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厌氧氨氧化技术工程化的全球现状及展望 被引量:66
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作者 郝晓地 仇付国 +1 位作者 W.R.L.van der star M.C.M.van Loosdrecht 《中国给水排水》 CAS CSCD 北大核心 2007年第18期15-19,共5页
厌氧氨氧化(ANAMMOX)技术因其细菌增长速率缓慢而难以实现工程化。在总结荷兰ANAMMOX技术工程化经验的基础上,介绍了ANAMMOX工程化的进程及其主要障碍,综述了以荷兰为代表的欧洲等国家研发、工程应用ANAMMOX技术的现状。同时,对ANAMMOX... 厌氧氨氧化(ANAMMOX)技术因其细菌增长速率缓慢而难以实现工程化。在总结荷兰ANAMMOX技术工程化经验的基础上,介绍了ANAMMOX工程化的进程及其主要障碍,综述了以荷兰为代表的欧洲等国家研发、工程应用ANAMMOX技术的现状。同时,对ANAMMOX技术工程化的应用前景进行了展望。 展开更多
关键词 厌氧氨氧化 "短程"脱氮 世代时间 颗粒污泥 亚硝化 一步ANAMMOX(CANON) 两步ANAMMOX
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深度学习模型中间层特征压缩技术综述 被引量:3
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作者 汪维 徐龙 陈卓 《计算机应用研究》 CSCD 北大核心 2023年第5期1281-1291,共11页
深度学习模型中间层特征压缩作为深度学习领域中一个新兴的研究热点被广泛关注并应用于边端—云端智能协同任务中。针对深度学习模型中间层特征压缩的研究现状,对当前压缩方式中存在的问题进行分析总结。首先,系统地分类阐述了基于图像... 深度学习模型中间层特征压缩作为深度学习领域中一个新兴的研究热点被广泛关注并应用于边端—云端智能协同任务中。针对深度学习模型中间层特征压缩的研究现状,对当前压缩方式中存在的问题进行分析总结。首先,系统地分类阐述了基于图像/视频编解码框架、基于特征通道比特分配和基于深度学习网络结构的三种深度学习模型中间层特征压缩方式;随后,对比了三种深度学习模型中间层特征压缩方式在数据集上的表现;最后,探讨了当前深度学习模型中间层特征压缩研究面临的挑战,展望了中间层特征压缩技术未来的发展趋势。 展开更多
关键词 深度学习 边云端智能协作 特征压缩 编码框架 比特分配
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Methods for a blind analysis of isobar data collected by the STAR collaboration 被引量:7
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作者 J.Adam L.Adamczyk +143 位作者 J.R.Adams J.K.Adkins G.Agakishiev M.M.Aggarwal Z.Ahammed I.Alekseev D.M.Anderson A.Aparin E.C.Aschenauer M.U.Ashraf F.G.Atetalla A.Attri G.S.Averichev V.Bairathi K.Barish A.Behera R.Bellwied A.Bhasin J.Bielcik J.Bielcikova L.C.Bland I.G.Bordyuzhin J.D.Brandenburg A.V.Brandin J.Butterworth H.Caines M.Calderon de la Barca Sanchez D.Cebra I.Chakaberia P.Chaloupka B.K.Chan F-H.Chang Z.Chang N.Chankova-Bunzarova A.Chatterjee D.Chen J.Chen J.H.Chen X.Chen Z.Chen J.Cheng M.Cherney M.Chevalier S.Choudhury W.Christie X.Chu H.J.Crawford M.Csanad M.Daugherity T.G.Dedovich I.M.Deppner A.A.Derevschikov L.Didenko X.Dong J.L.Drachenberg J.C.Dunlop T.Edmonds N.Elsey J.Engelage G.Eppley S.Esumi O.Evdokimov A.Ewigleben O.Eyser R.Fatemi S.Fazio P.Federic J.Fedorisin C.J.Feng Y.Feng P.Filip E.Finch Y.Fisyak A.Francisco L.Fulek C.A.Gagliardi T.Galatyuk F.Geurts A.Gibson K.Gopal X.Gou D.Grosnick W.Guryn A.I.Hamad A.Hamed S.Harabasz J.W.Harris S.He W.He X.H.He Y.He S.Heppelmann S.Heppelmann N.Herrmann E.Hoffman L.Holub Y.Hong S.Horvat Y.Hu H.Z.Huang S.L.Huang T.Huang X.Huang T.J.Humanic P.Huo G.Igo D.Isenhower W.W.Jacobs C.Jena A.Jentsch Y.Ji J.Jia K.Jiang S.Jowzaee X.Ju E.G.Judd S.Kabana M.L.Kabir S.Kagamaster D.Kalinkin K.Kang D.Kapukchyan K.Kauder H.W.Ke D.Keane A.Kechechyan M.Kelsey Y.V.Khyzhniak D.P.Kikoła C.Kim B.Kimelman D.Kincses T.A.Kinghorn I.Kisel A.Kiselev M.Kocan L.Kochenda L.K.Kosarzewski L.Kramarik P.Kravtsov K.Krueger N.Kulathunga Mudiyanselage L.Kumar S.Kumar 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2021年第5期43-50,共8页
