Low-frequency characteristics extension for vibration sensors     

杨学山  高峰  候兴民 《地震工程与工程振动(英文版)》2004,3(1):139-146

Traditional magneto-electric vibration sensors and servo accelerometers have severe shortcomings when used to measure vibration where low frequency components predominate. A low frequency characteristic extension for velocity vibration sensors is presented in this paper. The passive circuit technology, active compensation technology and the closedcycle pole compensation technology are used to extend the measurable range and to improve low frequency characteristics of sensors. Thses three types of low frequency velocity vibration sensors have been developed and widely adopted in China.  相似文献   

The origin of variable-δ18O zircons in Jurassic and Cretaceous Mo-bearing granitoids in the eastern Xing–Meng Orogenic Belt,Northeast China     

Xue-Gang Hou  Jun Gou  Dong-Guang Yang 《International Geology Review》2019,61(2):129-149

This study reports new zircon U–Pb ages, Lu–Hf isotope data, and oxygen isotope data for Mesozoic Mo-bearing granitoids in the eastern Xing–Meng Orogenic Belt (XMOB) of Northeast China, within the eastern Central Asian Orogenic Belt. Combining these new laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U–Pb ages with the results of previous research indicates that two stages of Mo-bearing granitoid magmatism occurred in the eastern XMOB, during the Early–Middle Jurassic (200–165 Ma) and the Early Cretaceous (ca. 111 Ma). The eastern XMOB also contains Mo-bearing granitoids with variable δ¹⁸O compositions that record variations in source oxygen isotopic compositions. Combining δ¹⁸O data with zircon U–Pb and Hf isotopic data provides evidence of the origin of these granitoids. Three types of zircon have been identified within these granitoids. Type 1 zircons formed during the Mesozoic and having high δ¹⁸O values (5.71–7.05‰) that are consistent with the compositions of magmatic zircons from the Luming, Jiapigou, and Kanchuangou areas. These zircons suggest that the Mo-bearing granitoids were derived from a source containing supracrustal materials. The type 2 zircons have extremely low and heterogeneous δ¹⁸O values (4.64–4.89‰) that are consistent with the compositions of magmatic zircons from the Jidetun and Fuanpu areas. These magmas were generated by the remelting of juvenile crustal material that was previously significantly modified by interaction with fluids. Type 3 zircons generally have mantle-like δ¹⁸O values (5.42–5.57‰), with several zircons yielding higher δ¹⁸O values, suggesting that these intrusions formed from mantle-derived magmas that assimilated and were metasomatized by crustal material. Combining these geochemical data with the geology of this region indicates that the Mo-bearing granitoids were generated as a result of subduction of the Palaeo-Pacific Plate beneath the Eurasian continent.  相似文献   

Climate Change and Silk Road Civilization Evolution in Arid Central Asia: Progress and Issues   总被引：1，自引：0，他引：1  

Fahu Chen  Guanghui Dong  Jianhui Chen  Yongqi Gao  Wei Huang  Tao Wang  Shengqian Chen  Juzhi Hou 《地球科学进展》2019,34(6):561-572

Arid central Asia is one of the regions most sensitive to global climate change, as well as the region with dramatically hydrological changes and fragile ecosystems. The region includes the main body of the ancient Silk Road, which played a key role in the cultural exchange and the rise and fall of Silk Road civilization. Scientific assessment of the risks faced by the sustainable development of human society in the arid central Asia under the background of global warming is a major scientific issue that has received much attention. The study of the relationship between cultural exchange, development of Silk Road civilization and climate change can provide a scientific basis for understanding the evolution rules of human-land relationship on different timescales in this area. This study summarized the research progress in the history of cultural exchanges, the rise and fall of Silk Road civilization, climate change during the Holocene, forcing mechanisms of climate and hydrological change on different timescales, as well as the process and rule of human-environment interaction. On this basis, we proposed that the study of the temporal and spatial patterns of Holocene climate change and the evolution of Silk Road civilization in arid central Asia, as well as the research on the interaction mechanisms between human and environment, are obviously insufficient. Solving the problems of regional imbalance of climate change and cultural evolution in arid central Asia and strengthening the cross-disciplinary study of geoscience and archaeology are effective ways to promote the study of climate change and changes of Silk Road civilization, which has important scientific and practical significance for understanding the evolution of human-land relations in the region, coping with the challenges of climate change, and serving the “One Belt, One Road” strategy.  相似文献   

Runoff Change in Taizihe River Basin Under Future Climate Change Based on HBV Model     

Mingyan Liu  Fenghua Sun  Yiling Hou  Chunyu Zhao  Xiaoyu Zhou 《地球科学进展》2019,34(6):650-659

Taking the Taizihe River Basin located in Liaoning Province as a study area, we applied HBV hydrological model to simulate the hydrological process of this river basin with the support of observed daily precipitation, mean temperature, hydrological data in Xiaolinzi hydrologic station, and global digital elevation model data from SRTM3, land utilization types, etc. According to the simulation results of daily runoff, the possible impact of future climate change on runoff was analyzed through forcing HBV model by RegCM4.4 dynamic downscaled climatic data. The results show that HBV model performed generally well for daily simulation of the Taizihe River Basin with Nash Sutcliffe coefficient and deterministic coefficient being all over 0.60 in the calibration period and validation period, and the response of flooding to precipitation were simulated better. This indicates the HBV model can be successfully applied to the Taizihe River Basin. Mean temperature will increase obviously with persistent rising trend by RegCM4.4 model in 2021-2070 under RCP4.5 scenario. Annual precipitation and runoff depth are expected to reduce a bit. Compared with the baseline period (1986-2005), annual runoff depth will increase by 9.79%. At the same time, the runoff depth will increase significantly in summer and autumn. The variation of runoff quantile indicates that both peak extreme runoff and dry extreme runoff will increase to different degrees than that in the baseline period. In the future, the Taizihe River Basin will be likely to experience extreme flooding.  相似文献   

