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    题名 作者 年代 出处 被引量
1微生物碳酸盐岩的成因、分类以及问题与展望——来自华北地台寒武系微生物碳酸盐岩研究的启示显示文摘微生物碳酸盐岩以其漫长的地史分布、多样的产出环境、复杂的沉积构成和与微生物活动密切相关的特性而成为沉积学研究的焦点,同时也是沉积学研究的难点,被誉为'最难研究的沉积岩之一'。其研究的中心主要是钙化微生物席和微生物膜及其地质记录,即石化/成岩作用的产物。从成因着手,系统总结和梳理了2个类型的微生物群落,较薄的生物膜和较厚的微生物席,经过生物/有机矿化作用和石化/成岩作用形成微生物碳酸盐岩的过程。提出除微生物群落自身的复杂性和沉积过程的复杂性之外,多重状生物膜是导致微生物碳酸盐岩多样性的另外一个重要原因。以中国华北地台寒武系微生物碳酸盐岩的研究为基础,梳理了不同类型的微生物碳酸盐岩的沉积特征和分类依据。认为微生物碳酸盐岩应该置于Embry和Kloven描述的黏结岩类下,根据宏观组构可进一步分为叠层石、凝块石、核形石、层纹石和均一石5类,树形石不易独立成类而应归于凝块石。微生物碳酸盐岩为整个地质历史时期与微生物活动相关的生物/有机矿化作用过程研究提供了有用信息,不但是了解地球表层环境演变的一个重要窗口,而且还形成和储集了较大规模的油气,具有重要的科学意义和经济价值。王龙 Khalid Latif Muhammad Riaz 刘晓晔 2018地球科学进展2018,33,10:18
2辽东半岛复州湾剖面寒武系第二统光合作用生物膜建造的核形石显示文摘作为一种经常大于鲕粒的包覆颗粒类型,核形石以其不平滑的圈层被解释为微生物成因,区别于成因存在较大争议的鲕粒,而且常与鲕粒和其他类型的碳酸盐颗粒相互共生;作为一种在围绕着生物碎屑和非生物碎屑核心的序列式纹层化作用过程中形成的球形或假球型生物沉积构造,核形石还常常单独产出和分布,所以又被解释为微生物碳酸盐岩,或者被归为球状叠层石。在辽东半岛寒武系第二统碱厂组和馒头组之中,厘米级别大小的核形石密集发育在三级层序的顶部,成为一种时间特化的相。另外,以下重要特征将辽东半岛寒武系第二统的核形石特征化,包括:(1)与凝块和微凝块共生;(2)多为球状和椭球状;(3)由不均一的非纹层状致密泥晶和微亮晶构成;(4)核形石皮层以及核形石间凝块中发育特别的蓝细菌鞘钙化化石等。尽管穿越成岩作用过滤器去解释古代核形石复杂的形成机理存在着巨大的挑战,也尽管形成这些核形石的复杂生物膜钙化作用细节需要更加深入地研究才能得到更好地了解,但是,辽东半岛第二统碱厂组和馒头组核形石中直接的微生物化石证据,尤其是核形石内较为丰富的钙化蓝细菌鞘化石,使其成为一个了解光合作用生物膜建造核形石的典型实例。梅冥相 Muhammad Riaz 刘丽 孟庆芬 2019古地理学报2019,21,1:16
3蓝细菌微生物席主导的芙蓉统均一石生物丘:以河北涞源祁家峪剖面为例显示文摘基于中等尺度的构造特征,常常将微生物碳酸盐岩划分为四个类型:纹层状的叠层石、凝块状的凝块石、贫乏构造的均一石、树枝状的树形石;在其中,均一石被定义为相对贫乏构造和非晶质的中等构造,而且作为'隐秘微生物'的同义语曾经与凝块石相混用。华北地台的芙蓉统,包括长山组和凤山组,可以进一步划分为3个淹没不整合面型三级沉积层序;在这些三级层序的强迫型海退体系域中,常常集中产出各种微生物碳酸盐岩所主导的生物丘,河北涞源祁家峪剖面的芙蓉统就是一个较为典型的实例。在该剖面,两套较为典型的均一石生物丘灰岩构成了较为壮观的沉积学现象,其内部特别的非均一组构与贫乏构造的宏观特征形成了强烈的反差,从而将这些均一石生物丘特征化,包括:①钙化蓝细菌化石如基座菌、葛万菌,以及可以类比于第谷菌的丝状蓝细菌鞘化石;②底栖鲕粒;③肾型菌状的钙化生物膜残余物;④海绵木乃伊;⑤底栖鲕粒填充的生物潜穴;⑥包覆着海绵木乃伊和生物潜穴的微叠层石。这些特征,表明了这些均一石生物丘可能形成于蓝细菌细胞外聚合物质(EPS)复杂的钙化作用,而且这样的EPS是蓝细菌微生物席及其内部的多重状生物膜的基本有机基质构成。由于均一石缺乏现代可以类比的典型实例,而且在其命名之后也很少描述在在古老的地层记录中,所以,河北涞源祁家峪剖面芙蓉统中的均一石生物丘为了解均一石形成的复杂机理提供了一个最为典型的实例。梅冥相 MUHAMMAD Riaz 刘丽 孟庆芬 2019地质论评2019,65,5:14
4鲕粒滩相灰岩特别的核形石灰岩帽——以山西繁峙茶坊子剖面寒武系张夏组为例显示文摘作为一种较为特别的微生物碳酸盐岩类型,核形石以双重属性而著称:①以不平滑的皮层和较大的大小而常常被解释为微生物成因,从而区别于而成因存在着较大争议的鲕粒,所以,核形石也可以作为一种包覆颗粒类型;②作为微生物碳酸盐岩的一种类型而被归为相互不连接的球状叠层石,因为核形石形成在围绕着核心的序列式纹层化作用过程之中,并且表现为球形或椭球型的生物沉积构造。在山西繁峙茶坊子剖面寒武系苗岭统张夏组块状鲕粒滩相灰岩的顶部,密集发育着厘米级别大小的高能泥晶核形石,核形石灰岩的厚度接近1 m,从而组成一个块状鲕粒滩相灰岩之上特征性的核形石灰岩帽。该层厚度较小的(小于1 m)核形石灰岩中的核形石,具有以下特征:①厘米级别的大小(1至3 cm);②球形或椭球形的形态学特征;③核形石皮层主导性的泥晶和少量的微亮晶构成;④核形石皮层中较高密度保存的丝状蓝细菌鞘化石;⑤核形石间特别的凝块基质,以及明显的丝状蓝细菌鞘化石构成的凝块。尽管穿越成岩作用过滤器去解释古代核形石复杂的形成机理将存在着巨大的挑战,也尽管形成这些核形石复杂的生物膜钙化作用机理还没有得到完全而且准确的了解,但是,山西省繁峙县茶坊子剖面张夏组顶部的核形石,壮观的宏观特征,核形石皮层中直接的微生物化石证据,尤其是在核形石内较为丰富的丝状蓝细菌鞘化石,使其成为一个了解光合作用生物膜建造核形石的典型实例,而且成为了解发育在高能鲕粒滩相灰岩之上最为特别的'藻坪'沉积的一个较为典型实例。梅冥相 MUHAMMAD Riaz 孟庆芬 刘丽 2019地质论评2019,65,4:12
