Making a Mountain Out of a Molehill? A Low-Cost and Time-Efficient Molehill Survey of the Lost Medieval Harbor Site of Monnikerede,Belgium

Grasslands pose a particular problem for archaeological survey involving artifact assessment, as no material is plowed up to the surface. Although finds in molehills are often the only source of information available on sites with such low visibility, an archaeology of molehills has thus far been largely disregarded. Yet, by applying a low-cost and time-efficient methodology, both the potential and the pitfalls of molehill archaeology come to the forefront. At the medieval harbor site of Monnikerede, it was possible to assess material culture and to locate certain structural elements. However, when artifact densities were compared with the underlying geophysical anomalies, a more complex relationship appeared at the level of individual features.     

Fluid effect on hydraulic fracture propagation behavior: a comparison between water and supercritical CO2‐like fluid

The initiation of hydraulic fractures during fluid injection in deep formations can be either engineered or induced unintentionally. Upon injection of CO₂, the pore fluids in deep formations can be changed from oil/saline water to CO₂ or CO₂ dominated. The type of fluid is important not only because the fluid must fracture the rock, but also because rocks saturated with different pore fluids behave differently. We investigated the influence of fluid properties on fracture propagation behavior by using the cohesive zone model in conjunction with a poroelasticity model. Simulation results indicate that the pore pressure fields are very different for different pore fluids even when the initial field conditions and injection schemes (rate and time) are kept the same. Low viscosity fluids with properties of supercritical CO₂ will create relatively thin and much shorter fractures in comparison with fluids exhibiting properties of water under similar injection schemes. Two significant times are recognized during fracture propagation: the time at which a crack ceases opening and the later time point at which a crack ceases propagating. These times are very different for different fluids. Both fluid compressibility and viscosity influence fracture propagation, with viscosity being the more important property. Viscosity can greatly affect hydraulic conductivity and the leak‐off coefficient. This analysis assumes the in‐situ pore fluid and injected fluid are the same and the pore space is 100% saturated by that fluid at the beginning of the simulation.     

英国新社会史思潮的兴起及其整体社会史研究的国际反响

“新社会史研究”作为一种史学新思潮,与西方史学的整体化趋势,几乎同时出现于现代国际史学舞台。英国新社会史思潮具有广泛和深刻的国内外史学渊源。英国新社会史学派宣扬的核心问题是坚持“自下而上”史学观念,它彰显了由此观念指导下的整体社会史取向和研究实践。从较广泛的分析角度看,在国际史学发展格局重新调整的现时背景下,英国马克思主义新社会史学派引起国内外史学界的广泛注意和效仿。它对国际史学发展的推动性作用是不可忽视的,这集中体现了该学派及其整体史学研究的国际反响。     

对青海省回族聚居区新农村建设问题的探讨

青海省是多民族聚居的省份。重视各个民族的新农村建设,因地制宜,因势利导,是加快全省新农村建设步伐的题中应有之义。该文从六个方面就青海省回族聚居区如何建设社会主义新农村进行了探索。     

“整理国故运动”兴盛原因探究

20世纪20～30年代,“整理国故运动”曾经在民国学术界风行一时。究其原因,一方面是缘于新史料的不断发现和新方法的逐步运用;另一方面,当时学者们普遍抱有的“与外人争胜”的心态,也在很大程度上促成了“整理国故运动”的长期兴盛。     

旅游生态足迹初探——以嵩山景区2005年"五一"黄金周为例

在生态足迹理论与方法的基础上,提出了旅游生态足迹的概念,运用旅游生态足迹计算模型,从旅游交通、旅游住宿、旅游餐饮和旅游购物等4个方面计算了2005年“五一”黄金周期间嵩山景区的旅游生态足迹,并与郑州市的生态足迹对比。结果表明:黄金周期间,嵩山景区游客的人均旅游生态足迹0.02264gha,是郑州市周人均生态足迹0.00436gha的5.19倍,旅游是一种对自然资源高需求、高消耗的生活方式。指出旅游生态足迹计算方法的特点,影响旅游生态足迹大小的关键因子,减少旅游生态足迹的途径和旅游生态足迹计算中存在的问题。     

坚持用唯物史观认识和把握中国国情——学习华岗史学思想的一点体会

华岗同志是一位忠诚于党的事业的革命前辈,卓越的马克思主义理论家.在思想理论战线,他所关注的领域,涉及哲学、政治学、美学、历史学诸方面.华岗的史学思想,具有鲜明的特色,至今仍有强烈的现实意义.他强调研究历史是为了推动历史、创造历史;他发扬中国史学的"求真"传统,把追求历史的真实看作是史学研究的生命;他大力提倡学术创新,认为创新是史学发展的本质要求.     

旅游视角下的上海F1大奖赛

F1作为世界三大赛事之一,将于2004年9月正式在中国举办上海大奖赛。F1大奖赛凭借其巨大的影响力,将为上海带来众多的社会经济效应。本文阐述了F1旅游活动的游客动机以及细分市场,分析了相关行业在F1旅游中的作用;同时,从城市旅游形象、旅游环境、基础设施、旅游经济、旅游产品几个方面论证了F1大奖赛是上海旅游发展的新极点。     

Thermal convection in faulted extensional sedimentary basins: theoretical results from finite-element modeling

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.