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Regularity of sediment transport and sedimentation during oods inthe lower Yellow River, China 预览
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作者 Qingchao Guo Zhao Zheng +1 位作者 Liemin Huang Anjun Deng 《国际泥沙研究:英文版》 SCIE 2020年第1期97-104,共8页
The flood season is the main period of flow,sediment transport,and sedimentation in the lower Yellow River(LYR).Within the flood season,most of the flow,sediment transport,and sedimentation occurs during flood events.... The flood season is the main period of flow,sediment transport,and sedimentation in the lower Yellow River(LYR).Within the flood season,most of the flow,sediment transport,and sedimentation occurs during flood events.Because of the importance of floods in forming riverbeds in the LYR,the regularity of sediment transport and sedimentation during floods in the LYR was studied.Measured daily discharge and sediment transport rate data for the LYR from 1960 to 2006 were used.A total of 299 floods were selected;these floods had a complete evolution of the flood process from the Xiaolangdi to the Lijin hydrological stations.For five hydrological stations(Xiaolangdi,Huayuankou,Gaocun,Aishan,and Lijin),a correlation was first established for floods of different magnitudes between the average sediment transport rate at a given station and the average sediment concentration at the closest upstream station.The results showed that the sediment transport rate at the downstream station was strongly correlated with the inflow(upstream station)sediment concentration during a flood event.A relation then was established between sedimentation in the LYR and the average sediment concentration at the Xiaolangdi station during a flood event.From this relation,the critical sediment concentrations were obtained for absolute erosion,sedimentation equilibrium,and absolute deposition during floods of different magnitudes in the LYR.The results of the current study contribute to a better understanding of the mechanisms of sediment transport and the regularity of sedimentation in the LYR during floods,and provide technical support to guide the joint operation of reservoirs and the regulation of the LYR. 展开更多
关键词 Sediment transport Floods SEDIMENTATION Lower Yellow River
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International Journal of Sediment Research(IJSR)-Order Form(2020)(ISSN 1001-6279) 预览
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《国际泥沙研究:英文版》 SCIE 2020年第1期I0002-I0004,共3页
IJSR is the journal of THE WORLD ASSOCIATION FOR SEDIMENTATION AND EROSION RESEARCH(WASER)and is edited by the International Research and Training Center on Erosion and Sedimentation(IRTCES).
关键词 SEDIMENTATION JOURNAL SEDIMENT
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Drainage Management Problems Evaluation: Case Study Baloza and EL-Farama Drains, North Sinai, Egypt 预览
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作者 Mohamed Gabr 《水资源与保护(英文)》 2019年第6期675-689,共15页