5寒武纪芙蓉统均一石沉积组构及环境特征——以河北涞源长山组为例显示文摘均一石以隐晶质岩性、无纹层与凝块结构发育为特征,与叠层石、凝块石、树形石并列为典型的微生物岩。然而,由于均一石在1995年命名以来很少在地层记录中得到识别和描述,并且缺乏现代实例的类比物,使得关于均一石的报道极具研究价值。为研究华北地台寒武系均一石沉积组构与形成环境特征,系统性地针对河北涞源祁家峪剖面芙蓉统长山组均一石生物丘进行研究。芙蓉统长山组从下部陆棚相钙质泥岩向上变浅至浅缓坡相厚层块状泥晶灰岩,组成了一个淹没不整合型三级层序。三级层序顶部的浅缓坡相厚层块状泥晶灰岩层,代表强迫型海退过程沉积,其内部发育一系列米级均一石生物丘。研究结果表明,这些生物丘主体为致密泥晶及少量微量晶组成,其中可见到附枝菌(Epiphyton)、葛万菌(Girvanella)、肾形菌(Renalcis)等钙化微生物化石。这些钙化微生物(蓝细菌)化石的出现,代表了显生宙第一幕蓝细菌钙化作用事件的证据,同时间接的说明均一石生物丘形成于蓝细菌主导的微生物席的钙化作用过程之中。同时,生物丘内还局部集中发育底栖鲕粒与草莓状黄铁矿颗粒,表明了生物丘形成过程中复杂的微生物沉积作用机制。因此,河北涞源长山组顶部的均一石生物丘,尽管泥晶和微亮晶是其基本构成,但是各种钙化蓝细菌化石以及底栖鲕粒与草莓状黄铁矿颗粒的局部出现表明了在蓝细菌主导的微生物席中复杂的微生物活动信号,成为了解生物丘形成机制、显生宙第一幕蓝细菌钙化作用事件的典型实例。肖恩照 王皓 覃英伦 Khalid Latif Muhammad Riaz 2020沉积学报2020,38,1:11
6吕梁山东北缘寒武系层序地层划分--以文水苍尔会剖面为例显示文摘为研究山西吕梁山地区寒武纪地层的地层学与沉积学问题,根据山西文水苍尔会剖面寒武系地层叠置关系,将该剖面寒武系地层划分为8个三级层序。基于沉积相的变化规律和地层叠置关系的旋回性研究结果,苍尔会剖面存在两个特殊的地层学与沉积学现象:下部为霍山组砂岩直接覆盖在太古宙变质岩系上,其较为良好的出露与明显的地层接触关系,为探讨山西中部霍山组砂岩的地层归属问题提供依据;在该剖面崮山组、长山组、凤山组中分别发育不同的均一石生物丘,代表华北地台寒武纪晚期—奥陶纪中期'随着后生动物辐射,微生物碳酸盐也在增加'微生物碳酸盐复苏期的基本沉积样式。在新的寒武纪年代地层框架下,对山西文水苍尔会剖面进行层序地层划分,不但为研究华北寒武系生物丘沉积组构多样性提供参考实例,同时也为探讨山西中部地区前寒武—寒武巨大的古地理变迁提供实例。肖恩照 覃英伦 Muhammad Riaz Khalid Latif 姚琳 王皓 2017东北石油大学学报2017,41,5:10
7微生物白云岩形成机制研究进展与存在问题显示文摘近年来,有关微生物白云岩沉淀作用机制的研究拓宽了沉积学中'白云岩问题'研究的视角。硫酸盐还原反应、产甲烷作用、有机分子水解等一系列可促进沉淀白云石的微生物代谢机制的发现,延伸了微生物白云石(岩)形成模式;有关可溶解硫化物催化白云石沉淀的研究,不但强调了硫酸盐还原反应机制,也为重新认识硫酸盐还原反应促进白云石沉淀机理提供了新线索。在现代环境中,微生物席内的原生白云石沉淀的发现,将微生物过程引入地表环境原生白云石沉淀作用和机理的研究,可能为寻找地层记录中的微生物白云石提供了更多有益的工作手段和思考途径。然而更加复杂的白云岩地层记录说明,运用微生物白云石去解释复杂的地质记录还存在着较多的局限性。肖恩照 隋明园 Khalid Latif Muhammad Riaz 2017大庆石油地质与开发2017,36,2:8
8多元醇络合硼对油菜苗期生长及生理特性的影响显示文摘以油菜品种Cao221167为试验材料,采用水培方法,研究山梨醇(S)、山梨醇-硼(SB)、甘露醇(M)、甘露醇-硼(MB)、丙三醇(G)、丙三醇-硼(GB)、硼酸(BA)、缺硼(B0)等不同硼处理对油菜农艺性状、根系活力、色素含量以及各部位硼的吸收分布的影响。结果表明:仅添加有机多元醇处理(S、M和G)的油菜幼苗各项形态和生理特性(株高、地上部干鲜质量、色素含量和根系活力)与缺硼处理无差异,而有机多元醇和硼酸络合后各指标均提高,说明有机多元醇与硼酸形成的有机多元醇络合硼对油菜幼苗生长起促进作用。有机多元醇络合硼处理(SB、MB和GB)和硼酸处理比较表明,有机多元醇络合硼和硼酸均能促进植株生长,但有机多元醇络合硼对油菜幼苗生长以及生理特性的营养作用更显著;其中,甘露醇-硼处理促进油菜幼苗干鲜质量的提高,总干鲜质量较硼酸处理分别增加40.56%和17.29%;不同有机多元醇络合硼处理和硼酸处理的油菜各部位钾、钙、镁等元素含量均高于缺硼处理;丙三醇-硼处理比硼酸处理显著提高油菜叶片色素含量、根系活力以及地上部硼含量。闫磊 姜存仓 董肖昌 吴秀文 Muhammad Riaz 卢晓佩 2017华中农业大学学报2017,36,2:8
9河北涞源祁家峪剖面寒武系层序地层划分显示文摘河北涞源祁家峪剖面寒武系出露连续,层序界面清楚且沉积现象丰富,是进行华北地台寒武系层序划分的较为典型的剖面之一。在新的寒武系年代地层框架下,依据地层的叠置形式、纵向上的沉积相变化及其内部的旋回特征,将该剖面寒武系划分为8个三级层序。结果表明:研究区域从馒头组、毛庄组的'TST+HST'沉积序列转变为'CS+HST'的淹没不整合型层序序列,反映出从混积潮坪沉积序列向缓坡型碳酸盐台地的演化过程,也意味着华北地台寒武系碳酸盐台地从发展阶段向成熟阶段的重大转变;该剖面芙蓉统内部的竹叶状灰岩与长山组顶部、凤山组第1个三级层序顶部发育的均一石生物丘代表了华北地台寒武系末期'贫乏骨骼的风暴海'以及'随着后生动物辐射,微生物碳酸盐岩也在增加'两大特殊沉积现象较为典型的沉积样式。基于层序地层框架内的沉积相叠加方式和地层记录中旋回特征的描述,对河北涞源祁家峪剖面进行层序地层划分,将为探索华北地台在太行山北缘广泛分布的寒武系提供参考实例,也为今后更大区域范围的对比研究提供线索。肖恩照 隋明园 覃英伦 Khalid Latif Muhammad Riaz 王皓 2017大庆石油地质与开发2017,36,6:7
