国内二语写作产出性词汇广度研究的回顾与思考

国内二语写作产出性词汇广度研究相对较晚,通过文献回顾的基础上分析国内该领域研究成果在基本趋势、研究内容和研究工具方面的现状,提出有待在研究成果评价、研究工具和统计方法方面进一步完善。

产出性词汇广度和场认知风格的界面研究──基于英语专业学生的演讲稿

梳理77名大二英语专业学生一学期内四篇英语演讲稿,探索其在产出性词汇广度上的发展变化,分析"场独立"认知风格和"场依存"认知风格的学生在产出性词汇广度上产生的异同,初步得出:大二英语专业的学生经过一个学期英语演讲课的学习,在演讲稿中呈现的词汇复杂性和词汇多样性大致呈下降的趋势,而且场认知风格的不同没有对产出性词汇广度产生显著影响。分析造成这种现象的原因,提出相应的词汇教学策略。

基于流畅性中介效应的二语词汇与阅读关系研究

以某高校122名非英语专业二年级学生为研究对象,运用结构方程模型,探究不同维度的词汇知识与阅读理解的关系,并采用自助法(Bootstrapping)与蒙地卡罗(Monte Carlo Method)进一步考察了词汇流畅性的中介作用。结果发现:一是接受性词汇深度对于阅读理解贡献最大、接受性词汇广度次之、产出性词汇广度位居第三、产出性词汇深度贡献最小。分别为:β=.48,p<.001,β=.31,p<.001,β=.28,p<.001,β=.19,p<.001;二是词汇知识四个维度对阅读理解的整体预测力为59%;三是词汇流畅性在产出性词汇广度与阅读理解之间的关系起到部分中介的作用;四是在词汇流畅性的介入下,词汇知识四个维度对阅读理解的影响力不同程度地有所增加。最后讨论了不同维度的词汇知识在L2阅读理解中的不同重要性,研究结论对二语词汇与阅读教学具有重要指导意义。

基于流畅性调节效应的词汇与听力关系研究

词汇是语言习得的基础,听力是语言发展的关键,了解词汇与听力的关系对于语言学习者提高专业水平至关重要。以某高校156名二语学习者为受试对象,运用结构方程模型(SEM)探讨接受性词汇与听力理解之间的相关性,并采用Ping的二阶段评估进一步考察词汇流畅性对接受性词汇与听力理解关系的调节作用。研究发现:接受性词汇广度和词汇流畅性与听力理解之间相关性最强(r=0.38 p<0.001);接受性词汇深度与听力理解之间相关性次之(r=0.21 p<0.001);听力理解的被解释力达到50%(R^(2)=0.50);词汇流畅性在接受性词汇与听力理解之间起到一定的调节作用;不同维度的接受性词汇在听力理解中具有不同重要性。

Chemical bonding and elastic properties of quaternary arsenide oxides YZnAsO and LaZnAsO investigated by first principles

The structural parameters, chemical bonding and elastic properties of the tetragonal phase quaternary arsenide oxides YZnAsO and LaZnAsO were investigated by using density-functional theory （DFT） within generalized gradient approximation （GGA）. The GGA calculated structural parameters are in agreement with the experimental results. Population analysis suggests that the chemical bonding in YZnAsO and LaZnAsO can be classified as a mixture of ionic and covalent characteristic. Single-crystal elastic constants were calculated and the polycrystalline elastic modules were estimated according to Voigt, Reuss and Hill＇s approximations （VRH）. The result shows that both YZnAsO and LaZnAsO are relatively soft materials exhibiting ductile behavior. The calculated polycrystalline elastic anisotropy result shows that LaZnAsO is more anisotropy in compressibility and YZnAsO is more anisotropy in shear.

Ultimate end bearing capacity of rock-socketed pile based on generalized nonlinear unified strength criterion

In order to study the mechanism of bearing behavior at the tip of a pile embedded in rock, the generalized nonlinear unified strength criterion and slip line principle for resolving the differential equation systems which govern the stress field were applied to derive the ultimate end beating capacity based on some reasonable hypothesis and failure plane model. Both numerical simulation and test results were compared with the theoretic solution. The results show good consistency with each other and verify the validity of the present approach. The depth effect with respective to embedment ratio and other influence factors like geological strength index, intermediate principal stress, overburden factor, and damage on end bearing capacity were discussed in the analytical solution. The results show that the proposed yield criterion can be much better for investigating the ultimate end bearing performance of rock-socketed pile. The end bearing capacity increases with embedment ratio and the increasing degree is influenced intensely by the above parameters. Furthermore, ignoring intermediate stress effect would underestimate the strength properties of the rock material and lead to a very conservative estimation value.

