长螺旋压灌扩底桩新施工工艺特点及工程优势浅析

普通钻孔灌注桩在施工过程中常造成倾斜过大、断桩、偏移、钻孔偏斜、桩承载力低、颈缩、孔壁坍塌和孔底沉渣等工程问题。通过对普通钻孔灌注桩施工工艺和长螺旋压灌扩底桩新施工工艺进行对比分析,对长螺旋压灌扩底桩的同步技术、振捣插筋逆作法、特制扩底钻头扩底技术、钻孔成桩一体化和压力灌注进行阐述,总结出长螺旋压灌扩底桩新施工工艺应用于工程中具有成桩质量好、经济性好、单桩承载力高、施工效率高和适用性好等工程优势。     

综合防灭火技术在采空区中的应用

三交河煤矿203工作面回采期间,采空区内CO浓度高达0.0047％,严重威胁着工作面搬家回撤.对此霍州煤电集团安全监察局通过技术研究,提出了"喷洒阻化剂+注氮"综合防灭火技术,并对采空区安装束管火灾监测系统进行实时监测,通过实际应用效果来看,采用注氮防灭火技术后203采空区CO浓度控制在0.0015％以下,取得了显著应...     

英语专业新生写作能力调查分析

为了了解基础教育的成效与问题,为英语专业本科课程的定位和设置以及正在进行的教学改革提供依据,北京外国语大学英语学院对2008年入学的本科生进行了综合素质调查,其中从英语写作能力的调查研究结果发现,来自外国语学校学生的写作成绩明显高于非外国语学校学生的写作成绩,在统计意义上达到显著性水平.大学英语基础阶段写作教学的侧重点应为词汇的丰富度和句式的多样化、行文的连贯性和条理性、以及批判性思维训练.     

Electrospun PEDOT:PSS/PVP nanofibers as the chemiresistor in chemical vapour sensing

Herein, PEDOT:PSS/PVP nanofibers were produced by electrospinning. The presence of PEDOT:PSS in the nanofibers was confirmed by FT-Raman spectroscopy. The applied voltage-dependent diameter of PEDOT:PSS/PVP nanofibers was observed. Also, sensing behaviors of electrospun PEDOT:PSS/PVP nanofibers were explored by measuring its response upon cyclic exposure to organic vapours such as ethanol, methanol, THF, and acetone at room temperature. When PEDOT:PSS/PVP nanofibers were exposed to each solvent, the protic and aprotic solvents resulted in opposite electrical responses. These findings exhibit that electrospun PEDOT:PSS/PVP nanofibers are the promising candidate for the organic vapour sensing material.     

基于遗传运算法QSPR模型预测润滑剂在铜箔表面的润湿能力

采用静态悬滴法研究了润滑剂中脂肪酸、醇类和酯类添加剂在压延铜箔表面的接触角和润湿行为。利用半经验的量子化学方法计算了这些化合物的一些结构参数对其接触角进行了研究。利用遗传运算(GFA)统计分析方法,通过分子折射率和几种结构参数研究了其定量结构-性质关系。结果表明计算的量子参数可用于预测润滑剂在压延铜箔表面的接触角和润湿能力。这些润滑剂的接触角是其粘度、界面张力和物理化学参数的函数。其中起到主要作用的参数中,分子的折射率、分子的折射率、分子的弹性、总分子质量、溶剂表面积、元素计数、总能量和偶极子最关键。值得注意的是,润滑剂在压延铜箔表面的研究使润湿理论能精确到微观尺度,这为预测润滑剂在压延铜箔表面的润湿能力提供了新的见解。     

Perovskite‐Induced Ultrasensitive and Highly Stable Humidity Sensor Systems Prepared by Aerosol Deposition at Room Temperature

A new capacitive‐type humidity sensor is proposed using novel materials and fabrication process for practical applications in sensitive environments and cost‐effective functional devices that require ultrasensing performances. Metal halide perovskites (CsPbBr₃ and CsPb₂Br₅) combined with diverse ceramics (Al₂O₃, TiO₂, and BaTiO₃) are selected as sensing materials for the first time, and nanocomposite powders are deposited by aerosol deposition (AD) process. A state‐of‐the‐art CsPb₂Br₅/BaTiO₃ nanocomposite humidity sensor prepared by AD process exhibits a significant increase in humidity sensing compared with CsPbBr₃/Al₂O₃ and CsPbBr₃/TiO₂ sensors. An outstanding humidity sensitivity (21426 pF RH%^?1) with superior linearity (0.991), fast response/recovery time (5 s), low hysteresis of 1.7%, and excellent stability in a wide range of relative humidity is obtained owing to a highly porous structure, effective charge separation, and water‐resistant characteristics of CsPb₂Br₅. Notably, this unprecedented result is obtained via a simple one‐step AD process within a few minutes at room temperature without any auxiliary treatment. The synergetic combination of AD technique and perovskite‐based nanocomposite can be potentially applied toward the development of multifunctional sensing devices.     

5G端到端网络切片进展与挑战分析

随着5G端到端网络切片商用部署的逐步推进,在切片实施过程中遇到一些问题和挑战,因此亟需对其当前的研究进展及挑战进一步分析.从对5G端到端网络切片的系统性论述切入,首先介绍了5G网络切片的架构和功能,之后梳理了目前国内外标准组织对网络切片及其增强技术的研究进展,最后识别并深入分析了端到端网络切片面临的挑战,包括SLA保障...