乡村湿地发展模式探讨:以泥仓溇乡村湿地为例

在当前城镇化快速发展的过程中,工农业发展对乡村湿地造成一定的影响和破坏。阐述了泥仓溇乡村湿地建设与保护的必要性,从改善区域水环境,科学分区管理,丰富生物多样性、传承湿地文化等方面对泥仓溇乡村湿地实施了因地制宜的生态恢复,构建良好的湿地生态系统,达到生态效益、社会效益、经济效益的共赢,以期为我国乡村湿地的生态保护与合理利用提供参考。     

Additional Samples: Where They Should Be Located

Information for mine planning requires to be close spaced, if compared to the grid used for exploration and resource assessment. The additional samples collected during quasimining usually are located in the same pattern of the original diamond drillholes net but closer spaced. This procedure is not the best in mathematical sense for selecting a location. The impact of an additional information to reduce the uncertainty about the parameter been modeled is not the same everywhere within the deposit. Some locations are more sensitive in reducing the local and global uncertainty than others. This study introduces a methodology to select additional sample locations based on stochastic simulation. The procedure takes into account data variability and their spatial location. Multiple equally probable models representing a geological attribute are generated via geostatistical simulation. These models share basically the same histogram and the same variogram obtained from the original data set. At each block belonging to the model a value is obtained from the n simulations and their combination allows one to access local variability. Variability is measured using an uncertainty index proposed. This index was used to map zones of high variability. A value extracted from a given simulation is added to the original data set from a zone identified as erratic in the previous maps. The process of adding samples and simulation is repeated and the benefit of the additional sample is evaluated. The benefit in terms of uncertainty reduction is measure locally and globally. The procedure showed to be robust and theoretically sound, mapping zones where the additional information is most beneficial. A case study in a coal mine using coal seam thickness illustrates the method.     

Contested geographical imaginings of reunification: A case study of urban change in Leipzig

Geopolitics and city restructuring are typically regarded as separate scales and processes: the international and national versus the local. The local politics of urban change in an east German city in the period after reunification question this divide. The ‘pathways’ approach to post-socialist transitions is utilized to illustrate how reunification is contested as much in neighbourhood restructuring and actions in response to incoming capital and the dominance of western legalpolitical norms as it is in national or international discourses and practices. Assumed divisions between East and West, professional and lay, and local and national are questioned.     

Mali’s many shields of its past

There is a civilization at risk. In the middle of West Africa, just south of the Sahara, where the Niger River spills into a vast floodplain (the Middle Niger), an indigenous urban civilization emerged around two thousand years ago. The story of that civilization is just beginning to be uncovered from the thousands of tells (ancient settlement mounds) that litter the Middle Niger, but archaeologists have until recently been loosing the race with the looters who plunder these sites for ancient statues and bronze art. The nation of Mali, and the local community of Jenne at the epicenter of this looting recently invented effective shields for the remains of this civilization, protections against local looters in the employ of a syndicate of wealthy European antiquities dealers. In the person of the new, democratically-elected archaeologist-President, the nation has articulated a vision of Mali’s future linked to the preservation of its past. The government has promulgated effective regulations and education programs, and initiated with the United States the world’s first bilateral import ban between a major “source” and a major “market” nation. This 1993 bilateral accord has become a prototype for many nations. In that same year, Mali established a Cultural Mission at Jenne to reinforce local pride in a local past. This local pride, in only a short period, has turned into a total protection of some 200 sites within a ten-kilometer radius of Jenne. These indigenous actions have, in less than a decade, transformed the nonrenewable archaeological resources of the Jenne region from surely one of the world’s most endangered, to a case study in local and national protection     

NUMERICAL STUDY ON THE LOCAL WIND STRUCTURES FORCED BY THE COMPLEX TERRAIN OF QINGDAO AREA

In this paper, some 2-D features of the down- and up-slope winds and sea-land-breeze generated over the com-plex terrain of the Qingdao area and the interaction between them are numerically analysed by use of a 2-Dnon-hydrostatic mesoscale model. The simulated results in the west-east vertical cross-section show that (1) when thelarge-scale wind is a southerly gentle one, the generated easterly down-slope wind is much stronger than with an oppo-site background wind, and the down-slope wind can trigger and intensify the land breeze corresponding to the easterncoast of Jiaozhou Bay; (2) a gentle westerly background wind will reduce the eastward sea breeze and up-slope windduring the daytime due to a cold advection, but shows a little effect on the mesoscale circulation formed in the nighttime.     

非线性最小二乘平差迭代解法的收敛性

本文讨论了非线性最小二乘平差中高斯—牛顿法和阻尼最小二乘法迭代程序的收敛性问题,找出了影响收敛的因素,给出了估算迭代程序收敛性的方法。     

LOCAL POTENTIAL AND PRINCIPLE OF VORTICITY CONSERVATION

In this paper,the local potential of nondivergent flow on beta plane is derived from the motion equa-tion.The conservation principle for vorticity is obtained when the local potential tends to be minimumwith the variational technique.Some other properties st,ch as Lagrangian of vorticity equation,energyetc.are also discussed briefly in the paper.     

硅酸盐固溶体矿物中组分的非韵律型空间分布及其形成过程的动力学机制

本文探讨了固溶体矿物中组分非韵律型空间分布的两种局域平衡结晶动力学模型: (1) 当固相中无扩散,而熔体中完全混合时,结晶作用满足如下模型: dx/ed=(x-f)/(1-e) (2) 当固相中无扩散,而熔体中仅有扩散时,结晶作用满足如下模型:提出了非韵律型组分空间分布的成因主要归因子岩浆的非平衡结晶和结晶过程中的动力学行为。     

有限元法解局部重力场

根据物埋大地测量边值问题的平面近似表达式,我们推导出适用于有限元法解算局部重力场的公式,然后用三维等参单元解算了一个地形模型。该模型是由地面上100m×100m的格网组成的121个结点(格网当然也可以是任意不规则的四边形)。模型中只需有结点上的重力异常。计算结果的中误差:m_ξ=±0.130″,m_η=±0.144″,m_ξ=±10.249×10~(-4)m,在西门子7570-C占用CPU的时间为8.15秒。通过试验证明:有限元法不仅可以解算物理大地测量的边值问题而且比其它方法计算速度快,布点灵活。方法适用于100×100km~2的区域,但是它需要4个以上的空间扰动位或其派生量。     

有效的正压原始方程拟能守恒保真（拟）谱模式

本工作遵循保真计算原理与方法,对正压原始方程气象传统全球（拟）谱模式方案进行改造,构造了正压原始方程拟能完全守恒（拟）谱模式新型保真计算方案,解决了正压原始方程的（非线性）计算稳定性问题和拟能守恒整体性质保持问题,改进了相应正压原始方程气象传统全球（拟）谱模式方案的计算效能。新型保真方案的数值实验表明,计算实践中,新方案在解决拟能守恒问题的同时,可解决（非线性）计算稳定问题,并在一定条件下可解决非线性计算收敛性问题。进一步的比较数值实验还表明,计算实践中,新型保真计算方案在提高相应气象传统方案的计算精度、