检索结果-南通市图书馆

Distinct community assembly processes underlie significant spatiotemporal dynamics of abundant and rare bacterioplankton in the Yangtze River

引用

Frontiers of Environmental Science & Engineering 2022年第6期16卷 145-158页

作者： Malan Yi Yao Fang Guoping Hu shufeng liu Jinren Ni Tang liu College of Environmental Sciences and Engineering Peking UniversityKey Laboratory of Water and Sediment Sciences(Ministry of Education)Beijing 100871China Fluid Science and Resources Division Department of Chemical EngineeringThe University of Western AustraliaCrawleyWA 6009Australia College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems Peking UniversityBeijing 100871China

The rare microbial biosphere provides broad ecological services and resilience to various ***,the biogeographical patterns and assembly processes of rare bacterioplankton communities in large rivers remain *** this study,we investigated the biogeography and community assembly processes of abundant and rare bacterioplankton taxa in the Yangtze River(China)covering a distance of 4300 *** results revealed similar spatiotemporal patterns of abundant taxa(AT)and rare taxa(RT)at both taxonomic and phylogenetic levels,and analysis of similarities revealed that RT was significantly influenced by season and landform than ***,RT correlated with more environmental factors than AT,whereas environmental and spatial factors explained a lower proportion of community shifts in RT than in *** steeper distance–decay slopes in AT indicated higher spatial turnover rates of abundant subcommunities than rare *** null model revealed that both AT and RT were mainly governed by stochastic ***,dispersal limitation primarily governed the AT,whereas the undominated process accounted for a higher fraction of stochastic processes in *** flow and suspended solids mediated the balance between the stochastic and deterministic processes in *** spatiotemporal dynamics and assembly processes of total taxa were more similar as AT than *** study provides new insights into both significant spatiotemporal dynamics and inconsistent assembly processes of AT and RT in large rivers.

关键词： Rare taxa Biogeography Community assembly Bacterioplankton The Yangtze River

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

DEXH-Box protein DHX30 is required for optimal function of the zinc-finger antiviral protein

引用

Protein & Cell 2010年第10期1卷 956-964页

作者： Peiying Ye shufeng liu Yiping Zhu Guifang Chen Guangxia Gao Center for Infection and Immunity Institute of BiophysicsChinese Academy of SciencesBeijing 100101China Graduate School of Chinese Academy of Sciences Beijing 100039China

The zinc-finger antiviral protein(ZAP)is a host factor that specifically inhibits the replication of certain viruses by eliminating viral mRNAs in the *** previous studies,we demonstrated that ZAP directly binds to the viral mRNAs and recruits the RNA exosome to degrade the target *** this article,we provide evidence that a DEXH box RNA helicase,DHX30,is required for optimal antiviral activity of ***-down and co-immunoprecipitation assays demonstrated that DHX30 and ZAP interacted with each other via their N terminal *** of DHX30 with shRNAs reduced ZAP’s antiviral *** data implicate that DHX30 is a cellular factor involved in the antiviral function of ZAP.

关键词： zinc-finger antiviral protein RNA helicase DHX30

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

Investigation of Abnormal Grain Growth in Sintered Nd-Fe-B Permanent Magnet

引用

Journal of Rare Earths 2004年第Z1期22卷 112-114页

作者： liu Guozheng liu shufeng Wu Bin Lu Weidong Zhao Mingjing Lu Fuqiang Zhao Ruijin Baotou Research Institute of Rare Earth Baotou 014010 China Inner Mongolia Xi Yuan Engineering and Technology Research Center of Rare Earth Fuctional Material Baotou 014010 China

The abnormal growth of grains of sintering Nd13.6 Dy0.4 Fe79.5 B6.5 magnets were investigated in low oxygen manufacturing *** abnormal growth of grains occurs easily when the sintering temperature is higher than 1080℃ during the manufacture *** the magnets, the oxygen content is less than 700 × 10-6 and the average particle size of powder is smaller than 4 μ*** squareness of demagnetization curve of magnet is *** high performance magnets, the abnormal growth grain should be avoided by selecting a suitable sintering temperature.

