检索结果-南通市图书馆

Microstructure Characterization of Bubbles in Gassy Soil Based on the Fractal Theory

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean university of{1. 2024年第1期23卷 129-137页

作者： WU Chen LIN Guoqing LIU Lele LIU tao LI Chengfeng GUO Zhenqi Shandong Provincial Key Laboratory of marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China Key Laboratory of Gas Hydrate Ministry of Natural ResourcesQingdao Institute of Marine GeologyQingdao 266237China College of environmental Science and Engineering Ocean University of ChinaQingdao 266100China Key Laboratory of marine Environment and Ecology Ministry of EducationOcean University of ChinaQingdao 266100China Qingdao National Laboratory for marine Science and Technology Qingdao 266237China

The microscopic characterization of isolated bubbles in gassy soil plays an important role in the macroscopic physical properties of sediments and is a key factor in the study of geological hazards in gas-bearing *** on the box-counting method and the pore fractal features in porous media,a fractal model of bubble microstructure parameters in gassy soil under different gas con-tents and vertical load conditions is established by using an industrial X-ray CT scanning *** results show that the fractal di-mension of bubbles in the sample is correlated with the volume fraction of bubbles,and it is also restricted by the vertical *** three-dimensional fractal dimension of the sample is about 1.larger than the average two-dimensional fractal dimension of all the slices from the same *** uniform porous media fractal model is used to test the equivalent diameter,and the results show that the variation of the measured pore diameter ratio is jointly restricted by the volume fraction and the vertical *** addition,the measured self-similarity interval of the bubble area distribution is tested by the porous media fractal capillary bundle model,and the fitting curve of measured pore area ratio in a small loading range is obtained in this paper.

关键词： gassy soil bubble microstructure parameters fractal dimension vertical load

金霉素和土霉素对生物除磷中微生物EPS的影响

在线全文

学校读者我要写书评

暂无评论

光谱学与光谱分析 2024年第4期44卷 1191-1200页

作者：陶传奇张华黄健奚姗姗何春华罗涛王金花张佳妹马牧野安徽建筑大学环境与能源工程学院安徽合肥230601 环境污染控制与废弃物资源化利用安徽省重点实验室安徽合肥230601 安徽省生态文明研究院安徽合肥230601

金霉素和土霉素在城市污水处理厂中检出率较高,通常以混合物的形式存在于污水中。微生物胞外聚合物(EPS)作为保护层抵御外界有害物质的侵害,在微生物生命活动中发挥着重要作用。目前,关于金霉素和土霉素对生物除磷中微生物EPS的影响较... 详细信息

金霉素和土霉素在城市污水处理厂中检出率较高,通常以混合物的形式存在于污水中。微生物胞外聚合物(EPS)作为保护层抵御外界有害物质的侵害,在微生物生命活动中发挥着重要作用。目前,关于金霉素和土霉素对生物除磷中微生物EPS的影响较少。为探究金霉素和土霉素对生物除磷中微生物EPS的影响,采用直接均分射线法设计3种不同浓度配比(L1.L2和L3)混合物,研究了不同浓度金霉素、土霉素单独作用及其混合物对EPS中蛋白质和多糖的影响。采用三维荧光光谱(3D-EEM)和傅里叶变换红外光谱(FTIR)分析金霉素和土霉素对EPS组分及结构的影响。结果表明:随着浓度增加和反应时间的延长,生物除磷系统性能逐渐恶化,微生物EPS中蛋白质和多糖含量均呈现先上升后下降的趋势,且蛋白质含量均高于多糖。3D-EEM分析表明,随金霉素、土霉素及其混合物浓度增加,EPS中类蛋白质物质荧光强度均先增强后减弱,浓度较高时产生了类腐殖酸物质和类富里酸物质。金霉素与土霉素之间存在拮抗作用,使得混合物荧光物质的荧光强度均弱于单独作用,只有配比L3中未出现类腐殖酸物质和类富里酸物质。FTIR分析表明,金霉素、土霉素及其混合物对EPS中1.53 cm^(-1.酰胺Ⅰ谱带的C O伸缩振动、1.03 cm^(-1.酰胺Ⅱ谱带的C O对称拉伸、1.66 cm^(-1.的P O伸缩振动、1.00 cm^(-1.的糖类C—OH伸缩振动均产生影响。金霉素与土霉素存在拮抗作用引起各官能团存在差异性,1.04 cm^(-1.的P—OH伸缩振动只存在于土霉素、配比L2、配比L3;900 cm^(-1.的P—O伸缩振动只存在于金霉素、土霉素、配比L2、配比L3;770 cm^(-1.的氨基酸COO变角振动只有金霉素中不存在。该研究将为科学评估金霉素和土霉素及其混合污染物对生物除磷中微生物EPS影响机制提供理论依据。

