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51.
Permian hydrothermal activity in the Tarim Basin may have been responsible for the invasion of hot brines into Ordovician carbonate reservoirs. Studies have been undertaken to explain the origin and geochemical characteristics of the diagenetic fluid present during this hydrothermal event although there is no consensus on it. We present a genetic model resulting from the study of δ13C, δ18O, δ34S, and 87Sr/86Sr isotope values and fluid inclusions (FIs) from fracture‐ and vug‐filling calcite, saddle dolomite, fluorite, barite, quartz, and anhydrite from Ordovician outcrops in northwest (NW) Tarim Basin and subsurface cores in Central Tarim Basin. The presence of hydrothermal fluid was confirmed by minerals with fluid inclusion homogenization temperatures being >10°C higher than the paleo‐formation burial temperatures both in the NW Tarim and in the Central Tarim areas. The mixing of hot (>200°C), high‐salinity (>24 wt% NaCl), 87Sr‐rich (up to 0.7104) hydrothermal fluid with cool (60–100°C), low‐salinity (0 to 3.5 wt% NaCl), also 87Sr‐rich (up to 0.7010) meteoric water in the Ordovician unit was supported by the salinity of fluid inclusions, and δ13C, δ18O, and 87Sr/86Sr isotopic values of the diagenetic minerals. Up‐migrated hydrothermal fluids from the deeper Cambrian strata may have contributed to the hot brine with high sulfate concentrations which promoted thermochemical sulfate reduction (TSR) in the Ordovician, resulting in the formation of 12C‐rich (δ13C as low as ?13.8‰) calcite and 34S‐rich (δ34S values from 21.4‰ to 29.7‰) H2S, pyrite, and elemental sulfur. Hydrothermal fluid mixing with fresh water in Ordovician strata in Tarim Basin was facilitated by deep‐seated faults and up‐reaching faults due to the pervasive Permian magmatic activity. Collectively, fluid mixing, hydrothermal dolomitization, TSR, and faulting may have locally dissolved the host carbonates and increased the reservoir porosity and permeability, which has significant implications for hydrocarbon exploration. 相似文献
52.
本文以广州荔枝湾涌历史文化街区为例,运用扎根理论研究荔枝湾涌1940年代以来地方发展变迁与居民地方感的关系,进而挖掘居民地方感变化机制。研究发现：荔枝湾涌居民的地方感主要受生态环境、建筑与配套服务、集体记忆、活动类型、人际关系等因素的影响,其中生态环境起主导性作用;积极地方感主要来源于集体记忆的保留与延续;消极地方感主要来源于破旧的居住环境及落后的配套服务;此外,文章提出内向型地方感和外向型地方感的概念,认为随着城市发展,在地方发展变迁过程中,地方感由内向型地方感转变为内向型和外向型相结合的地方感。两种地方感相互作用,互相调节,更有利于地方稳定、开放、包容地发展。 相似文献
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作者认为,要有效缓解当前我国城市已经出现的交通拥挤堵塞等问题,除了加强道路工程建设,还必须对政府各相关职能部门既有解决问题的思路、方式进行一些改革和创新。并认为这才是当前解决城市交通问题的关键所在。而交通管理和城市规划两部门作为政府分管城市交通的主要机构,首先要做上述工作。对此,本文进行了探讨。 相似文献
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基于分形理论的江苏省南通市城镇体系空间结构研究 总被引：5，自引：0，他引：5
基于非线性科学分形理论以及运用GIS相关软件,通过计算南通城镇体系的首位指数、中心城市吸引力以及城镇交通网络长度-半径维数、网络分枝维数,探讨了南通城镇体系等级规模结构分形、城镇体系空间关联性分形以及南通城镇交通网络分形特征,从描述城镇等级体系、城镇交通网络分布入手,通过对南通城镇具体区域指标的分析和处理,并以分形理论中的二城市指数、三城市指数、四城市指数和十一城市指数为定量依据,将分形理论引入城镇体系研究的实践中,结果表明:南通城镇体系空间结构呈现分形特征,从而有效验证了分形特征不仅存在于大城市空间结构,中等城市的城镇体系依然存在,进而为指导南通城镇体系空间上合理布局提供定量依据与决策参考,并据此提出了南通城镇体系空间结构合理化的建议。 相似文献
55.
This essay explores how the emperor s body was perceived in the imperial rulership and treated uniquely in legal culture in early Ming China. It argues that the ruling elite articulated four types of imperial bodies, i.e., the body cosmic, the body politic, the body social, and the body physical, each of which exemplified a specific dimension of rulership. The emperor s four bodies are manifested in the imperial laws. The imperial laws place the emperor s body cosmic inferior to Heaven, ensure the emperor s sole authority in communicating with Heaven, require the officials faithful service to the ruler, urge the ruler to observe rules, and strictly protect the emperor s physical body. The imperial laws, by regulating the different relationships in the embodied rulership, serve as the essential instrument to create the ideal cosmic order. 相似文献
56.
青铜粉状锈中生物因素的影响 总被引：2，自引：0，他引：2
本文探讨了青铜粉状锈中生物因素的影响。实验结果表明：微生物在青铜腐蚀中起了促进作用。 相似文献
57.
宝顶山石窟的风化治理 总被引：3，自引：2，他引：1
蒋思维 《文物保护与考古科学》1999,11(1):18-22
论述了宝顶山石窟的风化病害,提出选用有机硅树脂保护剂治理风化,并对材料的性能进行了分析。同时提出了治理风化的步骤：清除表面灰尘,起壳脱落部位的复原,保护剂的配制,封护加固以及封护加固结果的检测。 相似文献
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Biao Wei Peng Wang Menggang Yang Lizhong Jiang 《Journal of Earthquake Engineering》2013,17(2):325-342
This article attempted to improve the isolation performance of a rolling isolation system by assuming that the rolling friction force gradually and linearly increased with the relative displacement between the isolator and the ground. After the rolling isolation system under different ground motions was calculated by a numerical analysis method, it obtained more regular results than that of other uneven friction distributions. Results shows that the considered concavely distributed friction force can not only dissipate the earthquake energy, but also change the structural natural period. These functions improve the seismic isolation efficiency of the structural relative displacement in comparison with the general uniform distribution of rolling friction coefficient. 相似文献