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Search Results: 1 - 10 of 127173 matches for " Feipeng Li "
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The Investigation and Analysis of Teachers’ Involvement in Students’ Autonomous Learning  [PDF]
Chen Guan, Feipeng Li
Open Journal of Modern Linguistics (OJML) , 2014, DOI: 10.4236/ojml.2014.44044
Abstract: The cultivation of students’ autonomous learning ability is one of the important sections of English teaching reform at college in China. However, it doesn’t mean that teachers’ involvement is becoming less and less necessary; instead, teachers’ involvement is significant and indispensable to guarantee and promote learner autonomy. This paper firstly introduces the basic concept of students’ autonomous learning and teachers’ involvement briefly. Then, it analyzes the statistics of the questionnaire about teachers’ involvement in Baoding University. Finally, this paper illustrates the different roles that teachers should play in and after class with the reference of questionnaire data discussed above. Hopefully, this paper may have some enlightment for teachers’ involvement in students’ autonomous learning.
Charge density waves and phonon-electron coupling in ZrTe$_3$ investigated by Raman spectroscopy and first-principles calculations
Yuwen Hu,Feipeng Zheng,Xiao Ren,Ji Feng,Yuan Li
Physics , 2015, DOI: 10.1103/PhysRevB.91.144502
Abstract: Charge-density-wave (CDW) order has long been interpreted as arising from a Fermi-surface instability in the parent metallic phase. While phonon-electron coupling has been suggested to influence the formation of CDW order in quasi-two-dimensional (quasi-2D) systems, the presumed dominant importance of Fermi-surface nesting remains largely unquestioned in quasi-1D systems. Here we show that phonon-electron coupling is also important for the CDW formation in a model quasi-1D system ZrTe$_3$. Our joint experimental and computational study reveals that particular lattice vibrational patterns possess exceedingly strong coupling to the conduction electrons, and are directly linked to the lattice distortions associated with the CDW order. The dependence of the coupling matrix elements on electron momentum further dictates the opening of (partial) electronic gaps in the CDW phase. Since lattice distortions and electronic gaps are the defining signatures of CDW order, our result demonstrates that the conventional wisdom based on Fermi-surface geometry needs to be substantially supplemented by phonon-electron coupling even in the simplest quasi-1D case. As prerequisites for the CDW formation, the highly anisotropic electronic structure and strong phonon-electron coupling in ZrTe$_3$ give rise to a distinct Raman scattering effect, namely, measured phonon linewidths depend on the direction of momentum transfer in the scattering process.
Contamination by persistent toxic substances in surface sediment of urban rivers in Chaohu City, China
Feipeng Li,Haiping Zhang,Xiangzhou Meng,Ling Chen,Daqiang Yin,
Feipeng Li
,Haiping Zhang,Xiangzhou Meng,Ling Chen,Daqiang Yin

环境科学学报(英文版) , 2012,
Abstract: The concentration and spatial distribution of persistent toxic substances (PTS) in the river sediment in Chaohu City, China were investigated. A total of nine surface sediments were collected and the selected PTS pollutants including six heavy metals and nineteen polybrominated diphenyl ethers (PBDEs) were analyzed. The mean heavy metal concentrations (in mg/kg, dry weight) ranged within 0.18-1.53 (Hg), 50.08-200.18 (Cu), 118.70-313.65 (Zn), 50.77-310.85 (Cr), 37.12-92.72 (Pb) and 13.29-197.24 (As), and Cu, Zn and As have been regarded as the main metal pollutants. The levels of PBDEs (1.2-12.1 ng/g) and BDE-209 (2.4-30.5 ng/g) were at the middle level of the global range. BDE-209 was the predominant congener (67.0%-85.7%), which agrees with the fact that technical deca-BDE mixtures are the dominant PBDE formulation in China. The relative high level of PTS pollutants in the western part of the city is probably owing to the intensive agricultural activities and lack of sewerage system there. The ecological risk assessment with the sediment quality guidelines (SOGs) indicates that the urban river sediments in the city have been heavily contaminated by heavy metals with probable ecotoxicological impacts on freshwater organisms and the main toxic pollutants are Hg and As. The results of current study imply that the city, and perhaps many other small cities in China as well, requires immediate pollution control measures with emphasis on not only conventional organic pollutants but also on PTS such as heavy metals and PBDEs.

