深基坑支护结构设计的平面应变有限元法

采用平面应变有限元法讨论深基坑工程多支撑支护问题 ,与传统的静力平衡法、弹性抗力有限元法相比具有优越性 ,该方法将支护结构与土体作为 1个系统研究 ,充分考虑桩土间的协调作用 ,模拟桩土接触界面 ,能计算出不同开挖阶段坑底及地表的变形、支护结构的应力及弯矩 ,在基坑支护结构设计中具有重要应用价值。     

西北太平洋副热带高压等在渤海冬季气温预报中的应用

本文首先对渤海冬季温分为冷年的暖年，而后对西北太平洋副热带高压（简称副高，下同）强度指，亚洲极涡面积指数，赤道东太平洋海温与冷，暖年的关系进行了分析，得出：当渤海冬季气温属暖年时，其前期西北太平洋副热带高压偏强，亚洲极涡面积指数偏低，赤道东太平洋海温偏高，属冷年时，情况相反。     

原状和重塑海洋粘土经历动载后的静强度衰减

根据海洋粉质粘土原状和重塑土样的动三轴试验结果, 比较和分析了两种土样应力、应变、孔隙水压力和不排水抗剪强度行为, 得到了土样的静不排水抗剪强度衰减与波浪荷载作用下土样产生的动应变以及平均累积孔压之间的关系。 并将波浪荷载作用使土样内孔压升高, 有效应力降低, 形成拟超固结现象的理论, 应用到土样不排水抗剪强度衰减与平均累积孔压之间关系的分析;同时与重塑土样的超固结静态剪切试验结果进行比较, 得到了土样在波浪荷载作用后的归一化不排水抗剪强度与拟超固结比之间的关系式。 建议以少量原状土样, 配合大量重塑土样的动三轴试验结果, 实现对实际海洋粘土地基在波浪荷载作用后的静不排水抗剪强度衰化规律的评估。     

Variation of Wave Velocity and Porosity of Sandstone after High Temperature Heating

This paper reports the variations of mass, porosity, and wave velocity of sandstone after high temperature heating. The range of temperature to which the sandstone specimens have been exposed is 25–850°C, in a heating furnace. It has been shown that below 300°C, porosity and wave velocity change very little. Above 300°C, there is a rapid increase in porosity, but the wave velocity decreases significantly. The results of thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC) and mercury intrusion porosimetry (MIP) suggest that a series of changes occurred between 400 and 600°C in sandstone could be responsible for the different patterns of variation in porosity and wave velocity.     

K-bentonite beds and high-resolution integrated stratigraphy of the uppermost Ordovician Wufeng and the lowest Silurian Longmaxi formations in South China

More than 20 K-bentonite beds were discovered from the Wufeng Formation and the lowest Longmaxi Formation in two sections, both adjacent to the Ordovician-Silurian (O-S) boundary and located in Tongzi, Guizhou Province and Yichang, Hubei Province, some 500 km apart from each other in South China. This indicates that many volcanic eruptions occurred near the southeast margin of the Yangtze Platform between the latest Ordovician and the earliest Silurian. Mainly through biostratigraphic and sequence stratigraphic studies, it was found that almost all these far-apart K-bentonite beds may be correlated with each other. This is the first time that a succession of volcanic ash deposits with high potential of correlation was discovered within a strata interval on the main platforms of China. Therefore, these K-bentonite beds may afford excellent event-marker beds helpful to high-resolution research in integrated stratigraphy as well as other lines of research on the O-S boundary in South China.     

2003年10月河北省沧州秋季暴雨成因分析

通过对2003年10月10日夜间发生在沧州的秋季大暴雨过程的影响系统、触发机制、稳定度以及涡度、散度、垂直速度等物理量的分析，发现此次暴雨过程前后大气层结一直稳定，属于稳定型降水；能量积聚小于夏季，但是高低空急流较强，所配合物理量不小于夏季，暴雨出现在低层辐合高层辐散的强垂直运动上升区，表明急流为暴雨提供了很好的水汽及动力条件。     

Influences of the Internal Mixing of Anthropogenic Aerosols on Global Aridity Change

Influences of the mixing treatments of anthropogenic aerosols on their effective radiative forcing (ERF) and global aridity are evaluated by using the BCC_AGCM2.0_CUACE/Aero, an aerosol–climate online coupled model. Simulations show that the negative ERF due to external mixing (EM, a scheme in which all aerosol particles are treated as independent spheres formed by single substance) aerosols is largely reduced by the partial internal mixing (PIM, a scheme in which some of the aerosol particles are formed by one absorptive and one scattering substance) method. Compared to EM, PIM aerosols have much stronger absorptive ability and generally weaker hygroscopicity, which would lead to changes in radiative forcing, hence to climate. For the global mean values, the ERFs due to anthropogenic aerosols since the pre-industrial are–1.02 and–1.68 W m^–2 for PIM and EM schemes, respectively. The variables related to aridity such as global mean temperature, net radiation flux at the surface, and the potential evaporation capacity are all decreased by 2.18/1.61 K, 5.06/3.90 W m^–2, and 0.21/0.14 mm day^–1 since 1850 for EM and PIM schemes, respectively. According to the changes in aridity index, the anthropogenic aerosols have caused general humidification over central Asia, South America, Africa, and Australia, but great aridification over eastern China and the Tibetan Plateau since the pre-industrial in both mixing schemes. However, the aridification is considerably alleviated in China, but intensified in the Arabian Peninsula and East Africa in the PIM scheme.     

湿位涡诊断在青藏高原东北侧暴雪预报中的应用个例

利用湿位涡理论,对2006年1月18-19日发生在青藏高原东北侧大范围暴雪天气进行了诊断分析,以探讨湿位涡诊断在青藏高原东北侧暴雪预报中的应用前景.个例分析表明:850 hPa和东风回流以及横切变耦合的正湿位涡高值区和500 hPa青藏高原东侧大槽前正湿位涡平流、300 hPa青藏高原东侧大槽前新生正湿位涡中心的叠加,形成有利于暴雪发生发展的湿位涡和湿位涡平流配置的三维空间结构;850 hPa等压面湿位涡正压项(ξMPV2)等值线密集区和等压面湿位涡斜压项(ξMPV1)<-2.0 PVU的中α尺度对流不稳定区形成的耦合区,对暴雪落区有指示意义.     

Scaling Properties of Feldspar and Quartz in Micro-images of Ideal Granites

The properties of feldspar and quartze are studied in this article from a fractal point of view using gray-scale micro-images of granite samples collected at the Fangshan (房山) granite body in Hebei (河北) Province, China, which can be regarded as an ideal granite in the sense of Vistelius. We found that there exist power-law relationships between the eigenvalues of the gray-scale matrices and their ranks for the feldspar and quartz. The fractal model used here is a λ-R model similar to the N-λ model proposed by Qiuming Cheng in 2005. Meanwhile, we found that average variances for the gray-scale matrices of feldspar are larger than those of quartz on the same sections, and this may be useful for auto-identification of feldspar and quartz as well as other minerals.     

全差式光度法测定超痕量金

根据催化动力学方法，采用全差式光度计测定岩石、土壤及天然水中超痕量金。方法灵敏度高，设备简单；操作方便，选择性好。野外特快分离富集水中金装置简单实用。