融冰期北极楚科奇海陆架中心区硅限制与来源补充     

刘洁  李中乔  张安余  任健  白有成  庄燕培  李杨杰  李宏亮  金海燕  陈建芳 《地学前缘》2022,29(4):103-112

相对氮亏损(N:P约为7,小于16)的太平洋入流水携带的营养盐是支撑北冰洋上层生态系统的重要物质基础。海冰消退,光限制消失,楚科奇海陆架存在强烈的营养盐消耗与利用,广泛认为其表现为氮限制,因此该区域重点关注氮元素循环,对于硅元素的相关研究较少。本文基于2016年中国第七次北极科学考察和中国-俄罗斯首次联合北极科学考察两个同步进行的航次调查结果,全面展示了融冰期整个楚科奇海陆架区的营养盐分布格局。结果显示,硝酸盐和亚硝酸盐表层基本耗尽;硅酸盐表现为中心低,周围高,陆架中心区是强烈的硅限制区域,受到硅和氮的共同限制。沿着太平洋入流方向,S01、R01、LV77-01站位30 m以深硅酸盐浓度高于太平洋入流水端员,说明沉积物孔隙水向底层水释放硅酸盐,因此在浅水陆架区孔隙水可作为上层海洋硅酸盐的潜在来源。本研究结合文献数据计算得到楚科奇海陆架沉积物-水界面硅酸盐年通量为630.78 mmol·m^-2·a^-1,总量为3.75×10¹¹ mol·a^-1,是太平洋入流水所携带硅酸盐年通量的一半(6.59×10¹¹ mol·a^-1),表明沉积物孔隙水也是楚科奇海陆架硅酸盐的重要来源。  相似文献   

Hydro-mechanical coupled analyses on wall deformations caused by deep excavations and dewatering in a confined aquifer     

Peng  Chen-Xin  Liu  Nian-Wu  Li  Ming-Guang  Zhen  Liang  Chen  Jin-Jian 《Acta Geotechnica》2022,17(6):2465-2479

Acta Geotechnica - This study investigates the effect of dewatering on wall deformations of deep excavations through numerical analyses. A hydro-mechanical coupled method...  相似文献   

Hydro-mechanical analysis of a braced foundation pit affected by rainfall and excavation in unsaturated soils     

Zhang  Xiao-Qian  Li  Ming-Guang  Chen  Jin-Jian 《Acta Geotechnica》2022,17(12):5675-5690

Acta Geotechnica - A deep foundation pit constructed in unsaturated soils had encountered torrential rainfall during excavation, and measurements indicated an unexpected excavation deformation...  相似文献   

A unified constitutive model for cemented/non-cemented soils under monotonic and cyclic loading     

Lu  Yong  Zhu  Wen-xuan  Ye  Guan-lin  Zhang  Feng 《Acta Geotechnica》2022,17(6):2173-2191

Acta Geotechnica - In this paper, an elastoplastic constitutive model is proposed to uniformly describe the mechanical behavior of cemented/ non-cemented soil under different loading conditions. A...  相似文献   

Low-cost high performance distributed data storage for multi-channel observations     

《New Astronomy》2015

The New Vacuum Solar Telescope (NVST) is a 1-m solar telescope that aims to observe the fine structures in both the photosphere and the chromosphere of the Sun. The observational data acquired simultaneously from one channel for the chromosphere and two channels for the photosphere bring great challenges to the data storage of NVST. The multi-channel instruments of NVST, including scientific cameras and multi-band spectrometers, generate at least 3 terabytes data per day and require high access performance while storing massive short-exposure images. It is worth studying and implementing a storage system for NVST which would balance the data availability, access performance and the cost of development. In this paper, we build a distributed data storage system (DDSS) for NVST and then deeply evaluate the availability of real-time data storage on a distributed computing environment. The experimental results show that two factors, i.e., the number of concurrent read/write and the file size, are critically important for improving the performance of data access on a distributed environment. Referring to these two factors, three strategies for storing FITS files are presented and implemented to ensure the access performance of the DDSS under conditions of multi-host write and read simultaneously. The real applications of the DDSS proves that the system is capable of meeting the requirements of NVST real-time high performance observational data storage. Our study on the DDSS is the first attempt for modern astronomical telescope systems to store real-time observational data on a low-cost distributed system. The research results and corresponding techniques of the DDSS provide a new option for designing real-time massive astronomical data storage system and will be a reference for future astronomical data storage.  相似文献   

