论滑坡分类

在广泛查阅和总结国内外滑坡分类基础上 ,以滑坡监测预报与防治为目的 ,遵从滑坡活动各要素的地位与作用 ,根据分类体系的完备性需要 ,理清了已有各种滑坡分类的性质及其彼此间的关系 ,并对之进行了科学归纳、取舍和补充 ,建立了具有层次系统性的综合性滑坡分类体系。为建立滑坡监测预报地质模型体系奠定了基础 ,并有助于对滑坡活动的全面研究。     

古火灾历史重建的研究进展

火是地球系统的重要组成部分,与气候、植被、生物地球化学循环和人类活动密切相关。火对全球气候和生态系统的影响已成为目前全球变化研究的一个热点。火灾发生后会在周围的环境中留下许多燃烧产物,如黑碳、木炭屑、多环芳烃、左旋葡萄糖等,它们广泛存在于海洋、湖泊、河流、土壤和陆地风成沉积物中;还会留下一些火灾痕迹,如树木火疤、土壤磁...     

Relative pollen productivities of typical steppe species in northern China and their potential in past vegetation reconstruction

The Relative Pollen Productivities(RPPs)of common steppe species are estimated using Extended R-value(ERV)model based on pollen analysis and vegetation survey of 30 surface soil samples from typical steppe area of northern China.Artemisia,Chenopodiaceae,Poaceae,Cyperaceae,and Asteraceae are the dominant pollen types in pollen assemblages,reflecting the typical steppe communities well.The five dominant pollen types and six common types(Thalictrum,Iridaceae,Potentilla,Ephedra,Brassicaceae,and Ulmus)have strong wind transport abilities;the estimated Relevant Source Area of Pollen(RSAP)is ca.1000 m when the sediment basin radius is set at 0.5 m.Ulmus,Artemisia,Brassicaceae,Chenopodiaceae,and Thalictrum have relative high RPPs;Poaceae,Cyperaceae,Potentilla,and Ephedra pollen have moderate RPPs;Asteraceae and Iridaceae have low RPPs.The reliability test of RPPs revealed that most of the RPPs are reliable in past vegetation reconstruction.However,the RPPs of Asteraceae and Iridaceae are obviously underestimated,and those of Poaceae,Chenopodiaceae,and Ephedra are either slightly underestimated or slightly overestimated,suggesting that those RPPs should be considered with caution.These RPPs were applied to estimating plant abundances for two fossil pollen spectra(from the Lake Bayanchagan and Lake Haoluku)covering the Holocene in typical steppe area,using the"Regional Estimates of Vegetation Abundance from Large Sites"(REVEALS)model.The RPPs-based vegetation reconstruction revealed that meadow-steppe dominated by Poaceae,Cyperaceae,and Artemisia plants flourished in this area before 6500–5600 cal yr BP,and then was replaced by present typical steppe.     

The mechanism for the impact of sea surface temperature anomaly on the ridgeline surface of Western Pacific

Based on the atmospheric circulation data provided by ECMWF and the sea surface temperature data by NOAA, we studied the mechanism for the impact of sea surface temperature anomaly on the ridgeline surface of western Pacific using an improved high truncated spectral model. Our results show that the wave-wave interaction and the wave-mean flow interactions are weaker in the inner dynamic process of atmospheric circulation, when atmospheric circulation is forced by the sea surface temperature of El Niño pattern. With the external thermal forcing changed from winter to summer pattern, the range of ridgeline surface of western Pacific moving northward is smaller, which causes the ridgeline surface of western Pacific on south of normal. On the contrary, the wave-wave interaction and the wave-mean flow interaction are stronger, when atmospheric circulation is forced by the sea surface temperature of La Niña pattern. With the external thermal forcing turning from winter to summer pattern, the ridgeline surface of western Pacific shifts northward about 19 latitude degrees, which conduces the ridgeline surface of western Pacific on north of normal. After moving to certain latitude, the ridgeline surface of western Pacific oscillates with the most obvious 30–60 d period and the 4°–7° amplitude. It is one of the important reasons for the interannual variation of ridgeline surface of Western Pacific that the atmospheric inner dynamical process forced out by different sea surface temperature anomaly pattern is different.     