In 2018,the STAR collaboration collected data from^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr at√^(S)NN=200 Ge V to search for the presence of the chiral magnetic effect in collisions of nuclei.The isobar ... In 2018,the STAR collaboration collected data from^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr at√^(S)NN=200 Ge V to search for the presence of the chiral magnetic effect in collisions of nuclei.The isobar collision species alternated frequently between 9644 Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr.In order to conduct blind analyses of studies related to the chiral magnetic effect in these isobar data,STAR developed a three-step blind analysis procedure.Analysts are initially provided a"reference sample"of data,comprised of a mix of events from the two species,the order of which respects time-dependent changes in run conditions.After tuning analysis codes and performing time-dependent quality assurance on the reference sample,analysts are provided a species-blind sample suitable for calculating efficiencies and corrections for individual≈30-min data-taking runs.For this sample,species-specific information is disguised,but individual output files contain data from a single isobar species.Only run-by-run corrections and code alteration subsequent to these corrections are allowed at this stage.Following these modifications,the"frozen"code is passed over the fully un-blind data,completing the blind analysis.As a check of the feasibility of the blind analysis procedure,analysts completed a"mock data challenge,"analyzing data from Au+Au collisions at√^(S)NN=27 Ge V,collected in 2018.The Au+Au data were prepared in the same manner intended for the isobar blind data.The details of the blind analysis procedure and results from the mock data challenge are presented. 展开更多
关键词 Blind analysis Chiral magnetic effect Heavy-ion collisions
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Production performance and plasma metabolite concentrations of broiler chickens fed low crude protein diets differing in Thr and Gly 被引量:6
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作者 Laura star Sophie Tesseraud +3 位作者 Marije van Tol Ilaria Minussi Etienne Corrent William Lambert 《Animal Nutrition》 SCIE CSCD 2021年第2期472-480,共9页
The aim of the study was to test the interaction between Thr and Gly in low crude protein(CP)diets in 7 to 28 d broilers on production performance and plasma metabolites.A total of 2,040 broilers were allocated to 17 ... The aim of the study was to test the interaction between Thr and Gly in low crude protein(CP)diets in 7 to 28 d broilers on production performance and plasma metabolites.A total of 2,040 broilers were allocated to 17 treatments.A positive control(PC)diet(20.5%CP)was