检索结果-南通市图书馆

Isotherm and kinetic studies on the adsorption of humic acid molecular size fractions onto clay minerals

Acta Geochimica 2019年第6期38卷 863-871页

作者： Mohamed E.A.El-Sayed Moustafa M.R.Khalaf James a.rice Department of Chemistry and Biochemistry South Dakota State UniversityBrookingsSD 57007USA Soils Waterand Environmental Research InstituteAgriculture Research CenterEl-GizaEgypt Chemistry Department Faculty of ScienceMinia UniversityEl-Minia 61519Egypt

Humic acid(HA)can adsorb onto mineral surfaces,modifying the physicochemical properties of the ***,understanding the sorption behavior of HA onto mineral surfaces is of particular interest,since the fate and transport of many organic and inorganic contaminants are highly correlated to HA adsorbed onto clay *** to the extreme heterogeneity of HA,the extracted IHSS Leonardite humic acid(LHA)used in this work was fractionated using an ultrafiltration technique(UF)into different molecular size fractions(Fr1,>0.2μm;Fr2,0.2 pm-300,000 daltons;Fr3,300,000-50,000 daltons;Fr4,50,000-10,000 daltons;Fr5,10,000-1000 daltons).Equilibrium and the kinetics of LHA and fraction adsorption onto kaolinite and montmorillonite were *** results demonstrated that the maximum adsorption capacity of LHA,Frl,Fr2,Fr3,Fr4,and Fr5 was 5.99,13.69,10.29,7.02,5.9&and 5.09 on kaolinite while it was 8.29,22.62,13.17,8.91,8.62,and 5.69 on montmorillonite,*** adsorption equilibrium data showed that the adsorption behavior of LHA and its fractions could be described more practically by the Langmuir model than the Freundlich *** rate of humic acid fraction adsorption onto clays increased with decreasing molecular size fraction and increasing carboxylic group ***-first-and second-order models were used to assess the kinetic data and the rate *** results explained that LHA and its fractions adsorption on clay minerals conformed more to pseudosecondo rder.

关键词： Kaolinite Montmorillonite Leonardite humic acid Humic acid fractions Kinetics Equilibrium

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

Characterization of the archaeal community fouling a membrane bioreactor

引用

Journal of Environmental Sciences 2015年第3期27卷 115-123页

作者： Jinxue Luo Jinsong Zhang Xiaohui Tan Diane McDougald Guoqiang Zhuang Anthony G.Fane Staffan Kjelleberg Yehuda Cohen Scott a.rice Key Laboratory of Environmental Biotechnology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences School of Biological Sciences Nanyang Technological University Advanced Environmental Biotechnology Centre Nanyang Environment and Water Research Institute Nanyang Technological University Singapore Membrane Technology Centre Nanyang Environment and Water Research Institute Nanyang Technological University Centre for Marine Bio-Innovation School of Biotechnology and Biomolecular Sciences The University of New South Wales Singapore Centre on Environmental Life Sciences Engineering Nanyang Technological University

Biofilm formation, one of the primary causes of biofouling, results in reduced membrane flux or increased transmembrane pressure and thus represents a major impediment to the wider implementation of membrane bioreactor （MBR） technologies for water purification. Most studies have focused on the role of bacteria in membrane fouling as they are the most dominant and best studied organisms present in the MBR. In contrast, there is limited information on the role of the archaeal community in biofilm formation in MBRs. This study investigated the composition of the archaeal community during the process of biofouling in an MBR. The archaeal community was observed to have lower richness and diversity in the biofilm than the sludge during the establishment ofbiofilms at low transmembrane pressure （TMP）. Clustering of the communities based on the Bray-Curtis similarity matrix indicated that a subset of the sludge archaeal community formed the initial biofilms. The archaeal community in the biofilm was mainly composed of Thermoprotei, Thermoplasmata, Thermococci, Methanopyri, Methanomicrobia and Halobacteria. Among them, the Thermoprotei and Thermoplasmata were present at higher relative proportions in the biofilms than they were in the sludge. Additionally, the Thermoprotei, Thermoplasmata and Thermococci were the dominant organisms detected in the initial biofilms at low TMP, while as the TMP increased, the Methanopyri, Methanomicrobia, Aciduliprofundum and Halobacteria were present at higher abundances in the biofilms at high TMP.

