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641.
黎政 《广东海洋大学学报》2006,26(2):103-107
《邓小平文选》是领导者语言的范例,存在大量的礼貌现象,体现着礼貌的思想。它们的运用可以给交际对方留面子,从而使交际活动更好地进行下去。以Brown和Levinson的面子保全论为理论基础,运用Leech的礼貌原则及六个次准则分析了《邓小平文选》领导语言中的各种礼貌的语言现象,其实现途径以及它的内在语用机制。这说明礼貌理论对文本交际活动也具有很强的阐释力。 相似文献
642.
Weiguo Zhang Lizhong Yu Min Lu Xiangmin Zheng Junfeng Ji Limin Zhou Xiaoyong Wang 《Quaternary Science Reviews》2009,28(3-4):345-353
The Xiashu Loess, in comparison to the well-studied loess sequences in the Chinese Loess Plateau (CLP), provides a good opportunity for studying East Asian monsoon variations from a southern China perspective. Here we present a study of the iron oxide mineralogy of the Xiashu Loess using integrated geochemical and diffuse reflectance spectroscopy (DRS) measurements as well as magnetic data. Our results show that the free iron oxide (Fed) to total iron (Fet) ratio (Fed/Fet), hematite (Hm) to goethite (Gt) ratio (Hm/Gt) and saturation isothermal remanent magnetization (SIRM) to magnetic susceptibility (χ) ratio (SIRM/χ) all indicate particularly strong summer monsoons during the formation of paleosols PS5 and PS4 (equivalent to Marine Isotope Stage 13 and 11, respectively). However, magnetic susceptibility and Fed/Fet are not consistently reliable indicators of summer monsoon intensity for the whole section. Our results indicate that a multi-proxy approach can give a more reliable summer monsoon intensity reconstruction. The summer monsoon shows a cooling trend and a declining of precipitation from 0.5 to ~0.3 Ma, after which it becomes warmer and wetter towards the top of paleosol PS1 (equivalent to MIS 5). However, PS1 was formed under a relatively cooler temperature and wetter soil conditions in comparison to PS5 and PS4. Such supra-orbital variations in the East Asian summer monsoon superimposed on the effects of glacial–interglacial cycles in southern China are also reflected in the 0.4–0.5 Ma cycle of marine carbon isotopes in the global ocean, possibly indicating a strong link between terrestrial weathering and the global carbon cycle. 相似文献
643.
土地档案是在国土资源实践活动中直接形成的具有保存价值并归档保存的文字、图纸、图表、航卫片、电子文件、声像材料等。近年来,在转变国土资源利用方式和深化国土资源管理改革的新形势下,在转变政府职能,实行窗口办文,限时办结各类报件的新情况下,土地档案在国土资源业务活动 相似文献
644.
Variations in the Ice Phenology and Water Level of Ayakekumu Lake,Tibetan Plateau,Derived from MODIS and Satellite Altimetry Data 总被引:1,自引:0,他引:1
Jun Chen YongFeng Wang LiGuo Cao Jiajia Zheng 《Journal of the Indian Society of Remote Sensing》2018,46(10):1689-1699
The alpine lakes on the Tibetan Plateau (TP) are highly sensitive to variations in climate changes, and the lake ice phenology and water level are considered to be direct indicators of regional climate variability. In this study, we first used 14 years of moderate resolution imaging spectroradiometer snow cover products to analyse the freeze dates, ablation dates, and ice coverage durations. The lake level changes during 2002–2015 were estimated, derived from satellite altimetry and Hydroweb data. Unexpectedly, the freeze dates of lake ice greatly advanced, and the ablation dates were markedly delayed. The complete freezing duration lengthened by approximately 77 days. As a result of the warm-wet climate in the northern TP, the lake area expanded from 770 to 995 km2 during 2002–2015, and the water levels rose by 4.2 m in total, at a rate of 0.3 m/year. The progressive expansion of Ayakekumu Lake profoundly affected the ice phenology. Larger water volume with larger thermal capacity likely led to the delaying of ablation dates, with the freezing point depression caused by decreasing salinity. Some new narrow and shallow bays located in southern and eastern Ayakekumu Lake were conducive to early freezing of ice. Additionally, the changes in air temperature, precipitation, potential evaporation, and sunshine duration may be related to the prolonged ice cover duration since 2002. In sum, accurate measurements of lake ice and water levels are critical for understanding the water resource balance and hydrologic cycle in arid or semi-arid regions of China. 相似文献
645.
646.