formulated to be adequate in dietary Thr and Gly.A negative control(NC)diet(18.5%CP,deficient in Thr and Gly)was supplemented with crystalline L-Thr and Gly to obtain a 4 Thr×4 Gly design.Dietary Thr was tested at an apparent faecal digestibility(AFD)Thr-to-Lys ratio,which was 55%,58%,61%or 64%,and dietary Gly was tested at an AFD(Gly+Ser)-to-Lys ratio,which was 135%,142%,149%or 156%.Plasma samples were collected at 28 d.The low CP diet,formulated at 64%Thr and 156%Gly,resulted in a higher body weight gain(BWG)(P<0.01)and similar feed conversion ratio(FCR)as the high CP treatment(PC).FCR was improved(P<0.001)by L-Thr supplementation.Quadratic response to dietary Thr was significant for feed intake(FI),BWG and FCR(P<0.01).A near-significant interaction for Thr×Gly was observed for FI and BWG(Plinear=0.091 and P=0.074,respectively).Gly did not affect production performance.An interaction between Thr×Gly on plasma free AA level was observed(P<0.05).Free AA concentration in plasma linearly decreased with increase in AFD Thr-to-Lys ratio,and increased with increase in AFD(Gly+Ser)-to-Lys ratio.Plasma uric acid concentration was higher in PC than in all of the other diets,and plasma triglyceride concentration was decreased by L-Thr supplementation,but not by Gly.In conclusion,Gly was not limiting for growth at low dietary CP level unless Thr was deficient,showing that adequate amounts of Thr in broiler diets can overcome marginal supply of Gly and Ser and allow reduction of dietary CP from 20.5%to 18.5%for broilers from 7 to 28 d of age. 展开更多
关键词 BROILER THREONINE Glycine Low protein Performance Plasma metabolite
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二维材料“遇见”生物大分子:机遇与挑战 被引量:6
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作者 杜春保 胡小玲 +1 位作者 张刚 程渊 《物理化学学报》 SCIE CAS CSCD 北大核心 2019年第10期1078-1089,共12页
二维材料的超薄原子层结构使其具有独特的力学性能、导热导电性以及巨大的比表面积,在能源存储、催化、传感和生物医学等领域引起了国内外学者的广泛关注。将二维材料与具有生物活性的生物大分子相结合可以为开发具有优异电学、力学和... 二维材料的超薄原子层结构使其具有独特的力学性能、导热导电性以及巨大的比表面积,在能源存储、催化、传感和生物医学等领域引起了国内外学者的广泛关注。将二维材料与具有生物活性的生物大分子相结合可以为开发具有优异电学、力学和生物学功能的特种功能材料提供新的方法和途径。近年来,科研工作者针对这一方向展开了广泛的研究,取得了一系列重要的成果,使二维材料与生物大分子的结合与应用成为了新的研究热点。本文综述了近年来二维材料和生物大分子之间的相互作用及应用的研究进展,重点介绍了二维材料与生物大分子在分子水平上的相互作用机理,还总结了基于二维材料与生物大分子之间的相互作用在工程、疾病治疗和抗菌中的应用,并对其未来的研究趋势提出了展望。 展开更多
关键词 二维材料 生物大分子 非共价键 共价键 应用
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五四精神,生生不息——前辈我想对您说
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作者 牧阳渊 star luck(图) 《少先队员(成长树)》 2024年第5期11-15,共5页
百年前的星火生生不息,五四精神续至今。在民族危难之际,数万万的青年汇聚力量,点燃了黑暗中的亮光——他们中,有为寻求救国救民的真理而发奋读书学习,有为唤醒民众的爱国之心而奔走呼号,有志愿投身革命事业而甘愿牺牲、无怨无悔……
关键词 读书学习 五四精神 救国救民 危难之际 生生不息 爱国之心 志愿 无怨无悔
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激光增材制造过程中循环热输入对组织和性能的影响 被引量:4
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作者 王迪 黄锦辉 +1 位作者 谭超林 杨永强 《金属学报》 SCIE EI CAS CSCD 北大核心 2022年第10期1221-1235,共15页
