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.     

乌鲁木齐市现代化水平现状评价

基于前人的理论与经验 ,本文建立了乌鲁木齐现代化指标体系和标准 ,以 1998～ 2 0 0 0年统计数据为例 ,分析了乌鲁木齐现代化实现现状 ,根据其解析评价了乌鲁木齐现代化建设中主要存在的问题 ,进而提出相应的对策。     

文峪河灌区开栅高耗水区节水措施研究

根据开栅高效水区的土层结构特点，分析了该区耗水量大的主要原因，比较研究了多种节水措施，并提出了合理可行的节水方案。     

陕西苹果是如何走向市场的

通过对山西和陕西地理环境与自然条件的比较，介绍了在苹果销售上，陕西省通过采取开辟绿色通道、优化销售环境、规范销售合同、培育专业果品销售市场、建立果业销售信息网络、加强对果农的诚信教育等措施，使陕西苹果走向国内外市场的做法与经验.     

精密相干检测法研究

研究了精密相干检测法的原理,即采用共时钟方案,使与发送机有关的参考信号同接收机接收到的待测信号精密相干,同时精确检测出复合波信号中各主要谐波的振幅和相位.应用结果表明:该方法克服了微弱复合波信号的锁相放大、数据采集、叠加平均和获取多参数时遇到的困难,提高了观测系统的灵敏度、测量精度、抗干扰能力、探测分辨率和探测深度;精密相干检测法原理同样适用于其他观测系统和对其他类型信号的检测.     

网络信息安全特种保障初探

提出了特种保障的概念，分析了国家信息安全的危害因素，主要有CPU隐含指令，后门，恶意硬件等。通过研究非自主开发的计算机系统中的系统恶意功能集和触发条件以可以发现恶意功能的协议数据序列，给出了两种恶意功能的检测方法，即激励响应检测法和特征匹配检测法。据此给出了有关网络恶意功能的防治措施。     

AIP吸收器传质特性中试装置及KLa测试方法研究

基于不依赖空气动力装置（AIP）排出CO2气体旋转床吸收器传质特性研究要求，选择S-195型柴油机为AIP排出气体发生器，优化设计了气、水流程，建立了波纹碟片填料旋转床吸收器的传质特性中间试验装置（简称中试装置），该装置具有多参数调节和测试功能。针对在较高气体压力下，AIP排出气体旋转床传质试验无法直接测算其体积传质系数（Kla），提出了一种间接测算Kla实验值的方法。实验结果表明，用间接测算方法求取的Kla实验值与直接测算值相对误差小于10％。