Chang Yilin,Li Bingbing,Li Feipeng,

电子与信息学报 , 1996,
Abstract: This paper proposes a new block matching criterion called the bit-correlation matching function for sequence image coding. By using the same fast search algorithm, the bit-correlation matching function not only results in as nearly same a uracy in displacement estimation as mean square error function, but also makes the fast search algorithm low in computation complexity and easy to parallel operation, thus reducing the coding time of sequence image efficiently.
The emergy synthesis and sustainability analysis of city''''s environment and economy

LI Jinping,CHEN Feipeng,WANG Zhishi,

生态学报 , 2006,
Abstract: 澳门资源缺乏,人口高度密集,其生命支持系统几乎完全依赖进口。近年,澳门经历了经济的繁荣和社会的发展,澳门如何能克服其自身的缺点而生存?试图应用H.T.Odum创立的能值(Emergy)分析理论和方法,从城市生态系统的理论出发,对澳门的能值流进行系统分析研究,通过一系列能值指标,评价澳门城市生态系统自然环境和社会经济可持续发展的状况,为澳门制定发展策略和产业调整提供科学指导依据。2003年澳门城市生态系统应用能值为220×1020sej(Solaremjoules,太阳能焦耳,缩写为sej),输入的购买能值有216×1020sej,出口能值为140×1020sej。旅游博彩业为澳门带来52.1亿美元的收益,折算能值收益为86.5×1020sej,而游客只消费能值32.6×1020sej的商品和服务,旅游博彩业巨大的能值净收益为53.9×1020sej,旅游博彩业的贡献冲击比率为2.65。研究还发现,以相同的货币进行商品交换,中国大陆与澳门的能值交换比率是1.8倍。澳门旅游博彩业的能值剩余和澳门与中国大陆的能值交换优势,是维持澳门生态经济系统的关键因素。最后对澳门的可持续发展状况进行了讨论。
3D Face Recognition Based on Profile and Rigid Regions

LI Xiaoli,and DA Feipeng,

中国图象图形学报 , 2010,
Abstract: A two-step matching method for 3D face recognition is proposed. Feature points are detected based on curvature and geometric constraint. Then the symmetrical plane of 3D face is determined based on the feature points, and the profile is determined by the obtained symmetrical plane. The profile is used to form a rejection classifier, which quickly eliminates a large number of candidate faces at an early stage for an efficient recognition in case of large galleries. The remaining faces are then verified using a novel region-based matching approach, which is robust to facial expressions. This approach automatically segments the rigid regions, which are relatively less sensitive to expressions and it matches them separately using a modified iterative closest point (ICP) algorithm. The results of all the matching engines are fused using a sum rule to achieve higher accuracy. Our simulation experiment on 3D_RMA database demonstrates that the proposed method is simple, efficient and robust.
Highly Enantioselective Addition of Phenylethynylzinc to Aldehydes Catalyzed by Chiral Cyclopropane-Based Amino Alcohols
Bing Zheng,Zhiyuan Li,Feipeng Liu,Yanhua Wu,Junjian Shen,Qinghua Bian,Shicong Hou,Ming Wang
Molecules , 2013, DOI: 10.3390/molecules181215422
Abstract: The enantioselective addition of phenylethynylzinc to aldehydes catalyzed by a series of cyclopropane-based amino alcohol ligands 7 was investigated. The reactions afforded chiral propargylic alcohols in high yields (up to 96%) and with excellent enantioselectivities (up to 98% ee) under mild conditions. Furthermore, studies on the structural relationship show that the matching of the chiral center configuration is crucial to obtain the high enantioselectivity.
Microstructures and Mechanical Properties of Nb-Ti Bearing Hot-rolled TRIP Steels
Yu CHEN,Guoyi TANG,Haoyang TIAN,Feipeng LI,Yu ZHANG,Lihui WANG,Zhaojun DENG,Dexing LUO,

