The Great Dun Fell Experiment 1995: an overview

During March and April of 1995 a major international field project was conducted at the UMIST field station site on Great Dun Fell in Cumbria, Northern England. The hill cap cloud which frequently envelopes this site was used as a natural flow through reactor to examine the sensitivity of the cloud microphysics to the aerosol entering the cloud and also to investigate the effects of the cloud in changing the aerosol size distribution, chemical composition and associated optical properties. To investigate these processes, detailed measurements of the cloud water chemistry (including the chemistry of sulphur compounds, organic and inorganic oxidised nitrogen and ammonia), cloud microphysics and properties of the aerosol and trace gas concentrations upwind and downwind of the cap cloud were undertaken. It was found that the cloud droplet number was generally strongly correlated to aerosol number concentration, with up to 2000 activated droplets cm⁻³ being observed in the most polluted conditions. In such conditions it was inferred that hygroscopic organic compounds were important in the activation process. Often, the size distribution of the aerosol was substantially modified by the cloud processing, largely due to the aqueous phase oxidation of S(IV) to sulphate by hydrogen peroxide, but also through the uptake and fixing of gas phase nitric acid as nitrate, increasing the calculated optical scattering of the aerosol substantially (by up to 24%). New particle formation was also observed in the ultrafine aerosol mode (at about 5 nm) downwind of the cap cloud, particularly in conditions of low total aerosol surface area and in the presence of ammonia and HCl gases. This was seen to occur at night as well as during the day via a mechanism which is not yet understood. The implications of these results for parameterising aerosol growth in Global Climate Models are explored.     

信息空地传输显示系统及试用

针对人工影响天气作业时空中、地面信息交换的实际需求，建立了人影作业信息空地传输系统，采用远程无线通讯技术实现飞机作业的空地信息实时双向、多点、较大数据文件的远距离传输，利用MICAPS系统作为基础平台，建立了一套用于人影作业指挥的信息显示系统，以实现地面气象信息、空中探测信息的数据共享。     

FPSO结构低周疲劳寿命计算方法研究

FPSO在海洋环境中频繁地进行装载与卸载操作,使FPSO船体结构产生较大的应力幅值,尤其是承受货油压力的内底纵骨。由于局部的应力集中,应力幅值超过材料的屈服强度,其装卸载次数小于104时,结构将产生低周疲劳。研究一种新的计算方法,根据Neuber假设进行塑性修正,通过应变范围得到伪热点应力范围,并确定热点应力与伪热点应力之间的关系。推导出一种新的S-N曲线作为低周疲劳的设计曲线,以伪热点应力作为计算量来预测低周疲劳寿命,降低了船体结构低周疲劳寿命计算的难度。     

硬脂酸钠改性蒙脱石对水中亚甲基蓝的吸附性能研究

以阴离子表面活性剂硬脂酸钠为改性剂制备了硬脂酸钠改性蒙脱石(NaSTA-MMT).FI-IR和XRD分析表明插层剂已进入蒙脱石层间,且随着硬脂酸钠量的增加蒙脱石层间距从1.274 nm增加到4.805 nm。亚甲基蓝吸附实验表明,硬脂酸钠改性蒙脱石吸附行为遵循伪二级动力学方程。平衡吸附量与平衡质量浓度之间的关系符合Langmuir等温吸附方程所描述的规律。硬脂酸钠改性膨润吸附亚甲基蓝表现为自发的表面物理吸附过程,吸附活化能、吸附焓变和熵变分别为2.36 kJ/mol-、21.47 kJ/mol和-44.45 J/mol.K。     