Universality Class in Abelian Sandpile Models with Stochastic Toppling Rules

We present a stochastic critical slope sandpile model, where the amount of grains that fall in an overturning event is stochastic variable. The model is local, conservative, and Abelian. We apply the moment analysis to evaluate critical exponents and finite size scaling method to consistently test the obtained results. Numerical results show that this model, Oslo model, and one-dimensional Abelian Manna model have the same critical behavior although the three models have different stochastic toppling rules, which provides evidences suggesting that Abelian sandpile models with different stochastic toppling rules are in the same universality class.

A practical iterative two-view metric reconstruction with uncalibrated cameras

This paper presents a practical iterative algorithm for two-view metric reconstruction without any prior knowledge about the scene and motion in a nonsingular geometry configuration. The principal point is assumed to locate at the image center with zero skew and the same aspect ratio, and the interior parameters are fixed, so the self-calibration becomes focal-length cali- bration. Existing focal length calibration methods are direct solutions of a quadric composed of fundamental matrix, which are sensitive to noise. A quaternion-based linear iterative Least-Square Method is proposed in this paper, and one-dimensional searching for optimal focal length in a constrained region instead of solving optimization problems with inequality constraints is applied to simplify the computation complexity, then unique rotational matrix and translate vector are recovered. Experiments with simulation data and real images are given to verify the algorithm.

High-precision downward continuation of potential fi elds algorithm utilizing adaptive damping coeffi cient of generalized minimal residuals

The downward continuation of potential fields is a process of calculating their values in a lower plane based on those of a certain plane.This technology is not only a data processing method for resource exploration but also plays an extremely important role in military applications.However,the downward continuation of potential fields is a typical linear inverse problem that is ill-posed.Generalized minimal residuals(GMRES)is an eff ective solution to ill-posed inverse problems,but it is unstable under the condition wherein the GMRES is directly applied in the calculation process.Moreover,the long-term behavior of its iterative computation is a disordered,divergent result.Therefore,to obtain stable solutions,GMRES is applied to solve the normal equations of the downward continuation of potential fields;it is also used to prequalify for occasional interruptions in the operation process by adding the damping coefficient,thus strengthening the stability conditions of the equations of residual minimization.Finally,the stable downward continuation of the potential fields method is proposed.As indicated by the theoretical data and the measured testing data,the method proposed in this paper has the advantages of high-precision and excellent stability.Furthermore,compared with the Tikhonov iteration method,the proposed method avoids the need to choose regularization parameters.

A new 3-D element formulation on displacement of steel-concrete composite box beam

Slip of a composite box beam may reduce its stiffness, enlarge its deformation and affect its performance. In this work, the governing differential equations and boundary conditions of composite box beams were established. Analytic solutions of combined differential equations were also established. Partial degree of freedom was adopted to establish a new FEA element of three-dimensional beam, taking into account the slip effect. Slip and its first-order derivative were introduced into the nodes of composite box beams as generalized degree of freedom. Stiffness matrix and load array of beam elements were established. A three-dimensional nonlinear calculation program was worked out. The results show that the element is reliable and easy to divide and is suitable for special nonlinear analysis of large-span composite box beams.

New algorithm for variable-rate linear broadcast network coding

To adjust the variance of source rate in linear broadcast networks, global encoding kernels should have corresponding dimensions to instruct the decoding process. The algorithm of constructing such global encoding kernels is to adjust heterogeneous network to possible link failures. Linear algebra, graph theory and group theory are applied to construct one series of global encoding kernels which are applicable to all source rates. The effectiveness and existence of such global encoding kernels are proved. Based on 2 information flow, the algorithm of construction is explicitly given within polynomial time O（｜E｜ ｜T｜.ω^2max）, and the memory complexity of algorithm is O（｜E｜）. Both time and memory complexity of this algorithm proposed can be O（ωmax） less than those of algorithms in related works.

First-principle investigation on electronic structures and elastic properties of Al-doped MoSi_2

The electronic structures and elastic properties of Al-doped MoSi2 were calculated using the plane wave pseudo-potential method based on the density functional theory,in which the generalized-gradient approximation(GGA) was used to describe the exchange-correlation potential.Starting from the elastic constants,bulk modulus,shear modulus,elastic modulus and Poisson ratio of Al-doped MoSi2 were obtained by using the Hill method.The results indicate that conductivity of Al-doped MoSi2 is improved to some extent in comparison with that of pure MoSi2 due to the orbit hybridization of Mo 4d,Al 3p and Si 3p electrons.In addition,calculations show that the elastic modulus and the brittleness of Al-doped MoSi2 are smaller than those of pure MoSi2,which implies that it is feasible to toughen MoSi2 by doping Al.The agreement of the conclusion with experiment shows that the present theory is reasonable.