Drainage management activities aim at maintaining the performance of drainage networks by assessing the major drainage management problems regarding sedimentation, bank erosion, vegetation, water quality, and biodiver... Drainage management activities aim at maintaining the performance of drainage networks by assessing the major drainage management problems regarding sedimentation, bank erosion, vegetation, water quality, and biodiversity, to find appropriate solutions for channel improvement in order to increase agricultural productivity and maintain agricultural land and the surrounding environment. In this research, we evaluate the drainage management problems to the surface drains Baloza and EL-Farama in the cultivated Tina Plain region (21,000 hectares) North Sinai, Egypt to provide an accurate data to help decision-makers to know the status of maintenance of the watercourses and the need for improvement. For this, Intensive field investigations were carried out regarding a hydrographic survey of the actual drains cross-section using total station and aqua sounder devices, visual stream bank erosion survey, and vegetation survey. In addition, monthly water samples from the drainage water were treated and analyzed for physical and chemical, bacteriological related indices. The results showed, the studied drains suffer from sedimentation, vegetation infection, and bank erosion in some reaches and need remedy. Estimated sedimentation in EL-Farama Drain was 34369 m3/year and in Baloza Drain 29153 m3/year;bank slope failures upstream and downstream pump stations were recorded;the average weed infection ratio for both drains was 30%. The results of water quality parameters showed acceptable concentrations for BOD, DO, NO3, and total coliform according to Egypt decree, 92/2013 for the protection of the Nile River and its waterways from pollution, except TDS (more than 10,000 mg/L). The drainage water was classified as high saline and it was unacceptable for irrigation. Therefore, the author recommends to remove sedimentation and vegetation every 2 years by mechanical methods, applying gabions lining to prevent bank erosion, and treating drainage water using wetland system and utilizing the treated wastewater in fish farming. 展开更多
关键词 Drainage Management SEDIMENTATION VEGETATION Water Quality Surface DRAINS
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Assessment of Land-Use and Land Cover Change Effect on Melka Wakena Hydropower Dam in Melka Wakena Catchment of Sub-Upper Wabe-Shebelle Watershed, South Eastern Ethiopia 预览
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作者 Hussein Hayicho Mersha Alemu Haji Kedir 《农业科学(英文)》 2019年第6期819-840,共22页
Land degradation and sedimentation has been increasingly a crucial problem in upper Wabe-Shebele catchment, south eastern Ethiopia over the last two decades. Nevertheless, so far no detail research has been conducted ... Land degradation and sedimentation has been increasingly a crucial problem in upper Wabe-Shebele catchment, south eastern Ethiopia over the last two decades. Nevertheless, so far no detail research has been conducted to assess such problem. Therefore, the present study was conducted at Melka Wakena Catchment of Upper Wabe Shebelle Watershed to identify the trends of land use and land cover change and its effects on hydrology and land degradation. To achieve the objectives of the study different data sources such as satellite images, climate and rivers gage data;soil