Xiaopeng Gong Shengfeng Gu Yidong Lou Fu Zheng Maorong Ge Jingnan Liu 《Journal of Geodesy》2018,92(7):797-809
Global navigation satellite systems (GNSS) are acting as an indispensable tool for geodetic research and global monitoring of the Earth, and they have been rapidly developed over the past few years with abundant GNSS networks, modern constellations, and significant improvement in mathematic models of data processing. However, due to the increasing number of satellites and stations, the computational efficiency becomes a key issue and it could hamper the further development of GNSS applications. In this contribution, this problem is overcome from the aspects of both dense linear algebra algorithms and GNSS processing strategy. First, in order to fully explore the power of modern microprocessors, the square root information filter solution based on the blocked QR factorization employing as many matrix–matrix operations as possible is introduced. In addition, the algorithm complexity of GNSS data processing is further decreased by centralizing the carrier-phase observations and ambiguity parameters, as well as performing the real-time ambiguity resolution and elimination. Based on the QR factorization of the simulated matrix, we can conclude that compared to unblocked QR factorization, the blocked QR factorization can greatly improve processing efficiency with a magnitude of nearly two orders on a personal computer with four 3.30 GHz cores. Then, with 82 globally distributed stations, the processing efficiency is further validated in multi-GNSS (GPS/BDS/Galileo) satellite clock estimation. The results suggest that it will take about 31.38 s per epoch for the unblocked method. While, without any loss of accuracy, it only takes 0.50 and 0.31 s for our new algorithm per epoch for float and fixed clock solutions, respectively. 相似文献
647.
“一带一路”区域可持续发展生态环境遥感监测 总被引:2,自引:1,他引:1
2013年9月和10月,习近平主席在出访中亚和东南亚国家期间,先后提出了共建"丝绸之路经济带"和"21世纪海上丝绸之路"(简称"一带一路")的重大倡议。要全面保护"一带一路"区域生态环境,实现2030年可持续发展目标,是一个具有挑战性的问题。遥感技术对生态环境监测与评价发挥着十分重要的作用。本研究利用多尺度、多源遥感数据,对2015年"一带一路"区域的生态环境状况进行监测和分析,旨在提供可持续发展目标生态环境遥感监测的本底。本文选取了几个重要的生态环境方面开展监测与分析,主要包括宏观生态系统结构和植被状况、太阳能资源分布、水资源平衡、主要生态环境限制因素对经济走廊建设的影响、主要城市生态环境质量等。监测区域覆盖亚洲、非洲、欧洲和大洋洲的陆上区域。研究结果为生态环境评价与保护提供了有效的决策依据,有助于"一带一路"建设积极推进。 相似文献
648.
Lin Zhu Ren-Xu Chen Yong-Fei Zheng Jing Wang Bing Gong 《Geostandards and Geoanalytical Research》2023,47(1):105-124
An accurate determination of water content in garnet is critical to quantify the transport of water to the deep mantle by the subducted oceanic crust beyond the breakdown of hydrous phases. Fourier transform infrared spectroscopy (FTIR) is the most widely used approach to determine the species and contents of water in garnet. Accurate quantification of OH in garnet requires independent calibration using an external method, as OH absorbance is mineral and composition specific. To obtain the infrared absorption coefficients of structural hydroxyl in garnet, a combined study of spectrometric analyses by FTIR and a method combining a thermal conversion elemental analyser with isotope ratio mass spectrometry (TC/EA-MS) was carried out for fourteen gem-quality natural garnet crystals with variable compositions. The obtained molar absorption coefficients were 9322 ± 338 and 240 ± 26 l mol−1 cm−2 for grossular- and spessartine-rich garnet and pyrope-almandine garnet, respectively. These results are within the range of previous studies. A new molar absorption coefficient of 689 ± 177 l mol−1 cm−2 was obtained for pyrope-spessartine garnet. The large variation in the absorption coefficient indicates it is controlled by both garnet composition and OH-absorption bands. The obtained absorption coefficients are only appropriate for certain types of eclogitic garnet, and more studies should be carried out on eclogitic garnets. 相似文献
649.
Youjuan Li Brian R. Jicha Wanfeng Zhang Wen Chen Brad S. Singer Dewen Zheng Huaiyu He 《Geostandards and Geoanalytical Research》2023,47(3):657-668
The precision and accuracy of 40Ar/39Ar dates are ultimately linked to co-irradiated reference materials of known age. Here we provide new data from the SK01 sanidine, which was analysed in three different laboratories to evaluate it as a 40Ar/39Ar reference material. Aliquots of 5 mg, incrementally heated in two laboratories, yielded indistinguishable results with a weighted mean age of 27.58 ± 0.06 Ma (95% confidence level). Single-crystal step heating and single-crystal total fusion analyses of SK01 sanidine were undertaken in the third laboratory to further test the intracrystalline homogeneity. For the seven step-heating analyses, six crystals yielded nearly concordant age spectra with 40Ar/39Ar ages ranging from 26.853 ± 0.094 Ma to 26.963 ± 0.067 Ma, whereas one crystal gave an older age of 27.774 ± 0.071 Ma with a slightly discordant age spectrum. Twenty-three single-crystal total fusion analyses yielded 40Ar/39Ar ages ranging from 27.070 ± 0.108 Ma to 27.736 ± 0.062 Ma with a dispersion of ~ 3.8%. The older ages from single-crystal total fusion dates are interpreted to reflect an inherited or excess argon component in some crystals. This is an initial characterisation of the SK01 sanidine, and additional work needs to be conducted to further evaluate the age dispersion so that it can be utilised as a 40Ar/39Ar reference material. 相似文献
650.