关键词： Biofouling Biofilm formation Biofilm microbial community Archaeal community Membrane bioreactor

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

可可种植与生物多样性的保护

引用

AMBIO－人类环境杂志 2000年第3期29卷 167-173,179页

作者： Robert a.rice Russel Greenberg 孙颖 Smithsonian候鸟研究中心

可可(Theobroma cacao)是一种生长于热带湿润低地地区的作物,主要由小规模的种植者种植,通常生长在有遮荫树木树冠的农场上。在有不同的遮荫树木树冠被利用的情况下,可可农场比其它大多数其他热带作物更能支持高水平的生物多样性。种植... 详细信息

可可(Theobroma cacao)是一种生长于热带湿润低地地区的作物,主要由小规模的种植者种植,通常生长在有遮荫树木树冠的农场上。在有不同的遮荫树木树冠被利用的情况下,可可农场比其它大多数其他热带作物更能支持高水平的生物多样性。种植者们面临着很多问题:大量的细菌、真菌疾病、土壤肥力的丧失以及众多的社会经济问题。这些问题经常使地区性的可可生产无法维持可持续的发展。对新土地的不断开垦威胁着生物多样性,而且,新扩展的可可种植范围又在不断消失。这些问题可以通过提高现有可可农场的长期生产力和恢复废弃的耕地来解决。按照这一途径,改善对遮荫树木的管理可以给人们提供指导。与可可有关的研究机构应该与相关的组织建立协作关系,如,发展方面的组织、环境保护方面的组织,但最重要的是可可种植者自己。通过上述途径,开展一个研究、扩展和政策倡导计划,以致力于有多种遮荫树木树冠的田地上实现生态与经济上可持续的可可生产。

关键词：可可种植生物多样性保护树荫系统生产周期

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

地幔中的热逸散与新构造

地震地质译丛

引用

地震地质译丛 1981年第5期 13-19页

作者： a.rice R.W.Fairbridge 刘鼎文

对欧洲、北美两地和其它地区的复测水准分析,揭示了地台区的现代构造活动大约为1—10毫米/年(Mescherikov,1968)。在造山带甚至会遇到更大的数值。一些明显的归纳显然可用下列可资利用的证据来证实:(1)老构造穹丘再次趋向于上升,而盆地... 详细信息

对欧洲、北美两地和其它地区的复测水准分析,揭示了地台区的现代构造活动大约为1—10毫米/年(Mescherikov,1968)。在造山带甚至会遇到更大的数值。一些明显的归纳显然可用下列可资利用的证据来证实:(1)老构造穹丘再次趋向于上升,而盆地下沉。(2)当今运动的速率(在本世纪内)差不多比近50百万年期间的平均速率大3个数量级。

关键词：海底扩张洋底扩张上涌带旋回构造作用海侵海进新构造地质构造大洋地壳海洋地壳地壳运动地壳构造运动海退岩石圈构造圈火山活动扩张带

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

腐植酸在溶液中的聚集行为:不同组分的贡献

引用

腐植酸 2014年第1期 30-36页

作者： Gabriela Chilom Angela S.Bruns James a.rice 张志国南达科塔州立大学化学与生物化学院布鲁金斯999039 华东理工大学化学与分子工程学院上海200237

用表面张力法研究了脂类物质对几种来源不同的腐植酸在水溶液中的聚集行为。通过碱水和有机溶剂萃取相结合的方式,在每种腐植酸中分离出两种类腐植酸组分(HA1和HA2)和一种类脂类组分。HA1代表原始腐植酸中总有机碳近2/3的组分,此类物质... 详细信息

用表面张力法研究了脂类物质对几种来源不同的腐植酸在水溶液中的聚集行为。通过碱水和有机溶剂萃取相结合的方式,在每种腐植酸中分离出两种类腐植酸组分(HA1和HA2)和一种类脂类组分。HA1代表原始腐植酸中总有机碳近2/3的组分,此类物质在碱性溶液中表现出弱表面活性,仅仅能稍微降低水的表面张力。HA2代表腐植酸中几乎1/3的组分,该组分能够显著降低水的表面张力。HA2也与脂类组分紧密相关。与原始腐植酸不同的是,HA2在研究范围内都没有表现出类胶束聚集行为。HA1的聚集行为成为一种意外特性被讨论。由于腐植酸组分与起辅助作用的脂类物质之间发生相互作用引起HA2。

关键词：腐植酸聚集行为脂类组分表面活性

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

Reactive optical matter: light-induced motility in electrodynamically asymmetric nanoscale scatterers

引用

Light(Science & Applications) 2018年第1期7卷 26-32页

作者： Yuval Yifat Delphine Coursault Curtis W.Peterson John Parker Ying Bao Stephen K.Gray Stuart a.rice Norbert F.Scherer James Franck Institute The University of Chicago929 E.57th StreetChicagoIL 60637USA Department of Chemistry The University of Chicago929 East 57th StreetChicagoIL 60637USA Department of Physics The University of Chicago929 East 57th StreetChicagoIL 60637USA Center for Nanoscale Materials Argonne National Laboratory9700 South Cass AvenueArgonneIL 60439USA UniversitéBordeaux CNRS LOMAUMR 5798F-33400 TalenceFrance Department of Chemistry Western Washington University516 High StreetBellinghamWA 98225USA

From Newton’s third law,which is known as the principle of actio et reactio1,we expect the forces between interacting particles to be equal and opposite for closed ***,“nonreciprocal”forces can arise.2 This has been shown theoretically in the interaction between dissimilar optically trapped particles that are mediated by an external field.3 As a result,despite the incident external field not having a transverse component of momentum,the particle pair experiences a force in a direction that is transverse to the light propagation direction.3,4 In this letter,we directly measure the net nonreciprocal forces in electrodynamically interacting asymmetric nanoparticle dimers and nanoparticle structures that are illuminated by plane waves and confined to pseudo one-dimensional *** show via electrodynamic theory and simulations that interparticle interactions cause asymmetric scattering from ***,the putative nonreciprocal forces are actually a consequence of momentum *** study demonstrates that asymmetric scatterers exhibit directed motion due to the breakdown of mirror symmetry in their electrodynamic interactions with external fields.