sample data were collected and analyzed using relevant corresponding up to dated software. Based on pre-defined criterion, available satellite images for the years 1986, 2011, and 2015 were analyzed using ERDAS, ENVI and ArcGIS softwares. The study catchment stream flow and soil erosion information were computed using SWAT model. MUSLE was employed to assess the amount of sediment yields and rate of soil loss existed in the study area. The study showed that significant land use and land cover changes were recorded during the past nearly three decades. This change has been directly affecting the hydrology and sedimentation of the catchment. The annual surface runoff varied between 45.65 mm and 332.29 mm. The amount of surface runoff was generally increased from 1990 to 2010, whereas decreased until 2013 before beginning the increasing trend. The result of the sediment yield analysis showed that there was a general increasing trend from 1992 to 2010 and then declined up to 2013 before it started the rising trend. From the simulated results, it was observed that the long-term mean soil loss was 20.22 t/ha. Sustainable integrated watershed management practices should be practically implemented throughout the landscape of the catchment from upper to down streams. Above all, dam buffer area needs to be demarcated and protected from the current settlement: cultivation and over grazing. 展开更多
关键词 LAND Use/Land Cover Soil EROSION SEDIMENTATION Melka Wakena Ethiopia
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Poroelastic Modelling of Gravitational Compaction 预览
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作者 Pieter Broer van der Weg 《物理化学期刊(英文)》 2019年第3期126-169,共44页
A dynamic in-silico model captures the kinetics of 1-d gravity driven instabilities, in gravity or centrifuge, of fluid-infiltrated poroelastic media in a partial differential equation (pde). The pde yields the porosi... A dynamic in-silico model captures the kinetics of 1-d gravity driven instabilities, in gravity or centrifuge, of fluid-infiltrated poroelastic media in a partial differential equation (pde). The pde yields the porosity profile over height and time for the given initial and boundary conditions, during slow compaction in counter-current fluid drainage. Processes captured are amongst others sedimentation, creaming and subsidence. The most important limiting prerequisite is that the incompressible dispersed medium is sufficiently structured and/or concentrated that it compacts during slow drainage, without segregation in sizes or in components. For Unilever, modeling of gravitational instability of products is important to quantify or extrapolate long time behavior during shelf life or use centrifuge data to quickly predict long term shelf performance of products. 展开更多
关键词 POROELASTIC COMPACTION CONSOLIDATION Gravity CENTRIFUGE Sedimentation Creaming SUBSIDENCE Emulsion Dispersion
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Obtaining the Fluorescent Chitosan for Investigations in the Analytical Ultracentrifuge 预览
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作者 Murodkhon R. Kodirkhonov 《生物化学进展(英文)》 2019年第1期23-30,共8页
