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1.
前剂量饱和指数法测定瓷器的热释光年代   总被引:2,自引:2,他引:0  
用前剂量饱和指数法测定39件历代瓷器的热释光年代。结果表明,热释光年代与考古年代在一个标准偏差(±1σ)为29%以内的一致性非常良好。这样的误差在瓷器年代测定中是可以接受的。  相似文献   
2.
J. P. FAIRLEY 《Geofluids》2009,9(2):153-166
Previous studies have shown that most hydrothermal systems discharging at the land surface are associated with faulting, and that the location, temperature and rate of discharge of these systems are controlled by the geometry and style of the controlling fault(s). Unfortunately, the transport of heat and fluid in fault-controlled hydrothermal systems is difficult to model realistically; although heterogeneity and anisotropy are assumed to place important controls on flow in faults, few data or observations are available to constrain the distribution of hydraulic properties within active faults. Here, analytical and numerical models are combined with geostatistical models of spatially varying hydraulic properties to model the flow of heat and fluid in the Borax Lake fault of south-east Oregon, USA. A geometric mean permeability within the fault of 7 × 10−14 m2 with 2× vertical/horizontal anisotropy in correlation length scale is shown to give the closest match to field observations. Furthermore, the simulations demonstrate that continuity of flow paths is an important factor in reproducing the observed behavior. In addition to providing some insight into possible spatial distributions of hydraulic properties at the Borax Lake site, the study highlights one potential avenue for integrating field observations with simulation results in order to gain greater understanding of fluid flow in faults and fault-controlled hydrothermal and petroleum reservoirs.  相似文献   
3.
陶器古剂量P包含等效剂量Q和超线性修正I两个部分,为了提高古剂量测量的准确性,正确地计算古剂量的测量误差,本工作测试了10个古陶片样品,利用线性回归方法计算等效剂量Q和超线性修正I,并对不同的古剂量计算方法进行误差分析和评估。研究表明,线性回归方法(包括归平法和平归法)计算陶器古剂量的准确性优于目前采用的常规法;通过几种不同方法的误差比较和分析,归平法所得误差较其它方法更严谨、合理。该研究在提高古剂量测量的准确性和正确计算古剂量的测量误差两方面具有重要的意义,使得古剂量的测量更加合理,符合数理统计规律。  相似文献   
4.
王新安  杨秀云 《人文地理》2005,20(1):99-102
以资源为基础的可持续竞争优势理论认为,企业之间的资源是异质性的、不完全流动的,企业可通过对异质性资源的占有和有效利用,获取可持续的竞争优势。那么,面对激烈竞争的世界航空市场,中国各民航公司要成为世界竞争中的强者,就必须从分析自身的异质性资源入手,通过异质性资源的不断获取和有效利用,培养自身的可持续竞争优势。  相似文献   
5.
论空间批评     
刘进 《人文地理》2007,22(2):119-122
"空间批评"是西方一种重要的前沿批评形态,它是在当代西方"空间转向"趋势中,强调空间的本体性和异质性观念中形成的。"空间批评"突出文学对现实空间的参与性、并置性,强调文学空间来源的多元性和文本空间的异质性,凸现文学多重阐释中的批判功能。  相似文献   
6.
以山西省转型期旅游发展为例,选取2005、2011和2017年17项指标构建城市旅游发展综合实力评价体系,基于改进场强模型,借助GIS技术和地理探测器模型,分析旅游场强时空异质性特征及演变机制。结果表明:(1)旅游场强高值区范围扩大、逐步形成叶脉状网络空间形态,突破了早期"人"形格局限制;(2)各地市旅游场强前期整体上升,后期集中在大西高铁沿线,城市绝对差异增加,高级别场强类型主要以太原市为中心向边缘扩散演替;(3)旅游场强空间格局演变具有时序性特征,主导因子经历了二元、三元主导和多元共同作用阶段,对于旅游产业后发省份构建区域旅游场强空间格局具有借鉴和指导意义。  相似文献   
7.
