Time-division phase modulated single-photon interference in a Sagnac interferometer

We introduce a stable, long-distance singlephoton Sagnac interferometer, which has a balanced configuration to efficiently compensate phase drift caused by change of the fiber-optic path. By using time-division phase modulation, single-photon interference was realized at 1550nm in a 5-km-long as well as 27-km-long Sagnac fiber loops,with a fringe visibility higher than 90% and long-term stability. The stable performance of the single-photon interference indicated that the time-division phase-modulated Sagnac interferometer might readily lead to practical applications in single-photon routing and quantum cryptography.     

Loess-soil sequences in southern Anhui Province： Magnetostratigraphy and paleoclimatic significance

Two parallel loess-soil sequences from Xuancheng and Fanchang in southern Anhui Provinces are dated using geomagnetic and luminescence methods.The Brunhes/Matuyama(B/M) reversal boundary is recognized within the lower part of the so-calles Vermiculated Red Soil (VRS) in the Xuancheng section while the entire Fanchang sequence is of Brunhes age.This indicated that the most recent VRS in southern China,a stratigraphic marker and an indication of extremely warm-humid conditions,was formed during the middle Pleistocene,chronologically correlative with the S4 and S5 soil units in northern China.Microscopic and sedimentologic in vestigations reveal that eolian deposition started in this region at about 0.85 MaBp,roughly synchronous with the well-known Mid-Pleistocene climate change of global significance.The strengthening of both summer and winter monsoon circulations and the consequent river hydrological changes at that time would have provided favorable conditions for sustained eolian deposition in the middle-lower reaches of the Yangtze River since 0.85 MaBP.     

太原市发展屋顶绿化应注意的若干问题

屋顶绿化是我国城市建设的一个崭新亮点，它既有增加城市绿地面积、发挥生态林业的作用，又有美化城市、为居民提供活动场所的功能。简要介绍了国内外屋顶绿化的发展状况，分析了太原市发展屋顶绿化的技术难点，提出了地毯式、花槽连网架式、花园式3种屋顶绿化模式，并建议就不同模式进行试点。     

某第二类Fredholm积分方程的一种数值解法

我们考虑第二类 Fredholm积分方程的快速数值解法 .本文假设核函数除在 x=t处带有弱奇性外 ,是解析的 [1] .我们利用分片多项式插值逼近核函数 ,由此得到近似的系数矩阵 A.设 n为积分节点的个数 ,k2为每个小区域的插值节点数 ,我们证明矩阵 A的计算和矩阵 -向量相乘 Ax各需要 O( nk)次运算 ,存贮 A需要占用 O( nk)内存 .最后我们对算法的稳定性进行讨论并给出数值结果     

潮州体育馆的建筑声学设计

在潮州体育馆的建声设计中 ,利用馆内大面积玻璃幕墙的声学特性 ,设计了具有优良吸声特性的吸声天棚 ,使潮州体育馆在节约吸声材料的基础上 ,达到优良的声学指标     

面向装配的三维标准件库研制

在分析产品装配特征和国内外标准件建库技术的基础上，根据并行工程中装配建模的需要，提出了面向装配的三维标准件库的一般原则，给出标准件库的基本框架和关键技术解决方案，并且结合实例加以说明．     

钒和碳双注入钢的纳米结构、强化机制和抗磨损特性

研究了V C双重离子注入合成纳米结构、相变和抗磨损机制．研究表明，注入后可改变钢的成分，V与Fe原子比最高可达到28％；形成了纳米相弥散强化结构和无序相强化结构．从而提高了钢表面硬度，表面硬度可提高23％～146％；抗磨损也有着明显的提高，磨损阻抗为未注入钢的2．2～3．6倍．     

薄层扫描法测定乌鸡妇康糖浆中黄芪甲苷的质量含量

研究了乌鸡妇康糖浆中黄芪甲苷的定量方法。采用CS－9000在λs=510nm，λR=610nm扫描，V（氯仿）：V（甲醇）：V（水）＝13：7：2混合液的下层溶液为展开剂。结果表明黄芪甲苷在1－5μg之间线性关系良好，相关系数γ=0．9993，平均回收率为99．20％，相对标准差为3．50％。本法灵敏、简便、准确，可用于乌鸡妇康糖浆中有效成分黄芪甲苷的测定和制剂的质量控制。     

积域上一类相关于块空间的参数型Marcinkiewicz积分的L2有界性

给出了乘积域上一类粗糙核参数型Marcinkiewicz积分μρ,σΩ,h的L2有界性,其中核函数Ω∈B0,1q(Sn-1×Sm-1) (q>1),h(r1,r2)∈l∞(Ls)(R+×R+)(1相似文献