10不同形态硼对油菜幼苗铝毒的缓解效应及其FTIR特征分析显示文摘采用水培法,以油菜品种Cao 221167为试验材料,设置无机态硼酸(BA)和有机态山梨醇硼(SB)及不同Al^(3+)(0、100、200和500μmol L^(–1))处理,研究不同形态硼(B)对油菜幼苗铝(Al)毒的缓解作用及不同形态B之间的缓解效应差异,以及利用FTIR(傅里叶红外光谱)技术分析叶片各物质含量的变化。结果表明,Al毒胁迫下,不同形态B(BA和SB)处理,显著提高植株生物量和根系长度(0、100、200和500μmol L^(–1) Al毒胁迫下BA处理根长分别增加了52.15%、101.45%、366.70%和18.73%;SB处理分别增加了46.80%、133.98%、261.36%和10.77%),提高色素含量和SOD活性,而降低了Al含量、MDA含量和POD活性。不同形态B处理下,油菜幼苗在200μmol L^(–1) Al^(3+)处理下长势、生物量及色素含量最高。在500μmol L^(–1) Al^(3+)处理下,油菜幼苗株高、根长、总干鲜重及色素含量显著低于无Al处理;FTIR分析表明,Al毒胁迫下油菜叶片中蛋白质和低聚糖等含量明显上升,加硼明显降低了蛋白质和低聚糖的含量,且BA处理降低幅度明显高于SB处理。说明不同形态B(BA和SB)的添加均明显缓解Al毒,且BA对Al毒缓解效果优于SB,这为农业生产中施用何种硼肥来缓解Al毒起到一定的指导作用。闫磊 姜存仓 Muhammad Riaz 吴秀文 卢晓佩 杜晨晴 王宇函 2017作物学报2017,43,12:7
11Interaction between diet composition and gut microbiota and its impact on gastrointestinal tract health显示文摘A substantial amount of emerging research is indicating that the gut microbiota has a significant impact on human health.Alterations of gut microbiota have clear consequences on intestinal homeostasis,physiology,gut microbiome,immune system and host metabolic pathways.Diet composition plays an important role in the control of gut microbial populations and,thus,in the prevention,management and treatment of certain diseases such as cancer,diabetes.A comprehensive analysis of previously reported results revealed that the gut microbiota can be modulated by diet and the composition of gut microbiota can be influenced by various diet components.The symbiotic relationship between different gut microbial communities regulates the immune system and,therefore,any dysbiosis can dysregulate the immune system.Further research is needed to fully understand the mechanisms involved in the interactions between diet composition,gut microbiota and associated diseases.Muhammad Shahid Riaz Rajoka Junling Shi Hafiza Mahreen Mehwish Jing Zhu Qi Li Dongyan Shao Qingsheng Huang Hui Yang 2017Food Science and Human Wellness2017,6,3:7
12毛棉苗期抗旱性状的QTL定位显示文摘【目的】通过分析毛棉苗期抗旱相关性状的数量性状位点(Quantitative trait locus,QTL),以期检测稳定的主效QTL,促进栽培品种抗旱性状遗传改良及提高抗旱育种效率。【方法】以四倍体野生种毛棉(Gossypium tomentosum)和陆地棉品种中棉所12(CCRI 12)的种间杂种F2及其F2:3家系为研究材料,用于基因型分型的F2有188个系,用于表型分型的F2:3家系有149个株系。分别在干旱胁迫和正常灌水2个环境下调查表型数据。采用复合区间作图法对F2:3家系苗期相关性状抗旱系数进行QTL定位。【结果】对苗期相关性状抗旱系数的QTL定位分析,共得到16个QTL,其中与株高、叶片数、叶绿素含量、脯氨酸含量、丙二醛含量抗旱系数相关的QTL分别有5个、1个、3个、3个、4个,分布在13条染色体上。来自毛棉的5个加性QTL分别为qSHDC-19-1、qSHDC-19-2、qSLNDC-5-1、qMDADC-24-1、qMDADC-24-2,其加性效应值为0.10~0.22,解释变异9.4%~25.8%。【结论】这些与抗旱相关的QTL有助于棉花抗旱分子标记辅助选择。郑巨云 George Oluoch Khan Muhammad Kashif Riaz 周忠丽 王星星 蔡小彦 李雪源 王春英 王玉红 刘方 王坤波 2017棉花学报2017,29,1:6
