Temperature variations on the Tibetan Plateau over the last two millennia

The paleoclimate data recovered from ice cores,tree rings and lake sediments indicate regional features of cfimatic change on the Tibeta n Plateau (TP) during the last 2000 years. The composite temperature reconstructions in-dicate that several main climatic episodes, such as the “LittleIce Age“ between 1400 and 1900, the “Medieval Warm Pe-riod“ in 1150-1400, a less warm period in 800-1100, and an earlier cold period between the 3rd and 5th centuries,occurred in the TP. In addition, temperature varied from region to region. The period from AD 800 to 1100, which waswarm in northeastern TP, was contemporaneous with cool-ing in the western and southern TP. The southern TP ex-perienced warming between 1150 and 1400. For western TP,the δ^18O records of the Guliya ice core indicate that the pe-Hod 1250-1500 witnessed a clear warming. Large-scaletrends in the temperature history from northeastern TP aremore similar to those in eastern China than are the trendsfrom the Guliya ice cap far to the west and southern TP. The most prominent similarities between the temperature varia-tions of the TP and eastern China are such cold phases as 1100-1150, 1500-1550, 1650-1700 and 1800-1850, andthe latter three cold events match with three widespreadg lacial advances which occurred on the TP during the Little Ice A2e.     

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.     

Climatic significance of stable carbon isotope in tree rings of Abies spectabibis in southeastern Tibet

The annually cross-dated stable carbon isotope of tree-ring a-cellulose of Abies spectabibis collected from the southeastern Tibetan Plateau is used to examine its rela-tionship with climatic parameters. The residual D13C series in treerings is constructed after removing the effects of age trend and rising CO2. We found a close relationship between D13C in tree rings and the relative humidity of September—November of the previous year measured at the nearby Ny-ingchi Meteorological Station, albeit a strong 搇agged effect? Thus we developed a transfer function to reconstruct the autumn relative humidity for the Nyingchi region, which explained 37.9% of the total variance (p < 0.001). Our results suggest a high frequency and moderate amplitude variance of the relative humidity before 1800, and the variance re-versed afterwards.     

离心风机蜗壳进口周向来流的非均匀性对其旋涡流动影响的数值研究

运用CFD技术对一离心风机整机作数值模拟，研究了蜗壳进口周向非均匀来流对其内旋涡结构、演化过程的影响．计算结果表明，蜗壳内各径向截面上产生了3个旋涡，一个进口涡和一对梯形涡，且都经历了初生、发展、耗散和溃灭等过程．与单蜗壳在周向均匀来流的假设下计算所得的旋涡结构相比，两者存在很大的差别，这说明只有考虑蜗壳来流的非均匀性影响，才能比较准确地模拟其内的旋涡运动．     

历史时期乌兰布和沙漠环境变迁的再探讨

文章应用历史地理学方法，结合现代水文、河流、地貌、沉积等学科的研究成果，对历史时期乌兰布和沙漠北部环境变迁问题提出以下观点：1)乌兰布和沙漠北部在先奏为古屠申泽，其湖面远大于西汉至北魏时的屠中泽；2)西汉至北魏时屠中泽向北萎缩，湖面减为原来的44％，西汉所置窳浑，临戎、三封3县即位于河湖之滨的绿洲之上；3)黄河干流中滩～协成段受科里奥利力作用的影响，右岸冲刷较多，是该区黄河多次改道东移的惟一原因．黄河迳流是古屠申泽得以存在的惟一水源，故黄河改道是该湖不断萎缩终于干涸的根本原因；4)屠中泽干涸后湖盆受西北强烈干燥气流及沙漠流沙的侵袭，迅速沙漠化．小片绿洲亦因弃耕、缺乏植物覆盖而沙化、消亡；5)沙漠中湖泊对改善滨湖生态环境的作用显著，但其蒸发渗漏损失水量也十分巨大，对于极为缺水的黄河流域而言，维持湖泊的存在并不一定合算．     

IC卡技术在智能小区停车场管理系统的应用研究

阐述了智能小区停车场管理系统的主要设计与实现方法，通过非接触式IC卡产生的信息流，结合软硬件系统及技术，实现了小区停车场的科学化管理．     

硅压阻式传感器与AD7705芯片在压力测量中的应用

介绍一种新型测量压力的元件——硅半导体压阻式传感器，并以MPX2100压阻式传感器为例，配合AD7705芯片构成压力测量系统，阐述压力测量系统的工作原理，说明系统的软、硬件设计方法．     

绿色供应链整体绩效评价模型的构建

环境恶化和资源日益匮乏使制造业承担的环保压力越来越大,如何降低在产品生命周期中自己应承担的责任成为企业关注的问题.实施绿色供应链策略是有效的解决途径,文章在提出绿色供应链概念的基础上,建立了绿色供应链整体绩效的评价体系及模型.     

桥梁内部预应力钢绞线应变的长久监测与分析

重点研究应用埋入式光纤光栅传感器对正在施工中桥梁的预应力钢绞线应变进行跟踪监测的测试方法，分析温度、横向应变等多种因素对测量结果有效性的影响，同时考察了预应力钢绞线在复杂施工环境中的力学行为．研究发现在温度变化较大时应该对测量结果进行温度补偿，同时在非均匀横向应变场作用下光纤光栅不再遵循布拉格条件，对此应做进一步的研究分析，试验结果表明光纤光栅传感器具有易埋入、抗干扰能力强、可对应变进行绝对测量等优点，非常适合于结构内部健康的长期监测。