大跨预应力混凝土框架结构的静力弹塑性(pushover)分析

基于美国规范ATC-40和N2方法,建立了大跨预应力混凝土框架结构竖向地震反应的静力弹塑性(pushover)分析方法。编制了预应力混凝土构件截面弯矩-曲率的计算程序。这些为评价大跨预应力混凝土框架结构的竖向抗震能力提供了有益的参考。结合具体工程实例进一步说明了该方法的实施步骤。     

无机盐溶液作用下砂-膨润土竖向隔离屏障材料化学相容性试验研究

土-膨润土竖向隔离屏障广泛应用于城市工业污染场地。化学溶液作用下屏障材料的化学相容性,即渗透系数及其变化程度,是评价防污性能的关键因素。通过柔性壁渗透试验研究重金属铅-锌复合、六价铬作用下砂-膨润土竖向隔离屏障材料渗透系数的变化规律。由于无机盐溶液中铅、锌、钙对膨润土双电层的压缩,铅-锌复合、钙溶液作用下屏障材料试样渗透系数随金属浓度升高而增大。铅-锌复合作用下,金属浓度增至500mmol/L时试样渗透系数增幅达11倍,且无法满足防渗要求。相反,由于铬以阴离子络合形式存在,其对试样渗透系数影响相对小;与未污染状态测定结果相比,渗透系数增幅≤2倍。在膨润土孔隙比基础上,考虑无机盐溶液对膨润土膨胀特性的影响,建立无机盐溶液作用前后砂-膨润土竖向隔离屏障材料渗透系数统一预测方法。     

气流对物质和能量的输送量的垂直分布

给出了气流导致的物质和能量的输送量的一般公式。指出了空气对不同物质或者能量的输送量在不同高度上是不同的,输送量最大层次所在高度一般与高空急流并不重合。水汽的最大输送量出现在距离地面2km的低空：     

Impact of Anthropogenic Heat Release on Regional Climate in Three Vast Urban Agglomerations in China简

We simulated the impact of anthropogenic heat release （AHR） on the regional climate in three vast city agglomerations in China using the Weather Research and Forecasting model with nested high-resolution modeling.Based on energy consumption and high-quality land use data,we designed two scenarios to represent no-AHR and current-AHR conditions.By comparing the results of the two numerical experiments,changes of surface air temperature and precipitation due to AHR were quantified and analyzed.We concluded that AHR increases the temperature in these urbanized areas by about 0.5℃-1℃,and this increase is more pronounced in winter than in other seasons.The inclusion of AHR enhances the convergence of water vapor over urbanized areas.Together with the warming of the lower troposphere and the enhancement of ascending motions caused by AHR,the average convective available potential energy in urbanized areas is increased.Rainfall amounts in summer over urbanized areas are likely to increase and regional precipitation patterns to be altered to some extent.     

Retrieval of stratospheric O3 and NO2 vertical profiles using zenith scattered light observations

Daily zenith scattered light intensity observations were carried out in the morning twilight hours using home-made UV-visible spectrometer over the tropical station Pune (18‡31′, 73‡51′) for the years 2000–2003. These observations are obtained in the spectral range 462–498 nm for the solar zenith angles (SZAs) varying from 87‡ to 91.5‡. An algorithm has been developed to retrieve vertical profiles of ozone (O₃) and nitrogen dioxide (NO₂) from ground-based measurements using the Chahine iteration method. This retrieval method has been checked using measured and recalculated slant column densities (SCDs) and they are found to be well matching. O₃ and NO₂ vertical profiles have been retrieved using a set of their air mass factors (AMFs) and SCDs measured over a range of 87–91.5‡ SZA during the morning. The vertical profiles obtained by this method are compared with Umkehr profiles and ozonesondes and they are found to be in good agreement. The bulk of the column density is found near layer 20–25 km. Daily total column densities (TCDs) of O₃ and NO₂ along with their stratospheric and tropospheric counterparts are derived using their vertical profiles for the period 2000–2003. The total column, stratospheric column and tropospheric column amounts of both trace gases are found to be maximum in summer and minimum in the winter season. Increasing trend is found in column density of NO₂ in stratospheric, tropospheric and surface layers, but no trend is observed in O₃ columns for above layers during the period 2000–2003     

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长诏断裂带垂直运动与地震关系初探

利用跨断层短水准资料分析了长诏断裂带断层活动特征，结果表明：长诏断裂带总体活动性质基本相同．分时段活动性质有所不同。断层各段多数以压性逆断为主，不同于历史地质考察结果。此外，长诏断裂带各断裂都具有分段活动特点。     

承德市2015年2月20-21日强降雪成因分析

利用常规观测资料、卫星云图和NECP (1?? 1?)逐6h再分析资料,对承德市2015年2月20～21日强降雪过程环流形势和物理量场进行了分析。结果表明：在此次强降雪过程中,中、低层的西风槽、切变线和地面上东移加强的蒙古气旋构成了有利天气形势,在这些系统的共同作用下不断有干冷空气侵入承德地区与低层西南暖湿气流交汇,持续的西南暖湿气流对此次强降雪的形成和维持至关重要。相对湿度、水汽通量、垂直速度、涡度及垂直螺旋度的分布和演变很好的反映出了此次强降雪过程中物理量场特点：相对湿度和水汽通量的分布说明强降雪区上空湿度较大且有充足的水汽供应,水汽通量的增大与降雪的增强相一致,水汽通量大值中心与强降雪有很好对应关系。强降雪区上空伴有较强上升运动;降雪区上空均为正涡度时最有利于上升运动和降雪;降雪区上空垂直螺旋度均为正或呈"上负下正"的垂直结构均有利于降雪,低层正垂直螺旋度对强降雪变化有很好的指示意义。     

A long‐lived metamorphic history in the contact aureole of the Mooselookmeguntic pluton revealed by in situ dating of monazite grains preserved as inclusions in staurolite porphyroblasts

Emplacement of the Mooselookmeguntic pluton, located in the western Maine region of the northern Appalachians, was thought to have occurred towards the end of the Acadian deformation at around 370 Ma. Crystallization ages from different parts of the pluton suggest a more sequential emplacement history over a period of c. 20 Myr. Foliation inflection/intersection axes (FIAs) within porphyroblasts from its aureole reveal at least five periods of garnet and staurolite growth. The orientation of FIAs in both garnet and staurolite porphyroblasts trend successively from ESE–WNW, NNW–SSE, E–W, ENE–WSW to NE–SW. Electron probe microanalysis dating of monazite grains included in staurolite porphyroblasts containing one of these five periods of FIA development reveals a succession of apparent ages from 410 Ma to 345 Ma. A similar spread of crystallization ages can be observed for plutons from Maine and adjacent regions. This succession indicates that deformation and metamorphism began well before and continued long after what is classically regarded as the Acadian orogeny. The thermal structure of the orogen progressively evolved to enable pluton emplacement, and it continued to develop afterwards with magmatic fluids still forming at depth.     

A large class of non-zonal oceanic flows satisfying the arnold-blumen sufficient condition for stability

Abstract

Recently Andrews has discussed an example of a topographically-forced non-zonal now satisfying the Arnold-Blumen sufficient condition for stability. At large distances from the topographic centre this flow becomes purely zonal and westward. After underlining the richness of solutions of the Andrews model, the present paper goes on to show that Andrews' technique can be applied successfully to a model where the vertical profile of static stability resembles those found in the ocean. In particular we obtain a large class of hydrodynamic stable flows, forced by the bottom topography, for continuously stratified fluids (two layers each with uniform Brunt-Väisälä frequency).