地球化学工程学——为环境治理服务的地球化学新分支

地球化学工程学是地球化学的新分支学科,一经提出就由于富有哲理的科学思想、高效简单的技术、巨大的环境-经济-社会效益而受到地球化学家、环境学家、环保公司和政府部门的重视,并迅速进入NASDAQ市场。地球化学工程学的概念和应用包括稳定化、净化和适宜化,治理途径可归结为降解、中和、浓缩、稀释、隔离和固定等自然界常见的地球化学作用。许多看起来简单的地球化学过程在环境治理与管理中发挥了巨大作用。     

A hybrid Lagrangian-Eulerian numerical model for sea-ice dynamics

A hybrid Lagrangian-Eulerian(HLE) method is developed for sea ice dynamics,which combines the high computational efficiency of finite difference method(FDM) with the high numerical accuracy of smoothed particle hydrodynamics(SPH).In this HLE model,the sea ice cover is represented by a group of Lagrangian ice particles with their own thicknesses and concentrations.These ice variables are interpolated to the Eularian gird nodes using the Gaussian interpolation function.The FDM is used to determine the ice velocities at Eulerian grid nodes,and the velocities of Lagrangian ice particles are interpolated from these grid velocities with the Gaussian function also.The thicknesses and concentrations of ice particles are determined based on their new locations.With the HLE numerical model,the ice ridging process in a rectangular basin is simulated,and the simulated results are validated with the analytical solution.This method is also applied to the simulation of sea ice dynamics in a vortex wind field.At last,this HLE model is applied to the Bohai Sea,and the simulated concentration,thickness and velocity match the satellite images and the field observed data well.     

Development and evaluation of a DNA microarray assay for the simultaneous detection of nine harmful algal species in ship ballast and seaport waters

Rapid, high-throughput and reliable methods are urgently required to accurately detect and monitor harmful algae, which are responsible for algal blooms, such as red and green tides. In this study, we successfully developed a multiplex PCR-based DNA microarray method capable of detecting nine harmful algal species simultaneously, namely Alexandrium tamarense, Gyrodinium instriatum, Heterosigma akashiwo, Karenia mikimotoi, Prorocentrum donghaiense, Prorocentrum minimum, Ulva compressa, Ulva ohnoi and Ulva prolifera. This method achieved a limit of detection (LOD) of 0.5 ng of genomic DNA (orders of magnitude of the deci-nanogram range) in the tested algae cultures. Altogether, 230 field samples from ship ballast waters and seaport waters were used to evaluate the DNA microarray. The clinical sensitivity and specificity of the DNA microarray assay in detecting field samples were 96.4% and 90.9%, respectively, relative to conventional morphological methods. This indicated that this high-throughput, automatic, and specific method is well suited for the detection of algae in water samples.     

长江三角洲地区城镇空间扩展特征及机制

城镇空间扩展是城市化作用于地理空间的直接结果,揭示城镇空间扩展过程、格局及机制已成为识别城镇发展阶段、认知城镇发展规律的有效手段。基于长江三角洲地区多时相卫星遥感影像数据,以城镇用地扩展空间分异与关联特征为切入点,利用间隙度指数、分形维数、扩展强度指数、扩展速度指数和空间关联模型,定量揭示了区域城镇空间扩展特征的多样性、空间组织异质性和“热点区”格局演化。结果表明：20 世纪80 年代以来,长三角洲地区城镇空间扩展在以中心城市集聚为主导的过程中,遵循“小集聚,大分散”的特点,围绕“Z”形区域发展轴线,大致经历了点轴扩展、沾粘式增长和蔓延扩张的过程,区域融合现象凸显;空间扩展的“热点区”格局不断演化,“热点区”的核心集聚作用在减弱,沪宁沿线、沪杭沿线、杭甬沿线和沿江地区成为驱动长三角城镇社会经济发展的核心区;同时,在城镇空间扩展的不同阶段,驱动机制有所差异,经济全球化和区域城市化推动着长三角城镇空间一体化进程。     

