检索结果-南通市图书馆

A novel and promising engineering application of carbon dots:Enhancing the chloride binding performance of cement

Chinese Chemical Letters 2024年第6期35卷 409-416页

作者： Wu-Jian Long Yang Yu Chuang He Guangdong Provincial key lab.ratory of Durability for Marine Civil Engineering Key Lab of Coastal Urban Resilient InfrastructureMOECollege of Civil and Transportation EngineeringShenzhen UniversityShenzhen 518060China

Corrosion of reinforcement induced by chloride invasion is extensively considered as the dominating deterioration mechanism of reinforced concrete(RC)structures,leading to serious safety hazards and tremendous economic ***,it still lacks well dispersive and cost-efficient nanomaterials to improve the anti-chloride-corrosion ability of RC ***,specific carbon dots(CDs)with high dispersity and low cost are deliberately designed,successfully prepared by hydrothermal processing,and then firstly applied to immensely enhance chloride binding performance of cement,thereby contributing to suppressing the corrosion of ***,the tailored CDs are composed of the carbon core with highly crystalline sp^(2)C structures and oxygen-containing groups connecting on the carbon core;The typical equilibrium test confirms that with respect to that of the blank cement paste,the chloride binding capacity of cement paste involving 0.2 wt%(by weight of cement)CDs is increased by 109% after 14-day exposure to 3 mol/L Na Cl solution;according to comprehensive analyses of phase compositions,the chloride binding mechanism of CDs-modified cement is rationally attributed to the fact that the incorporation of CDs advances the formation of calcium silicate hydrate(C-S-H)gels and Friedel's salt(Fs),thus enormously enhancing the physically adsorbed and chemically bound chloride ions of cement *** work not only firstly provides a novel high-dispersity and low-cost nanomaterial toward the durability enhancement of RC structures,but also broadens the application of CDs in the field of engineering,conducing to stimulating their industrialization development.

关键词： Carbon dots Chloride binding Cement Chloride binding mechanism Friedel’s salt

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Depth-dependent expression of obliquely incident wave induced radiation stress

引用

Progress in Natural Science:Materials International 2007年第9期17卷 1067-1073页

作者： Zheng Jinhai(State key lab.ratory of Hydrogy-Water Resources and Hydrautic Engineering,moe key lab.ratory of coastal disaster and defence,Hohai University,Nanjing 210098,China) moe key lab. of coastal disaster and defence Hohai University Nanjing 210098 China

The vertically dependent expressions of obliquely incident waves induced radiation stress are derived by use of the second order Stokes wave theory within three regions of the water column,that is,above the mean water level,below the wave trough level,and between these two *** indicate that the wave-induced radiation stress below the wave trough level is from the water wave particle velocity only,whereas both the water wave particle velocity and the wave pressure contribute to the tensor above the wave trough level;the vertical variations of the wave-induced radiation stress are influenced substantially by the velocity component in the direction of wave propagation;the distributions of the wave-induced radiation stress tensor over depth are non-uniform and the proportion of the tensor below the wave trough level becomes considerable in the shallow water;from water surface to seabed,the reversed variations occur for the predominant tensor components.

关键词： second order Stokes wave radiation stress depth-dependent expression

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Anti-aging performance improvement and enhanced combustion efficiency of boron via the coating of PDA

引用

defence Technology（防务技术） 2024年第3期33卷 399-410页

作者： Shuai Ma Qinghai Shu Mengyang Zhang Hongyu Huang Yansong Shi Xijuan Lv Shuai Zhao School of Materials Science and Engineering Beijing Institute of TechnologyBeijing100081China key lab.of Advanced Optoelectronic Quantum Architecture and Measurement(moe) Beijing Key Lab of Nanophotonics&Ultrafine Optoelectronic SystemsSchool of PhysicsBeijing Institute of TechnologyBeijing100081China Tangshan Research Institute of Beijing Institute of Technology Tangshan063000HebeiChina

Boron is an ambitious fuel in energetic materials since its high heat release values,but its application is prohibited by low combustion efficiency and oxidization during *** polydopamine(PDA)was introduced into boron particles,investigating the impact of PDA content on the energetic behavior of *** results indicated that the PDA coating formed a fishing net structure on the surface of boron *** heat release results showed that the combustion calorific value of B@PDA was higher than that of the raw ***,the actual combustion heat of boron powder in B@10%PDA increased by 38.08%.Meanwhile,the DSC peak temperature decreased by 100.65℃under similar oxidation rate compared to raw ***,the B@PDA@AP and B@AP composites were prepared,and their combustion properties were *** was demonstrated that B@10%PDA@AP exhibited superior performance in terms of peak pressure and burning time,*** peak pressure is 12.43 kPa more than B@AP and burning time is 2.22 times higher than B@***,the coating of PDA effectively inhibits the oxidization of boron during storage and enhances the energetic behavior of boron and corresponding composites.

