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Wigner-Ville distribution and cross Wigner-Ville distribution of noisy signals

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Journal of Systems Engineering and Electronics 2008年第5期19卷 1053-1057页

作者： Chen Guanghua ma Shiwei Liu Ming Zhu Jingming Zeng Weimin k.y Laboratory of Advanced Display and System Applications Ministry of Education & Microelectronic Research and Development Center Shanghai Univ. Shanghai 200072 P. R. China

The Wigner-Ville distribution （WVD） and the cross Wigner-Ville distribution （XWVD） have been shown to be efficient in the estimation of instantaneous frequency （IF）. But the statistical result of the IF estimation from XWVD peak.is much better than using WVD peak. The reason is given from a statistical point of view. Theoretical studies show that XWVD of the analyzed signal can be estimated from XWVD of the noise-contaminated signal. The estimation is unbiased, and the variance is equal to that of noise. In this case, WVD cannot be estimated from W-VD of the noise-contaminated signal. Therefore, higher SNR is required when WVD is used to analyze signals.

关键词： Wigner-Ville distribution cross Wigner-Ville distribution instantaneous frequency expectation variance.

Surface composites fabricated by vacuum infiltration casting technique

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Journal of University of Science and Technology Beijing 2005年第5期12卷 455-459页

作者： Guirong yang yuan Hao Wenming Song Jinjun Lii ying ma State k.y Laboratory for New Nonferrous Metal materials School of Materials Science and Engineering Lanzhou University of Technology Lanzhou730050 China Laboratory of Solid Lubrication Lanzhou Institute of Chinese Academy of Sciences Lanzhou 730000 China

Alumina （Al2O3） particles reinforced copper matrix surface composites were fabricated on the bronze substrate using the vacuum infiltration casting technique. Three cases were obtained in the vacuum infiltration casting technique： no infiltration, partial infiltration and full infiltration （the thick.ess of preforms do not exceed 3.5mm）. The reason of no infiltration is that the vacuum degree is not enough so that the force acting on the liquid metal is lower than the resistance due to the surface tension. Partial infiltration is because of somewhat lower vacuum degree and pouring temperature. Full desired infiltration is on account of suitable infiltration casting conditions, such as vacuum degree, pouring temperature, grain size and preheating temperature of the preform. The most important factor of affecting formation of surface composites is the vacuum degree, then pouring temperature and particle size. The infiltration mechanism was discussed on the bases of different processing conditions. The surface composite up to 3.5 mm in thick.ess with uniformly distributed Al2O3 particles could be fabricated via the vacuum infiltration casting technique.

关键词： alumina vacuum infiltration casting surface composite preform

Thermodynamic analysis and preparation of β-SiC/ZrO_2 composites

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International Journal of Minerals,Metallurgy and materials 2009年第5期16卷 581-585页

作者： Bei-yue ma Jing-k.n yu Qiang Zhu yong Sun School of materials and Metallurgy Northeastern University Shenyang 110004 China

A predominance area diagram for the Zr-Si-C-O system at 1773 k.was plotted according to correlative thermodynamic data. β-SiC/ZrO2 composites were prepared based on the phase diagram by carbothermal reduction of zircon （ZrSiO4） in argon atmosphere. Zircon and carbon black.were mixed according to the C/ZrSiO4 mass ratio of 0.2, and with 0, 1wt% and 2wt% extra addition of La2O3. Phase evolution of the mixture was investigated at 1723-1803 k.by X-ray powder diffraction, and the microstructure of the product prepared at 1803 k.for 4 h was examined by scanning electronic microscope. The results show that the decomposition of ZrSiO4 and the formation of β-SIC can be promoted by increasing the heating temperature and adding La2O3. The β-SiC/ZrO2 composites can be prepared at 1803 k.for 4 h in a mixture of zircon, carbon black.and La2O3, and the contents of β-SIC and m-ZrO2 in the product sample with 2wt% La2O3 reach the highest values of 10.8wt% and 89.2wt%, respectively. The crystal size of the products is about 200 nm.

