The age of formation of the mirabilite and sand wedges in the Hexi Corridor and their paleoclimatic interpretation

The Hexi Corridor is located at the transition zone of the Asian summer monsoon and westerly airflow, and lies in an important position in terms of its ecological fragility and climatic sensitivity. During a recent field expedition to this region, we found a sedimentary mirabilite layer in a number of localities including Suwushan, Yanchi, Baitujing, Yanchi Gaotai, Huahai, Yumen, Halanuo扙r, and Dunhuang (Fig. 1), which have the potential to provide important information about environmenta…     

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.     

基于DSP和EPLD的无线电引信数据采集记录装置的设计

为评估无线电引信的启动特性和验证引信处理机信号处理算法的有效性，用零中频数据采集器和引信数据采集器分别记录引信试验的各种数据，用启动效率评估软件对这些数据进行分析处理．通过对采集到的数据的分析，可以使整个引信试验过程再现．通过对几种引信恒虚警算法的比较，找到一种合适的引信信号处理算法．该系统可以对引信启动效率进行全面的分析，为引信处理机性能的提高提供了重要参考。     

高校图书馆管理与重点学科建设

阐明了重点学科建设是高等学校管理中的重要内容，在分析高校图书馆信息服务与重点学科建设关系的基础上，探讨了高校图书馆为重点学科建设服务的内容和方法，即要做好科技论文的检索服务工作和科研课题立项的查新工作，深入开发信息资源，建立学科建设专题数据库等。     

失信行为的博弈分析

失信行为是目前市场经济环境中普遍存在的现象 .用一个简单的消费者与企业之间的参与者、三阶段的博弈模型来描述和分析这种现象 ,指出缺乏完善的信用和信息传递机制与法律体系的不完备是产生这种情况的重要因素 ,必须从以上两方面入手采取必要的措施才能从根本上消除失信行为     

Ni／α—Al2O3上CH4／CO2重整制取合成气的研究

本文采用固定床流动反应装置对Ｎｉ／α－Ａｌ２Ｏ３上甲烷二氧化碳重整制合成气的反应进行了研究，在一定ＣＨ４／ＣＯ２配比下，考察了镍负载量、助剂及助剂添加量对催化活性和积炭量的影响。     

捕食者种群具有常投放率的Ⅱ类功能性反应模型的定性分析

文「１」讨论了捕食者种群具有常收获率的Ⅱ类功能性反应模型，证明了此系统存在正平衡点时，在第一象限必全局不稳定，如果将常收获率改为常投放率，这时的数学模型变成｛ｘ＝ｘ（ａ－βｙ／１＋ωｘ） ｙ＝ｙ（－ｂ＋γｘ／１＋ωｘ）＋Ｋ。系统①中所有系数均任意正常数。     

废弃聚乙烯塑料热解过程能量收支理论分析

从理论上探讨了废弃聚乙烯塑料热解催化成汽油，柴油、渣油和石油气的能量投入和产出。结果表明：裂解１ｋｇ废弃聚乙烯塑料约需１３２０ｋｊ的热量；从产物的燃烧热值计算，净得的能量相当于１．６７ｋｇ标准煤的发热量，从而指出热解催化废充塑料回收燃油和燃气不仅具有显著的环境效益，而且具有可观的经济效益，本研究结果可为该技术的推广应用提供理论依据。