13Synthesis of graphene materials by electrochemical exfoliation: Recent progress and future potential显示文摘Synthesis of structurally controlled graphene materials is critical for realizing their practical applications.The electrochemical exfoliation of graphite has emerged as a simple method to produce graphene materials.This review examines research progress in the last 5 years,from 2015 to 2019.Graphene material synthesis methods generally have a trade‐off between increasing production yield and achieving better material property control.The synthesis conditions for synthesizing pristine graphene,graphene oxide(GO),and graphene composites are significantly different.Thus,in this review,we first discuss synthesis methods for graphene materials with high C/O ratios from four aspects:graphite electrodes,equipment engineering,electrolytes,and additional reduction methods.Next,we survey synthesis methods for GO and examine how the pretreatment of the graphite electrodes,electrolytes,and operation parameters,such as applied voltages,electrolyte temperatures,and mechanical forces,affect the quality of GO.Further,we summarize electrochemical exfoliation methods used to dope graphene materials,introduce covalent functional groups,incorporate various nanoparticles,and assembly of graphene architectures.For all synthesis methods,we compare the properties of resulting graphene materials such as C/O ratios,lateral size,layer numbers,and quality characterized by Raman spectroscopy.Lastly,we propose our perspectives on further research.We hope this review stimulates more studies to realize the on‐demand production of graphene materials with desired properties using electrochemical exfoliation methods.Fei Liu Chaojun Wang Xiao Sui Muhammad Adil Riaz Meiying Xu Li Wei Yuan Chen 2019Carbon Energy2019,1,2:6
14Stability analysis of different cotton genotypes under normal and water-deficit conditions显示文摘Cotton plant observes significant reduction in seed cotton yield when subjected to water stress.To find out genotypes having better drought tolerance,seven genotypes of Gossypium hirsutum L.were tested under two moisture levels,i.e.,normal and water deficit stress conditions at five locations of Punjab,Pakistan(Faisalabad,Sahiwal,Vehari,Rahim Yar Khan,and Bahawalpur)in 2013 and 2014.Genotype×environment interaction(GEI)was studied using the genotype main effects and genotype by environment interaction(GGE)biplot and additive