1) In order to achieve the visibility of the chitosan macromolecule for the UV optical system of the analytical ultracentrifuge on investigation of the molecular characteristics and polymers interactions, the labeling... 1) In order to achieve the visibility of the chitosan macromolecule for the UV optical system of the analytical ultracentrifuge on investigation of the molecular characteristics and polymers interactions, the labeling of chitosan by a new fluorophore of fluorescein-5-isothiocyanat was carried out. 2) Samples of fluorescent chitosan with two different degrees of fluorophore substitution and various degrees of acetylation were obtained. 3) The labeled chitosans with the fluorescein-5-isothiocyanat allowed estimating the sedimentation coefficient and the molecular characteristic in the analytical ultracentrifuge. 4) The sensitivity of the UV-optical system of the analytical ultracentrifuge for the obtained fluorescent samples of chitosan relatively to the fixation of the meniscus and the influence of the wavelength and rotation speed were estimated. 展开更多
关键词 POLYSACCHARIDE CHITOSAN ANALYTICAL Ultracentrifuge Fluorescein-5-Isothiocyanat FLUORESCENT CHITOSAN Labeling Sedimentation Degree of Substitution UV Absorption
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Sedimentation Management of Man-Made Water for Restoring the Quality of the River Resource 预览
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作者 Oleksiy Nazarenko Oleksandr Ryabenko +2 位作者 Valeriy Bakhtin Iryna Nazarenko Iryna Ovchinnykova 《地球科学和环境保护期刊(英文)》 2019年第8期327-337,共11页
Research of water resources restoration of natural Dnieper river and man-made nature was carried out. The studies of water quality at working and peak operating modes of production cooling equipment were carried out. ... Research of water resources restoration of natural Dnieper river and man-made nature was carried out. The studies of water quality at working and peak operating modes of production cooling equipment were carried out. The conditions for the supersaturation of poorly soluble salts of the basin ( = 72.34;= 12.54) and accumulation of sediments of the reservoir are determined. The gravity tools for the restoration of water resources are proposed. A criterion equation for recharge the circulating system at peak mode was obtained. The granulometric potential of waste sediments at environmental feasibility is analyzed. The research involved supercritical temperature modes, taking into account precipitation hyperthermia. In the process of conducting a hydrological study, an evolutionary equation sediment model has been developed. The calculations of the technological flow capacity limits by of 125 W/m2 due to turbidity (750 mg/l) and hardness (up to 12 mg ekv per liter) of water resources are obtained. Mechanical sedimentation of the water stream increasing the energy potential up to 275 W/m2 was determined. The use of chemical agents (ozone) as a combined treatment increasing the flow potential up to 650 W/m2 is achieved. The application of technical way to natural water improving power to 975 W/m2 is received. Erosion of the bottom of the basin reduces the hydrological potential due to the unfinished state of biodegradation of sediments. The hydrological characteristics of the stream at a distance of 3000 m with characteristic technogenic inclusions were obtained. The study was conducted at natural Dnieper river and laboratory conditions with chemical catalyst and mechanical activator. 展开更多