激光增材制造(LAM)中逐层沉积形成独特的循环热输入,能对沉积材料产生原位热处理(IHT)效应,具有调整微观结构和提高材料力学性能的潜力。本文针对LAM中循环热输入现象进行了详细阐述,分析了工艺参数、沉积方向、层间延时、基板预热、激... 激光增材制造(LAM)中逐层沉积形成独特的循环热输入,能对沉积材料产生原位热处理(IHT)效应,具有调整微观结构和提高材料力学性能的潜力。本文针对LAM中循环热输入现象进行了详细阐述,分析了工艺参数、沉积方向、层间延时、基板预热、激光重熔等对循环热输入的影响行为。不同的循环热输入能对晶粒取向、相组成、第二相析出等微观组织产生明显的影响,进而影响其力学性能。循环热输入产生的IHT效应,为改善材料性能和研发新材料提供了契机。因此本文提出了理解和建立成分-工艺-IHT效应-组织结构-力学性能之间关系的理论,进而为基于IHT效应的LAM专用新材料的研究和发展提供启示。 展开更多
关键词 激光增材制造 循环热输入 原位热处理 各向异性 新材料研发
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Sofosbuvir, a Significant Paradigm Change in HCV Treatment 被引量:4
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作者 Thomas McQuaid Carolyn Savini star Seyedkazemi 《Journal of Clinical and Translational Hepatology》 SCIE 2015年第1期27-35,共9页
Nucleotide compounds like sofosbuvir,acyclovir,and tenofovir have proven to be amongst the most potent orally available antiviral treatments.These drugs exhibit high efficacy and a wide therapeutic index,with demonstr... Nucleotide compounds like sofosbuvir,acyclovir,and tenofovir have proven to be amongst the most potent orally available antiviral treatments.These drugs exhibit high efficacy and a wide therapeutic index,with demonstrated utility in a number of chronic viral infections.The approval of SovaldiTM,brand name for sofosbuvir,by the U.S.Food and Drug Administration heralded improvements in chronic hepatitis C virus (HCV) treatment.Sofosbuvir was originally discovered by Pharmasset Corporation and named PSI-7977.It was subsequently acquired and advanced through phase 3 development by Gilead Sciences,Inc.In Sofosbuvir both a unique pharmacology and a high specificity for the HCV ribonucleic acid polymerase are present in a molecule that is well tolerated and highly efficacious.Phase 2 and 3 clinical trials have consistently demonstrated durable and high rates of sustained virologic response (SVR),curing patients in excess of 80% in all genotypes and >90% in treatment-na(i)ve subjects being administered combination therapy with other agents.Harvoni~ is the combination of sofosbuvir and the NS5A inhibitor ledipasvir in a fixed-dose oral tablet,and it has demonstrated high SVR rates in patients infected with HCV genotype 1,without the need for exogenous interferon and/or ribavirin.Here,we discuss the discovery,development,pharmacologic characterization,and results from the phase 3 trials of sofosbuvir.Hepatitis C is a chronic disease,for which most patients have been undiagnosed,are unwilling to start treatment,or are ineligible for treatment because of the high toxicity and low efficacy of interferon and ribavirin-based therapy.Clinical studies with sofosbuvir have demonstrated significant improvement over the prior standard of care,thus ushering in a new paradigm of HCV treatment and an update of treatment guidelines. 展开更多
关键词 Ledipasvir Sofosbuvir Direct acting antivirals
