城市居住空间分异的理论基础与研究层次

本系统总结国外城市社会地理学自60年代以来的发展,作认为激进马克思主义流派的社会空间统一体理论应当是城市居住空间分异研究的理论基础。该理论认为城市地域内人地关系一一人类与他们生活的物质、社会环境的关系构成研究城市社会地理的基础。人(个体与群体)与周围的环境之间的双向互动(Interacting)的连续过程,就是社会空间统一体：一方面,人创造、调整城市空间,同时他们生活工作的空间又是他们存在的物质、社会基础。邻里、社区可改变、创造和保持定居的价值观、态度和行为;另一方面,价值观、态度和行为这些派生之物也不可避免地影响邻里和社区,而且连续的城市过程产生变化的城市空间,使经济、人口、社会和科技力量在不同水平上相互作用得以延续和发展。本系统介绍了社会空间统一体理论的发展沿革,然后指明城市居住空间研究的层次。     

古代文物表面常见天然有机物的显微共聚焦拉曼光谱研究

为了鉴别文物表面常见的天然有机物,采用显微共聚焦拉曼光谱技术采集了古代常用的蛋白类、多糖类、脂肪酸类、树脂类4类6种有代表性的天然有机物的拉曼光谱。通过对皮胶、桃胶、蜂蜡、棕榈蜡、达玛树脂和琥珀标准样品的拉曼光谱分析,发现蛋白类的特征振动峰位于1657cm-1、1305~1252cm-1、1033cm-1及1003cm-1附近;多糖类的特征振动峰位于1463cm-1、1328cm-1、1258cm-1、1088cm-1、977cm-1等;蜡类的特征振动峰位于1470~1350cm-1区间,1659cm-1、1303cm-1、1636 cm-1及1610cm-1;树脂类的特征振动峰位于1660~1650cm-1区间和1460~1440cm-1区间。在对6种天然有机物光谱特征分析的基础上,得出了使用拉曼光谱法可实现古代文物表面常见天然有机物种类鉴别的结论。     

家乡的水

我的家乡坐落在互助土族自治县东北部的一个小山村,她有一个美丽而环保的名字——泽林。顾名思义,这里不仅有山,而且有沼泽、有林木。深山大泽,实生龙     

清宫针黹活计品种及其功用的转变

针黹＂活计＂是中国古代对妇女刺绣、缝纫一类女红及其作品的统称。这类作品一般用于传统服装的佩饰,或是卧室幔帐内悬挂用品,以荷包、香囊类最为常见。清代宫廷针黹活计用途广泛,从服装配饰到日常用品、掌中把玩,甚至在一些重要的礼仪场合可以承载皇帝的主观意志和政治意图。虽长宽不盈掌心,但集织造工艺、刺绣工艺、     

宁安市渤海上京城发现的铜佛像

佛教是渤海国时期信奉的大教,遗憾的是至今尚未发现渤海留下的佛教典籍,但在上京龙泉府遗址内各寺庙址附近发现数量较多的渤海佛像.     

咸亨酒店与麦当劳的隐喻

长期以来,食物和饮食方式构成了人类学研究的传统议题。列维一斯特劳斯尝试在食物语言建立普遍的意义系统,玛丽·道格拉斯解读了膳食社会符号,萨林斯则分析了关于内部与外部、人类与野蛮的食物隐喻。阎云翔、郭于华、景军等也对中国饮食文化作了细致深刻的描述和分析。稍微不同的是,本文试图以咸亨酒店和麦当劳为例,检视全球化社会变迁进程中中国饮食消费社会空间和社会形式的演变过程及其社会文化后果。     

文物的赋存环境及其预防性保护问题

我国是世界上历史最悠久的古国之一,拥有为数众多的具有历史、科学、社会及经济价值的文物。本研究尝试综述了从文物与其赋存环境关系的角度,将文物赋存环境分为全曝露自然环境、半曝露自然环境及人工营造环境,通过分析赋存环境对文物的影响,探讨文物赋存环境的转化过程,提出不同环境条件下文物的预防性保护问题。     