关键词： asymmetric forces reciprocal

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

自组装和化学成分对腐植酸矿化影响的比较

引用

腐植酸 2015年第5期 29-40页

作者： Moustafa M.R.Khalaf Gabriela Chilom James a.rice 张水勤袁亮美国南达科塔州立大学化学与生物化学系布鲁金斯sd57007 埃及米尼亚大学理学院化学系米尼亚61519 中国农业科学院农业资源与农业区划研究所北京100081

为了定量评估有机质自组装对其抗微生物矿化作用的影响,从风化褐煤、2种泥炭和1种矿质土壤中分离出的腐植酸用作有机质样品,因为其在来源和有机成分性质方面具有广泛的可变性。以苯-甲醇为提取剂,将原始的腐植酸样品分解成为腐植酸组分... 详细信息

为了定量评估有机质自组装对其抗微生物矿化作用的影响,从风化褐煤、2种泥炭和1种矿质土壤中分离出的腐植酸用作有机质样品,因为其在来源和有机成分性质方面具有广泛的可变性。以苯-甲醇为提取剂,将原始的腐植酸样品分解成为腐植酸组分和腐植酸-脂质复合物,用碱溶液从腐植酸-脂质复合物中进一步提取出两性腐植酸组分和脂质组分。根据以上各组分在腐植酸中的准确比例,混合各自固体组分,制成与自组装样品化学成分一致的物理混合物。添加原始的腐植酸及其相应的混合物作为唯一的碳源,使用矿质土壤中分离出的微生物菌群开展独立的有氧培养试验。矿化培养125天后,自组装样品矿化量比相应的物理混合物高70%。13C固态核磁共振光谱所得的碳类型分布和疏水性指数结果表明,自组装样品的矿化程度与其化学成分不相关。物理混合物和组分的矿化程度因化学成分而不同,且存在着烷基碳优先矿化的现象。以上研究结果表明,腐植酸的微生物矿化与其自组装程度有关。

关键词：土壤有机质腐植酸自组装矿化热容量核磁共振量热法

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

Speed and surface steepness affect internal tibial loading during running

引用

Journal of Sport and Health Science 2024年第1期13卷 118-124页

作者： Hannah rice Markus Kurz Patrick Mai Leon Robertz Kevin Bill Timothy R.Derrick Steffen Willwacher Department of Physical Performance Norwegian School of Sport SciencesOslo 0806Norway Sports Tech Research Centre Mid Sweden UniversityÖstersund SE-83125Sweden Department of Mechanical and Process Engineering Offenburg University of Applied SciencesOffenburg 77652Germany Institute of Biomechanics and Orthopaedics German Sport University CologneCologne 50933Germany Department of Kinesiology Iowa State UniversityAmesIA 50011USA

Background:Internal tibial loading is influenced by modifiable factors with implications for the risk of stress *** encounter varied surface steepness(gradients)when running outdoors and may adapt their speed according to the *** study aimed to quantify tibial bending moments and stress at the anterior and posterior peripheries when running at different speeds on surfaces of different ***:Twenty recreational runners ran on a treadmill at 3 different speeds(2.5 m/s,3.0 m/s,and 3.5 m/s)and gradients(level:0%;uphill:+5%,+10%,and+15%;downhill:-5%,-10%,and-15%).Force and marker data were collected synchronously *** moments were estimated at the distal third centroid of the tibia about the medial-lateral axis by ensuring static equilibrium at each 1%of *** was derived from bending moments at the anterior and posterior peripheries by modeling the tibia as a hollow ***-way repeated-measures analysis of variance were conducted using both functional and discrete statistical ***:There were significant main effects for running speed and gradient on peak bending moments and peak anterior and posterior *** running speeds resulted in greater tibial *** uphill at+10%and+15%resulted in greater tibial loading than level *** downhill at-10%and-15%resulted in reduced tibial loading compared to level *** was no difference between+5%or-5%and level ***:Running at faster speeds and uphill on gradients≥+10%increased internal tibial loading,whereas slower running and downhill running on gradients≥-10%reduced internal *** running speed according to the gradient could be a protective mechanism,providing runners with a strategy to minimize the risk of tibial stress injuries.

关键词： Bending moments Gradient Musculoskeletal modeling Overuse injury Tibial stress Training factors

来源：

维普期刊数据库

同方期刊数据库评论