress–strain curve of the sample compressed at 500 °C consists of rapid increase of true stress and steady stage. However, rapid increase of true stress and decrease of true stress and steady stage are involved in the true stress–strain curves of the samples compressed at 550, 560, 570, 580 and 590 °C.The true stress–strain curve at 600 °C is similar to that at 500 °C. Apparent viscosity decreases with an increase of shear rate, indicating a shear thinning occurrence. When soaking time increases from 5 min to 15 min, the peak stress and steady stress decrease significantly. A further increase of the soaking time led to a slight change. Peak stress and steady stress increase with increasing volume fraction of Si C particles. A sudden increase or decrease of compression velocity led to a significant increase or decrease of the steady stress. The destruction of the samples compressed at solid state temperature mainly depends on cracks parallel to compression direction. However, the destruction forms of the samples compressed at semisolid temperatures consist of cracks parallel to compression direction and partial collapse. Increasing soaking time led to an obvious change of the destruction forms. Compression velocity affects slightly the macro appearance of the sample compressed at semisolid temperatures. | Jufu Jiang Gang Chen Ying Wang | 2016 | Journal of Materials Science & Technology2016，32，11： | 5 |
| 3 | Downsampling sparse representation and discriminant information aided occluded face recognition显示文摘In this paper,a strategy is proposed to deal with a challenging research topic,occluded face recognition.Our approach relies on sparse representation on downsampled input image to first locate unoccluded face parts,and then exploits the linear discriminant ability of those pixels to identify the input subject.The advantages and novelties of our method include,1)since the sparse representation based occlusion detection is conducted on dowsampled image,our algorithm is much faster than classic SRC;2)the discriminant information learned from training samples is combined with sparse representation to recognize occluded face for the first time.The verification experiments are conducted on both simulated block occlusion images and genuine occluded images. | LI YueLong MENG Li FENG JuFu WU JiGang | 2014 | Science China(Information Sciences)2014，57，3： | 5 |
| 4 | Robust sparse representation based face recognition in an adaptive weighted spatial pyramid structure显示文摘The sparse representation based classification methods has achieved significant performance in recent years. To fully exploit both the holistic and locality information of face samples, a series of sparse representation based methods in spatial pyramid structure have been proposed. However, there are still some limitations for these sparse representation methods in spatial pyramid structure. Firstly, all the spatial patches in these methods are directly aggregated with same weights, ignoring the differences of patches' reliability. Secondly, all these methods are not quite robust to poses, expression and misalignment variations, especially in under-sampled cases. In this paper, a novel method named robust sparse representation based classification in an adaptive weighted spatial pyramid structure(RSRC-ASP) is proposed. RSRC-ASP builds a spatial pyramid structure for sparse representation based classification with a self-adaptive weighting strategy for residuals' aggregation. In addition, three strategies, local-neighbourhood representation, local intra-class Bayesian residual criterion, and local auxiliary dictionary, are exploited to enhance the robustness of RSRC-ASP. Experiments on various data sets show that RSRC-ASP outperforms the classical sparse representation based classification methods especially for under-sampled face recognition problems. | Xiao MA Fandong ZHANG Yuelong LI Jufu FENG | 2018 | Science China(Information Sciences)2018，61，1： | 4 |
| 5 | High-resolution palmprint minutiae extraction based on Gabor feature显示文摘Extracting effective minutiae is difficult for high-resolution palmprint, because of the strong influence from principal lines, creases, and other noises. In this paper, a novel minutiae detection and reliability measurement method is proposed for high-resolution palmprint minutiae extraction. Firstly, we propose the Gabor Amplitude-Phase model for palmprint representation, which contains sufficient palmprint information and consists of the phase field and amplitude field. Because of the explicit meanings of minutiae in phase field,a minutiae descriptor is constructed to detect them directly. Also, to measure minutiae reliability and remove the unreliable ones, the Gabor Amplitude-Phase feature vector is designed. It can be used for describing the local area of a minutia redundantly. Then, the Adaboost algorithm is introduced in model training to select best features and corresponding weak classifiers for minutiae authenticity discriminant. Finally, the response value of weighted linear combination of selected weak classifiers is used for minutiae reliability measurement and unreliable ones removal. According to our analysis, the selected features are meaningful and useful for describing the minutiae area and measuring their reliability. Experimental results show that our proposed method is effective for minutiae extraction and can improve the matching performance. | FENG JuFu LIU ChongJin WANG Han SUN Bing | 2014 | Science China(Information Sciences)2014，57，11： | 4 |