关键词：金霉素土霉素胞外聚合物生物除磷

Fine particle trace elements at a mountain site in southern china:Source identification,transport,and health risks

在线全文

学校读者我要写书评

暂无评论

Journal of environmental Sciences 2024年第7期141卷 166-181页

作者： Jiaoping Xing Runping Ding Feifeng Chen Linyu Peng Wenhua Wang Xiaoyan Song Qing ye Yuanqiu Liu Key Laboratory of State Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed School of ForestryJiangxi Agricultural UniversityNanchang 330045China school of {1. and materials Northeastern University at QinhuangdaoQinhuangdao 066004China College of Geosciences and Engineering North China University of Water Resources&Electric PowerZhengzhou 450046China

Trace elements in atmospheric particulate matter play a significant role in air quality,human health,and biogeochemical *** this study,the trace elements(Ca,Al,K,Fe,Na,Mg,Zn,Pb,Mn,Ti,Cu,Cr,Sr,Ni)in PM2.5samples collected at the summit of *** were analyzed to quantify their abundance,source,transport,and health *** the whole sampling period,the major trace elements was Ca,Al,and *** the trace metals with the lowest concentrations were Sr,Ni,Rb,and *** trace elements were influenced by air mass transport routes,exhibiting an increasing trend of crustal elements in the northwesterly airmass and anthropogenic elements(Zn,Mn,Cu,and Ni)in the easterly air *** dust,coal+biomass burning,vehicle emission,urban nitrate-rich+urban waste incineration emissions,and soil dust+industry emissions were common sources of PM2.5on *** air mass transport routes had various source contribution *** results indicate that trace elements at *** are influenced by regional anthropogenic emissions and monsoon-dominated trace element *** total resulting cancer risk value that these elements posed were below the acceptable risk value of 1.1.^(-6),while the non-carcinogenic risk value(1.72)was higher than the safety level,suggesting that non-carcinogenic effects due to these trace elements inhalation were likely to *** emission and coal+biomass burning were the common dominant sources of non-cancer risks posed by trace elements at ***.

关键词： Trace elements Risk assessment Cluster analysis Source apportionment

基于Pasternak海床模型的椭圆余弦波浪荷载作用下埋置管线动力响应解析解

在线全文

学校读者我要写书评

暂无评论

工程力学 2024年第1期41卷 76-89页

作者：张治国叶铜张成平 PAN Yu-tao 沈安鑫吴钟腾上海理工大学环境与建筑学院上海200093 自然资源部丘陵山地地质灾害防治重点实验室福建省地质灾害重点实验室福州350002 国家海洋局北海预报中心山东省海洋生态环境与防灾减灾重点实验室青岛266061 北京交通大学城市地下工程教育部重点实验室北京100044 Department of Civil and environmental Engineering National University of SingaporeSingapore 119077

通过两阶段分析方法,针对椭圆余弦波作用下埋置管线的动力响应进行了探究。基于椭圆余弦波理论,采用Biot固结方程推导了非线性波浪作用下浅水区埋置管线所受的周期波浪压力;将管线考虑为动力Pasternak海床模型上的Euler-Bernoulli梁,将... 详细信息

