简论曹操对乌桓的征讨及意义

乌桓和袁绍势力的联合是导致曹操征讨乌桓的主要原因之一。在如何对待乌桓的问题上,曹操势力内部意见最初并不统一,但曹操最终采纳了郭嘉的建议,决定出兵乌桓。曹操北征乌桓的胜利,不仅将北疆分立的各政权纳入自己的管辖之下,实现了对北部地区的统一,而且为整军南下,专力于对付割据江东的孙权,以及亡命南方的刘备等解除了后顾之忧,但更重要的是中断了乌桓实现民族统一的历史进程,为乌桓人最终融合于汉等其他民族提供了前提。     

金融危机对青海地方税收的影响及对策

由美国次贷危机引发的全球金融危机,给我国经济发展带来了一定影响,进而对地方税收也产生了较大影响。本文结合青海实际,首先分析了金融危机背景下青海地方税收呈现的主要特点;进而从不同角度深入分析了影响青海地方税收增减的主要因素;最后提出了金融危机背景下促进青海地方税收增长的路径选择等。     

行政边界区域土地利用与空间发展模式研究——以长株潭结合部为例

以长株潭结合部暮云镇为例,主要采用2004与2010年土地利用数据,从动态变化与多维综合视角,对行政边界区域土地利用与空间发展的特征、机制及问题进行系统分析,在此基础上归纳理论模式。研究表明:①暮云镇土地利用结构由农村型向城镇型快速转变,城镇用地比重年均约增加2个百分点,其中居住、教育科研、交通和工业等用地增加显著;②受主体功能定位、过境通道建设、周边城市辐射差异和规划管理制度变迁等因素影响,暮云镇空间格局与扩张模式快速演变,芙蓉大道沿线新增城镇用地占全镇82.78%,北、中、南区域开发强度分别上升20.95%、7.96%和1.58%,城镇用地平均图斑面积增长2.04倍。③研究区土地利用与空间发展存在诸多阶段性和结构性问题,应加强综合路网建设、公共设施用地供给、建设用地优化布局与集约利用以及生态环境保护。     

过滤理论的起源、概念及研究进展

过滤是住房的生命周期与家庭的生命周期之间相互作用的产物,包括两大支流:以建立经济理论和模型为代表的关注住房的过滤研究、有关居民迁居的强调家庭的过滤研究。过滤理论的地理学视角可以追溯到霍伊特(Hoyt)的扇形模型,提供了关于居民迁居和城市社会空间结构之关系的解释。过滤理论意义主要有:为低收入群体提供合适住房、解释城市微观和宏观空间变化、分析和解释与住房市场有关的社会问题。过滤理论是中国城市转型研究的新视角。     

Chemical modification of pyroclastic rock by hot water: an experimental investigation of mass transport at the fluid–solid interface

Hydrothermal water–(pyroclastic) rock interactions were examined using flow-through experiments to deduce the effect of mass transport phenomena on the reaction process. A series of experiments were conducted over the temperature range 75–250°C, with a constant temperature for each experiment, and at saturated vapour pressure, to estimate the apparent rate constants as a function of temperature.
Based on the chemistry of analysed solutions, the water–rock interaction in the experiments was controlled by diffusion from the reaction surface and by the existence of a surface layer at the rock–fluid interface, which regulated the chemical reaction rate. The reaction progress depended to a high degree on flow velocity and temperature conditions, with element abundances in the fluid significantly affected by these factors. Mass transport coefficients for diffusion from the rock surface to the bulk solution have been estimated. Ca is selectively depleted under lower temperature conditions ( T  < 150°C), whereas Na is greatly depleted under higher temperature conditions ( T  > 150°C), and K reaction rates are increased when flow velocity increases. Using these conditions, specific alkali and alkali earth cations were selectively leached from mineral surfaces. The 'surface layer' comprised a 0.5–1.8 mm boundary film on the solution side (the thickness of this layer has no dependence on chemical character) and a reaction layer. The reaction layer was composed of a Si, Al-rich cation-leached layer, whose thickness was dependent on temperature, flow velocity and reaction length. The reaction layer varied in thickness from about 10⁻⁴ to 10⁻⁷ mm under high temperature/low fluid velocity and low temperature/high fluid velocity conditions, respectively.     