main effect and multiplicative interaction analysis.The genotypes G3(7001/11)and G6(FH-942)were stable under normal condition,while under drought condition,the stable genotype was G5(FH-326)when analysed using additive main effects and multiplicative interaction(AMMI)biplot scheme.While GGE biplot analysis on the basis of best performance revealed that under normal condition the genotypes,G1(L-13/10)and G2(FH-2056/10),carrying the common position in biplot.Whereas,under water deficit stress condition,G5 was the best adaptive genotype at all five locations.In the same way,ranking of genotypes showed that the G5 was the ideal genotype under both conditions.So,it is concluded that the genotype G5(FH-326)was found best for water deficit stress condition and can be cultivated under water scarce areas of Punjab.Muhammad Riaz Jehanzeb Farooq Saghir Ahmed Muhammad Amin Waqas Shafqat Chattha Maria Ayoub Riaz Ahmed Kainth 2019Journal of Integrative Agriculture2019,18,6:5
15Metamorphic Temperature Investigation of Coexisting Calcite and Dolomite Marble Examples from Nikani Ghar Marble and Nowshera Formation,Peshawar Basin,Pakistan显示文摘用从从北巴基斯坦的 Nikani Ghar 云石和 Nowshera 形成的云石样品,变态的温度的决心在方解石白云石 solvus 地温计的帮助下被承担。云石的二种类型,也就是说,方解石白云石大理石和忍受石英的方解石白云石大理石被选择。Petrographic 和白云石样品的扫描电子显微镜分析显示了不同谷物尺寸。X 光检查衍射技术显示了方解石 MgCO 3 内容直到 7.93 mol.% 。Nikani Ghar 云石样品从 Nowshera 形成作为与样品相比显示出 MgCO 3 的更低的内容。calcite-dolomite-quartz 云石也显示出相对更低的 MgCO 3 内容和因此相当低的温度(~ 500 使活跃之物转变生长因素贝它 1 独立,而吗?Muhammad Fahad Yaseen Iqbal Mohammad Riaz Rick Ubic Simon A. T. Redfern 2016Journal of Earth Science2016,27,6:3
16Optical spin-symmetry breaking for high-efficiency directional helicity-multiplexed metaholograms显示文摘Helicity-multiplexed metasurfaces based on symmetric spin–orbit interactions (SOIs) have practical limits because they cannot provide central-symmetric holographic imaging. Asymmetric SOIs can effectively address such limitations, with several exciting applications in various fields ranging from asymmetric data inscription in communications to dual side displays in smart mobile devices. Low-loss dielectric materials provide an excellent platform for realizing such exotic phenomena efficiently. In this paper, we demonstrate an asymmetric SOI-dependent transmission-type metasurface in the visible domain using hydrogenated amorphous silicon (a-Si:H) nanoresonators. The proposed design approach is equipped with an additional degree of freedom in designing bi-directional helicity-multiplexed metasurfaces by breaking the conventional limit imposed