通过两阶段分析方法,针对椭圆余弦波作用下埋置管线的动力响应进行了探究。基于椭圆余弦波理论,采用Biot固结方程推导了非线性波浪作用下浅水区埋置管线所受的周期波浪压力;将管线考虑为动力Pasternak海床模型上的Euler-Bernoulli梁,将波浪动荷载施加到管线上获得无限长管线的动力响应偏微分控制方程;利用Fourier变换和Laplace变换并借助卷积定理得到管线挠度、速度、加速度、转角、弯矩和剪力的动力响应解。通过与三维有限元数值算例及既有试验结果对比验证了解析解的正确性与适用性。对椭圆余弦波作用下埋置管线的动力响应特性进行了敏感参数分析,结果表明:波浪高度H显著影响了波面形状与海床内波浪力大小,不同浪高下管线转角、弯矩和剪力的变化更明显,而挠度、速度和加速度响应敏感性则较低。

关键词：非线性波浪埋置管线渗流力管土作用动力Pasternak海床模型

维普期刊数据库博看期刊

Blocking the PD-1.signal transduction by occupying the phosphorylated ITSM recognition site of SHP-2

在线全文

学校读者我要写书评

暂无评论

Science china Life Sciences 2024年

作者： Wenjie Li Wenyi Mei Hewei Jiang Jie Wang Xiaoli Li Lina Quan Yanyan Diao Yanni ma Sisi Fan Zhuwei Xie Mengdie Gong Huan Zhu Dewen Bi Feng Zhang Lei ma Jian Zhang Yufeng Gao Aris Paschalidis Honghuang Lin Fangfang Liu Kangdong Liu Mingliang ye Zhenjiang Zhao Yajun Duan Zhuo Chen Yufang Xu Weilie Xiao Shengce tao Lili Zhu Honglin Li Innovation Center for AI and Drug Discovery East China Normal University Shanghai Key Laboratory of New Drug Design School of PharmacyEast China University of Science&Technology Shanghai Center for Systems Biomedicine Key Laboratory of Systems Biomedicine (Ministry of Education)Shanghai Jiao Tong University Lingang Laboratory Key Laboratory of Medicinal Chemistry for Natural Resource Ministry of EducationYunnan Characteristic Plant Extraction LaboratoryYunnan Provincial Center for Research&Development of Natural ProductsState Key Laboratory for Conservation and Utilization of Bio-Resources in YunnanSchool of Pharmacy and School of Chemical Science and TechnologyYunnan University CAS Key Laboratory of Separation Sciences for Analytical Chemistry National Chromatographic R&A CenterDalian Institute of Chemical PhysicsChinese Academy of Sciences Department of Cardiology The First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of China Department of Infectious Diseases The First Affiliated Hospital of Anhui Medical University Department of Medicine University of Massachusetts Chan Medical School Department of Pathophysiology School of Basic Medical SciencesAcademy of Medical ScienceCollege of MedicineZhengzhou University

Targeting the PD-1.PD-L1.axis with small-molecular inhibitors is a promising approach for immunotherapy. Here, we identify a natural pentacyclic triterpenoid, Pygenic Acid A(PA), as a PD-1.signaling inhibitor. PA exerts anti-tumor activity in hPD-1.knock-in C57BL/6 mice and enhances effector functions of T cells to promote immune responses by disrupting the PD-1.signaling transduction. Furthermore, we identify SHP-2 as the direct molecular target of PA for inhibiting the PD-1.signaling transduction. Subsequently, mechanistic studies suggest that PA binds to a new druggable site in the phosphorylated PD-1.ITSM recognition site of SHP-2, inhibiting the recruitment of SHP-2 by PD-1. Taken together, our findings demonstrate that PA has a potential application in cancer immunotherapy and occupying the phosphorylated ITSM recognition site of SHP-2 may serve as an alternative strategy to develop PD-1.signaling inhibitors. In addition, our success in target recognition provides a paradigm of target identification and confirmation for natural products.