Two‐Stage Sulfide Mineral Assemblages in the Mineralized Ultramafic Rocks of the Laowangzhai Gold Deposit (Yunnan,SW China): Implications for Metallogenic Evolution     

Huichao Zhang  Peng Chai  Hongrui Zhang  Zengqian Hou  Shouming Chen  Yanbin Sun  Qing Peng 《Resource Geology》2019,69(3):270-286

The Laowangzhai gold deposit, located in the Ailaoshan gold belt (SW China), is hosted in various types of rocks, including in quartz porphyry, carbonaceous slate, meta‐sandstone, lamprophyre, and altered ultramafic rocks. In contrast to other wall rocks, the orebodies in altered ultramafic rocks are characterized by the occurrence of a large amount of Ni‐bearing minerals. The ore‐forming process of the orebodies hosted by altered ultramafic rocks can be divided into two stages: pyrite‐vaesite‐native gold and gersdorffite‐violarite stages. The contents of As and Sb increased during the evolution of ore‐forming fluid based on the mineral assemblages. Thermodynamic modeling of the Ni‐Cu‐As‐Fe‐S system using the SUPCRT92 software package with the updated database of slop16.dat indicates the fS₂ in ore‐forming fluid decreases significantly from stage I to stage II. The decreases of fS₂ due to crystallization of sulfides and fO₂ due to fluid–rock reaction were responsible for ore formation in altered ultramafic rocks of the Laowangzhai gold deposit. Geological evidence, the in situ sulfur isotope values of pyrite, and the other published isotopic data suggest that the ore‐forming fluid for ultramafic rock ores was dominantly composed of evolved magmatic fluid with the important input of sediments.  相似文献   

太阳星云凝聚过程的岩石学模型：（Ⅱ）非球陨石、C1陨石及类C1陨石的凝聚成因和小行星区星云凝聚作用     

侯渭  欧阳自远  谢鸿森  胡桂兴 《岩石学报》1996,12(3)

综述了非球陨石（铁陨石，石铁陨石和无球粒陨石）在成分结构方面的非分异成因证据，推断其成因是：星云盘中心层中的星云发生气－液凝聚作用形成的熔滴，在较高温度下彼此合并形成了较大熔体，熔体固化后形成该类陨石母体。根据Ｃ１陨石不含球粒和其它成分特征，推断它们是星云只发生气－固凝聚作用的产物。对近年来新发现的一些特殊成分的碳质球粒陨石进行了综合分析，暂定名为类Ｃ１陨石。通过类Ｃ１陨石与其它球粒陨石及Ｃ１陨石成分结构特征的对比，推断它们是星云盘边缘层星云发生气－液－固和气－固联合凝聚作用，同时发生水化作用的产物。最后，在对所有陨石凝聚成因进行解释的基础上，建立了小行星区星云凝聚模型。  相似文献   

太阳星云凝聚过程的岩石学模型：（Ⅲ）类地行星区星云凝聚作用和地球原始成分的估算     

侯渭  欧阳自远  谢鸿森  胡桂兴 《岩石学报》1996,12(3)

在建立了小行星区星云凝聚模型的基础上，对类地行星区中上物质（硅酸盐、氧化物、金属、硫化物等）的凝聚作用，以及凝聚物的水化作用进行了讨论，进而建立了包括小行星区在内的整个类地行星区的星云凝聚模式。根据地球核慢质量比和关于地球初期演化的研究结果；使用顽火辉石球粒陨石和Ｃ１陨石的化学成分分别做为地球形成区中类顽火辉石球粒陨石质星子和类Ｃ１陨石质星子的成分数据；假定类顽火辉石无球粒陨石质星子的成分与类顽火辉石球粒陨石质星子的硅酸盐部分成分相同，计算出原始地球可能由１．５８％的类铁陨石质星子、１３．９％的类顽火辉石无球粒陨石质星子、８２．５２％类顽火辉石球粒陨石质星子、２％的类Ｃ１陨石质星子组成。  相似文献   

地理信息系统支持下的煤岩煤质资料分析     

代世锋  张建华 《煤田地质与勘探》1996,24(6):19-22

以内蒙古自治区乌达矿区为例，介绍了地理信息系统在煤岩煤质资料分析中应用的可能性、基本原理、方法、优势及其展望。在分析中使用了该系统的软件和ｄＢＡＳＥⅣ，以科学的、系统的方式连接各类地质资料，从而提供了一种利用这些信息的简单方便的方法。  相似文献   

四川北川埃洛石矿物学特征及工业利用前景   总被引：6，自引：0，他引：6  

易发成  陈廷芳 《矿物岩石》1997,17(3):11-14

本文对四川北川埃洛石的矿物学特征进行研究表明，埃洛石呈管状，其ＴＦｅ２Ｏ３，ＴｉＯ２，ＭｎＯ等杂质含量低，其化学成分接近理论值，ＸＲＤ，ＩＲ，ＤＴＡ等分析均表明其为埃洛石矿物。对埃洛石的主要工艺性能测试研究表明，北川埃洛石型粘土具有优良的工艺性能，应用前景广阔。  相似文献   

控制龙门地热田的构造因素   总被引：3，自引：0，他引：3  

钱关民  傅在林 《中国煤田地质》1996,8(1):28-31

根据龙门地热田构造特点以及与其地热异常和温泉分布的关系，论述了龙门地热田构造及控热特征，为在地热田内寻找热矿水赋存的有利地段提供了必要依据。  相似文献