关键词： Boron particles Polydopamine Anti-aging performance improvement Heat release

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microseismic observations reveal that internal waves intensify seabed methane release

引用

Science China Earth Sciences 2024年第10期67卷 3186-3203页

作者： Zhaoyang TIAN Yonggang JIA Junjiang ZHU Tian CHEN Hui WANG Chunsheng JI Chengyu LIU Longyu LU Manchao HE Shandong Provincial key lab.ratory of Marine Environment and Geological Engineering Ocean University of China Frontiers Science Center for Deep Ocean Multispheres and Earth System Key Lab of Submarine Geosciences and Prospecting TechniquesMOE and College of Marine Geosciences Ocean University of China Guangzhou Marine Geological Survey China Geological Survey Shandong Earthquake Agency State key lab.ratory for Tunnel Engineering China University of Mining and Technology (Beijing)

Internal waves transport material and energy from the upper water column to the deep ocean, disturbing seabed sediments and resulting in phenomena such as seabed erosion and changes in topography. On the northern slope of the South China Sea and in many coastal margins worldwide, the zones with internal wave action closely overlap with areas where natural gas hydrates are present. However, due to significant differences in the spatial and temporal scales, understanding the influence of internal waves on methane releases from deep seabeds is challenging. In this study, in situ observations of seabed microseismicity and internal waves are conducted at water depths of 655 meters and 1450 meters in the Pearl River Canyon of the South China Sea. The microseismicity caused by internal waves and seabed methane releases is identified, and a method to establish the correlation between internal waves and seabed methane releases through the use of microseismic recordings is proposed, aiming to obtain direct observational evidence of internal waves intensifying seabed methane releases. The results show that internal waves and seabed methane releases generate significant microseismic signals, indicating the continuous influence of internal waves on the deep seabed of the northern slope of the South China Sea and revealing active methane release phenomena on the seabed. At both long and short time scales, internal waves increase the frequency of seabed methane releases by 4.2 times and 2.4 times, respectively, while also enhancing the intensity of these releases. These changes are influenced by the alterations in seabed flow velocity, pressure, and temperature that are induced by internal wave activities. This study emphasizes that microseismic signals are effective carriers of information for multiscale geological processes on seabeds and suggests that internal waves exacerbate marine geological hazards and contribute to global climate change by intensifying seabed methane relea

关键词： Internal waves Seabed methane release Microseismic observation Ocean bottom seismometer Northern slope of the South China Sea

来源：

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Seasonal changes in tannin and nitrogen contents of Casuarina equisetifolia branchlets

引用

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第2期10卷 103-111页

作者： Li-hua ZHANG Gong-fu YE Yi-ming LIN Hai-chao ZHOU Qi ZENG moe key lab.for coastal and Wetland Ecosystems School of Life Sciences Xiamen University Xiamen 361005 China Fujian Academy of Forestry Fuzhou 350012 China

Seasonal dynamics of total phenolics (TP), extractable condensed tannins (ECT), protein-bound condensed tannins (PBCT), fiber-bound condensed tannins (FBCT), total condensed tannins (TCT), and protein precipitation capacity (PPC) in young, mature and senescent branchlets of Casuarina equisetifolia were studied at Chishan Forestry Center of Dongshan County, Fujian Province, China. In addition, nitrogen contents of branchlets at the different developmental stages were also determined. The contents of TP and ECT, and PPC in young branchlets were significantly higher than those in mature and senescent branchlets through the season. However, PBCT contents were significantly higher in senescent branchlets than those in young and mature branchlets; FBCT fluctuated with season. Young branchlets had the highest N content, which decreased during branch maturity and senescence. The highest contents of TP and the lowest contents of TCT and N in young and mature branchlets were observed in summer. There was a significant negative correlation between TP and N contents. In contrast, TCT contents were positively correlated to N contents. Nutrient resorption during senescence and high TCT:N ratios in senescent branchlets are the important nutrient conservation strategies for C. equisetifolia.