关键词 WATER Basin Precipitation HYPERTHERMIA SEDIMENTATION CIRCULATING System HYDROLOGICAL Characteristics
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二连盆地乌里雅斯太凹陷H区阿尔善油层组储层特征及影响因素 预览
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作者 任江丽 杜玉洪 +7 位作者 郭发军 王红梅 刘林玉 朱玉双 朱月珍 王伟 陈大友 王振川 《地质科技情报》 CAS CSCD 北大核心 2019年第1期160-167,共8页
为了研究二连盆地乌里雅斯太凹陷H区阿尔善油层组储层特征及影响因素,采用储层岩心观察、铸体薄片、扫描电镜、常规压汞等测试资料,对储层岩石学特征、孔隙特征、物性特征、沉积作用和成岩作用进行了分析,结果表明阿尔善油层组为近源、... 为了研究二连盆地乌里雅斯太凹陷H区阿尔善油层组储层特征及影响因素,采用储层岩心观察、铸体薄片、扫描电镜、常规压汞等测试资料,对储层岩石学特征、孔隙特征、物性特征、沉积作用和成岩作用进行了分析,结果表明阿尔善油层组为近源、快速堆积,砂岩类型主要是长石质岩屑砂岩和岩屑质长石砂岩,表现为胶结物含量高、结构成熟度低和成分成熟度低的'一高两低'特点。储层受碎屑粒径、压实程度、碳酸盐含量的影响,主要发育中-细喉道,储集空间以残余粒间孔和粒间溶孔为主,物性分析判断为低孔-低渗储层。研究区最好的储层为扇三角洲前缘水下分流河道砂,其次为远端席状砂和河口坝砂。研究区目的层原始孔渗分布主要受沉积作用控制;成岩作用中胶结作用对储层既有部分破坏作用又有部分改善作用,压实作用主要起破坏作用,溶解作用主要起改善作用。 展开更多
关键词 储层特征 沉积作用 成岩作用 阿尔善油层组 乌里雅斯太凹陷
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2016—2017年调水调沙中断后黄河口演变特征 预览
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作者 陈俊卿 范勇勇 +2 位作者 吴文娟 高洁 李小娟 《人民黄河》 CAS 北大核心 2019年第8期6-9,116共5页
从2002年开始持续进行的黄河调水调沙,在2016年和2017年因黄河水沙总量明显减少而中断,2018年恢复调水调沙。为了解调水调沙中断后河口地形演变特征和沉积物粒度变化特征、给黄河三角洲的开发及生态保护提供科学依据,根据2015—2018年... 从2002年开始持续进行的黄河调水调沙,在2016年和2017年因黄河水沙总量明显减少而中断,2018年恢复调水调沙。为了解调水调沙中断后河口地形演变特征和沉积物粒度变化特征、给黄河三角洲的开发及生态保护提供科学依据,根据2015—2018年黄河口海域实测地形资料以及沉积物粒度资料,结合同期黄河利津水文站来水来沙情况,分析了2016—2017年调水调沙中断后及2018年恢复调水调沙后河口地形和沉积物粒度演变特征及其影响因素,结果表明:2015—2018年黄河口海域经历了冲刷—微淤—显著淤积的过程,这与黄河入海沙量的变化相一致;2017年入海沙量较少,研究区海域底质沉积物受到冲刷筛选,而2018年研究区海域受到大量黄河入海较细粒泥沙的补给,底质沉积物中值粒径和平均粒径变小,粒度表现为相对较细。为更好地监测黄河来水来沙对河口地形演变的影响,应对黄河口海域测验范围、时间、频次等进行优化设计。 展开更多
关键词 调水调沙 中断 河口演变 沉积物 黄河口
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淤地坝淤积对漫顶溃坝洪水影响数值模拟研究 预览
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作者 张兆安 侯精明 +3 位作者 刘占衍 马利平 李占斌 李小纲 《水资源与水工程学报》 CSCD 2019年第4期148-153,158共7页
为分析淤地坝淤积高度对漫顶溃坝洪水的影响,选择理想沟道和某小流域内的淤地坝为研究对象,采用耦合溃口演变过程的水动力数值模型,模拟分析了不同淤积程度下淤地坝溃坝洪水过程。研究表明:溃坝洪水流量随淤积高度的增加而减小,且洪峰... 为分析淤地坝淤积高度对漫顶溃坝洪水的影响,选择理想沟道和某小流域内的淤地坝为研究对象,采用耦合溃口演变过程的水动力数值模型,模拟分析了不同淤积程度下淤地坝溃坝洪水过程。研究表明:溃坝洪水流量随淤积高度的增加而减小,且洪峰流量与淤积高度的关系可用二次多项式拟合,相关系数均在0.99左右,拟合精度较高;淤积高度至坝高20%和40%时,洪峰流量削减率分别达40.50%和68.71%,可见在淤地坝运行初期和中期,淤积对洪峰流量的削减效果显著。研究成果对淤地坝系规划及安全度汛有指导意义。 展开更多
关键词 淤地坝 漫顶溃坝 洪水 淤积 水动力模型
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西昆仑山前印支运动期构造对后期构造和沉积的影响 预览
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作者 程晓敢 吴鸿翔 +3 位作者 李勇 陈汉林 章凤奇 师骏 《新疆石油地质》 CAS CSCD 北大核心 2019年第1期27-33,共7页
印支运动期古构造对塔里木盆地西南缘西昆仑山前后期的构造变形和侏罗纪—白垩纪的沉积都具有十分重要的控制作用。但由于新生代以来的强烈改造,研究区印支运动期构造特征识别较为困难。选择新生代构造活动相对较弱的西昆仑山前中段,野... 印支运动期古构造对塔里木盆地西南缘西昆仑山前后期的构造变形和侏罗纪—白垩纪的沉积都具有十分重要的控制作用。但由于新生代以来的强烈改造,研究区印支运动期构造特征识别较为困难。选择新生代构造活动相对较弱的西昆仑山前中段,野外露头调查、钻井和地震资料等综合研究表明,西昆仑山前发育印支运动期褶皱冲断带,形成一系列逆冲断层和北东翼陡、南西翼缓的背斜,这与晚三叠世塔里木板块与羌塘地体最终完成陆—陆碰撞形成的北—北东向挤压有关。印支运动期发育的古断层在喜马拉雅运动晚期挤压下复活,从而造成两期背斜上下叠置,构造高点重合。因此,印支运动期构造格局极大地限制了喜马拉雅运动晚期的构造变形。印支运动期古构造奠定了中生代的古地形格局,并对侏罗纪—白垩纪沉积起到了重要的控制作用。受深部印支运动期逆冲断层控制的北西—南东向斜列式分布的古隆起,是造成该区白垩系分布和储集层物性差异的重要原因。 展开更多
关键词 塔里木盆地 西昆仑山前 印支运动期 古隆起 构造变形 沉积
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三峡水库不同类型支流河口泥沙淤积成因及趋势 被引量:1
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作者 朱玲玲 许全喜 鄢丽丽 《地理学报》 EI CSSCI CSCD 北大核心 2019年第1期131-145,共15页
