探地雷达在隧道衬砌质量检测中的应用

本文介绍了探地雷达作为一种新的检测方法在隧道衬砌质量检测中的应用,阐述了探地雷达的工作原理和方法,并对在隧道衬砌中常见的缺陷雷达图像进行了分析和解释.作为一种快速、高效、分辨率高、无损坏的检测方法,探地雷达是比较理想的检测方法.     

基于单片机仿真的雷达实验教学系统开发

由于现代航海雷达的发射机、接收机和天线都集中安装在桅杆部位的集成环境中,内有高压电源,在教学中虽然可进行雷达功能演示,但不易进行各关键原理信号的测量和教学演示。为优化雷达实验教学环境和提高实验教学效果,开发了以单片机为核心的雷达信号发生器,研制了基于单片机的雷达实验教学系统。此系统实现了雷达触发脉冲、方位信号、船首信号、视频信号的产生、测试和演示,在雷达收发机关闭的情况下,实时产生任意地域环境和不同目标特征的雷达图像。实践证明,此系统较理想地解决了雷达实验教学中关键信号脉冲的实时测量和演示难题,延长了雷达的教学使用寿命,大大改善了教学效果。本文详细介绍了系统实现的原理、控制方式、设计思想。     

基于PCI总线的数据采集卡设计

高速数据采集是雷达采集系统的关键部分,利用PCI总线的高速传输特性,给出了一种设计方法.介绍以Xilinx公司的CPLD芯片XC95144XL控制模块和总线接口芯片PLX9054为核心的多通道数据采集卡的设计,包括原理设计、芯片选择、PCB制作等.通过在探地雷达探测地下矿产资源中对数据采集卡的测试分析,证明该采集系统能够满足探地雷达中高速数据传输和处理的实时性的要求.     

《蝙蝠和雷达》板书设计及说明

《蝙蝠和雷达》是一篇常识性说明文。其教学重点是搞清蝙蝠的嘴与耳朵的作用,了解蝙蝠与雷达之间的关系。从板书中可清楚地看出蝙蝠嘴与耳朵的作用,蝙蝠与雷达的探路原理。带箭头的虚线表示雷达是在蝙蝠的启示下制造出来的。另外,利用板书亦可阐明夜航的飞机为什么能安全地飞行的道理。     

《蝙蝠和雷达》板书设计及说明

说明:《蝙蝠和雷达》是一篇常识性说明文.其教学重点是搞清蝙幅的嘴与耳朵的作用,了解蝙蝠与雷达之间的关系.从板书中可清楚地看出编幅嘴与耳朵的作用,蝙蝠与雷达的探路道理.虚线箭头表示了雷达是在蝙幅启示下制造出来的.另外,利用该板书亦可阐明夜航的飞机何以安全地飞行的道理.     

隐形战机如何“隐形”

隐形战机被形象地喻为“空中幽灵”,它们行踪诡秘,能有效地躲避雷达跟踪。其实,它的奥秘在于使用了能吸收雷达波的“隐形”材料。这种材料,可以使隐形战机能轻而易举地从雷达眼皮底下逃之夭夭。隐形轰炸机的雷达吸波材料可通过阻止反射无线电波来干扰雷达系统。雷达吸波材料多种多样,其中包括非共振磁性雷达吸波材料和共振雷达吸波材料。由非共振磁性雷达吸波材料制造的涂料含铁酸盐粒子,可将轰炸机表面“吸收”的雷达波作为热量散发掉。这种材料可降低雷达的“可见度”,并在一个宽广的雷达波频率范围内使用。共振雷达吸波材料则只在一个很…     

临近空间双基地雷达探测性能分析

探索了临近空间双基地雷达在探测范围上的能力,以一种比传统极坐标表示更易于理解的方法对该体制下的雷达探测低空目标的性能进行建模分析,并在不同变量条件下进行仿真。同时讨论了发射机发射功率和发射波长对临近空间双基地雷达探测性能的影响。通过对仿真结果的分析得出了一些有价值的结论,为进一步研究该型雷达提供了一定的理论支持。     

文学史视野中的本土批评和主体批评——“雷达的文学评论与中国化批评诗学建设研讨会”综述

“雷达的文学评论与中国化批评诗学建设研讨会”于2013年6月1日在兰州召开,会议由中国当代文学研究会、兰州大学文学院等单位主办。李敬泽、贾平凹、程金城、赵学勇等评论家、作家、学者70余人出席会议。与会者分别从雷达批评的中国化风格、雷达批评的文学史价值、雷达批评与个性气质的关系、雷达创作和批评的关系、雷达批评的学术评价、雷达的批评家定位、雷达批评的引导意义,以及雷达批评的不足之处等议题进行了深入探讨,对于在当下批评语境中建构现场批评、本土批评和专业批评富有启示意义。     