关键词： Casuarina equisetifolia Condensed tannins Total phenolics Nitrogen Seasonal dynamics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

FUSAR-Ship:building a high-resolution SAR-AIS matchup dataset of Gaofen-3 for ship detection and recognition

引用

Science China(Information Sciences) 2020年第4期63卷 40-58页

作者： Xiyue HOU Wei AO Qian SONG Jian LAI Haipeng WANG Feng XU key lab.for Information Science of Electromagnetic Waves (moe) Fudan University

Gaofen-3(GF-3) is China’s first civil C-band fully polarimetric spaceborne synthetic aperture radar(SAR) primarily missioned for ocean remote sensing and marine monitoring. This paper proposes an automatic sea segmentation, ship detection, and SAR-AIS matchup procedure and an extensible marine target taxonomy of 15 primary ship categories, 98 sub-categories, and many non-ship targets. The FUSARShip high-resolution GF-3SAR dataset is constructed by running the procedure on a total of 126 GF-3 scenes covering a large variety of sea, land, coast, river and island scenarios. It includes more than 5000 ship chips with AIS messages as well as samples of strong scatterer, bridge, coastal land, islands, sea and land clutter. FUSAR-Ship is intended as an open benchmark dataset for ship and marine target detection and recognition. A preliminary 8-type ship classification experiment based on convolutional neural networks demonstrated that an average of 79% test accuracy can be achieved.

关键词： FUSAR-Ship Gaofen-3 SAR-AIS matchup automatic target recognition multi-scale CFAR deep learning

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Estimation of Extreme Marine Hydrodynamic Variables in Western Laizhou Bay

引用

Journal of Ocean University of China 2015年第3期14卷 425-432页

作者： DAI Yanchen QIAO Lulu XU Jishang ZHOU Chunyan DING Dong BI Wei key lab.of Submarine Sciences & Prospecting Techniques MOE Ocean University of China China Petroleum & Chemical Corporation Shengli Oilfield Branch College of Marine Geosciences Ocean University of China State key lab.ratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University Qingdao Meteorological Bureau

Laizhou Bay and its adjacent waters are of great importance to China＇s marine oil and gas development. It is therefore crucial to estimate retttrn-period values of marine environmental variables in this region to ensure the safety and success of maritime engineering and maritime exploration. In this study, we used numerical simulations to estimate extreme wave height, sea current velocity and sea-level height in westem Laizhou Bay. The results show that the sea-level rise starts at the mouth of the bay, increases toward west/southwest, and reaches its maximum in the deepest basin of the bay. The 100-year return-period values of sea level rise can reach 3.4-4.0m in the western bay. The elevation of the western part of the Qingdong Oil Field would remain above the sea sur- face during extreme low sea level, while the rest of the oil field would be 1,6-2.4m below the sea surface. The return-period value of wave height is strongly affected by water depth; in fact, its spatial distribution is similar to the isobath＇s. The 100-year return-period values of effective wave height can be 6m or higher in the central bay and be more than 1 m in the shallow water near shore. The 100-year return-period values of current velocity is about 1.2-1.8 ms-1 in the Qingdong Oil Field. These results provide scientific basis for ensuring construction safety and reducing construction cost,

关键词： Laizhou Bay extreme value current velocity wave surface elevation return period

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Taylor Dispersion of Contaminants by Dual-peak Spectral Random Waves

引用

China Ocean Engineering 2019年第5期33卷 537-543页

作者： HUANG Guo-xing Adrian Wing-Keung LAW GUO Xiao-meng State key lab.ratory of coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China School of Civil and Environmental Engineering and Environmental Process Modelling Centre Nanyang Environment and Water Resources Institute (NEWRI) Nanyang Technological University Singapore 639798 Singapore State key lab.ratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research Institute Nanjing 210029 China

