对外语教师角色的反思

本文基于外语教学的相关研究和论述,从外语课的特点、教学的文化背景、外语教师三个方面讨论了在新形式下外语教师的角色定位.强调外语教师在面临新的社会环境带来的从单一角色向多角色转换的挑战时,仍应重视在课堂上给学生提供准确、流利的语言输入;在采用新的学习方法以及担任新的角色时,要考虑到学生已有的观念,加强对学生学习观念的了解并在教学中注重打造符合自己个性的独特的教学风格.     

建筑砖砌体裂缝原因及其防治

砖砌体由于各种各样的原因可能会产生一定数量的裂缝.本文根据理论和施工经验对其裂缝产生的原因进行分析,并且提出相应的治理的原则.     

Eigenvalues of the antiplane-shear crack problem for a power-law material

This paper discusses the problem of finding the eigenvalue spectrum in determining the stress and strain fields at the tip of an antiplane-shear crack in a power-law material. It is shown that the perturbation method provides an analytical dependence of the eigenvalue on the material nonlinearity parameter and the eigenvalue of the linear problem. Thus, it is possible to find the entire spectrum of eigenvalues and not only the eigenvalue of the Hutchinson-Rice-Rosengren problem. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 1, pp. 173–180, January–February, 2008.     

CFG桩施工引起桩周土体开裂的原因探讨

由于郑东新区特殊的工程地质条件，长螺旋CFG（Cement Flyash Gravel）桩施工常常引起桩周土体开裂和周围建筑物开裂等施工事故。本文通过郑州某工地现场试验分析，否定了空桩效应引起桩周土体开裂的猜想，并分析了郑东新区由于CFG桩施工引起桩周土体开裂的原因。     

Non-elliptic deformation field near the tip of a mixed-mode crack in a compressible hyperelastic material

This paper gives an asymptotic analysis of the deformation field near the tip of an arbitrary mixed-mode crack in a compressible hyperelastic harmonic material which loses ellipticity at sufficiently large deformations. It is found that the near-tip deformation field is characterized by a localized non-elliptic deformation band issuing from the crack-tip and bounded by two curves of discontinuous deformation gradient. Explicit expression for the near-tip deformation field is obtained both inside and outside the localized deformation band. In particular, a simple relation is derived that determines the orientation of the deformation band in terms of two complex governing parameters of the near-tip fields inside and outside the deformation band, respectively.     

Radiation heat transfer in axisymmetric quartz glass tubes

A mathematical model is proposed to describe the heat transfer in quartz glass axisymmetric tubes. Heat is transferred inside the glass by radiation and conduction. Scattering of thermal radiation inside the glass is ignored. At the boundaries of the tube the radiative intensity is specularly reflected. The spectral dependent radiative intensity and the temperature distribution inside the tube are determined. The model is applied to simulate the cooling process of a quartz glass tube. The calculated temperature is in agreement with that obtained from an experiment. Furthermore, steady-state temperature distributions in quartz glass tubes of different lengths have been determined.     

Thermoelastoplastic deformation of a thick-walled cylinder with a radial crack

The thermoelastoplastic fracture mechanics problem of a thick-walled cylinder subjected to internal pressure and a nonuniform temperature field is solved by the method of elastic solutions combined with the finite-element method. The correctness of the solution is provided by using the Barenblatt crack model, in which the stress and strain fields are regular. The elastoplastic problem of a cracked cylinder subjected to internal pressure and a nonuniform temperature field are solved. The calculation results are compared with available data. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 3, pp. 173–183, May–June, 2008.     

桥梁工程中大体积混凝土裂缝的原因与控制

分析了桥梁结构中大体积混凝土产生裂缝的原因,提出了防止大体积混凝土裂缝的主要技术措施。     

Static and dynamic detection of axial surface defects on metallic wires by conical triple laser reflection

The quality of the surface of metallic wires is relevant for different applications. The reflection of a laser beam on the surface of a metallic cylindrical wire provides an efficient way to inspect the quality of its surface. Our interest is focused in the detection of axially oriented defects, which are the most relevant for the wire drawing process. We present a simple interference-geometrical model to describe the light pattern reflected from a wire with defects. This model adequately accounts for the observed results from an industrial prototype developed for the purpose. It incorporates three-laser beams incident on the wire at equidistant locations in its perimeter, which produce three reflection cones with a CCD. This configuration permits to explore the whole perimeter of the wire. Several results are presented, both in static operation and in production line, in agreement with qualitative and quantitative predictions.     

科学设置日语课程,提高教学效果——对应届毕业生日语教学调查分析

前不久,笔者对我院即将毕业的第一届科技日语专业学生进行了一次问卷调查,旨在掌握、了解首届学生的学习状况,提高教学质量和效果,满足社会和学生的需求。该文针对教学存在的问题进行了分析研究,并提出了改进措施。