Stress corrosion cracking and its anisotropy of a PZT ferroelectric ceramics

It is known that some types of ceramics, like Al2O3 and ZrO2, undergo stress corrosion cracking (SCC) or static fatigue fracture under static loading, ever in a rela-tively mild environment, such as moist atmosphere or water at room temperature, which leads to a time-dependent fracture[1—4]. For a transmission electron microscopy specimen of YBa2Cu3O7-x ceramics superconductor, SCC induced by residual stress can occur in an atmosphere with low moisture content[5]. For a lead zirconate ti…     

Do multiple cycles of aeolian deposit-pedogenesis exist in the reticulate red clay sections in southern China?

Since the Quaternary scientists successfully dis-closed the paleoclimatic significance of the loess-paleo- sol sequence in the Loess Plateau, Northwest China, the loess-paleosol sequence has become well-known terres-trial materials revealing the multiple cyclic changes of Quaternary climates. As a carrier of paleoenvironmental information, it could compare beauty with the deep ocean deposit[8]. In recent years, however, the researchers began to put their sights to southern China. They try t…     

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.     

皮革废渣渗漏液中铬的测定

对皮革废渣(蓝皮屑)渗漏液中铬的二苯碳酰二肼分光光度测定法进行了研究，结果表明此方法的线性范围0-0.400mg／L，吸光度A对浓度c(mg／L)关系回归方程为：A=0．779c-0．0005，线性相关系数为0．9993，检出限为0．007mg／L，相对标准偏差小于3％，加标回收率为100％～105％，用此法对废渣渗漏液中铬的测定表明铬的形态为三价铬，因此，测定总铬时需先加H2SO4-HNO3进行消解，再以KMnO4氧化，二苯碳酰二肼显色，分光光度法测定．     

试论如何开展图书馆的电子书服务

电子图书产业是伴随因特网发展而出现的一个新的产业，是数字化图书馆建设不可缺少的一个部分。文章从网络传播、电子图书内容、知识产权等方面对图书馆如何开展电子图书的服务进行了论述。     

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．     

电子邮件的自动截取与分析系统的设计与实现

介绍了一种对电子邮件进行自动截取分析系统的后台程序的设计与实现．该系统能够根据用户预先设定的截取关键词对电子邮件进行自动截取分析，然后对截取的电子邮件在前台进行相应的处理，以防止电子邮件传播非法的、不健康的内容。