改性坡缕石粘土的全孔分布研究

为改善坡缕石粘土的表面性能和提高其实用价值,采用酸浸、酸浸 加热、酸浸 加热 甲醛浸渍3种方法处理天然坡缕石粘土,并通过扫描电镜(SEM)、傅立叶变换红外光谱(FT_IR)、X荧光光谱(XRF)、BET_比表面积分析(BET_SSA)及全孔分布等分析手段来评估坡缕石粘土的处理效果。结果表明与未经处理的原土相比,经过3种方法处理,坡缕石粘土内部细长而致密有序的晶束被打断、破碎和分散,微晶表面粗糙度增大;杂质特别是碳酸盐的去除效果显著,比表面积是原土的2倍多,总孔容积几乎增加1倍,中孔容积从0.092cm3/g增加到0.15cm3/g左右,平均孔径减小2~3nm;处理后坡缕石粘土的假孔分布峰值在17nm,比原土假孔分布峰值22nm减小约5nm,而且4个样品中的孔几乎都在介孔2~50nm范围内,大孔和微孔很少。但3种处理方法对于坡缕石粘土的处理结果没有太大的差异。     

地表复杂地区的资料处理

山西晋城煤业集团的赵庄矿大巷区,地处太行山西麓中低山区,区内大面积黄土覆盖,局部基岩裸露,地表庄稼、林木较多,建筑物较为密集,浅层地震地质条件较为复杂。对该区原始资料运用了静校正、干扰波去除、反褶积测试、精细速度分析、偏移成像、修饰性处理等处理技术,较好地解决了地表高差问题、增强了有效信号,剖面的信噪比明显提高。处理后的剖面构造形态清晰可靠,层位接触关系清楚,波组特征明显,较好地解决了煤矿采区地质构造问题。     

关于饰面用灰岩勘查开发工业指标问题探讨——以广西为例

文章根据我国地质勘查规范中有关饰面用灰岩工业指标与广西饰面用灰岩勘查与开发利用的不匹配案例,分析了广西饰面用灰岩勘查与开发利用的实际情况,认为有必要结合开发现状和市场需求,对饰面用灰岩矿产工业指标具体内容进行调整和灵活运用。     

柱化剂研究进展

柱化剂是层柱粘土的重要组成部分，也是层柱化研究中的主要内容。层柱多孔材料孔结构和性能的可调控性正来自于该领域最活跃的研究对象--柱化剂。本对柱化剂的研究进展作了较全面的介绍，并将各种柱化剂分为有机、无机和有机/无机三大类七小类。     

地市级人影作业指挥系统实现方案探讨

人影作业指挥系统是提高人影作业科学性和有效性的关键环节,为人工影响天气在防灾减灾、空中水资源开发、生态环境改善等方面发挥更大的作用提供技术支持。本文根据业务应用成果,就地市级人影作业指挥系统的实现思路和方案进行了介绍。     

Effects of short flexible seagrass Zostera noltei on flow,erosion and deposition processes determined using flume experiments

Innovative flume experiments were conducted in a recirculating straight flume. Zostera noltei meadows were sampled in their natural bed sediments in the field at contrasting stages of their seasonal growth. The aims of this study were: (i) to quantify the combined effects of leaf flexibility and development characteristics of Zostera noltei canopies on their interaction with hydrodynamics; and (ii) to quantify the role of Zostera noltei meadows in suspended sediment trapping and bed sediment resuspension related with changes in hydrodynamic forcing caused by the seasonal development of seagrasses. Velocity within the canopy was significantly damped. The attenuation in velocity ranged from 34 to 87% compared with bare sediments and was associated with a density threshold resulting from the flow‐induced canopy reconfiguration. The reduction in flow was higher in dense canopies at higher velocities than in less dense canopies, in which the reduction in flow was greater at low velocities. These contrasted results can be explained by competition between a rough‐wall boundary layer caused by the bed and a shear layer caused by the canopy. The velocity attenuation was associated with a two to three‐fold increase in bottom shear stress compared with unvegetated sediment. Despite the increase in near‐bed turbulence, protection of the sediment against erosion increased under a fully developed meadow, while sediment properties were found to be the main factor controlling erosion in a less developed meadow. Deposition fluxes were higher on the vegetated bed than on bare sediments, and these fluxes increased with leaf density. Fewer freshly deposited sediments were resuspended in vegetated beds, resulting in an increase in net sediment deposition with meadow growth. However, in the case of a very high leaf area index, sediment was mostly deposited on leaves, which facilitated subsequent resuspension and resulted in less efficient sediment trapping than in the less developed meadow.