土质文物盐害中硫酸钠的研究——从微观到宏观

土遗址和壁画遗址可溶盐主要为NaCl和Na_2SO_4,其中Na_2SO_4是破坏程度最严重的盐。一般认为,硫酸钠只有在温度、湿度变化时才不稳定,才发生得失结晶水引起的晶型及体积变化。为研究土质文物盐害的形成机制及内在原因,调研了全国几处典型土遗址和壁画遗址的盐害状况并取样分析。分析发现:1)土遗址和壁画遗址中硫酸钠的形貌、结构是动态变化的(无论在任何极端干燥环境甚至真空条件下);2)环境因素如温度、相对湿度的变化只是加剧上述变化进程。硫酸钠结晶析出时,其体积膨胀约4倍。这一系列的过程,深刻影响着硫酸钠的相变复杂性和对依存土质文物本体的破坏性。本工作从微观和宏观两个层面探讨了这些发现,并通过不同盐分(不同浓度氯化钠、硫酸钠)侵蚀破坏模拟试验、不同温度条件下模拟试验、不同相对湿度下模拟试验,从宏观层面印证了上述微观机制在土遗址和壁画遗址本体的外在表现。本研究发现土遗址中硫酸钠的形貌、结构是动态变化的,该工作弥补了以往研究和认识上的局限。本研究将对阻止、延缓及预测土质文物盐害的发生、发展提供科学参考。     

Spatial Distribution of City Tweets and Their Densities

Social media outlets such as Twitter constitute valuable data sources for understanding human activities in the virtual world from a geographic perspective. This article examines spatial distribution of tweets and densities within cities. The cities refer to natural cities that are automatically aggregated from a country's small street blocks, so called city blocks. We adopted street blocks (rather than census tracts) as the basic geographic units and topological center (rather than geometric center) to assess how tweets and densities vary from the center to the peripheral border. We found that, within a city from the center to the periphery, the tweets first increase and then decrease, while the densities decrease in general. These increases and decreases fluctuate dramatically, and differ significantly from those if census tracts are used as the basic geographic units. We also found that the decrease of densities from the center to the periphery is less significant, and even disappears, if an arbitrarily defined city border is adopted. These findings prove that natural cities and their topological centers are better than their counterparts (conventionally defined cities and city centers) for geographic research. Based on this study, we believe that tweet densities can be a good surrogate of population densities. If this belief is proved to be true, social media data could help solve the dispute surrounding exponential or power function of urban population density.     

Direct inversion of Young's and Poisson impedances for fluid discrimination

Seismic inversion with prestack seismic data such as amplitude variation with offsets (AVO) inversion is an important tool in the estimation of elastic parameters for predicting lithology and discriminating fluid in conventional or unconventional hydrocarbon reservoirs. The product of Young's modulus and density (Young's impedance, YI) and the product of Poisson ratio and density (Poisson ratio impedance, PI) show great potential in lithology prediction and fluid discrimination of unconventional resources such as shale gas or oil. The high quality requirements for prestack data in density inversion render the estimation of YI and PI arduous and inaccurate with a conventional prestack inversion approach. In this study, a direct AVO inversion approach is proposed to estimate YI, PI, and density directly from P‐wave seismic data. The linearized P‐wave reflectivity approximate equation in terms of YI, PI, and density is initially derived. Five models, including four typical AVO classes, are utilized to verify the accuracy of the derived linearized P‐wave reflectivity equation in comparison with the exact P‐wave reflectivity equation and the frequently used linearized reflectivity approximate equation involving P‐ and S‐wave velocities and density. Parameter sensitivity analysis illustrates that YI and PI can reasonably be estimated from P‐wave reflectivity if a decorrelation scheme is utilized in the inversion algorithm. In addition, a pragmatic AVO inversion using a Bayesian scheme is suggested for the direct inversion of YI and PI from prestack seismic data. Synthetic and field data examples demonstrate the feasibility of the proposed inversion approach in the estimation of YI and PI and show the potential of this approach in fluid discrimination.