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CO_(2)/O_(2)环境对柴油着火及燃烧特性的影响
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作者 万源 刘永峰 +2 位作者 毕贵军 刘海峰 张璐 《内燃机工程》 CAS CSCD 北大核心 2023年第3期44-54,共11页
为研究CO_(2)/O_(2)环境对柴油着火和燃烧特性的影响,以正庚烷为柴油表征燃料,利用CONVERGE计算了不同CO_(2)/O_(2)环境下正庚烷的着火和燃烧过程,并搭建了可视化定容燃烧弹试验平台进行了验证。使用高速摄影机记录了初始温度850 K,初... 为研究CO_(2)/O_(2)环境对柴油着火和燃烧特性的影响,以正庚烷为柴油表征燃料,利用CONVERGE计算了不同CO_(2)/O_(2)环境下正庚烷的着火和燃烧过程,并搭建了可视化定容燃烧弹试验平台进行了验证。使用高速摄影机记录了初始温度850 K,初始压力3 MPa,CO_(2)体积分数分别为35%、40%、50%和60%时正庚烷燃烧的自发光强度,利用CHEMKIN中定容均质反应器分析了CO_(2)物理和化学作用对着火的影响。研究结果表明:在CO_(2)体积分数35%时存在爆燃的现象,随着CO_(2)体积分数增长,着火延迟时间增长,着火位置远离喷嘴,稳态燃烧阶段火焰的长度和宽度也增大,CO_(2)体积分数在50%~60%之间时火焰自发光强度峰值明显下降;CO_(2)的物理作用抑制了着火,第三体作用对着火的促进作用大于直接参与反应对着火的抑制作用,造成CO_(2)的化学作用缩短了着火延迟时间,并且随着CO_(2)体积分数增大,化学作用对着火的促进作用更加明显。 展开更多
关键词 CO_(2)/O_(2)环境 定容燃烧弹 着火过程 火焰自发光强度 第三体作用
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纳米材料热传导中的新奇物理效应 被引量:4
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作者 张刚 段文晖 《物理》 CAS 北大核心 2020年第10期668-678,共11页
纳米尺度热传导是物理科学、材料科学和工程热物理等相关学科的研究热点。除基础研究上的意义外,这个方向的研究在微纳米器件温度控制、新能源、热防护等重大工程技术领域也有着重要的应用价值。文章主要介绍一维、二维纳米材料(包括纳... 纳米尺度热传导是物理科学、材料科学和工程热物理等相关学科的研究热点。除基础研究上的意义外,这个方向的研究在微纳米器件温度控制、新能源、热防护等重大工程技术领域也有着重要的应用价值。文章主要介绍一维、二维纳米材料(包括纳米管、纳米线、石墨烯及其他二维材料)的热传导性质。由于篇幅所限,文章集中讨论在低维体系热传导中的新奇物理效应,如碳纳米管热导率随长度的发散行为,硅纳米线中的声子相干性,以及石墨烯热传导性质的尺寸效应。文章侧重强调低维纳米材料热传导与宏观体材料热传导特性的本质区别。 展开更多
关键词 热传导 碳纳米管 半导体纳米线 石墨烯 二维材料
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单层和双层二硫化钼化学气相沉积生长的动力学蒙特卡罗模拟研究(英文) 被引量:3
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作者 陈帅 高峻峰 +1 位作者 SRINIVASAN Bharathi M. 张永伟 《物理化学学报》 SCIE CAS CSCD 北大核心 2019年第10期1119-1127,共9页
通过化学气相沉积方法,可控合成所需层数的二硫化钼仍然是一个挑战。因此,建立一个能够定量预测单层和多层二硫化钼生长的理论模型,并为实验制备提供指导,是十分必要的。在本文中,我们建立了一个动力学蒙特卡罗模型,来预测单层和双层二... 通过化学气相沉积方法,可控合成所需层数的二硫化钼仍然是一个挑战。因此,建立一个能够定量预测单层和多层二硫化钼生长的理论模型,并为实验制备提供指导,是十分必要的。在本文中,我们建立了一个动力学蒙特卡罗模型,来预测单层和双层二硫化钼的化学气相沉积生长。首先,我们提出了第一层和第二层的生长速率受吸附原子浓度分布的控制,以及紧凑三角形二硫化钼的生长过程为扭结成核和传播。其中,原子浓度是由吸附原子流量,吸附原子的有效寿命,生长温度,边的单位长度能量,单层和双层的单位面积结合能,成核准则决定的。扭结成核和传播是由锯齿边和扶手边附加原子所需的能量势垒决定的。然后,我们采用热力学理论准则对这些参数进行了标定。通过标定的动力学蒙特卡罗模型,我们发现第二层的生长速率与第一层的尺寸有很强的依赖性。随着第一层尺寸增加,第二层的生长速率呈单调递减趋势,甚至在第一层达到某个尺寸时,第二层的生长会被抑制。此外,我们还分析了不同生长温度和吸附原子流量下,双层二硫化钼的尺寸和形貌演化。在双层二硫化钼的整个生长过程中,第一层和第二层的形貌保持紧凑三角形,验证了扭结成核和传播模型的正确性。模拟结果表明,生长温度的升高或吸附原子流量的降低,促进了双层二硫化钼的生长,这与已报导的实验结果相吻合。生长温度升高使得第二层二硫化钼边缘的吸附原子浓度,随着远离第二层边缘的吸附原子浓度降低而相应降低,促进了双层二硫化钼的生长。同样,吸附原子流量降低减小了基体上的吸附原子浓度,降低了第一层远离边缘和靠近边缘的吸附原子浓度差,从而减缓了第一层的生长。第一层的生长减慢,减缓了第二层远离边缘和靠近边缘的吸附原子浓度差减小到零,从而促进双层二硫化� 展开更多
关键词 二硫化钼 单层生长 双层生长 化学气相沉积 动力学蒙特卡罗
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Comprehensive evaluation of mechanism of "chimney effect" using principles of magnetism, geochemistry and mineralogy 被引量:3
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作者 LIU Qingsheng 1, CHENG Tongjin 2 and LIU Shugen 3 1. Department of Applied Geophysics, China University of Geosciences, Wuhan 430074, China 2. Center of Petroleum Geochemistry, China National star Petroleum Corporation, Hefei 230022, China 3. The St 《Chinese Science Bulletin》 SCIE EI CAS 1998年第9期743-748,共6页
