浅析英语语言中性别差异的表现

语言与社会互相依存,是反映社会的镜子。英语语言中的性别差异现象是社会语言学的重要研究内容,也是各种文化共有的现象。本文试图从语音、语义和使用三个方面来对英语语言中的性别差异做初步探讨。     

CO2激光气化切割非金属材料的机制分析

研究了CO2激光气化切割高吸收率非金属材料的机制。基于实验拍摄的前沿形状和切缝形状，经过理论分析建立了激光气化切割非金属材料的三维能量耦合模型，分析了实际弯曲切割前沿和两壁面对激光的反射和能量吸收过程。前沿和壁面的能量吸收主要决定于入射光束的前三次入射(即两次反射)，前沿本身的多次反射增强了前沿底部的功率密度，而壁面的多次反射增强了前沿中下部位的功率密度。正是由于多次反射的存在，使得整个前沿都有功率密度分布。两切口壁面对入射激光有波导作用，入射激光在左右两壁面之间相互反射，朝着切口深部传输，即所谓的“壁面聚焦效应”(Wall focusing effect)。     

"光电检测技术"课程的教学体会

"光电检测技术"课程的内容多,知识涉及面广,在工业、农业、军事、航空航天以及日常生活中皆有着非常广泛的应用,是现代工科学生必须掌握的一门知识.为了提高教学质量、提升教学效果,使学生能够更好地了解相关知识、掌握基本原理、灵活运用所学知识、理论与实际相结合,笔者从本科生培养要求出发,根据自身教学实践,就内容组织、安排和教学方法,谈一些教学体会.     

应用小波变换剔除超声多重反射的研究

利用小波变换具有空间局部化的特性和表征信号奇异性的能力,在适当尺度下刻画待检对象表面第1次超声回波信号的极大值点,从中选择最大值点作为脉冲重复频率(PRF)技术“与操作”的基准点,以满足PRF技术在消除超声多重反射时对“与操作”基准点需高精度定位的要求,从而解决传统方法对检测设备和操作条件严格一致的弊端。计算机仿真与实验研究表明提出的方法是可行的,并具有较强的鲁棒性和适用性。     

英国艾塞克斯大学教育考察和反思

结合访学见闻,对英国艾塞克斯大学和邻近大学的教学理念、教学模式、人才培养和管理方法等进行了考察,进而对英国教育体系中专业模式的多元化、学制弹性化、基础课程宽泛化,课程设置模块化、教学个性化、课堂教学多元化及师资队伍和生源的国际化等进行了探析,认为其在增强专业设置的灵活性,课程设置的灵活性、开放性,尊重教育规律,注重服务意识,彰显以人为本理念,注重反思和批判精神培养5个方面有启示意义。     

谷幅变形对拱坝工程安全影响案例分析及有关启示

为充分认识谷幅变形对拱坝的安全影响,收集了国内外受到谷幅变形收缩影响的拱坝案例,分析并讨论了拱坝的运行情况和应对谷幅变形的措施。综合这些工程案例,建议高拱坝工程建设应尽早开展谷幅变形相关监测,对出现的谷幅变形需开展相关机理研究,同时应结合大坝安全监测资料,采用多种方法分析谷幅变形对拱坝的安全影响,并可采取提高水库最低运行水位等措施改善大坝受力状态,避免谷幅变形对拱坝造成损伤。     

对勘察施工企业队伍素质问题的思考

通过对目前勘察施工企业队伍结构与素质现状的分析,提出了提高勘察施工企业队伍素质的措施和对策。     

ZrB2 – SiC ceramics: Residual stresses and mechanical properties

The stress-strain state of ZrB₂-SiC ultra-high-temperature ceramics, produced using commercial powders with different impurity levels, was investigated by X-ray diffraction. Upon analysis of ZrB₂ and SiC diffraction lines shift, the level of thermal stresses (strains) of the different phases was determined. An increase of internal stresses in ceramics with rising viscous-brittle transition temperatures, T_ve, was attributed to increased grain boundary strength. Ceramics, for which high T_ve and high level of internal stresses were estimated, exhibited high strength, up to 700 MPa at 1400 °C. A field of compressive thermal stresses in the matrix phase resulted to be necessary for achieving high strength at low-temperatures. On the contrary, the presence of low-melting impurities at the grain boundaries negatively impacted on the stress level in ZrB₂ boundaries in the high temperature regime.     

Fabrication of carbon-doped ZnCo2O4 yolk-shell microspheres compounded with magnetic graphene for enhanced electromagnetic wave absorption performance

Carbon-doped ZnCo₂O₄ (ZnCo₂O₄/C) yolk-shell microspheres are synthesized by a method of thermally decomposing precursor and then successfully compounded with magnetic graphene (MG) via co-precipitation in combination with a reduction pathway. The fabrication processes and characterizations (XRD, XPS, TEM, EDS and SEM) are described and explained in detail. It is confirmed that amorphous carbon (in situ decomposition from PVP) is uniformly doped into ZnCo₂O₄ yolk-shell microspheres. In addition, the reflection loss (RL) and electromagnetic (EM) wave absorption mechanisms of as-prepared ZnCo₂O₄/C/MG composites are calculated and analyzed exhaustively. The results show that absorption bandwidth with RL exceeding −10 dB reaches up to 4.48 GHz with a matching thickness of 3.5 mm while the maximum RL is up to −52.9 dB at 7.52 GHz with a matching thickness of 3.9 mm. Enhanced EM wave absorption performance can be attributed to good dielectric and magnetic loss, excellent impedance matching, diverse interfacial polarization and multiple reflections caused by special structures.