by the symmetric SOI in half employment of metasurfaces for one circular handedness. Two on-axis, distinct wavefronts are produced with high transmission efficiencies, demonstrating the concept of asymmetric wavefront generation in two antiparallel directions. Additionally, the CMOS compatibility of a-Si:H makes it a cost-effective alternative to gallium nitride (GaN) and titanium dioxide (TiO2) for visible light. The cost-effective fabrication and simplicity of the proposed design technique provide an excellent candidate for high-efficiency, multifunctional, and chip-integrated demonstration of various phenomena.Muhammad Ashar Naveed Muhammad Afnan Ansari Inki Kim Trevon Badloe Joohoon Kim Dong Kyo Oh Kashif Riaz Tauseef Tauqeer Usman Younis Murtaza Saleem Muhammad Sabieh Anwar Muhammad Zubair Muhammad Qasim Mehmood Junsuk Rho 2021Microsystems & Nanoengineering2021,7,2:3
17Isothermal, kinetic, and thermodynamic studies for solid-phase extraction of uranium(VI) via hydrazine-impregnated carbonbased material as efficient adsorbent显示文摘The current study describes the application of a new extraction method for efficient uranium adsorption via cost-effective hydrazine-impregnated activated carbon.Various experimental parameters such as time, adsorbent weight, temperature(°C), and uranium concentration were thoroughly investigated. The synthesized adsorbent was characterized via X-ray diffraction, Fourier transformation infrared spectroscopy(FT-IR), scanning electron microscopy, and thermogravimetric analysis. The results showed86% uranium extraction under optimized conditions(20% P2O5 at 25 °C, 120 min). The obtained findings fit well with thermodynamic and isothermal(Langmuir and Freundlich isotherms) models and pseudo second-order kinetics. In thermodynamic studies, the negative sign of(DG°) specified the spontaneity of process, the negative sign of(DH°) revealed endothermicity, and the positive sign of(DS°) showed high randomness after adsorption.A.Morsy M.H.Taha Muhammad Saeed Amir Waseem Muhammad Asad Riaz M.M.Elmaadawy 2019Nuclear Science and Techniques2019,30,11:3
18Exploring the potential of Sentinel-2A satellite data for aboveground biomass estimation in fragmented Himalayan subtropical pine forest显示文摘The Sentinel-2 A satellite having embedded advantage of red edge spectral bands offers multispectral imageries with improved spatial,spectral and temporal resolutions as compared to the other contemporary satellites providing medium resolution data.Our study was aimed at exploring the potential of