Study of forming mechanism of "chimney-effect" (CE) has important significance for basic theory and applications of non-seismic geophysical and geochemical methods locating oil/gas reservoirs. The theoretica... Study of forming mechanism of "chimney-effect" (CE) has important significance for basic theory and applications of non-seismic geophysical and geochemical methods locating oil/gas reservoirs. The theoretical basis of comprehensive evaluation of mechanism of CE using principles of magnetism, geochemistry and mineralogy has been reviewed, with the problems to be solved: (ⅰ) study for the relationship between process of oil/gas migration and geochemical field; (ⅱ) analysis of genesis of magnetic, geochemical and mineralogical anomaly; (ⅲ) interpretation of surface soil magnetism and geochemical anomaly combined with seismic data. 展开更多
关键词 CHIMNEY effect (CE) HYDROCARBON microseepage oil/gas accumulation.
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基于EPICS和差分进化算法的同步辐射光束线智能调束系统 被引量:2
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作者 时英智 高梅 +4 位作者 贾文红 阴广志 高兴宇 杜永华 郑丽芳 《核技术》 CAS CSCD 北大核心 2020年第5期1-7,共7页
针对无规律变化的光源光束点和手动调束费时费力问题,本文实现了基于实验物理及工业控制系统(Experimental Physics and Industrial Control System,EPICS)的同步辐射光束线智能优化调束。该系统基于差分进化算法,建立光束线智能优化模... 针对无规律变化的光源光束点和手动调束费时费力问题,本文实现了基于实验物理及工业控制系统(Experimental Physics and Industrial Control System,EPICS)的同步辐射光束线智能优化调束。该系统基于差分进化算法,建立光束线智能优化模型,应用LabVIEW程序实现调束过程的自动优化。系统可以自由选择待优化的电机及其搜索范围,设置算法参数,跟踪进化进程,通过CaLab接口模块与光束线EPICS软件平台进行通信,控制电机运动。对该系统在上海光源衍射线站进行了在线测试,首次成功地在EPICS控制平台上实现了光束线的智能调束优化。测试结果表明:该智能调束系统能够较快地收敛于最优解,收敛时间大约30 min,较手动优化效率提高一个数量级以上。 展开更多
关键词 差分进化算法 光束线 智能优化 EPICS
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Integrated Geophysical and Hydrogeochemical Characterization and Assessment of Groundwater Studies in Adum West Area of Benue State,Nigeria 被引量:2
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作者 Moses Oghenenyoreme Eyankware Christopher Ogwah Umayah Otitie star 《Journal of Geological Research》 2021年第3期14-27,共14页
Integration of geophysical and hydrogeochemical methods has been scientifically proven to be useful in vulnerability study and groundwater characterization.Subsurface geoelectric parameters such as resistivity and thi... Integration of geophysical and hydrogeochemical methods has been scientifically proven to be useful in vulnerability study and groundwater characterization.Subsurface geoelectric parameters such as resistivity and thickness obtained from geophysical method(Vertical Electrical Sounding VES)was used to determine aquifers vulnerability,longitudinal resistance(ρL)and transverse unit resistance(Rt).Thirty four water samples were collected