关键词： composites silicon carbide zirconium dioxide carbothermal reduction thermodynamic analysis

Additive-state-decomposition-based station-k.eping control for autonomous aerial refueling

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Science China(Information Sciences) 2021年第11期64卷 240-242页

作者： Jinrui REN Quan QUAN Haibiao ma k.i-yuan CAI School of Automation Science and Electrical Engineering Beihang University

Dear editor,Aerial refueling(AR) is an effective method of increasing the endurance and range of aircraft by refueling them in flight [1, 2]. Station-k.eping control is the basis of autonomous aerial refueling(AAR). The station-k.eping control for AAR is a difficult task.for two main reasons. First,the receiver is disturbed by the atmospheric turbulence and the wak. vortex of the tank.r. Secondly, owing to the fuel injection in the refueling process, the mass and the center of mass of the receiver will change.

关键词： Aerial refueling station k.eping two-degree-of-freedom additive state decomposition varying mass

miR-152在结直肠癌组织中的表达及其与预后的关系

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中华肿瘤杂志 2016年第10期38卷 763-766页

作者：汪毅袁伟马肖马洁国家癌症中心中国医学科学院北京协和医学院肿瘤医院VIP病房 100021 国家癌症中心中国医学科学院北京协和医学院肿瘤医院分子肿瘤学国家重点实验室 100021

目的探讨结直肠癌及癌旁组织中miR-152的表达水平及其与结直肠癌术后患者预后的关系。方法采用实时荧光定量PCR法检测202例结直肠癌及癌旁组织中miR-152的表达水平，采用Cox比例风险模型分析miR-152的表达水平与结直肠癌患者预后的关系... 详细信息

目的探讨结直肠癌及癌旁组织中miR-152的表达水平及其与结直肠癌术后患者预后的关系。方法采用实时荧光定量PCR法检测202例结直肠癌及癌旁组织中miR-152的表达水平，采用Cox比例风险模型分析miR-152的表达水平与结直肠癌患者预后的关系。结果miR-152在结直肠癌及癌旁组织巾的相对表达水平分别为2．109±0．217和15．860±6．647，差异有统计学意义（P〈0．001）．miR-152在有、无淋巴结转移的结直肠癌组织中的相对表达水平分别为2．582±0．344和1．640±0．258．差异有统计学意义（P=0．001）。miR-152在Ⅰ～Ⅱ期、Ⅲ期和Ⅳ期结直肠癌组织中的相对表达水平分别为1．640±0．258、2．187±0．361和4．403±0．877，差异有统计学意义（P〈0．05）。单因素Cox回归分析显示，分化程度、淋巴结转移情况、TNM分期和miR-152的表达水平与结直肠癌术后患者的预后均有关（均P〈0．05）。多因素Cox回归分析显示，分化程度和TNM分期为影响结直肠癌患者预后的独立因素（均P〈0．001）。miR-152高表达与结直肠癌患者的不良预后有关（P〈0．05）。结论miR-152在结直肠癌组织中的表达水平低于相应的癌旁组织，miR-152表达水平与结直肠癌患者的淋巴结转移和TNM分期有关。miR-152有可能作为提示结直肠癌患者预后的潜在标志物。

关键词：微RNAs 结直肠肿瘤肿瘤分期肿瘤转移预后

Pseudoconformal equation of state in compact-star matter from topology change and hidden symmetries of QCD

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Science China(Physics,Mechanics & Astronomy) 2019年第11期62卷 87-92页

作者： yong-Liang ma Hyun k.u Lee Won-Gi Paeng mannque Rho Center for Theoretical Physics and College of Physics Jilin UniversityChangchun 130012China Department of Physics Hanyang UniversitySeoul 133-791Korea Rare Isotope Science Project Institute for Basic ScienceDaejeon 305-811Korea Institut de Physique Theorique CEA Saclay91191 Gif-sur-Yvette cedexFrance

