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51.
GIS技术在萨拉乌苏考古遗址公园规划设计中的应用   总被引:1,自引:0,他引:1  
传统规划设计工作的技术平台多以计算机辅助设计(CAD)为主,本工作以内蒙古自治区鄂尔多斯萨拉乌苏考古遗址公园规划为例,将Arc GIS Desktop作为技术平台应用到公园的规划设计工作中。首先,通过对规划区的实地踏勘,采集相关数据和资料,进行规划区数据库建设;其次,在数据库建设的基础上,通过GIS技术构建与现实环境对应的虚拟地理信息空间,实现规划区景观的三维可视化;最后,利用三维景观模型对现实地理环境进行模拟、分析及虚拟场景飞行。不同于传统CAD的二维工作平台,本工作借助GIS对空间数据和属性数据的强大处理功能及其三维景观可视化模块,为实现内蒙古鄂尔多斯萨拉乌苏考古遗址公园的科学规划提供辅助。  相似文献   
52.
The ground penetrating radar (GPR) technique was used to investigate the subsurface in an urban area located in Mesagne (Italy) to obtain a map of the archaeological features in the ground. The GPR survey was undertaken at selected locations placed near (about 50 m) to a necropolis dating from the Messapian to the Roman imperial age, using a GSSI Sir System 2 incorporating 200 and 500 MHz centre frequency antennae. The selected areas (A and B) were surveyed along parallel 1 m spaced profiles using a 200 MHz antenna in area A and along parallel 0.5 m spaced profiles using a 500 MHz antenna in area B. For the selected areas the processed data were visualised in 3D space not only by means of the standard time slice technique, but also by means of a recently proposed approach, namely by iso-amplitude surfaces of the complex trace amplitude. The immediacy in revealing the spatial positioning of highly reflecting bodies, such as the anomaly interpreted as an old hypogeum room in area A, makes 3D visualisation techniques very attractive in archaeological applications of GPR. Their sensitivity to the signal/noise ratio is, on the other hand, highlighted by the quite poor performance in area B, where the only reliable result provided by all the techniques was the ancient living surface reflection, whereas none of them could effectively enhance the visibility of weak hyperbola reflections noted on 2D sections and probably related to the walls located on the ancient living surface. The performance of the various techniques in these two different situations allowed insights into their main advantages and drawbacks to be gained.  相似文献   
53.
M. A. Simms  G. Garven 《Geofluids》2004,4(2):109-130
Thermal convection has the potential to be a significant and widespread mechanism of fluid flow, mass transport, and heat transport in rift and other extensional basins. Based on numerical simulation results, large‐scale convection can occur on the scale of the basin thickness, depending on the Rayleigh number for the basin. Our analysis indicates that for syn‐rift and early post‐rift settings with a basin thickness of 5 km, thermal convection can occur for basal heat flows ranging from 80 to 150 mW m?2, when the vertical hydraulic conductivity is on the order of 1.5 m year?1 and lower. The convection cells have characteristic wavelengths and flow patterns depending on the thermal and hydraulic boundary conditions. Steeply dipping extensional faults can provide pathways for vertical fluid flow across large thicknesses of basin sediments and can modify the dynamics of thermal convection. The presence of faults perturbs the thermal convective flow pattern and can constrain the size and locations of convection cells. Depending on the spacing of the faults and the hydraulic properties of the faults and basin sediments, the convection cells can be spatially organized to align with adjacent faults. A fault‐bounded cell occurs when one convection cell is constrained to occupy a fault block so that the up‐flow zone converges into one fault zone and the down‐flow zone is centred on the adjacent fault. A fault‐bounded cell pair occurs when two convection cells occupy a fault block with the up‐flow zone located between the faults and the down‐flow zones centred on the adjacent faults or with the reverse pattern of flow. Fault‐bounded cells and cell pairs can be referred to collectively as fault‐bounded convective flow. The flow paths in fault‐bounded convective flow can be lengthened significantly with respect to those of convection cells unperturbed by the presence of faults. The cell pattern and sense of circulation depend on the fault spacing, sediment and fault permeabilities, lithologic heterogeneity, and the basal heat flow. The presence of fault zones also extends the range of conditions for which thermal convection can occur to basin settings with Rayleigh numbers below the critical value for large‐scale convection to occur in a basin without faults. The widespread potential for the occurrence of thermal convection suggests that it may play a role in controlling geological processes in rift basins including the acquisition and deposition of metals by basin fluids, the distribution of diagenetic processes, the temperature field and heat flow, petroleum generation and migration, and the geochemical evolution of basin fluids. Fault‐bounded cells and cell pairs can focus mass and heat transport from longer flow paths into fault zones, and their discharge zones are a particularly favourable setting for the formation of sediment‐hosted ore deposits near the sea floor.  相似文献   
54.
国洪梅 《史学集刊》2004,(3):62-65,88
新政时期,罗斯福总统在扩大政府规模的过程中,通过“政治庇护制”任命文官,使行政部门特别是行政部门中的“政治文官”以多种方式直接参与立法和政策的制订,自主地执行联邦政府的政策,导致美国文官政治化倾向的加强。这种现象不仅源于政治与行政的特殊关系,源于“政治文官”自身的优势,也源于美国特殊的政治体制和社会结构。  相似文献   
55.