为揭示三峡水库库区不同类型支流河口泥沙淤积的内在机理和变化趋势,本文充分利用水文、泥沙、固定断面和河道地形等原型观测资料,从支流水沙输移规律和河口局部水沙分布特征出发,研究了不同类型支流河口段泥沙淤积规律及主要影响因素... 为揭示三峡水库库区不同类型支流河口泥沙淤积的内在机理和变化趋势,本文充分利用水文、泥沙、固定断面和河道地形等原型观测资料,从支流水沙输移规律和河口局部水沙分布特征出发,研究了不同类型支流河口段泥沙淤积规律及主要影响因素的作用机理,探讨其淤积趋势及形成拦门沙的风险。结果表明:三峡水库蓄水后,库区不同类型支流河口普遍淤积,淤积范围及河道形态的变化各有特点;水库蓄水造成水动力条件减弱是河口泥沙淤积的根本原因,淤积幅度和范围主要取决于干支流来沙量和局部河势。在干支流来沙均明显减少的情况下,三峡水库库区支流河口泥沙淤积速度显著下降,形成拦门沙坎的可能性较小。 展开更多
关键词 三峡水库 磨刀溪 香溪河 顶托作用 泥沙淤积
Sediment Provenance and Climate Changes Since the Middle Pleistocene in the Yingqiong Continental Slope of the South China Sea 预览
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作者 XIAO Xiao FENG Xiuli LIU Jie 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第6期1282-1290,共9页
The age,grain size compositions and major elemental compositions for sediments in core YQ1 from the Yingqiong continental slope in the South China Sea was determined in this paper.It is noted that the periodically cyc... The age,grain size compositions and major elemental compositions for sediments in core YQ1 from the Yingqiong continental slope in the South China Sea was determined in this paper.It is noted that the periodically cyclic change of sedimentation rates occurred in the Yingqiong continental slope in the South China Sea.During the interglacial periods,the sedimentation rates were high,while the sedimentation rates exhibited low values during the glacial periods.During Marine Isotope Stage 1(MIS1),the sedimentary rate could reach about 800 cm kyr-1 and during the MIS6 this area is characterized by the lowest sedimentary rate,which is lower than 3 cm kyr-1.According to the R-mode factor analysis of the major element data,three factors F1(Al2O3,Fe2O3,TiO2 and K2O),F2(MgO and MnO)and F3(Na2O and P2O5)were obtained,which shows that vertical change of the major elemental concentrations in the core was mainly controlled by the nearby terrestrial inputs and the early diagenesis,while the effect of volcanic and biogenous inputs was less.The obvious glacial-interglacial cyclic features are presented in the changes of the typical terrestrial element ratios contained in factor F1,which reflects the impact of glacial-interglacial climatic cycle on the evolution of the East Asian monsoon.This indicates that the major element ratios in terrestrial sediments are significant indicators of regional climate changes. 展开更多
关键词 the South China Sea Yingqiong continental slope major element composition sedimentation rate climate change glacial-interglacial cycle
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基于FLOW-3D的尾矿库逐渐溃坝三维数值模拟 预览
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作者 李火坤 梁萱 +2 位作者 刘瀚和 唐笑 王建伟 《南昌大学学报:工科版》 CAS 2019年第2期120-126,共7页
为了分析尾矿库逐渐溃坝时溃口随时间的变化过程以及溃坝后尾砂的淹没范围,基于FLOW 3D软件建立了三维数值模型。模拟了水槽内的逐渐溃坝,将计算得出的溃口形态变化数据以及水位数据与实验数据进行对比,结果基本吻合,验证了数值模拟的... 为了分析尾矿库逐渐溃坝时溃口随时间的变化过程以及溃坝后尾砂的淹没范围,基于FLOW 3D软件建立了三维数值模型。模拟了水槽内的逐渐溃坝,将计算得出的溃口形态变化数据以及水位数据与实验数据进行对比,结果基本吻合,验证了数值模拟的精确性和可靠性。以某尾矿库为例,利用该数值模型模拟逐渐溃坝,结果表明:尾矿坝溃决时先冲刷溃口底部,而后逐渐向两侧侵蚀,坝体侵蚀断面呈U型分布,随着水量减少,泥沙慢慢沉积,最终稳定,泥沙下泄量约为总泥沙量的31.1%,随着距离的推移,泥沙淤积量沿程减少,下游房屋监测点最大水深15.44 m。 展开更多
关键词 尾矿库 逐渐溃坝 溃口变化 泥沙淤积 FLOW-3D
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Prediction of sedimentation in reservoirs by combining catchment based model and stream based model with limited data 预览