材料科学技术学报 , 2006,
Abstract: Nb-Ti hot-rolled TRIP-assisted steel with high plasticity and appropriate volume percentage of retained austenite based on fine ferrite grain have been developed in the experiment. The test results showed that niobium tend to exist in solution state in matrix with less precipitation, and niobium-titanium could be precipitated in form of (Nb, Ti)C or (Nb, Ti) (C, N), which play an important role in increasing yield strength (from 495 MPa to 610 MPa). Besides, the retained austenite had a positive effect on improving the plasticity by transformation into martensite during tensile deformation.
Optical Limiting and Stabilization Properties of a Liquid Dye on 1064 nm Nanosecond Laser Pulses  [PDF]
Liuheng Wang, Rongzong Peng, Yuxia Zhao, Feipeng Wu
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.32B008

A novel liquid dye 2-((2E,5E)-2,5-bis(4-(methyl(2,5, 8,11-tetraoxatridecan-13-yl)amino)benzylidene)cyclopentylidene) malononitrile (TO-BDCM) was synthesized by incorporating two oligo(ethenyl glycol) groups into the backbone of a prototype malononitrile derivative (BDCM) for the purpose of increasing its solubility in organic solvents. The nonlinear absorption properties of this liquid dye on 1064 nm ns pulsed laser were investigated in DMF with remarkably high concentration up to ~1M, showing a superior large nonlinear absorption coefficient of 55.6 cm3/GW2. Fairly good optical limiting and stabilization effects were achieved. Meanwhile, the liquid dye exhibited equivalent stability under laser irradiation compared to its prototype dye BDCM.

Syntheses and Co-Fluorescence of Complexes of Eu (III)/Gd (III) with Thienyltrifluoroacetonate, Terephthalic Acid and Phenanthroline  [PDF]
Xuehui Zhao, Zhongliang Hu, Haiyun Jiang, Feipeng Jiao, Zhengxiang Wang
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.517137
Abstract: A series of complexes of europium (III)/gadolinium (III) with 2-thienyltrifluoroacetonate (HTTA), terephthalic acid (TPA) and phenanthroline (Phen) were synthesized by coprecipitation. The resulting complexes including Eu2(TPA)(TTA)4Phen2, Eu1.4Gd0.6(TPA)(TTA)4Phen2, Eu1.0Gd1.0(TPA)(TTA)4Phen2 and Eu0.8Gd1.2(TPA)(TTA)4Phen2 were characterized by elemental analysis, IR spectroscopy and thermal stability analysis. The results of analysis indicate that the complexes obtained have similar binuclear structure with each other. The thermal stability analysis indicates that the complexes Eu2(TPA)(TTA)4Phen2and Eu1.0Gd1.0(TPA)(TTA)4Phen2 possess good thermal stability, which melt at ~241°C and decompose at ~370°C - 430°C corresponding to the formation of the complexes. The fluorescence spectra of Eu2(1-x)Gd2x(TPA)(TTA)4Phen2 (x = 0 - 1) complex powders and their doped silica gels were studied. The co-fluorescence effect of Gd3+ ions in complex powders is different from that of their doped silica gels. The optimum concentration of Gd3+ for complex powders and their doped silica gels is 0.5 and 0.3 (molar fraction), respectively. The co-fluorescence distinction of Gd3+ ions for complex powders and their doped silica gels is preferably interpreted from the proposed binuclear structure together with monomolecular compositions of the complexes for the first time. Both intermolecular energy transfer and intra molecular energy transfer in cross binuclear monomolecular EuGd(TPA)(TTA)4Phen2 are thought to be responsible for the co-fluorescence effect of the complex powders; yet only the latter is thought to be responsible for the co-fluorescence effect in silica gels, for the complex molecules in this case are isolated from each other.
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