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481.
�������ʹ������ϵ���е��α������̽�� 总被引:2,自引:2,他引:0
施一民 《大地测量与地球动力学》2007,27(1):65-68
?????????м?????λ??????????????????????????????????????????λ????????′???????????γ??????????????????????????????????α????????????????????????????????λ??????????????????????????????????????????????????????????????????????????????????????????????λ????λ???????????????б?????????????????????????????? 相似文献
482.
大姚6级双震前的地震前兆特征 总被引:8,自引:2,他引:6
在连续形变观测资料中除了存在于整个时间域的短周期潮汐信息(固体潮)外,还有出现在某个时间段的长周期非潮汐信息.如何从时间或空间上认识和提取这些信息.成为认识地震过程和进行地震预报关键和迫切的问题之一。利用小波分析的时一频特性和奇异性检测特性,对大姚6级双震前的连续形变观测资料进行了处理,提取潮汐资料中的非潮汐信息。发现在地震前震中附近的形变台站都接收到了相同频段的异常信号.周期为几天到十几天,出现在各个台站的时间也大致相同。这些在震前具有一定时、空分布的信息有可能是地震前兆。 相似文献
483.
Based on Hagget's theory of spatial structure,researches on the nodes and field of tourist origins to Huang-cheng Village in Shanxi Province of China have been explored.Nodal hierarchy structure of tourist origins is analyzed with cluster analysis and the gravity model.And field of tourist origins is analyzed with attraction radius index(R)and geography concentration index(G).In the field analysis,R and G of Huangcheng Village are compared with Xidi Village that is a world heritage located in Huangshan City of Anhui Province in China.According to comparison of loca-tions of two areas,influential factors for field area of Huangcheng Village are identified.It is concluded that:1)cluster analysis and gravity model can be complementary methods to each other for nodal hierarchy structure analysis of tour-ist origins;and 2)as far as location is concerned,the weak intensity effect of tourism resources in the tourist region is a major cause for explaining why tourist origins to Huangcheng Village are mainly its neighboring areas.Moreover,it is suggested that the regional effect of tourist resources should be regarded as a component of destination attractiveness when applying gravity model. 相似文献
484.
The feasibility of using fluorescence excitation-emission matrix (EEM) along with parallel factor analysis (PARAFAC) and nonnegative least squares (NNLS) method for the differentiation of phytoplankton taxonomic groups was investigated. Forty-one phytoplankton species belonging to 28 genera of five divisions were studied. First, the PARAFAC model was applied to EEMs, and 15 fluorescence components were generated. Second, 15 fluorescence components were found to have a strong discriminating capability based on Bayesian discriminant analysis (BDA). Third, all spectra of the fluorescence component compositions for the 41 phytoplankton species were spectrographically sorted into 61 reference spectra using hierarchical cluster analysis (HCA), and then, the reference spectra were used to establish a database. Finally, the phytoplankton taxonomic groups was differentiated by the reference spectra database using the NNLS method. The five phytoplankton groups were differentiated with the correct discrimination ratios (CDRs) of 100% for single-species samples at the division level. The CDRs for the mixtures were above 91% for the dominant phytoplankton species and above 73% for the subdominant phytoplankton species. Sixteen of the 85 field samples collected from the Changjiang River estuary were analyzed by both HPLC-CHEMTAX and the fluorometric technique developed. The results of both methods reveal that Bacillariophyta was the dominant algal group in these 16 samples and that the subdominant algal groups comprised Dinophyta, Chlorophyta and Cryptophyta. The differentiation results by the fluorometric technique were in good agreement with those from HPLC-CHEMTAX. The results indicate that the fluorometric technique could differentiate algal taxonomic groups accurately at the division level. 相似文献
485.
486.
We sampled the sediments of the East China Sea during 2005 and 2006, and analysed the contents of the biogenic mat-ters: biogenic silica, organic carbon, and organic nitrogen. From the surface distribu... 相似文献
487.
吉尔吉斯斯坦北天山构造带的矿床学数据缺乏,制约了天山造山带境内外成矿对比。布丘克金矿床位于吉尔吉斯斯坦北天山构造带中部。金矿体为石英复脉,呈带状发育于NWW向韧性剪切带中。矿体倾向SSW,倾角60°~70°,赋矿围岩主要为侵入于早古生代变质碎屑杂岩中的正长斑岩。布丘克金矿床成矿期石英流体包裹体观察、石英H-O同位素、硫化物S同位素测试结果显示,布丘克金矿床石英脉中包裹体大小集中在2~10μm之间,类型以H2O-CO2型、富CO2型、水溶液型包裹体为主,成分以富CO2、含CH4为特征。成矿流体具有中温(200~320℃)、低盐度(3%~7%NaCleqv)特征;石英δDV-SMOW值介于-108.1‰~-90.2‰之间,δ18O流体值介于4.86‰~9.26‰之间;黄铁矿δ34S分布在0‰左右(-0.9‰~1.6‰)。综合本文数据、矿床地质特征、区域地质资料,本文认为布丘... 相似文献
488.