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作者 Abebe Tadesse Wenhong Dai 《国际泥沙研究:英文版》 SCIE 2019年第1期27-37,共11页
Estimation of sedimentation in reservoirs helps in the management and design of the reservoir's useful capacity.This research was done on the Awash River basin at the Koka Dam Reservoir in Ethiopia.The method appl... Estimation of sedimentation in reservoirs helps in the management and design of the reservoir's useful capacity.This research was done on the Awash River basin at the Koka Dam Reservoir in Ethiopia.The method applied was the loose integration of the Soil and Water Assessment Tool(SWAT)model and Hydrologic Engineering Center-River Analysis System(HEC-RAS)model for the estimation of the sediment load reaching the reservoir.The SWAT model was used for the estimation of erosion at the catchment level,and the HEC-RAS model was applied to estimate the sediment transport in the river channel.The implemented method allows sedimentation in the floodplains and bed shear stress to be considered in the sediment modeling,which cannot be considered in the SWAT model.In addition,the river cross sectional properties and the hydrodynamic processes in the rivers were considered in the modeling process.The data used in this study are a combination of i)observed data collected by government agencies,ii)data available online in data repositories,and iii)data extracted from remote sensing in the Shuttle Radar Topographic Mission(SRTM)Digital Elevation Model(DEM).The calibration and validation of the SWAT model was done by using Sequential Uncertainty Fitting(SUIF-2)calibration and validation tools.The HEC-RAS model was calibrated by adjusting the roughness factor.The output from the integrated approaches gives better estimates of flow and sediment near the inlet to the reservoir,with coefficients of determination of 0.85 and 0.67,respectively,and Nash Sutcliffe coefficients of model fit efficiency of 0.90 and 0.62,respectively,for daily simulations. 展开更多
关键词 Reservoir SEDIMENTATION Awash River SWAT HEC-RAS Rating curve
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Increased sedimentation of a Pseudomonas–Saccharomyces microbial consortium producing medium chain length polyhydroxyalkanoates
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作者 Chang Liu Lin Qi +2 位作者 Songyuan Yang Yun He Xiaoqiang Jia 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第7期1659-1665,共7页
Concerns about feasibility,separability,settleability,efficiency once hampered studies on polyhydroxyalkanoates(PHAs)production,which mainly focused on single strain microorganism or activated sludge rather than artif... Concerns about feasibility,separability,settleability,efficiency once hampered studies on polyhydroxyalkanoates(PHAs)production,which mainly focused on single strain microorganism or activated sludge rather than artificial microbial consortia.Here,a medium chain length PHAs(mcl-PHAs)producing Pseudomonas-Saccharomyces consortium with xylose as the main substrate was studied.Mcl-PHAs accumulation increased from 12.69 mg·L^-1 to 152.3 mg·L^-1 without any optimization method.The presence of Saccharomyces cerevisiae,though in a relatively low concentration,improved the sedimentation of cell mass of the mixed culture by 60%.Reasons for better sedimentation of the consortium were complex:first,the length of Pseudomonas putida increased two to three times in the consortium;second,the positive surface charge of P.putida was neutralized by S.cerevisiae;third,the adhesion proteins on the surface of S.cerevisiae interacted with the P.putida. 展开更多