探地雷达实验教学方法研究

探地雷达方法是工程与环境地球物理学的重要教学内容之一。为了提高实验教学质量、完善实验教学手段,在实验室内建设了大型实验砂槽,开展地下管线探测、地下结构物探测以及隧道衬砌质量检测模拟实验。实验中引导学生灵活运用学到的理论知识,达到理论联系实际的实验教学目的,拉近了理论教学与实际生产间的距离,训练了学生解决实际工程问题的能力,为学生今后开展探地雷达探测工作打下了基础。     

紧扣三种联系,教学《蝙蝠和雷达》

《蝙蝠和雷达》(五年制小学语文第六册)是一篇揭示“蝙蝠”与“雷达”的关系,说明雷达是蝙蝠的仿生物的介绍性说明文。这是一篇讲读课文。我紧扣文中的三种联系,进行教学,不仅让学生在轻松愉快的气氛中深刻地理解、领悟了课文内容,而且培养了学生的自学能力,发展了学生的思维。 一、扣“标题”与“内容”的联系     

On Ugliness in Words,in Politics,in Tour-ism

Many educational theoretical approaches to cosmopolitanism tend towards an unconditional appreciation of mobility, diversity and rootlessness. The recent interest of educational philosophy in the rhizome, de-territorialization and diversity contributes to this understanding of cosmopolitanism as movement across a borderless and imperfect world. Without downplaying such insights (and related political education), this article displaces and de-temporalizes them. It takes the form of a parody of the rhizome to view those insights from a different perspective and make them strike a different pedagogical note.     

扎实扎好建配管努力搞好用教研

通过对小学师资队伍现状的分析，提出网络环境下小学教师应具备的基本素质并对小学师资队伍建设的途径进行探讨。     

Self-concept differences in student teachers in primary,elementary, secondary,and special education

Self-concept, intelligence and academic achievement were examined in students preparing to teach in primary, elementary, secondary, and special education (N = 267). The measures were the Tennessee Self-Concept Scale, a group intelligence test, and school grades. Differences in self-concept, but not in intelligence and academic achievement, were found among groups of student teachers. Secondary education majors reported a more positive self-concept than primary or elementary, with special education majors reporting the least positive self-concept of all.     

Genotypic and environmental variation in cadmium, chromium, arsenic, nickel, and lead concentrations in rice grains

Genotypic and environmental variation in Cd, Cr, As, Ni and Pb concentrations of grains, and the relationships between these heavy metals and Fe, Zn were investigated using 9 rice genotypes grown in 6 locations for two successive years. Significant genotypic variation was detected in the five heavy metal concentrations in grains, indicating the possibility to reduce the concentration of these heavy metals in grains through breeding approach. The environmental effect varied with metal, with Pb and Ni having greater variation than the other three metals. There was significant genotype-environment （location） interaction of the concentrations of all five heavy metals in grains, suggesting the importance of cultivar choice in producing rice with low heavy metal concentrations in grains for a given location. Correlation analysis showed that Cd and As, Cr and Ni, and As and Pb concentrations in rice grains were closely associated, and that Ni concentration in grains was negatively correlated with Zn concentration.     

江西婺源蓝尾石龙子形态特征的两性异形

报道了江西婺源地区蓝尾石龙子（Eumeces elegans）头、体大小的两性异形.蓝尾石龙子成体体长存在显著的两性差异（雄性大于雌性）,雄性个体有较大的头部（头长和头宽）,雄性头部增长速率明显大于雌性,表明成年雄体分配较多的能量用于头部和身体的生长;而成年雌体则相对延缓头部的生长,以维持躯干生长,增大腹腔容纳量,可提高其繁殖输出.     

Knowledge, Concepts, and Inferences in Childhood

The role of knowledge in children's inferences was investigated in 3 experiments. Experiment 1 examined developmental changes in the role of categorical membership, perceptual appearance, and item complexity in inferences for natural kind and artifact concepts. Preschoolers (5-year-olds), second graders (8-year-olds), and fourth graders (10-year-olds) were taught novel properties about target concepts and asked whether each of 4 probes had those properties. Probes varied in category membership and perceptual appearance relative to the target item. Item complexity also varied. Experiments 2 and 3 examined inferences with known and unknown concepts for familiar and unfamiliar properties. Older children's knowledge led to differential weighting of categorical information over appearance but only for known concepts and/or familiar properties. Preschoolers made no distinction between category and appearance for either known or unknown concepts. Additionally, as target item complexity increased, older children made more inferences than preschoolers. No differences between inferences about natural kind and artifact concepts were found. The role of theories and knowledge in children's drawing of inferences is discussed.