关键词： condensed state physis Nd-Fe-B magnets M-H loop squareness abnormal grains growth microstructure rare earths

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

TAILORING OF PORE SIZE IN MESOPOROUS SILICA WITH STEARIC ACID AND PVP

引用

China Particuology 2005年第6期3卷 379-382页

作者： Haidi liu shufeng Ye Yunfa Chen Multi-phase Reaction Engineering Laboratory Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 P.R. China

Mesoporous silica was prepared using tetrathoxysilane （TEOS）, cetadecyltrimethylammonium bromide （CTAB）, aqueous ammonia, acetone and water as silica source, template agent, precipitator and solvent respectively. Stearic acid and polyvinylpyrrolidone （PVP） were employed as additional templates to tailor the pore size in the resultant porous silica. BET, SAXRD and SEM analyses were used to characterize the surface area, pore size, pore structure, pore regularity and morphology of the sample. BET measurement results showed that PVP could increase the surface area but diminish the pore size while stearic acid could decrease the surface area but enlarge the pore size. SAXRD analysis indicated that more additional template introduction gave rise to less order-structured products. All these various results could be attributed to the differently modified CTAB micelles involving stearic acid and PVP addition.

关键词： mesoporous silica PVP stearic acid pore size tailoring

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

Research on purification and modification of I/S bentonite

引用

Global Geology 2008年第3期11卷 188-190页

作者： Deli YU shufeng liu Liyu TIAN Peiping ZHANG College of Material Science and Engineering Jilin University Changchun 130061 China Beijing General Research Institute for Non-ferrous Metals Beijing 100088 China Testing Center of Jilin University Changchun 130061 China

Analyzing raw material＇s structure and performance of bentonite from Panzhihua in Sichuan, the authors think that it is adequate for agglomerant of iron smelting. According to its composition and property we have researched the purification and modification of I/S bentonite under conditions of different dispersants and sodium agent. XRD test result reveals that the essential minerals of Panzhihua bentonite are I/S mixed-layer ones, and FTIR analysis shows that when adding 1.5% sodium pyrophosphate to the bentonite slurry during purification, the composition of quartz in bentonite decreases to less than 4% and I/S is more than 90%. The optimized modification technic conditions are Na2CO3 （4%） and CMC-Na （3%） as modified agents, the clay and water are 10 vs. 1, and the temperature is 75℃. It is 40 min for stirring time and reacting time is 4 h. Under the conditions we can get the modified I/S bentonite with colloid index more than 500 nd/15 g.

关键词： I/S bentonite purification modification

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

湿热环境对树脂基复合材料性能影响的分析

引用

高分子材料科学与工程 2014年第9期30卷 183-190页

作者：刘淑峰程小全包建文北京航空航天大学航空科学与工程学院北京100191 北京航空材料研究院先进复合材料重点实验室北京100095

从试验和理论两方面对复合材料湿热性能的研究工作进行了分析和总结。湿热环境对复合材料的影响主要有两方面:一是组分材料的性能随着温度和湿度变化而改变;二是湿热环境会造成材料内部应力状态的变化。根据试验得到不同湿热环境下复合... 详细信息

从试验和理论两方面对复合材料湿热性能的研究工作进行了分析和总结。湿热环境对复合材料的影响主要有两方面:一是组分材料的性能随着温度和湿度变化而改变;二是湿热环境会造成材料内部应力状态的变化。根据试验得到不同湿热环境下复合材料力学性能的变化规律,发现湿热对树脂基体的影响尤为严重,工程应用设计中应根据使用环境合理选择树脂种类。在理论研究方面,大多都基于上述两方面的影响建立湿热分析模型,模型中的假设条件和简化较多,因而具有各种各样的局限性,还需进一步研究并建立多尺度的湿/热/力多物理场数值模型。

关键词：复合材料树脂湿热力学性能

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

Property and performance amelioration of pelagic clay from the East Pacific

引用

Global Geology 2008年第2期11卷 110-114页

作者： Peiping ZHANG shufeng liu Xuefa SHI Huahua LU Juanjuan liu Xiaoguo CHI College of Earth Sciences Jilin University Changchun 130061 China Beijing General Research Institute for Non-ferrous Metals Beijing 100088 China Key Laboratory of Marine Sedimentology and Environmental Geology the First Institute of Oceanography State Oceanic Administration Qingdao 260061 Shandong China

To make use of the pelagic clay as polymer filling,the properties of clay sediments from the ocean investigation zone of China in the East Pacific were studied by the SSA,XRF,ICP/MAS,FTIR,XRD,SEM,DTA/TG and granularity distributing etc.,and experiments were settled to improve the whiteness and activation of the clay based on these *** with land clay,pelagic clay holds many particular features,such as fine particles and incompact accumulation,worse crystallization and more defects,high activity,complex mineral and chemical components,and low whiteness *** the purified pelagic clay with acids and zinc,then baked it at different temperatures,the whiteness of clay can be increased from 23.8% to 73.1%,and the optimized conditions is:consistency of vitriol 25%,ratio of clay to water 4∶1,reaction time 4h,reaction temperature 90℃,dosage of zinc 2.0 g/L,and baking temperature 700℃.And the SSA of whited clay is increased *** the dry milling method to modify the pelagic clay with organic reagents,the optimized technique is KH550,concentration 1.5%,reaction time 20 ***,FTIR and SEM testing indicate that the mechanism of organic activation was mainly surface absorbing and chemical combination secondly.

