广义Gibson地基内部作用线源荷载的基本解

针对广义Gibson地基在埋藏线源荷载作用下的静力学问题,通过将内源线荷载等效为在相同深度范围内连续的集中点荷载的累加,采用Hankel积分变换方法,再结合具体的边界条件,推导得到地基土体在内源点荷载作用下的Hankel变换域中的解,并利用Hankel逆变换将变换域内的解转换为物理域内的积分形式解。然后对该解沿深度方向积分求得了地基土体在三种沿深度分布线荷载作用下的竖向位移解,并对地基内部沿深度分布线源荷载作用下地基表面土体变形问题通过具体算例,运用数值积分计算方法,分析了地基土体的非均质性、荷载分布深度等因素对地基表面土体竖向位移的影响。结果表明:①地基土体的非均质性对地基表面竖向位移有较大影响,相对而言,线源荷载竖向分布深度及荷载分布形式对地表竖向位移的影响较小,且地表竖向位移主要受浅层荷载的影响;②荷载分布深度对地表位移的影响主要体现在土体非均质性较小情况下,且在荷载沿深度减小分布时最为显著。

世界遗产不可复制——保护都江堰水利工程刻不容缓

5·12大地震过去了3年,灾后重建所取得的巨大成果,举世瞩目。党中央、国务院的坚强领导和中华民族的强大凝聚力感动着世人。我们将永远铭记。

狠抓两种能力的提高——九八○年高考作文评卷札记

今年高考作文题目是(《读〈画蛋〉有感》,要求考生仔细阅读短文《画蛋》,联系自己的实际情况,写一篇读后感。读后感属于议论文的范畴,它具有一般议论文的论点、论据、论证三个要素,但是它又有自己的特点。这些特点表现在:它的论点是从所阅读的文章里分析归纳出来的;它的论据一般来自生活实际,特别是来自作者的亲身经历或实践,它不一定要对论点展开全面的系统的论证,重点在谈作者自己的感想和体会,通常采用夹叙夹议的写法。

Fabrication of broadband antireflection coatings using broadband optical monitoring mixed with time monitoring

Multi-layer optical coatings with complex spectrum requirements, such as multi-band pass filters, notch filters, and ultra-broadband antireflection coating, which usually contain very thin layers and sensitive layers, are difficult to be fabricated using a quartz crystal monitoring method or a single wavelength optical monitoring system（SWLOMS）. In this paper, a broadband antireflection（AR） coating applied in the wavelength range from 800 nm to 1800 nm was designed and deposited by ion beam sputtering（IBS）. Ta2O5 and Si O2 were chosen as high and low refractive index coating materials,respectively. The optimized coating structure contains 9 non-quarter-wave（QW） layers totally with ultra-thin layers and sensitive layers in this coating stack. In order to obtain high transmittance, it is very important to realize the thickness accurate control on these thin layers and sensitive layers. A broadband optical monitoring mixed with time monitoring strategy was successfully used to control the layer thickness during the deposition process. At last, the measured transmittance of AR coating is quite close to the theoretical value. A 0.6% variation in short wavelength edge across the central 180 mm diameter is demonstrated. A spectrum shift of less than 0.5% for 2 continuous runs is also presented.

《红太阳颂》简析

这是一篇抒情散文。发表于一九七六年十二月二十五日《人民日报》副刊《战地》上。作者刘白羽。全文除引子外,共分五部分,选作教材时,删去了其中第二部分。一九七六年十二月二十六日,是伟大领袖和导师毛主席逝世后的第一个诞辰。在这个不平常的日子的前夕,作者激情澎湃,思绪万千,发表了这一篇《红太阳颂》。在当今,无论在中国还是在外国,革命人民都深情地、亲切地把毛主席比作红太阳,只要一提到红太阳。

Photonic bandgap amorphous chalcogenide thin films with multilayered structure grown by pulsed laser deposition method

Amorphous chalcogenide thin films were fabricated by the pulsed laser deposition technique. Thereafter, the stacks of multilayered thin films for reflectors and microcavity were designed for telecommunication wavelength. The prepared multilayered thin films for reflectors show good compatibility. The microcavity structure consists of Ge_(25)Ga)5Sb_(10)S_(65)(doped with Er^(3+)) spacer layer surrounded by two 5-layer As_(40)Se_(60)/Ge_(25)Sb_(5)S_(70) reflectors. Scanning/transmission electron microscopy results show good periodicity, great adherence and smooth interfaces between the alternating dielectric layers, which confirms a suitable compatibility between different materials. The results demonstrate that the chalcogenides can be used for preparing vertical Bragg reflectors and microcavity with high quality.

Ag纳米颗粒增强的Ho^(3+)/Tm^(3+)共掺铋锗酸盐玻璃的2μm发光研究

采用基于传统熔融淬冷技术的热化学还原法制备了系列Ag纳米颗粒复合Ho3+/Tm3+共掺铋锗酸盐玻璃样品,研究了Ag纳米颗粒含量对玻璃2μm发光特性的影响.结果表明,Ag纳米颗粒的表面等离子体共振带位于500—900 nm,峰值位于650 nm,透射电子显微镜图像中观察到均匀分布的Ag纳米颗粒,尺寸约为5—10 nm.通过测试玻璃样品在1.7—2.3μm波段的荧光光谱发现,Ag掺杂后Ho3+离子2μm处的荧光强度得到了极大的提高,其中AgCl掺杂质量分数为0.3%时的荧光强度比未掺杂时的荧光强度增强10倍,这归因于Ag纳米颗粒的局域场增强作用.计算得到Ho3+离子的吸收截面为0.491×10-20cm-2,发射截面为1.03×10-20cm-2,当增益系数为0.2时即可实现正的增益.

深入推进产学研用深度融合——以安徽智能制造产学研合作交流平台为例

2019年两会期间,李克强总理提出要健全以企业为主体的产学研一体化创新机制,要充分尊重和信任科研人员,赋予创新团队和领军人才更大的人财物支配权和技术路线决策权。针对企业自主创新能力不足、高校及科研院所研发成果产业化艰难的问题,本文认为可以搭建供产学研三方进行合作交流的平台及联合研发中心,形成校企合作的'生态圈,提升高校、科研院所智能制造研发成果产业化效率,实现产学研共赢的局面,从而推进产学研用深度融合。