司徒美堂与抗日战争   总被引:2,自引:0,他引:2  
任贵祥 《史学月刊》2004,(11):57-63,69
美洲著名爱国侨领司徒美堂为祖国抗战做出了重大的贡献。他从九一八事变后即率先投身于抗日救亡运动,积极声援自发奋起抗战的国民党官兵;全国抗战爆发后,他出任抗日救国侨团的首领,带领广大华侨开展抗日救亡活动;他万里迢迢回国慰劳抗日军民,为祖国抗战出计献策,在途经香港陷入日军魔掌的危险时刻,表现出了铁骨铮铮的民族气节;他团结美洲洪门侨胞,报效祖国抗战,使这一古老的帮会组织焕发青春;他呼吁祖国团结抗战,反对妥协投降,有力地维护了国共合作抗战的大局。他是广大华侨抗日救国的领袖和楷模,其爱国思想在支援祖国抗战中进一步得到升华。  相似文献   
56.
A 3-D optical scanner was used to obtain precise and complete representations of lithic artifacts. A computer algorithm, which was specially developed for the purpose, was used to position the artifacts in a way which enables the extraction of the standard metric parameters (length, width, width at 1/2 length, etc.). In this way, the ambiguities which affect the traditional manual measurements were eliminated. This new methodology creates accurate and objective databases. Several other parameters (center of mass position, volume, surface area) were also computed. The advantages of our method are illustrated by the analysis of 90 scanned Lower Paleolithic handaxes.  相似文献   
57.
Optically stimulated luminescence (OSL) measurements are reported for single grains of quartz from deposits within Sibudu rock shelter. Such measurements enable rejection of unrepresentative grains and application of the finite mixture and central age models to obtain the most reliable age estimates. Three types of single-grain equivalent dose (De) distributions were observed: one sample represented a single dose population, three samples indicated mixing between Iron Age (IA) and Middle Stone Age (MSA) deposits, and 10 samples (in addition to the three mixed samples) showed scattered distributions. The latter type resulted from differences in the beta dose received by individual grains. For these samples, the beta doses were modelled and adjusted accordingly. Ages for the 14 samples collected from MSA deposits post-dating the Howiesons Poort (HP) resulted in three age clusters, which are stratigraphically consistent with the three informally named cultural phases at Sibudu: namely, the post-HP, late MSA and final MSA. Weighted mean ages of 58.5 ± 1.4 ka, 47.7 ± 1.4 ka and 38.6 ± 1.9 ka were calculated for these phases, respectively. The three phases were separated by two occupational hiatuses with durations of 10.8 ± 1.3 ka and 9.1 ± 3.6 ka. We hypothesise that the punctuated presence of humans at Sibudu was determined by large-scale fluctuations in climate during oxygen isotope stage (OIS) 3, which resulted in alternating wet and dry periods. Phases of occupation correspond to wet periods when fresh water was available in the Tongati River, whereas intervals of site abandonment correspond to dry periods when people were forced to migrate in search of a reliable source of fresh water. Where people migrated to, remains unresolved.  相似文献   
58.
心智模决定人们的思维方式和行为习惯。章认为接近与嫡系不良心智模式是旅行社增强竞争力的主要障碍。旅行社应积极倡导学习与效益型的心智模式。  相似文献   
59.
Where there was a settled political geography of state power and responsibilities, the remarkable growth of global finance has put enormous pressure on national economic, political and social institutions. Furthermore, the looming crisis facing many continental European social security systems has raised many doubts about the long-term viability of the German model compared to its Anglo-American rivals. In this context, large German corporations have sought ways of sustaining their global competitiveness by, in part, restructuring their national and regional commitments. To illustrate, in this paper we concentrate on the nature and organization of German employer-sponsored pension institutions in relation to Anglo-American management practice. Two issues drive the analysis. One has to do with an emerging coalition between corporate management and shareholders with respect to the market value of the firm. The second issue has to do with the allocation of risk and uncertainty between the social partners when negotiating the financing and final value of promised retirement income. The institutional framework of collective decision-making common to many of Germany's largest firms is under pressure; three models of investment decision making relevant to pension assets and liabilities are used to illustrate this point. In doing so, we suggest that the German model is more fragile than commonly realized. We also suggest that Anglo-American management practices have penetrated and affected German corporate (national and regional) institutions and regulations. The social market lauded by advocates of stakeholder capitalism is changing rapidly, at least in the sphere of large firms and global finance.  相似文献   
60.
Book Reviews     
Books reviewed:
Cyberspace: The World in WiresRob Kitchin
Mike Crang, Phil Crang and Jon May, (eds.) Virtual Geographies: Bodies, Space and Relations
Joanne P. Sharp, Paul Routledge, Chris Philo and Ronan Paddison, (eds.) Entanglements of Power: Geographies of domination/resistance
Steven Daniels, Humphrey Repton: Landscape Gardening and the Geography of Georgian England
David Harvey, Spaces of Hope
Robert J. Mayhew, Enlightenment geography: the political languages of British geography 1650-1850
Felix Driver, Geography Militant: Cultures of Exploration and Empire
Eric Sheppard and Trevor Barnes, (eds.) A Companion to Economic Geography
Gordon L. Clark, Maryann P. Feldman and Meric S. Gertler, (eds.) The Oxford Handbook of Economic Geography  相似文献   
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