关键词：

Disaster effects of climate change in High Mountain Asia:State of art and scientific challenges Disaster effects of climate change in High Mountain Asia:State of art and scientific challenges

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2024年第3期15卷 367-389页

作者： Hao WANG Bin-Bin WANG Peng CUI Yao-Ming ma Yan WANG Jian-Sheng HAO Yu WANG Ya-Mei LI Li-Jun SUN Jiao WANG Guo-{1. ZHANG Wei-Mo LI Yu LEI Wen-Qing ZHAO Jin-Bo TANG Chao-Yue LI Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China State Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Institute of Geographic Sciences and Natural resources Research Chinese Academy of SciencesBeijing 100101China china‒Pakistan Joint Research Center on Earth Sciences Chinese Academy of SciencesIslamabad 45320Pakistan College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China College of Atmospheric Science Lanzhou UniversityLanzhou 730000China National Observation and Research Station for Qomolongma Special Atmospheric Processes and {1. Changes Dingri 858200China

High Mountain Asia(Hma)shows a remarkable warming tendency and divergent trend of regional precipitation with enhanced meteorological *** rapid thawing of the Hma cryosphere may alter the magnitude and frequency of nature *** reviewed the influence of climate change on various types of nature hazards in Hma region,including their phenomena,mechanisms and *** reveals that:1)the occurrences of extreme rainfall,heavy snowfall,and drifting snow hazards are escalating;accelerated ice and snow melting have advanced the onset and increased the magnitude of snowmelt floods;2)due to elevating trigger factors,such as glacier debuttressing and the rapid shift of thermal and hydrological regime of bedrock/snow/ice interface or subsurface,the mass flow hazards including bedrock landslide,snow avalanche,ice-rock avalanches or glacier detachment,and debris flow will become more severe;3)increased active-layer detachment and retrogressive thaw slumps slope failures,thaw settlement and thermokarst lake will damage many important engineering structures and infrastructure in permafrost region;4)multi-hazards cascading hazard in Hma,such as the glacial lake outburst flood(GLOF)and avalanche-induced mass flow may greatly enlarge the destructive power of the primary hazard by amplifying its volume,mobility,and impact force;and 5)enhanced slope instability and sediment supply in the highland areas could impose remote catastrophic impacts upon lowland regions,and threat hydropower security and future water *** future,ongoing thawing of Hma will profoundly weaken the multiple-phase material of bedrock,ice,water,and soil,and enhance activities of nature *** and cascading hazards of high magnitude will prevail in *** the glacier runoff overpasses the peak water,low flow or droughts in lowland areas downstream of glacierized mountain regions will became more frequent and *** escalating hazards in the Hma region requires tackling s

关键词： High Mountain Asia Climate change Cryosphere degradation Nature hazards Disaster risk

Interactions Between Exogenous Rare Earth Elements and Phosphorus Leaching in Packed Soil Columns

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

Pedosphere 2010年第5期20卷 616-622页

作者： LIANG tao SONG Wen-Chong WANG Ling-Qing P. J. A. KLEIN{1.N CAO Hong-Ying Institute of Geographic Sciences and Natural resources Research Chinese Academy of Sciences Beijing 100101 (China) USDA-ARS Pasture Systems and Watershed Management Research Unit University Park PA 16802-3702 (USA)

Rare earth elements （REEs） increasingly used in agriculture as an amendment for crop growth may help to lessen {1. losses of phosphorus （P） from heavily fertilized soils. The vertical transport characteristics of P and REEs, lanthanum （La）, neodymium （Nd）, samarium （Sin）, and cerium （Ce）, were investigated with addition of exogenous REEs at various doses to packed soil columns （20 cm deep）. Vertical transfers of REEs and P were relatively small, with transport depths less than 6 cm for most REEs and P. Export of applied REEs in leachate accounted for less that 5% of inputs. The addition of Ce, Nd and Sm to soil columns significantly decreased concentrations of extractable soil P up to a depth of 4 cm, with soil P concentrations unaffected at depths 〉 4 cm. In general, REEs had little effect on the vertical leaching of P in packed soil columns.