Sentinel-2 A imagery to estimate Above Ground Biomass(AGB) of Subtropical Pine Forest in Pakistan administered Kashmir.We developed an AGB predictive model using field inventory and Sentinel 2 A based spectral and textural parameters along with topographic features derived from ALOS Digital Elevation Model(DEM).Field inventory data was collected from 108 randomly distributed plots(0.1 ha each) across the study area.The stepwise linear regression method was employed to investigate the potential relationship between field data and corresponding satellite data.Biomass and carbon mapping of the study area was carried out through established AGB estimation model with R(o.86),R2(0.74),adjusted R2(0.72) and RMSE value of 33 t/ha.Our results showed that first order textures(mean,standard deviation and variance) significantly contributed in AGB predictive modeling while only one spectral band ratio made contribution from spectral domain.Our study leads to the conclusion that Sentinel-2 A optical data is a potential source for AGB estimation in subtropical pine forest of the area of interest with added benefit of its free of cost availability,higher quality data and long-term continuity that can be utilized for biomass carbon distribution mapping in the resource constraint study area for sustainable forest management.Mobushir Riaz KHANI Iftikhar Ahmad KHAN Muhammad Hasan Ali BAIG LIU Zheng-jia Muhammad Irfan ASHRAF 2020Journal of Mountain Science2020,17,12:2
19Regolith thickness modeling using a GIS approach for landslide distribution analysis, NW Himalayas显示文摘Regolith thickness is considered as a contributing factor for the occurrence of landslides.Although, mostly it is ignored because of complex nature and as it requires more time and resources for investigation. This study aimed to appraise the role of regolith thickness on landslide distribution in the Muzaffarabad and surrounding areas, NW Himalayas.For this purpose regolith thickness samples were evenly collected from all the lithological units at representative sites within different slope and elevation classes in the field. Topographic attributes(slope, aspect, drainage, Topographic Wetness Index,elevation and curvature) were derived from the Digital Elevation Model(DEM)(12.5 m resolution).Arc GIS Model Builder was used to develop the regolith thickness model. Stepwise regression technique was used to explore the spatial variation of regolith thickness using topographic attributes and lithological units. The derived model explains about 88% regolith thickness