OALib Journal期刊

ISSN: 2333-9721




2019 ( 22 )

2018 ( 193 )

2017 ( 209 )

2016 ( 242 )


匹配条件: “Yanfang Yu” ,找到相关结果约59000条。
Analysis of the Operational Effects of Danish Flexicurity Model
Xinxuan Cheng,Yanfang Yu
Review of European Studies , 2010, DOI: 10.5539/res.v2n2p87
Abstract: European Union’s flexicurity model is an operational method that reinforces the elasticity of the labor markets of its member countries and improves the employment level. This model emphasizes that flexibility and security are not contradictory but mutually supplementary and supportive. Labor policies constituted by all countries consider the trade-off between the flexibility and security to coordinate roles of the labor policies. The flexicurity model shows its validity in solving the employment problems in member countries of European Union, especially in Danmark. This paper first introduces the connotation of European Union’s flexicurity model, highlights its flexibility and safeguarding; second, it introduces the operational method and results of European Union’s flexicurity model in Denmark ; finally, this paper considers the features of the disadvantaged groups in China and proposes the way to construct the flexicurity system of the employment of disadvantaged groups from the perspectives of choosing the balance point of the flexicurity model, strengthening education and training system, reinforcing unemployment insurance, implementing active labor market policies, establishing and improving social dialogue mechanism, etc.
Design and Development of High School Artificial Intelligence Textbook Based on Computational Thinking  [PDF]
Yanfang Yu, Yuan Chen
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104898
Big data and deep learning technology have once again set off a boom in artificial intelligence. Artificial intelligence has been a major development strategy in many countries. The Chinese government has also written this into the “13th Five-Year Plan”, and the Ministry of Education has also launched with the reform measures for artificial intelligence education, the deep integration of “artificial intelligence education” has been opened. In this context, China’s artificial intelligence disciplines and professional construction have set off a major reform storm from colleges to basic education. The revision of this high school artificial intelligence textbook was carried out in this context. The biggest feature of this high school artificial intelligence textbook revision is the integration of computational thinking into the core literacy design. Computational thinking is an indispensable ability of learners in the 21st century. As a typical “digital aboriginal”, high school students must have computational thinking in order to cope with the challenges brought about by the rapid changes in social technology in the future. At present, all developed countries have incorporated computational thinking into national curriculum standards. China has also written computational thinking into national curriculum standards and listed it as one of the core literacies of information technology disciplines.
IL-17 and IL-22 in Cerebrospinal Fluid and Plasma Are Elevated in Guillain-Barré Syndrome
Shujuan Li,Ming Yu,Haifeng Li,Hongliang Zhang,Yanfang Jiang
Mediators of Inflammation , 2012, DOI: 10.1155/2012/260473
Abstract: Guillain-Barré syndrome (GBS) is an acute autoimmune-mediated inflammatory demyelinating disease that causes rapidly progressing paralysis and occasionally respiratory failure. We hypothesized that interleukin (IL)-17 and IL-22 are elevated in GBS and participate in the autoimmune inflammatory response of GBS. We used sandwich enzyme-linked immunosorbent assay (ELISA) to measure the IL-17 and IL-22 levels in the CSF, and plasma from 22 GBS patients at the acute phase and 18 healthy controls (HC). The results show that CSF and plasma levels of IL-17 and IL-22 are elevated in GBS patients compared with HC. IL-17 and IL-22 levels in CSF, respectively, are correlated with GBS disability scale scores (GDSs). Meanwhile, IL-17 and IL-22 levels in CSF, IL-22 in CSF, and plasma of GBS patients have positive correlation, respectively. The increased levels of IL-17 and IL-22 in CSF may be explained by the disruption of blood-brain barrier (BBB) and peripheral nervous system (PNS) local inflammation in GBS. Meanwhile, the elevated levels of these two cytokines in plasma suggest the activation of Th17 and Th22 cells in the systemic immune response of GBS. Our data provide preliminary evidence that GBS is associated with high levels of IL-17 and IL-22 in CSF and plasma. These cytokines display pathogenic potential and may serve as useful biomarkers for GBS. 1. Introduction Guillain-Barré syndrome (GBS) is an acute autoimmune-mediated inflammatory demyelinating disease that affects the peripheral nerves involving myelin sheath and axons [1]. It is clinically