There is much concern in the UK about the effects on community cohesion of antisocial behaviour, but to date relatively little is known about the geography of such behaviour: for what sort of people, and in what sort of places, are high levels of antisocial behaviour a problem? What are the links, if any, between such behaviour and local socio-economic conditions, and how do such perceptions relate to local crime rates? Using data from the British Crime Survey and other secondary datasets, we develop and extend previous work that has investigated links between individual socio-economic characteristics, neighbourhood characteristics and individual perceptions of antisocial behaviour. A multilevel modelling approach is used to ensure that individual- and area-level effects are not conflated. Secondly we extend the substantive knowledge surrounding the relationship between neighbourhood ethnic heterogeneity and individual perceptions of antisocial behaviour. In so doing, we challenge recent contentions that heterogeneity is associated with declining social cohesion and trust. We conclude that at a small-area scale for England, the primary area-level determinants of high levels of antisocial behaviour lie in material circumstances, and that ethnic heterogeneity has no discernible effect on perceptions of antisocial behaviour.  相似文献   
8.
In 2009, Walker and colleagues questioned the validity of the iron‐deficiency anemia hypothesis as an explanatory mechanism for the presence of porotic hyperostosis (PH) and cribra orbitalia. They presented evidence demonstrating that iron deficiency inhibits, rather than promotes, marrow hypertrophy and argued a link between both PH and hemolytic or megaloblasic anemias (including vitamin B12 deficiency). This paper suggests that dismissing the iron‐deficiency anemia hypothesis may be premature, but, if dismissed, may result in unforeseen consequences. Vitamin B12 deficiency and iron deficiency often result from similar proximate causes, i.e. lack of animal protein in the diet and sanitation problems that lead to parasitic or diarrheal diseases, thereby promoting nutrient losses. As a result, vitamin B12 deficiency and iron deficiency commonly co‐occur. In individuals with a co‐occurrence of iron deficiency and vitamin B12 deficiency, a possible inhibition of marrow hypertrophy caused by iron deficiency may prevent the development of PH, despite the presence of (vitamin B12) nutritional deficiency. The implications of dismissing the iron‐deficiency anemia hypothesis are that many skeletal populations may exhibit hidden heterogeneity, i.e. individuals who are the most nutritionally stressed, with multiple nutrient deficiencies, would mimic the non‐stressed individuals and neither would show evidence of PH. However, the inclusion of multiple stress indicators and greater understanding of biocultural context in bioarchaeological analyses may mitigate the potential impacts of hidden heterogeneity in the expression of PH. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
9.
企业迁移成效的差异是经济区位理论和区域发展政策关注的重要科学问题。区域产业转移实践往往呈现出多个行业的产业转移到相同区域的特征,以及产业转出地和转入地之间对不同行业的空间黏性存在差异,导致区域产业转移效果存在差异和理论解释的复杂性。基于此,本文从企业迁移的微观视角出发,以珠三角地区转移到粤北地区的产业转移园为例,通过行业投产数据的比较和空间盈利边界的理论演绎,分析区域不同行业产业转移效果的差异及其成因。研究表明,企业迁移成效存在行业异质性的差异,这是由于不同行业企业的对转出地的空间黏性大小不同造成的。空间黏性较小的企业比空间黏性较大的企业有更多的空间盈利。  相似文献   
10.
本文利用2000—2019年工商企业注册数据库中的企业投资汇总数据构建京津冀城市群的产业投资网络,采用社会网络分析法研究其演变特征及行业差异,在此基础上利用QAP回归分析探讨其影响因素。主要结论为:产业投资规模呈阶段性增长,投资空间范围扩大,投资格局从单核辐射网络演变为“双层三角联动辐射网络”,核心—边缘结构明显但极化现象逐步减弱。产业投资网络存在行业异质性,制造业呈现等级辐射网络,科学研究与技术服务业呈现单核辐射网络。影响因素从以经济规模和劳动力成本为主演变为行政界线、劳动力成本、科研创新、金融市场、经济规模多种因素共同作用,影响因素也存在行业异质性。  相似文献   
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