En‐De Wang Chang‐Ik Han Jian‐Ming Xia Jian‐Fei Fu Guang‐Su Li San‐Shi Jia Ye‐Kai Men 《Geological Journal》2016,51(3):480-498
The Anshan–Benxi iron producing area, which is located at the northeastern margin of the North China Craton, is the main distribution area of Archaean BIFs in China. In their eastern part, including the Gongchangling and Waitoushan deposits, BIFs mainly are hosted in the Archaean middle Anshan Group. Amphibolites are widely distributed in the iron‐bearing rock series, reflecting the tectonic setting of BIFs. Amphibolites not only have MORB‐like compositional characteristics, but also have island arc‐like ones, and they are consistent with back‐arc basin basalts (BABB). In the study area, the protolith of amphibolites belongs to Okinawa‐type BABB; it indicates that tectonic setting of BIFs is the intra‐continental back‐arc basin. In the study area, the formation of sedimentary basins for BIFs had been associated with oceanic plate subduction. Amphibolites from Gongchangling deposit are characterized by relative enrichments in LILE and LREE, and depletions in HFSE. This indicates that they had a relatively large influence of subduction in their formation. Amphibolites from Waitoushan deposit are characterized by relative enrichments in LILE without conspicuous depletions in HFSE, indicating relatively low subduction rates. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
489.
实现地面气象要素自动观测是近年来我国气象观测领域的发展趋势,观测自动化给地面观测业务和观测数据的应用推广带来较大改变。本文研究了基于自动观测的天气现象代码表WMO4680,分析得出WMO4680简化了视程障碍和降水阵性的代码分类,比WMO4677编码更适合自动观测设备的特点。结合我国业务天气现象电码编制原则,设计实现了现在天气现象电码和过去天气现象电码的自动编制。根据我国目前可自动化观测的要素数目,经过流程设计和当前最新业务改革内容,可以实现46个天气电码的自动编报。 相似文献
490.
A multi-proxy reconstruction of spatial and temporal variations in Asian summer temperatures over the last millennium 总被引:1,自引:0,他引:1
Feng?Shi Quansheng?GeEmail author Bao?Yang Jianping?Li Fengmei?Yang Fredrik?Charpentier?Ljungqvist Olga?Solomina Takeshi?Nakatsuka Ninglian?Wang Sen?Zhao Chenxi?Xu Keyan?Fang Masaki?Sano Guoqiang?Chu Zexin?Fan Narayan?P.?Gaire Muhammad?Usama?Zafar 《Climatic change》2015,131(4):663-676
To investigate climate variability in Asia during the last millennium, the spatial and temporal evolution of summer (June–July–August; JJA) temperature in eastern and south-central Asia is reconstructed using multi-proxy records and the regularized expectation maximization (RegEM) algorithm with truncated total least squares (TTLS), under a point-by-point regression (PPR) framework. The temperature index reconstructions show that the late 20th century was the warmest period in Asia over the past millennium. The temperature field reconstructions illustrate that temperatures in central, eastern, and southern China during the 11th and 13th centuries, and in western Asia during the 12th century, were significantly higher than those in other regions, and comparable to levels in the 20th century. Except for the most recent warming, all identified warm events showed distinct regional expressions and none were uniform over the entire reconstruction area. The main finding of the study is that spatial temperature patterns have, on centennial time-scales, varied greatly over the last millennium. Moreover, seven climate model simulations, from the Coupled Model Intercomparison Project Phase 5 (CMIP5), over the same region of Asia, are all consistent with the temperature index reconstruction at the 99 % confidence level. Only spatial temperature patterns extracted as the first empirical orthogonal function (EOF) from the GISS-E2-R and MPI-ESM-P model simulations are significant and consistent with the temperature field reconstruction over the past millennium in Asia at the 90 % confidence level. This indicates that both the reconstruction and the simulations depict the temporal climate variability well over the past millennium. However, the spatial simulation or reconstruction capability of climate variability over the past millennium could be still limited. For reconstruction, some grid points do not pass validation tests and reveal the need for more proxies with high temporal resolution, accurate dating, and sensitive temperature signals, especially in central Asia and before AD 1400. 相似文献