关键词： pelagic clay property whiteness increasing, performance amelioration

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

年鉴编辑出版评价体系研究

引用

出版发行研究 2023年第6期 45-50页

作者：刘书峰中国传媒大学《中国广播电视年鉴》编辑部国家语言资源监测与研究有声媒体中心

年鉴编辑出版评价体系建设对于提高年鉴质量水平、引导年鉴发展方向、指导读者有效利用、提供馆藏备选目录、促进年鉴事业繁荣具有重要意义。建设新时代年鉴编辑出版评价体系,应注重导向性原则、全面性原则和可操作性原则,保证评价结果... 详细信息

年鉴编辑出版评价体系建设对于提高年鉴质量水平、引导年鉴发展方向、指导读者有效利用、提供馆藏备选目录、促进年鉴事业繁荣具有重要意义。建设新时代年鉴编辑出版评价体系,应注重导向性原则、全面性原则和可操作性原则,保证评价结果的科学、公正。本研究从年鉴编辑出版质量和年鉴编辑出版事业两个方面提出评价体系、设置评价指标。

关键词：评价体系编辑出版年鉴质量年鉴事业

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

Establishment of a Knock-in Rat Model in Acute Intermittent Porphyria

Establishment of a Knock-in Rat Model in Acute Intermittent ...

引用

第十六届中国实验动物科学年会

作者： Long Zheng Qian Xu Chao liu Jie Hou shufeng liu Hebei Key Lab of Laboratory Animal Science Department of Laboratory AnimalsHebei Medical University

Acute intermittent porphyria(AIP) is an inborn heme-related disease that is caused by deficient porphobilinogen deaminase(PBGD) *** autosomal dominant disorder is characterized by life-threatening neurovisceral ***,it is characterized by acute attacks of abdominal pain,motor and sensory neurological deficits,psychiatric symptoms,and circulatory disturbances,which if untreated may become *** are frequently precipitated by drugs,alcohol,and low caloric *** study the pathogenesis of AIP,we generated PBGD-deficient rats using clustered regularly interspaced short palindromic repeats(CRISPR)-CRISPR-associated 9(Cas9)-mediated genome ***-in rats with the missense substitution mutation c.8474849 TGG>GCC(p.W283 A) were generated.W283 A-homozygous rats had approximately 20%-50% of normal PBGD activity and had increased urinary excretion of the heme precursors δ-aminolevulinic acid and porphobilinogen after treatment with ***,histopathological analysis revealed sciatic axon loss and kidney injury in these *** nerve injury in W283 A-homozygous rats resembled that of the previously established T1/T2 mouse model of ***,chronic kidney disease was observed in W283 A rats,which does not occur in T1/T2 *** findings indicate that these rats exhibit many of the typical biochemical and histopathological characteristics of human AIP and provide a new animal model of this disease.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

我国房地产业集中与市场结构优化

引用

现代经济探讨 2009年第6期 22-26页

作者：刘树枫西安建筑科技大学西安财经学院

我国房地产业市场集中度低,导致产业内企业规模不经济,阻碍了房地产市场结构的优化。该文用产业组织理论的研究方法对房地产业的市场结构研究发现,市场规模扩大过快、房地产企业进入数量多、规模障碍系数低是房地产业集中度低的主要原因... 详细信息

我国房地产业市场集中度低,导致产业内企业规模不经济,阻碍了房地产市场结构的优化。该文用产业组织理论的研究方法对房地产业的市场结构研究发现,市场规模扩大过快、房地产企业进入数量多、规模障碍系数低是房地产业集中度低的主要原因;并以房地产行业市场集中度作为房地产市场结构主要衡量指标,采用集中率(CRn指数)和赫希曼—赫佛因得指数(HI指数)两个指标考察中国房地产业市场集中状况,指出我国房地产市场应进行适度集中的结构优化,为房地产业的健康发展提供了理论及实际操作依据。

关键词：房地产业市场集中结构优化

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：