The radiocarbon reservoir effect: new evidence from the cemeteries of the middle and lower Dnieper basin,Ukraine

This paper presents preliminary results of new radiocarbon dating of human, faunal and fish skeletal remains from a number of the cemeteries from the Middle and Lower Dnieper Basin, Ukraine. The results appear to demonstrate the presence of a radiocarbon reservoir effect during the Neolithic–Eneolithic periods, the first time that this has been identified in this region. The data indicate that the radiocarbon reservoir effect is currently only evident during these periods, and not in the earlier Epipalaeolithic–Mesolithic periods, prompting the suggestion that the radiocarbon reservoir effect is associated with elevated fish consumption from the Neolithic period onwards.     

Radiocarbon dating of marine shell samples. The marine radiocarbon reservoir effect of coastal waters off Atlantic Iberia during Late Neolithic and Chalcolithic Periods

Radiocarbon dates on marine shells have not been used as extensively as charcoal or bone dates for the setting up of absolute chronologies because interpreting these dates is complicated by the marine radiocarbon reservoir effect. Nevertheless marine shellfish were used widely at least during the Holocene and their shells are abundant and usually well preserved in archaeological deposits located near shorelines. Consequently prior research concerning the oceanographic conditions and the marine radiocarbon reservoir effect of a particular coastal area is needed in order to set up reliable chronologies for that region. Values of regional marine radiocarbon reservoir effect – ΔR – of coastal waters off Atlantic Iberia, some of its variability along the Holocene and its correlation with the upwelling phenomenon were determined during previous research. More data related to the ΔR values for western Portuguese coastal waters during the Late Neolithic and the Chalcolithic, a time interval badly sampled in previous research, were recently obtained. These values can be compared with ΔR values already determined for the Gulf of Cadiz. Besides the importance of these values for a better knowledge of the palaeoceanography and palaeoclimatology of Atlantic Iberia, from now on archaeologists can set up reliable chronologies for Late Neolithic and Chalcolithic contexts using marine shell samples of that origin for radiocarbon dating.     

THE SYNTAX OF OBJECTS AND THE REPRESENTATION OF HISTORY: SPEAKING OF SLAVERY IN NEW YORK

The representation of history continues to evolve in the domain of museum exhibitions. This evolution is informed in part by the creation of new display methods—many of which depart from the traditional conventions used to achieve the "museum effect"—in part by an increased attention to the museum-visitor relationship. In this context the ethical force of bearing witness, at times a crucial aspect of the museum experience, has emerged as a particularly compelling issue. In seeking to represent and address atrocity, injustice, and the abrogation of human rights, museums have the potential to become "sites of conscience" and to encourage "historical consciousness." Through a series of three exhibitions devoted to slavery, the New-York Historical Society demonstrated how such sites can be constructed and how objects can be deployed to represent extreme or "limit cases." In this review/essay I investigate and interrogate these exhibitions, looking closely at the use of objects as a source of "indirect testimony" (Marc Bloch) and at the "dialogical situation" (Paul Ricoeur) that might arise in an encounter among objects, exhibit narratives, and visitors. Thinking in terms of point of view, I look at the variety of rhetorical platforms from which objects speak in these exhibitions; thinking in terms of syntax, I look at the effects of ordering and of the radical juxtaposition of objects; thinking in terms of irony, I look at the provocations of double-voiced narratives and at how objects are used to support those historical sentences.     

郭世宝博士与加拿大华人新移民研究述评

论文评述了加拿大卡尔加里大学教育学院教授郭世宝在加拿大华人新移民研究方面的学术成果。认为他在华人新移民、华人社团、移民的外国文凭认证、文化多元化与高等及成人教育研究方面成就突出,其中在华人新移民研究方面有两项理论创新：在华人新移民融合研究方面提出了＂三重玻璃效应＂理论;在华人新移民回流研究方面运用了＂双重离散＂理论。     

试论“雍正安南勘界案”秉承的依据和原则

文章对“雍正安南勘界”的缘起、双方划界过程中的争执以及最后结局进行了梳理,认为双方虽有不同的划界依据,但原则基本上是相同的,即自然因素、政治因素和文化因素,这也基本上符合现代国际划界的原则。只是这样的原则在实际划界过程中并没有得到贯彻和执行,由于受当时清王朝与安南宗藩关系的影响,最高统治者的政治观念或者文化心态成为此次划界的决定因素。