关键词 MEDIUM chain length POLYHYDROXYALKANOATES Pseudomonas–Saccharomyces consortium SEDIMENTATION XYLOSE
响应面法优化玄武岩陶瓷纤维分散的工艺参数 预览
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作者 华晓青 萧礼标 薛群虎 《硅酸盐通报》 CAS 北大核心 2019年第6期1953-1959,共7页
利用响应面设计法(RSM),对分散玄武岩陶瓷纤维的工艺参数进行了研究。选择纤维分散剂、分散剂添加量、纤维浓度作为三个影响因素,分别建立了以MATLAB软件进行图像分析得到的均方差和沉降试验得到的分散度作为响应值的二次多项式模型,分... 利用响应面设计法(RSM),对分散玄武岩陶瓷纤维的工艺参数进行了研究。选择纤维分散剂、分散剂添加量、纤维浓度作为三个影响因素,分别建立了以MATLAB软件进行图像分析得到的均方差和沉降试验得到的分散度作为响应值的二次多项式模型,分析了各因素交互作用对纤维分散性的影响。两组试验进行相互验证,实验数据结果一致。研究表明,纤维高分散性的最佳工艺条件为:纤维分散剂选用羧甲基纤维素,分散剂添加量为10wt%,纤维浓度为1.17g/L,得到的均方差为34.1883,分散度为75.14%。 展开更多
关键词 响应面法 陶瓷纤维 分散性 MATLAB 沉降法
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马瑞原油储存过程水滴沉降规律 预览
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作者 韩璐媛 汪岩 +1 位作者 梁法春 李军 《科学技术与工程》 北大核心 2019年第28期411-416,共6页
在原油储存过程中,含水率通常会随时间和空间变化。明确不同含水率下油水的沉降规律,对于原油含水率变化趋势的分析与国内外检测数据分析有重要的意义。采集马瑞原油储罐内不同高度原油样品,利用400倍显微镜拍摄照片,拍摄照片的像素为68... 在原油储存过程中,含水率通常会随时间和空间变化。明确不同含水率下油水的沉降规律,对于原油含水率变化趋势的分析与国内外检测数据分析有重要的意义。采集马瑞原油储罐内不同高度原油样品,利用400倍显微镜拍摄照片,拍摄照片的像素为683×512,得知越靠近储罐底部,水滴粒径小、数量越多且分布均匀,原油中水滴粒径集中在0~3μm,其粒径分布规律符合Rosin-Rammler分布。并基于电容法设计并制作了一个串状环形圆筒电容器,为减少环境的误差,设计了恒温水浴装置展开含水原油的沉降实验。从实验的角度结合现场原油储罐沉降规律可知,含水率越高,沉降速度越快,且该装置不仅可以测量储罐中含水率的瞬时值,监测储罐中含水率变化,还可以反映出水层的高度范围,且不受介质的影响。 展开更多
关键词 含水率 沉降 储罐 电容器
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日本海末次冰期以来沉积作用和环境演化及其控制要素 预览
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作者 石学法 邹建军 +2 位作者 姚政权 豆汝席 Gorbarenko Sergey 《海洋地质与第四纪地质》 CAS CSCD 北大核心 2019年第3期1-11,共11页
基于对日本海南部、中部和西部3个沉积岩芯的综合研究,探讨了末次冰期以来日本海不同区域的沉积作用、环境演化特征及其控制因素。结果发现:在距今8ka以前,日本海南部、中部和西部陆源碎屑物质分别由河流物质、西风携带的风尘物质和海... 基于对日本海南部、中部和西部3个沉积岩芯的综合研究,探讨了末次冰期以来日本海不同区域的沉积作用、环境演化特征及其控制因素。结果发现:在距今8ka以前,日本海南部、中部和西部陆源碎屑物质分别由河流物质、西风携带的风尘物质和海冰输运的物质组成;8ka以来日本海西部沉积物中存在连续分布的火山物质,推测与利曼寒流形成有关,标志着现代日本海表层环流格局的形成。在末次冰期,日本海中部和南部因为水体层化较强,导致底层水通风较弱,而日本海西部则由于盐析作用,通风较强。在冰消期早期,随着海平面上升,东海北部高盐水团再次入侵日本海,改善了日本海深层水体通风条件,但在日本海西部因受到常年海冰覆盖的影响,沉积物氧含量显著减小;在冰消期晚期和早全新世,日本海南部深层水体通风减弱,而在日本海中部和西部通风较好;但8ka以来日本海通风普遍增强。日本海的沉积作用和环境演化受海平面、东亚季风(西风环流)和对马暖流控制,但不同海域对上述3个因子的响应程度存在差异。海平面变化是控制日本海环境变化的首要因子,它直接制约着日本海与周围水体的交换程度;东亚夏季风影响日本海表层水体层化,而东亚冬季风则控制着日本海西部海冰的形成和深层水体垂向对流;8ka以来对马暖流成为控制日本海环境演化的重要因子,它的入侵增强了表层和底层水体交换,提高了日本海深层水体和沉积物溶解氧的更新速率。 展开更多
关键词 沉积作用 环境演化 控制因素 末次冰期 日本海
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三甲港闸下引河水沙过程分析 预览
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作者 张国庆 曹杰 +1 位作者 纪为刚 王元叶 《水运工程》 北大核心 2019年第6期132-135,151共5页
为掌握引河延长后闸前水域的水沙变化,以2015年6月17—19日洪季大潮期间三甲港下游引河内定点水沙测验资料为基础,结合周边岸线变化,系统分析水闸开、关运行时的水沙过程。结果表明:近年来周边整治工程陆续实施,闸下引河外推约1.3km,引... 为掌握引河延长后闸前水域的水沙变化,以2015年6月17—19日洪季大潮期间三甲港下游引河内定点水沙测验资料为基础,结合周边岸线变化,系统分析水闸开、关运行时的水沙过程。结果表明:近年来周边整治工程陆续实施,闸下引河外推约1.3km,引河内受停靠船舶及出水浅滩影响形成双滞流区;闸前引河受潮汐控制,潮流为旋转流;关闸期间引河内水动力较弱,引河上游流速不足0.1ms,泥沙向上游输移;开闸期间瞬时下泄流速、含沙量呈单峰分布,流速衰减较快。 展开更多
关键词 引河 淤积 潮流 泥沙
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