We construct a new effective field theory approach to the equation of state(EoS), dubbed pseudo-confomal model 'PCM', for nuclear and compact star matter entirely in terms of effective hadron degrees of freedom. The possible transition at n ^(2-4)n0(where n0 is the normal nuclear matter density) from hadron degrees of freedom to strongly-coupled quark.degrees of freedom,giving rise to a soft-to-hard changeover in the EoS that can accommodate the massive stars observed, is effectuated by the topology change at n1/2>~ 2n0 from sk.rmions to half-sk.rmions without involving local order-parameter fields. The mechanism exploits possible emergence of hidden scale and local symmetries of QCD at high density, leading to a precocious 'pseudo-conformal'sound velocity vs2= 1/3(in unit of c = 1) for n>~ 3n0. The resulting prediction signals a drastic departure from standard nuclear many-body theory in the density regime involved in the massive stars. We suggest that the tidal deformability implemented in gravitational waves coming from coalescing neutron stars in LIGO/Virgo-type observations could pin down the location of the topology change density n1/2.

关键词： equation of state compact star tidal deformability conformal sound velocity

A network.aware error-resilient method using prioritized intra refresh for wireless video communications

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第8期10卷 1169-1176页

作者： Han-jie ma Fan ZHOU Rong-xin JIANG yao-wu CHEN Institute of Advanced Digital Technology and Instrumentation Zhejiang University Hangzhou 310027 China

We propose a novel prioritized intra refresh method for the wireless video *** proposed method considers the characteristics of the human visual system,the error-sensitivity of the bitstream,and the state of the time-varying wireless channel *** expected perceptual distortion model was used to adjust the intra refresh rate *** model consists of the perceptual weight map based on an attention model,the bit error probability map based on bitstream size,and the dynamic channel state information(CSI).Experimental results indicate that,compared with other intra refresh methods that consider only the content of the video or the CSI,the proposed method improves the average peak.signal-to-noise ratio(PSNR) of the whole frame by about 0.5 dB,and improves the average PSNR of the attention-area by about 0.8 dB.

关键词： Intra refresh. Distortion. Perceotual weieht. Error-sensitivity. Channel state information (CSI)

Low-Complexity LS Algorithm Using Coordinate Transformation

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Chinese Journal of Electronics 2017年第1期26卷 156-159页

作者： yAN Wen XIE yizhuang ZHU Bocheng CHEN He ma Cuimei School of Information and Electronics Beijing Institute of Technology School of Electronics Engineering and Computer Science Peking University

To reduce the computational complexity, decrease hardware resource consumption, and mak. it practicable, we propose a novel coordinate transformation based low-complexity Least squares(LS) algorithm. The positive integral variable is set as a reference coordinate and coefficients are transformed to be constant. The fitting polynomial in the reference coordinate system can be easily realized with lower complexity. To achieve the fitting curve in the original coordinate system, coordinate transformation is needed. Compared with the conventional LS fitting, our implementation results show that the proposed LS fitting algorithm can greatly reduce hardware resources in the premise of meeting the precision requirements.

关键词： Least squares(LS) fitting Reference coordinate Coordinate transformation Low computational complexity

A quantum‐lik. approach for text generation from k.owledge graphs

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CAAI Transactions on Intelligence Technology 2023年第4期8卷 1455-1463页

作者： Jia Zhu Xiaodong ma Zhihao Lin Pasquale De Meo k.y Laboratory of Intelligent Education Technology and Application of Zhejiang Province Zhejiang Normal UniversityJinhuaChina School of Computer Science South China Normal UniversityGuangzhouChina DICAM Department University of MessinaMessinaItaly

Recent text generation methods frequently learn node representations from graph‐based data via global or local aggregation,such as k.owledge *** all nodes are connected directly,node global representation encoding enables direct communication between two distant nodes while disregarding graph *** local representation encoding,which captures the graph structure,considers the connections between nearby nodes but misses out onlong‐range relations.A quantum‐lik. approach to learning bettercontextualised node embeddings is proposed using a fusion model that combines both encoding *** methods significantly improve on two graph‐to‐text datasets compared to state‐of‐the‐art models in various experiments.

关键词： data mining k.owledge‐based vision machine learning natural language processing text analysis