形态学重度污染文本图像去噪处理

为处理扫描与复印图像产生的重度污染噪声,对噪声与文本信息的形态差异进行研究。利用灰度形态学原理,构建四方向形态学结构元素模版去除复杂的背影噪声,保留具有明显方向性的文字信息。针对噪声与文字在图像局部梯度上的特点,引入局部结构张量信息构造动态尺度的形态学结构元素,在可能的噪声区域采用较大尺度结构元素较好地滤除噪声,在可能含有文字的区域采用较小的结构元素以完整地保留易丢失的文字笔划与标点。最后利用灰度形态学重建恢复原始的文本内容,得到只含文本信息的图像。     

Damming effect on the distribution of mercury in Wujiang River

Seasonal changes in total mercury concentrations in surface water were observed for the Wujiang River, with higher values at the time of greater flow. The total mercury in this river was mostly associated with suspended particles, particulate mercury accounting for 84% of the total mercury flux on average during the high flow period, and 52% of the total mercury flux on average in the low flow period. Significant losses of Hg from the water were observed in the downstreams of the reservoir. In addition, the concentrations of particulate mercury in the downstreams of reservoir appeared to have been enhanced by sediment re-suspension and shoreline erosion caused by flood discharge, while the filtered portion decreased. These observations suggested that reservoirs played an important role in controlling the transport and fate of mercury in the Wujiang River.     

中国东部冷、热夏与近海强热带气旋变化的若干特征

利用１９５１－１９９４年台风鉴和气温资料，在划分冷、热夏标准的基础上，分别统计分析了我国东部近海强热带气旋活动的某些特征。结果发现，我国东部冷夏年近海强热带气旋无论在其频数，路径，强度和移速变化等均与热夏年迥然不同。讨论了这种差异的环流背景特征。     

长江三角洲区域开放开发政策的内涵与演变

以改革开放以来长江三角洲实施的区域开放开发政策为样本,将开放开发政策分为宏观开放开发政策、经济特区与综合配套改革试验区政策、开发区政策3个能级,从政策内容、工具、作用强度3个维度分析了区域开放开发政策演变的过程。长江三角洲国家级/省级宏观区域开放开发政策的目标从对外开放转为综合开发,对外开放在空间演化上呈从点到面、从沿海到内地、从中心城区到农村的梯度开放特征,政策工具从财税政策和行政控制转为发展社会资本与改善发展环境,前期的财税优惠政策和开放政策逐渐削弱甚至消亡,一些区域规划上升为国家战略而得到增强。上海浦东经历了从经济特区向综合配套改革试验区的转变,政策工具从优惠政策转向全方位的优先探试权。开发区政策集中在经济领域,省级开发区政策效应较国家级开发区弱,不同开发区间的政策逐渐趋同,强度在不断弱化。     

An improved nonstationary model for flood frequency analysis and its implication for the Three Gorges Dam,China

This study proposes an improved nonstationary model for flood frequency analysis by investigating the relationship between flood peak and flood volume, using the Three Gorges Dam (TGD), China, for verification. First, the generalized additive model for location, scale and shape (GAMLSS) is used as the prior distribution. Then, under Bayesian theory, the prior distribution is updated using the conditional distribution, which is derived from the copula function. The results show that the improvement of the proposed model is significant compared with the GAMLSS-based prior distribution. Meanwhile, selection of a suitable prior distribution has a significant effect on the results of the improvement. For applications to the TGD, the nonstationary model can obviously increase the engineering management benefits and reduce the perceived risks of large floods. This study provides guidance for the dynamic management of hydraulic engineering under nonstationary conditions.     

软刚臂上铰节点疲劳失效分析和现场监测方案设计

海洋环境荷载非平稳性、时变性等特点为海洋工程结构设计带来挑战。海洋工程结构设计的不准确性可导致其真实服役时间低于自身设计寿命。针对塔架软刚臂系泊系统上铰节点服役过程中出现的疲劳磨损问题,发展出一种基于原型监测技术的铰节点疲劳寿命实时预估方法。通过开展有限元模拟,建立系泊腿在指定摆动角度下摩擦系数和热点区域应力分布的对应关系,提出了软刚臂上铰节点的原型监测方案。结合不同摩擦系数对铰节点接触面损伤行为的影响,提出了软刚臂主铰结构疲劳寿命计算评估方法,能够实现铰节点疲劳的完整性分析。