characterized by rapidly progressing symmetrical weakness and hyporeflexia/areflexia followed mostly by recovery [1, 2]. The severity of weakness ranges from mild limb asthenia to absolute paralysis, occasionally with respiratory failure that may lead to death [1, 2]. Meanwhile, the cerebrospinal fluid (CSF) of GBS patients usually shows characteristic albumin-cytological dissociation, that is, elevated protein levels and approximately normal cell counts, from two weeks after the disease onset [2]. There is strong evidence proving that both humoral and cellular immune mechanisms are involved in the pathogenesis of GBS: (i) serum antibodies to various gangliosides in human peripheral nerves have been found in about half of GBS patients [3]; (ii) pathological findings in GBS include lymphocytic infiltration in spinal roots and peripheral nerves, followed by macrophage-mediated, multifocal stripping of myelin [4]; (iii) plasma exchange (PE) and intravenous immunoglobulin (IVIg) therapies are effective in the
Time-frequency analysis of Hilbert spectrum of pressure fluctuation time series in a Kenics Static Mixer based on empirical mode decomposition
Meng, Huibo;Liu, Zhiqiang;Yu, Yanfang;Wu, Jianhua;
Brazilian Journal of Chemical Engineering , 2012, DOI: 10.1590/S0104-66322012000100018
Abstract: the turbulent flow in a kenics static mixer (ksm) was intensified under the mutual-coupling effect between the twisted leaves and the tube-wall. in order to understand the intrinsic features of turbulent flow in ksm, the hilbert-huang transform based on empirical mode decomposition were first introduced to describe the time-frequency features of the pressure fluctuation. the hilbert spectra of pressure fluctuation time series were quantitatively evaluated under different reynolds numbers, and different radial and axial positions, respectively. the experimental results showed that: the fluctuation frequencies of pressure signals in a ksm were mainly distributed below 40 hz, and more than 68% of the energy of signals is concentrated within 10 hz. compared with the other imfs, the pressure component of c6 in the range of 7.82~15.63 hz has the maximum fluctuation energy ratio. as the flow rate increases, the energy of fluctuation of fluid micelles and the proportion of low-frequency energy increases. the pressure fluctuation with higher energy ratio of low frequency (0~10 hz) had lower amplitudes at r/r=0.3 because of the core of forced vortex. nevertheless, the effect of the free vortex was that the pressure fluctuation with lower energy ratio of low frequency had higher amplitudes at r/r=0.8. the higher amplitudes of pressure fluctuation at cross sections of cs3 (z=420 mm) and cs5 (z=620 mm) proved that the transitions between the adjacent mixing element had better mixing performance.
Influences of Al doping on the electronic structure of Mg(0001) and dissociation property of H2
Yanfang Li,Yu Yang,Yinghui Wei,Ping Zhang
Physics , 2009, DOI: 10.1016/j.physleta.2009.12.011
Abstract: By using the density functional theory method, we systematically study the influences of the doping of an Al atom on the electronic structures of the Mg(0001) surface and dissociation behaviors of H2 molecules. We find that for the Al-doped surfaces, the surface relaxation around the doping layer changes from expansion of a clean Mg(0001) surface to contraction, due to the redistribution of electrons. After doping, the work function is enlarged, and the electronic states around the Fermi energy have a major distribution around the doping layer. For the dissociation of H2 molecules, we find that the energy barrier is enlarged for the doped surfaces. Especially, when the Al atom is doped at the first layer, the energy barrier is enlarged by 0.30 eV. For different doping lengths, however, the dissociation energy barrier decreases slowly to the value on a clean Mg(0001) surface when the doping layer is far away from the top surface. Our results well describe the electronic changes after Al-doping for the Mg(0001) surface, and reveal some possible mechanisms for improving the resistance to corrosion of the Mg(0001) surface by doping of Al atoms.
Dissociation of hydrogen molecules on the clean and hydrogen-preadsorbed Be(0001) surface
Yanfang Li,Yu Yang,Bo Sun,Yinghui Wei,Ping Zhang
Physics , 2009, DOI: 10.1016/j.physleta.2011.05.001
Abstract: Using first-principles calculations, we systematically study the potential energy surfaces and dissociation processes for hydrogen molecules on the clean and hydrogen-preadsorbed Be(0001) surfaces. It is found that the most energetically favored dissociation channel for H2 molecules on the clean Be surface is at the surface top site, with the minimum energy barrier of 0.75 eV. It is further found that after dissociation, hydrogen atoms do not like to cluster with each other, as well as to penetrate into subsurface sites. For the hydrogen-preadsorbed Be(0001) surface, the smallest dissociation energy barrier for H2 molecules is found to be 0.50 eV, which is smaller than the dissociation energy barrier on a clean Be(0001) surface. The critical dependence of the dissociation energy barriers for H2 molecules on their horizontal distances from the preadsorbed hydrogen atom is revealed. Our studies well describe the adsorption behaviors of hydrogen on the Be(0001) surface.
