非理想流体自引力坍缩体系的熵变

本文利用共动度规讨论了非理想流体开放体系在自引力作用下的坍缩过程之熵变,结果表明,形成视界之前,体系的总熵不增,这说明黑洞的高熵产生于突变之中。     

Uniform Permian 40Ar/39Ar detrital mica ages in the eastern Qaidam Basin (NW China): where is the source?

New single‐grain ⁴⁰Ar/³⁹Ar detrital white‐mica ages from the Lulehe section at the eastern Qaidam Basin yield uniform Permian ages between 250 ± 3 and 279 ± 3 Ma throughout the whole Cenozoic sequence. This is inconsistent with the present hinterland, which is composed of early Palaeozoic metamorphic units with subordinate early Palaeozoic and few Permian granites. The new data indicate that Permian tectonic units are likely more widespread at the north‐eastern margin of the Tibetan plateau as known at present, particularly within the Qilian Mountains. The preferred explanation is that the Qaidam block represents a rigid indenter, which indented during late Tertiary times into early Palaeozoic orogenic units. This is consistent with recent findings of a NW‐trending sinistral Permian ductile shear zone and a dextral, NW‐trending Tertiary fault system close to the north‐eastern margin of the Qaidam Basin.     

Studies on extraction procedure and antioxidative activity of phlorotannins fromSargassum kjellmanianum

Known only in phaeophyceae, phlorotannins (brown algal polyphenols) are natural products with potential uses in pharmacology. This study yielded an extraction procedure to obtain high purity, high molecular weight phlorotannins fromSargassum kjellmanianum and revealed the characteristics of their infrared and flourescence spectra. The antioxidative activity of phlorotannins, which was about 2.6 times as strong as that of 0.02% BHT (tert-butyl-4-hydroxytoluene), showed potential for preventing oil rancidification. Contribution No. 2918 from the Institute of Oceanology, Chinese Academy of Sciences. The project was supported by The State Ninth-five Key Program of China. (No. 96-916-04-01).     

Type III Bursts Associated with Millisecond Spikes Which Occurred Within the Frequency Range from 230 to 300 MHz

The metric spectral data obtained at the Yunnan Observatory from July 1990 to December 1991 are analysed and some type III bursts associated with millisecond spikes are found. Their different morphologies reveal the relation between the type III bursts and the millisecond spikes. Based on the occurrence time and the characteristics of continuity and changes of the morphologies in the spikes and the type III bursts of two typical events, we verify that the acceleration region of the coronal electrons is located above the emitting region of the millisecond spikes and the type III bursts. The observations show that the interface frequency of a pair of type III bursts lies near 250 MHz. Finally the authors attempt to explain qualitatively the generating mechanism of the metric millisecond spike-type III bursts by means of the plasma hypothesis.     

均质土坡潜在滑面的搜索

均质土坡潜在滑面的确定 ,是对均质土坡进行稳定性计算的必要前提。传统的以瑞典圆弧法为代表的刚体极限平衡方法 ,虽然能够确定出均质土坡的滑面 ,但工作量较大 ,使用不方便。因此 ,在塑性极限分析方法的基础上 ,提出了一种新的搜索滑面的方法     

建筑地基与基坑变形监测刍议

随着城市建设的高速发展 ,高层、超高层建筑在原建筑物稠密区大量兴建 ,加之过量超采城市地下水 ,带来的地基与基坑变形问题越来越突出。为了防治建筑地基与基坑变形灾害 ,必须建立操作性较强的变形监测系统 ,及时作好预警、预报工作 ,使变形监测的方法、技术更加完善。     

多面函数和移动法综合模型支持下的区域垂直形变场拟合

地壳垂直运动的研究中,多面函数法是一种传统并得到广泛应用的方法。本文通过首都圈和晋冀蒙两个地区的实例,对多面函数和移动法综合拟合模型与多面函数模型等几种模型进行了对比研究。结果表明,多面函数和移动法综合拟合模型在拟合精度上优于其他几种模型,拟合残差更稳定,具有一定的实际应用价值。     

一种基于控制点集的实体地貌辅助建模方法

针对常规实体地貌建模方法效率低且工作量大的问题提出一种基于控制点集的实体地貌辅助建模方法。该方法建立了控制地貌基本形态的等高线集合,根据实际建模需求确定内插控制插签点的数量及位置以引导地性线走向,并构建多级数据库存储、管理和调用建模数据。通过实验测试获得3组对比实验结果,对结果数据进行分析后提出实体地貌建模辅助决策方法。该方法能够在不同地貌建模需求下实现快速准确决策,提高建模效率。     

静力水准自动化监测系统在运营地铁中的 应用与研究

静力水准自动化监测系统具有高效、连续、动态、数据实时分析等优势。本文通过介绍静力水准自动化监测系统的构成及原理,并结合广州地铁2号线某站监测实例,对静力水准自动化监测系统的具体实施过程进行了分析和应用探索。研究结果表明,该系统在地铁运营和停运两个时段的监测精度都能满足GB50911-2013《城市轨道交通工程监测技术规范》的要求,极大地提高了监测效率,可以较稳定地代替人工进行监测。     

Influence of underground space development mode on the groundwater flow field in Xiong’an new area

The degree and scale of underground space development are growing with the continuous advancement of urbanization in China. The lack of research on the change of the groundwater flow field before and after the development of underground space has led to various problems in the process of underground space development and operation. This paper took the key development zone of the Xiong’an New Area as the study area, and used the Groundwater modeling system software (GMS) to analyse the influence on the groundwater flow field under the point, line, and surface development modes. The main results showed that the underground space development would lead to the expansion and deepening of the cone of depression in the aquifer. The groundwater level on the upstream face of the underground structure would rise, while the water level on the downstream face would drop. The “line” concurrent development has the least impact on the groundwater flow field, and the maximum rise of water level on the upstream side of the underground structure is expected to be approximately 3.05 m. The “surface” development has the greatest impact on the groundwater flow field, and the maximum rise of water level is expected to be 7.17 m.