Recent extensive and important studies have provided detailed information and compelling evidence on how the presence of waves influences the vertical diffusivity/dispersivity in the coastal environment, which can affect various water quality considerations such as the distribution of suspended sediments in the water column as well as the potential of eutrophication. Comparatively, how the presence of waves influences the horizontal diffusivity/dispersivity has received only scant attention in the literature. Our previous works investigated the role played by the Taylor mechanism due to the wave-induced drift profile which leads to the longitudinal dispersion of contaminants in the horizontal direction, under regular sinusoidal waves and random waves with single-peak spectra. Natural waves in the coastal environment, however, often possess dual-peak spectra, comprising both higher frequency wind waves and lower frequency swells. In this study, the Taylor dispersion of contaminants under random waves with dual-peak spectra is examined through analytical derivation and numerical calculations. The effects of various dual-peak spectral parameters on the horizontal dispersion, including the proportion of lower frequency energy, peak frequency ratio and spectral shape parameter, are investigated. The results show that the relative energy distribution between the dual peaks has the most significant effect. Compared with single-peak spectra with equivalent energy, the Taylor dispersion with dual-peak spectra is stronger when the lower frequency is close to the peak frequency of the single-peak spectrum, and weaker with the higher frequency instead. Thus, it can be concluded that with a dual-peak wave spectrum, wind-dominated seas with higher frequency lead to stronger dispersion in the horizontal direction than swell-dominated seas with lower frequency.

关键词： Taylor dispersion dual-peak spectrum random waves

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

In situ measurements of benthic oxygen fluxes in Hui-quan Bay of Qingdao by eddy correlation techniques:short term pattern variations in gravel beach

引用

Marine Science Bulletin 2020年第2期22卷 36-52页

作者： CUI Shanggong YU Xinsheng ZHAO Guangtao National Marine Data and Information Service Tianjin 300171China key lab.of Submarine Geosciences and Prospecting Techniques MOECollege of Marine GeosciencesOcean University of ChinaQingdao266100Shandong provinceChina

The oxygen fluxe across the sediment-water interface(SWI)in coastal region is a key measure to fully understand the regulation of biogeochemical cycles in an aquatic ***,studies on fluxes of dissolved oxygen in gravel beach are limited,because of the difficulty in sample collection and instrumentations *** this study,benthic oxygen fluxes across rocky substratum in an intertidal zone of Huiquan Bay was estimated by using noninvasive eddy correlation techniques.A total of 10 burst measurements were *** oxygen flux fluctuated from-5.7888±2.6 to+49.3344±2.6 mmol O2 m-2/d were *** cospectra analysis showed that the oxygen flux at the frequency band between 0.093 and 0.279 Hz(at a period from 3.58 to 10.75 s)contributed 50.19%to the total spectrum on *** results showed that the major contribution band moved to the high frequency region gradually and reached a steady state with increasing tidal *** is demonstrated that wave movement and wave breaking interaction resulted in the change of oxygen flux between gravel beach and shallow waters at the start and the end of a rising tide period,*** eddy correlation techniques offer an efficient means for flux measurement over a gravel or mixed sand and gravel beaches.

关键词： sediment-water interface(SWI) oxygen fluxes eddy correlation gravel beaches in situ measurement

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Prediction of Shale Gas Pressure based on Multi-channel Seismic Inversion in Fuling

引用

Acta Geologica Sinica(English Edition) 2022年第4期96卷 1237-1245页

作者： XING Lei LI Yu LI Qianqian LIU Yaowen WAN Yunqiang YANG Huiliang key lab.ratory of Submarine Geosciences and Prospecting Techniques Ministry of EducationOcean University of ChinaQingdaoShandong 266100China Evaluation and Detection Technology lab.ratory of Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdaoShandong 266237China Sinopec Chongqing Fuling Shale Gas Exploration and Development Co.Ltd. Lidu New District Shale Gas BaseFuling DistrictChongqing 408000China Yantai coastal Zone Geological Survey Center Chinese Geological SurveyYantaiShandong 264011China

The accurate prediction of formation pressure is important in oil/gas exploration and ***,the achievement of this goal remains challenging,due to insufficient logging data and the low predictive data accuracy from seismic *** this work,a case study was carried out in the Baima area of Wulong,in order to develop a workflow for accurately predicting shale gas formation *** multi-channel stack method was first used,as well as the inversion of single-channel seismic data,to construct velocity and density models of the *** with the existing welllogging data,the velocity and density models of the whole well section were *** shale gas formation pressure was then estimated using the Eaton *** results show that the multi-channel seismic stacking method has a higher accuracy than the inversion of the formation velocity obtained by the single-channel seismic *** discrepancies between our predicted formation pressure and the actual formation pressure measurement are within an acceptable range,indicating that our workflow is effective.

关键词： seismic stack shale gas pressure prediction precision multi-channel

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：