Interannual and Seasonal Variability of Winter-Spring Cohort of Neon Flying Squid Abundance in the Northwest Pacific Ocean During 1995–2011

The neon flying squid, Ommastrephes bartramii, is a species of economically important cephalopod in the Northwest Pacific Ocean. Its short lifespan increases the susceptibility of the distribution and abundance to the direct impact of the environmental conditions. Based on the generalized linear model(GLM) and generalized additive model(GAM), the commercial fishery data from the Chinese squid-jigging fleets during 1995 to 2011 were used to examine the interannual and seasonal variability in the abundance of O. bartramii, and to evaluate the influences of variables on the abundance(catch per unit effort, CPUE). The results from GLM suggested that year, month, latitude, sea surface temperature(SST), mixed layer depth(MLD), and the interaction term(SST×MLD) were significant factors. The optimal model based on GAM included all the six significant variables and could explain 42.43% of the variance in nominal CPUE. The importance of the six variables was ranked by decreasing magnitude: year, month, latitude, SST, MLD and SST×MLD. The squid was mainly distributed in the waters between 40?N and 44?N in the Northwest Pacific Ocean. The optimal ranges of SST and MLD were from 14 to 20℃ and from 10 to 30 m, respectively. The squid abundance greatly fluctuated from 1995 to 2011. The CPUE was low during 1995–2002 and high during 2003–2008. Furthermore, the squid abundance was typically high in August. The interannual and seasonal variabilities in the squid abundance were associated with the variations of marine environmental conditions and the life history characteristics of squid.

Constructing Measure by Repeated Infinite Subdivision

This paper generalizes the method of constructing measure by repeated finite subdivision in fractal geometry to that by infinite subdivision. Two conditions for the existing method are removed. A measure on the interval [0, 1] is constructed using this generalized method.

Evaluating the impact of spatio-temporal scale on CPUE standardization

This study focused on the quantitative evaluation of the impact of the spatio-temporal scale used in data collection and grouping on the standardization of CPUE(catch per unit effort).We used the Chinese squid-jigging fishery in the northwestern Pacific Ocean as an example to evaluate 24 scenarios at different spatio-temporal scales,with a combination of four levels of temporal scale(weekly,biweekly,monthly,and bimonthly)and six levels of spatial scale(longitude×latitude:0.5°×0.5°,0.5°×1°,0.5°×2°,1°×0.5°,1°×1°,and 1°×2°).We applied generalized additive models and generalized linear models to analyze the24 scenarios for CPUE standardization,and then the differences in the standardized CPUE among these scenarios were quantified.This study shows that combinations of different spatial and temporal scales could have different impacts on the standardization of CPUE.However,at a fine temporal scale(weekly)different spatial scales yielded similar results for standardized CPUE.The choice of spatio-temporal scale used in data collection and analysis may create added uncertainty in fisheries stock assessment and management.To identify a cost-effective spatio-temporal scale for data collection,we recommend a similar study be undertaken to facilitate the design of effective monitoring programs.

First principles study on electronic structure and optical properties of novel Na-hP4 high pressure phase

The electronic structure and optical properties of novel Na-hP4 high pressure phase at different pressures(260,320,400 and 600 GPa)were investigated by the density functional theory(DFT)with the generalized gradient approximation(GGA)for the exchange and correlation energy.The band structure along the higher symmetry axes in the Brillouin zone,the density of states(DOS) and the partial density of states(PDOS)were presented.The band gap increases and the energy band expands to some extent with the pressure increasing.The dielectric function,reflectivity,energy-loss function,optical absorption coefficient,optical conductivity, refractive index and extinction coefficient were calculated for discussing the optical properties of Na-hP4 high pressure phase at different pressures.

Quantum Gravitational Effects on Tunneling Rate of Reissner-Nordstroum Black Hole Emission and Generalized Second Law

The semi-classical black hole tunneling radiation (Parikh-Wilczek tunneling proposal) is calculated undera minimal length uncertainty analysis.It is shown that,the generalized second law of thermodynamics may bound thetunneling probability radiation of a Reissner-Nordstrom black hole radiation.

Magnetism and Sound Velocities of Iron Carbide （Fe3C） under Pressure

The elastic property and sound velocity of FeaC under high pressure are investigated by using the spin-polarized generalized gradient approximation within density-functional theory. It is found that the magnetic phase transition from the ground ferromagnetic （FM） state to the nonmagnetic （NM） state occurs at ～73 GPa. Based on the predicted Hugoniot of Fe3C, we calculate the sound velocities of FM-Fe3C and NM-Fe3C from elastic constants. Compared with pure iron, NM-FeaC provides a better match of compressional and shear sound velocities with the seismic data of the inner core, supporting carbon as one of the light elements in the inner core.

英语专业学生产出性词汇发展状况研究及对策

本文从广度知识和深度知识两个维度入手,分析英语专业同一自然班学生在一、二、三个学年期末考试中所写的英语作文,研究其产出性词汇发展过程。结果发现,受试的广度知识和深度知识都出现了僵化现象,单词各类知识停滞发展。

新知100满足知道分子深度需求

当各种资讯每天从睁开眼睛就不断涌入时。我们既害怕缺失资讯而落伍于自己的圈子。同时又恐惧被无边的资讯所埋没。如何帮助知道分子们面对资讯困惑．以不同的方式获取更有价值的资讯？