variation. The model was validated and shows good agreement(70%) between observed and predicted values. Subsequently, the derived regolith model was used to understand the relationship between regolith thickness and landslide distribution. The analysis shows that most of the landslides were located within 1-5 m regolith thickness. However, landslide concentration is highest within 5-10 m regolith thickness, which shows that regolith thickness played a significant role for the occurrence of landslide in the studied area.Muhammad BASHARAT Masood QASIM Muhammad SHAFIQUE Nasir HAMEED Muhammad Tayyib RIAZ Muhammad Rustam KHAN 2018Journal of Mountain Science2018,15,11:2
20MHD Maxwell Fluid with Heat Transfer Analysis under Ramp Velocity and Ramp Temperature Subject to Non-Integer Differentiable Operators显示文摘The main focus of this study is to investigate the impact of heat generation/absorption with ramp velocity and ramp temperature on magnetohydrodynamic(MHD)time-dependent Maxwell fluid over an unbounded plate embedded in a permeable medium.Non-dimensional parameters along with Laplace transformation and inversion algorithms are used to find the solution of shear stress,energy,and velocity profile.Recently,new fractional differential operators are used to define ramped temperature and ramped velocity.The obtained analytical solutions are plotted for different values of emerging parameters.Fractional time derivatives are used to analyze the impact of fractional parameters(memory effect)on the dynamics of the fluid.While making a comparison,it is observed that the fractional-order model is best to explain the memory effect as compared to classical models.Our results suggest that the velocity profile decrease by increasing the effective Prandtl number.The existence of an effective Prandtl number may reflect the control of the thickness of momentum and enlargement of thermal conductivity.The incremental value of the M is observed for a decrease in the velocity field,which reflects to control resistive force.Further,it is noted that the Atangana-Baleanu derivative in Caputo sense(ABC)is the best to highlight the dynamics of the fluid.The influence of pertinent parameters is analyzed graphically for velocity and energy profile.Expressions for skin friction and Nusselt number are also derived for fractional differential operators.Thabet Abdeljawad Muhammad Bilal Riaz Syed Tauseef Saeed Nazish Iftikhar 2021Computer Modeling in Engineering & Sciences2021,,2:2
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