Atomic hydrogen adsorption and incipient hydrogenation of the Mg(0001) surface: A density-functional theory study
Yanfang Li,Ping Zhang,Bo Sun,Yu Yang,Yinghui Wei
Physics , 2009,
Abstract: We investigate the atomic hydrogen adsorption on Mg(0001) by using density-functional theory within the generalized gradient approximation and a supercell approach. The coverage dependence of the adsorption structures and energetics is systematically studied for a wide range of coverage and adsorption sites. In the coverage range $0<\Theta<1.0, the most stable among all possible adsorption sites is the on-surface fcc site followed by the hcp site, and the binding energy increases with the coverage, thus indicating the higher stability of on-surface adsorption and a tendecy to the formation of H islands (clusters) when increasing the coverage within the region $0<\Theta<1.0. The on-surface diffusion path energetics of atomic hydrogen, as well as the activation barriers for hydrogen penetration from the on-surface to the subsurface sites, are also presented at low coverage. At high coverage of $1.00<\Theta<2.0, it is found that the coadsorption configuration with 1.0 monolayer of H's residing on the surface fcc sites and the remaining monolayer of H's occupying the subsurface tetra-I sites is most energetically favourable. The resultant H-Mg-H sandwich structure for this most stable coadsorption configuration displays similar spectral features to the bulk hydride MgH$_{2}$ in the density of states. The other properties of the H/Mg(0001) system, including the charge distribution, the lattice relaxation, the work function, and the electronic density of states, are also studied and discussed in detail. It is pointed out that the H-Mg chemical bonding during surface hydrogenation displays a mixed ionic/covalent character.
Dynamic Shortest Path Algorithm in Stochastic Traffic Networks Using PSO Based on Fluid Neural Network  [PDF]
Yanfang Deng, Hengqing Tong
Journal of Intelligent Learning Systems and Applications (JILSA) , 2011, DOI: 10.4236/jilsa.2011.31002
Abstract: The shortest path planning issure is critical for dynamic traffic assignment and route guidance in intelligent transportation systems. In this paper, a Particle Swarm Optimization (PSO) algorithm with priority-based encoding scheme based on fluid neural network (FNN) to search for the shortest path in stochastic traffic networks is introduced. The proposed algorithm overcomes the weight coefficient symmetry restrictions of the traditional FNN and disadvantage of easily getting into a local optimum for PSO. Simulation experiments have been carried out on different traffic network topologies consisting of 15-65 nodes and the results showed that the proposed approach can find the optimal path and closer sub-optimal paths with good success ratio. At the same time, the algorithms greatly improve the convergence efficiency of fluid neuron network.
A Tentative Study of How to Improve the Effectiveness of Classroom Interaction
Yanfang LU
Studies in Literature and Language , 2011, DOI: 10.3968/j.sll.1923156320110203.011
Abstract: The effectiveness of English learning and teaching is the ultimate goal of English education. Yet in China, English teaching is far from being effective. There is a lack of effective interaction between teacher and students in class. Using the framework of Conversation Analysis, this thesis summarizes four most frequently used classroom interaction models and their characteristics. Then it proposes some strategies on how to improve classroom interaction, they are: Clarification Requests, Confirmation Checks, Comprehension Checks, Conversational Adjustments, Partial, Exact, Expanded, and Total Self-Repetition, Partial, Complete, Expanded, and Total Other-Repetition. Key words: Effectiveness; English teaching; Conversation Analysis
Research on Cost Strategies in Railway Construction Business Based on Value Chain Analysis
Yanfang WU
Management Science and Engineering , 2012, DOI: 10.3968/j.mse.1913035x20120603.2699
Abstract: Based on the completive advantage and value chain, this paper analyzes the key link of value chain construction and value creation of railway construction enterprises, after this, we discussed the effective approaches and methods for railway construction enterprises to carry out cost strategy and promote the market development. Key word: Railway construction enterprises; Value chain; Cost strategies

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