浅谈水文地质参数的计算与应用

结合多个场地的抽水试验和室内试验资料,分析评价了工程勘察中不同水文地质参数的应用范围及在参数求取过程中应注意的问题,根据实测数据得出野外抽水试验渗透系数是室内渗透试验所测得的10~14倍,影响半径约为裘布依影响半径的5.8~17.7倍;分析了产生这种情况的原因,指出在工程实践中应根据不同的要求选取不同方法计算得出的水文地质参数;针对导水系数、释水系数及给水度在计算及应用过程中应注意的问题进行了评述。     

土压力问题的变分解答

用变分学方法导出了与朗肯土压力公式和库伦土压力公式完全一致的土压力计算公式，并且一般情况下的极值曲线线不同一条直线，而是比较复杂的曲线，在 倾斜边坡情况下的伦公式仅仅是一个特解。     

Influence of aquatic plants on the hydrogen isotope composition of sedimentary long-chain n-alkanes in the Lake Qinghai region,Qinghai-Tibet Plateau

The hydrogen isotopic composition(δD) of leaf wax long-chain n-alkanes(C27, C29, and C31) from lacustrine sediments has been widely applied to reconstruct terrestrial paleoclimatic and paleohydrological changes. However, few studies have addressed whether the aquatic-derived n-alkanes can affect the δD values of lake sedimentary long-chain n-alkanes, which are usually regarded as a recorder of the terrestrial hydrological signals. Here we systematically investigated δD values of long-chain n-alkanes from modern aquatic plants, both near-shore and off-shore surface sediments, surrounding terrestrial plant litters, as well as river water and lake water in Lake Qinghai and its satellite lakes on the northeastern Qinghai-Tibet Plateau. Our data showed that(i) δD values of long-chain n-alkanes from aquatic plants varied from-184‰ to-132‰ for n-C27, from-183‰ to-138‰ for n-C29, and from-189‰ to-130‰ for n-C31, respectively, with no significant differences among the three n-alkanes homologues;(ii) δD values of long-chain n-alkanes from aquatic plants were generally more positive than those from surrounding terrestrial plants, possibly because that they recorded the D-enrichment of lake water in this semi-arid region;(iii) δD values of long-chain n-alkanes from surface sediments showed significant differences among the three n-alkanes homologues, due to the larger aquatic input of n-C27 to the sedimentary lipid pool than that of n-C31, and(iv) n-C27 δD values of near-shore aquatic plants and near-shore sediments are more negative than those from off-shore as a result of lower δD values of near-shore lake water. Our findings indicate that in this region(i) the offset between sedimentary n-C27 and n-C31 δD values(ΔδDC27-C31) could potentially be used to evaluate if sedimentary long-chain n-alkanes are derived from a single source;(ii) while δD values of n-C27 may be influenced by lake water hydrological changes, sedimentary n-C31 is derived predominantly from terrestrial plants and thus its δD can serve as a relatively reliable indicator for terrestrial paleoclimatic and paleohydrological reconstructions.     

地电故障数据处理系统

地电故障数据处理系统软件研制的目的在于当地电仪器出现故障,无法采集到仪器内存中原始数据时,能根据地电纸带上仅有的一些原始数据,利用该系统可以准确、快速、方面地转换成特定格式的数据文件,及时上报至中国地震局。该系统的开发,将会减轻台站工作人员的负担,杜绝了数据格式的不正解性,防止了数据迟报现象的发生。     

PHoToNs–A parallel heterogeneous and threads oriented code for cosmological N-body simulation

We introduce a new code for cosmological simulations, PHo To Ns, which incorporates features for performing massive cosmological simulations on heterogeneous high performance computer(HPC) systems and threads oriented programming. PHo To Ns adopts a hybrid scheme to compute gravitational force, with the conventional Particle-Mesh(PM) algorithm to compute the long-range force,the Tree algorithm to compute the short range force and the direct summation Particle-Particle(PP) algorithm to compute gravity from very close particles. A self-similar space filling a Peano-Hilbert curve is used to decompose the computing domain. Threads programming is advantageously used to more flexibly manage the domain communication, PM calculation and synchronization, as well as Dual Tree Traversal on the CPU+MIC platform. PHo To Ns scales well and efficiency of the PP kernel achieves68.6% of peak performance on MIC and 74.4% on CPU platforms. We also test the accuracy of the code against the much used Gadget-2 in the community and found excellent agreement.     

Hard X-ray Source Distributions on EUV Bright Kernels in a Solar Flare

We explore the hard X-ray source distributions of an C1.1 flare occurred on 14 December 2007. Both Hinode/EIS and RHESSI observations are used. One of EIS rasters perfectly covers the double hard X-ray footpoints, where the EUV emission appears strong from the cool line of He ii (log T=4.7) to the hot line of Fe xvi (log T=6.4). We analyze RHESSI X-ray images at different energies and different times before the hard X-ray maximum. The results show a similar topology for the time-dependent source distribution (i.e. at 14:14:35 UT) as that for energy-dependent source distribution (i.e. at a given energy band of 6 – 9 keV) overlapped on EUV bright kernels, which seems to be consistent with the evaporation model.