The iron emission lines Kα and Kβ in active galactic nuclei — A further piece of evidence for the Cerenkov line-like radiation     

《Chinese Astronomy and Astrophysics》2006,30(3):256-262

It has been recently observed by XMM-Newton that besides the emission line of iron Kα at 6.4 keV there also exists in the Seyfert 1 galaxy NGC 3783 the very intense emission line of iron Kβ at 7.0 keV. Moreover, the ratio of equivalent widths (EWs) of these two lines can hardly be interpreted with the traditional mechanism of “photoelectric absorption — fluorescence emission”. By using the mechanism of Cerenkov line-like radiation proposed by YOU Jun-hian et al., the ratio of EW_Kα/EW_Kβ may be reasonably interpreted by means of a detailed model theoretical computation. As shown by the results, the iron K lines in active galactic nuclei (AGNs) are formed not only by the fluorescence mechanism, but also by the Cerenkov line-like radiation. Both coexist in AGNs, with the latter playing the dominant role.  相似文献   

The kinetics of O2(aq) reduction by structural ferrous iron in naturally occurring ferrous silicate minerals     

《Applied Geochemistry》2005,20(11):2003-2016

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Rapid determination of chemical and physical properties in marine sediments using a near-infrared reflectance spectroscopic technique     

《Applied Geochemistry》2005,20(9):1637-1647

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Forecasting the western Pacific subtropical high index during typhoon activity using a hybrid deep learning model     

Jianyin Zhou  Mingyang Sun  Jie Xiang  Jiping Guan  Huadong Du  Lei Zhou 《海洋学报(英文版)》2022,41(4):101-108

Seasonal location and intensity changes in the western Pacific subtropical high(WPSH) are important factors dominating the synoptic weather and the distribution and magnitude of precipitation in the rain belt over East Asia. Therefore, this article delves into the forecast of the western Pacific subtropical high index during typhoon activity by adopting a hybrid deep learning model. Firstly, the predictors, which are the inputs of the model, are analysed based on three characteristics: the first...  相似文献   

New approaches for archaeal genome-guided cultivation     

Wang  Yinzhao  Kamagata  Yoichi  Li  Meng  Han  Feifei  Wang  Fengping  Xiao  Xiang 《中国科学:地球科学(英文版)》2021,64(10):1658-1673

Archaea, one of the three domains of life along with Bacteria and Eukarya, contains ancient life forms such as methanogen that are observed today on Earth, and one lineage Asgard archaea is also considered the closest ancestor of Eukarya.Recently, with the development of interdisciplinary studies from Earth and Life sciences, archaeal organisms are considered to play pivotal roles in geochemical cycling in nature. However, our understanding of the attributes, origin and evolution, geochemical and ecological functions of Archaea is hampered by the scarcity of archaeal isolates, which has represented a challenge to researchers for the last 40 years. Cultivation-independent sequencing and phylogenomic analyses have demonstrated a considerable diversity of Archaea with more than 20 novel phyla. However, only four archaeal phyla have cultured representatives, leaving large gaps in our knowledge of the metabolic capabilities and ecological functions of the majority of archaeal strains identified exclusively by DNA sequencing. In this review, we summarize the discovery and development of archaeal research, highlight the knowledge gap between uncultured and cultured archaeal microbes, and call on the importance of devoting greater research efforts to archaeal cultivation. Finally, we outlined new ideas and strategic approaches, namely,(1)genome-based methods,(2) microbial network information-based methods,(3) genome-scale model-guided methods, and(4)machine learning methods, to enable the cultivation of uncultivated archaeal microbes using accumulated high-throughput sequencing data.  相似文献