| 6 | Boosting and margin theory显示文摘许多研究人员在理论研究了 AdaBoosts 好试验性的结果的解释。一些工作以边缘分发功能给归纳错误的上面的界限,当 Breiman 基于最小的边缘给了更锋利的归纳错误界限时。他也开发了 arcgv 算法最大化最小的边缘,然后使最小的边缘比 AdaBoost 大。然而,它的实验结果比 AdaBoost 甚至更坏。因此,最小的边缘界限是不实际的吗?这份报纸比最小的边缘跳的给一个新概念叫的平衡边缘(Emargin ) 并且证明一个新归纳错误用 Emargin 跳了,它总是好。另外,我们证明 Emargin 是归纳的好指示物。然后,我们进行证明 AdaBoost 的 Emargin 比 arc-gv 大,但是 Ada 增加的归纳错误通常更好的实验。 | Jufu FENG Liwei WANG Masashi SUGIYAMA Cheng YANG Zhi-Hua ZHOU Chicheng ZHANG | 2012 | Frontiers of Electrical and Electronic Engineering in China2012，7，1： | 4 |
| 7 | Formation of Fine Spheroidal Microstructure of Semi-Solid Al—Zn—Mg—Cu Alloy by Hyperthermally and Subsequent Isothermally Reheating显示文摘The high strength 7xxx series aluminium alloys are usually difficult to be prepared as semi-solid feedstock,because some dispersoid particles(soluble only in liquid) could pin at grain and subgrain boundary to make the alloy difficultly recrystallise.In this work,a novel multistep reheating regime is developed for recrystallisation and partial melting(RAP) route to prepare fine spheroidal microstructure of semi-solid AleZne MgeCu alloy.After reheating to 665℃,holding for 4 min and subsequent isothermally holding at 620℃ with total heating time of 15 min,fine spheroidal microstructures with grain size of w40 mm were prepared without remained unrecrystallised grains and directionality,which are much finer than the conventionally obtained microstructures(w100 mm). | Gang Chen Jufu Jiang Zhiming Du Qi Cao Hongwei Li Xin Zhang | 2013 | Journal of Materials Science & Technology2013，29，10： | 2 |
| 8 | Microstructure and properties of AZ80 alloy semisolid billets fabricated by new strain induced melt activated method 显示文摘 | Jiang Jufu Wang Ying Du Zhiming | 2012 | Transactions of Nonferrous Metals Society of China2012，22，2： | 1 |
| 9 | On the Euclidean Distance of Images显示文摘 | Wang Liwei Zhang Yan Feng Jufu | | 0，，08： | 1 |
| 10 | An analytic relation for the thickness of accretion flows显示文摘We take the vertical distribution of the radial and azimuthal velocities into account in spherical coordinates,and find that the analytic relation cs0/υKΘ = [(γ-1)/2γ]1/2 is valid for both geometrically thin and thick accretion flows,where cs0 is the sound speed on the equatorial plane,υK is the Keplerian velocity,Θ is the half-opening angle of the flow,and γ is the adiabatic index. | CAI ZhenYi,GU WeiMin,XUE Li & LU JuFu Department of Physics and Institute of Theoretical Physics and Astrophysics,Xiamen University,Xiamen 361005,China | 2010 | Science China(Physics,Mechanics & Astronomy)2010，53，S1： | 1 |
| 11 | On the euclidean distance of images显示文摘 | Wang Liwei Zhang Yan Feng Jufu | 2000 | IEEE Transaction On Pattern Analysis And Machine Intelligence2000，27，8： | 1 |
| 12 | Subspace distance analysis with application to adaptive Bayesian face recognition显示文摘 | WANG Liwei WANG Xiao FENG Jufu | 2006 | Pattern Recognition2006，39，3： | 1 |
| 13 | Further results on the subspace distance显示文摘 | SUN Xichen WANG Liwei FENG Jufu | 2007 | Pattern Recognition2007，40，1： | 1 |
| 14 | On the Euclidean distance of images显示文摘 | Wang Liwei Zhang Yan Feng Jufu | 2005 | IEEE Transactions on Pattern Analysis and Machine Intelligence2005，27，8： | 1 |
| 15 | On the Euclidean distance of images 显示文摘 | WANG Liwei ZHANG Yan FENG Jufu | 2005 | IEEE Transactions on Pattern A- nalysis and Machine Intelligence2005，27，8： | 1 |
| 16 | On the euclidean distance of images显示文摘 | Wang Liwei Zhang Yan Feng Jufu | 2005 | IEEE Trans PAMI2005，27，8： | 1 |
| 17 | On the euclidean distance of images显示文摘 | Wang Liwei Zhang Yan Feng Jufu | 2005 | IEEE Transaction on Patten Analysis and Machine Intelligence2005，27，8： | 1 |
| 18 | Microstructure and mechanical properties of the semisolid slurriesand rheoformed component of nano-sized SIC/7075 aluminum matrix composite prepared by ultrasonic-assisted semisolid stir- ring显示文摘 | JIANG Jufu WANG Ying | 2015 | Materials Science & Engineering2015，639，： | 1 |
| 19 | Numerical simulation and experiment validation of thixoforming angle frame of AZ61 magnesium alloy 显示文摘 | Jiang Jufu Wang Ying Qu Jianjun | 2010 | Transactions of Nonferrous Metals Society of China2010，20，3： | 1 |
| 20 | Application of equal channel angular extrusion to semi-solid processing of magnesium alloy 显示文摘 | Jiang Jufu Wang Ying Luo Shoujing | 2007 | Materials Characterization2007，58，： | 1 |
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