关键词： extractable soil P manure mobility translocation vertical transport

在线全文

学校读者我要写书评

暂无评论

黑河中游张掖地区沙漠化土地动态变化

山地学报 2005年第2期23卷 153-157页

作者：齐善忠王涛罗芳丁建亮山东师范大学人口、资源与环境学院中国科学院寒区旱区环境与工程研究所山东省淄博市第十七中学山东济南25001. 甘肃兰州73.000 山东淄博255000

在我国的西北干旱区,由于所处的自然地理位置生态环境脆弱,加之人类不合理的经济活动,使得该区土地沙漠化现象严重,生态环境恶化。位于黑河流域中游的张掖地区,是我国西北地区重要的商品粮生产基地。由于近年来人口、经济快速增长的压... 详细信息

在我国的西北干旱区,由于所处的自然地理位置生态环境脆弱,加之人类不合理的经济活动,使得该区土地沙漠化现象严重,生态环境恶化。位于黑河流域中游的张掖地区,是我国西北地区重要的商品粮生产基地。由于近年来人口、经济快速增长的压力和人类对土地资源不合理的开发利用,产生了土地沙漠化等一系列环境问题,而且土地沙漠化总体呈上升扩展的趋势,严重地阻碍了绿洲经济和社会的持续、稳定发展。以1.94年和2 0 0 0年具有相同时相(秋季)的LandsatTM 4、3、2波段(分别赋予红、绿、蓝三种颜色)、分辨率为30m的标准假彩色合成卫星影像的两期TM影像为信息源,利用Erdas8 4遥感图象处理软件、Arcinfo8 1.Arcview3 2等GIS软件,对黑河流域中游张掖地区的沙漠化土地进行了动态监测研究和分析。结果表明:研究区的沙漠化土地类型共有8类,分别为流动沙地(丘)、半固定沙地(丘)、固定沙地(丘)、风蚀残丘、戈壁、闯田、潜在沙漠化土地和非生物治沙工程地;张掖地区各类沙漠化土地发展和逆转同时存在,1.94～2 0 0 0年沙漠化土地面积增加了6 4 2 1.km2 。其中,临泽、山丹、民乐和肃南4县的沙漠化土地面积增加了71. 85km2 ,而张掖市和高台县沙漠化土地面积减少了72 6 8km2 。从总体上来看,全区的各类沙漠化土地变化仍呈上升

关键词：张掖地区沙漠化土地动态变化地理信息系统(GIS)

红壤地区地形位置和利用方式对土壤物理性质的影响

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

水土保持学报 2004年第1期18卷 22-26页

作者：柳云龙胡宏涛浙江大学环境与资源学院

对不同地形部位和不同利用方式下的低丘红壤进行了采样和分析,结果表明地形变化和利用方式对土壤的理化性质和水分特性有明显的影响。对受人为扰动较小的林地和茶园而言,随地形位置的降低,土壤粘粒含量降低,有机质含量、土壤水稳性团聚... 详细信息

对不同地形部位和不同利用方式下的低丘红壤进行了采样和分析,结果表明地形变化和利用方式对土壤的理化性质和水分特性有明显的影响。对受人为扰动较小的林地和茶园而言,随地形位置的降低,土壤粘粒含量降低,有机质含量、土壤水稳性团聚体数量、土壤通气性均明显增加,而对受人为耕作影响较大的旱地和桔园,其养分含量、土壤结构性质变化没有明显规律。红壤的持水和供水性质也受到影响,坡顶的持水量比坡中和坡底要大,同时由于毛管孔隙数量比例小,土壤难以保证连续快速的水分供应是红壤作物易旱的重要原因。

关键词：红壤地区地形位置利用方式土壤物理性质影响因素