from groundwater sources for physicochemical analysis.Estimated results from longitudinal conductance(S),(Rt)and(ρL)showed that the values ranges from 0.03 to 2.5mhos,103.64 to 1964417.8Ω/m^(2) and 215.41 to 65731.68Ω-m respectively.Result from S suggested that 50%of groundwater is considered to be vulnerable to contamination from the earth surface,while the remaining 50%is considered to be slightly vulnerable to surface contamination.Further findings obtained from hydrogeochemical analysis such as Gibb’s and Chadba plots revealed that groundwater is highly influenced by rock water interaction,groundwater is classified to be Na^(+)+HCO_(3)^(-),Ca^(2+)+Mg^(2+)+HCO_(3)^(-),Na^(+)+Cl^(-)and Ca^(2+)+Mg^(2+)+Cl^(-)water type.Deduction from Soltan classification suggested that groundwater is classified to be of Na^(+)+HCO_(3)^(-) and Na^(+)-SO_(4)^(2-) water type.Results obtained from Ec and pH suggested that the values were below WHO permissible limit,while result obtained from TDS showed that at some sampling points TDS values were above WHO limit.Based on pH value obtained groundwater within the study area fell within slightly basic to acidic. 展开更多
关键词 GROUNDWATER RESISTIVITY Contamination Aquifer protective capacity NIGERIA
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TiO_2纳米纺锤体负载Pt在氧还原反应中的应用(英文)
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作者 彭桂明 巫素琴 +4 位作者 彭全明 BURKERT Seth C. 杜瑞安 余长林 star Alexander 《新能源进展》 2018年第2期163-168,共6页
燃料电池中催化剂的稳定性是影响其实际应用的关键问题之一。本研究合成了锐钛矿型纺锤状TiO_2纳米材料,并负载纳米Pt制备了TiO_2-Pt双组分复合催化材料。将其制作成电极材料后,进行了TEM、XRD、拉曼光谱、电化学特性分析。结果表明:TiO... 燃料电池中催化剂的稳定性是影响其实际应用的关键问题之一。本研究合成了锐钛矿型纺锤状TiO_2纳米材料,并负载纳米Pt制备了TiO_2-Pt双组分复合催化材料。将其制作成电极材料后,进行了TEM、XRD、拉曼光谱、电化学特性分析。结果表明:TiO_2-Pt材料中Pt纳米颗粒的TEM形貌与TiO_2的表面亲和力有关;该双组分催化剂呈现出两个单独的氧还原反应(ORR)峰;在负载Pt后,材料电荷传输电阻明显减小,使得TiO_2-Pt中TiO_2纺锤体组分上的ORR性能明显增强;紫外光可同时促进TiO_2-Pt中两组分的ORR性能;TiO_2-Pt比炭黑负载Pt具有更好的稳定性。 展开更多
关键词 二氧化钛 纳米纺锤体 氧还原反应 紫外光 光电催化化学
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National trends in total hip arthroplasty for traumatic hip fractures:An analysis of a nationwide all-payer database 被引量:1
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作者 Anthony J Boniello Alexander M Lieber +3 位作者 Kevin Denehy Priscilla Cavanaugh Yehuda E Kerbel Andrew star 《World Journal of Orthopedics》 2020年第1期18-26,共9页
BACKGROUND Hemiarthroplasty(HA)has traditionally been the treatment of choice for elderly patients with displaced femoral neck fractures.Ideal treatment for younger,ambulatory patients is not as clear.Total hip arthro... BACKGROUND Hemiarthroplasty(HA)has traditionally been the treatment of choice for elderly patients with displaced femoral neck fractures.Ideal treatment for younger,ambulatory patients is not as clear.Total hip arthroplasty(THA)has been increasingly utilized in this population however the factors associated with undergoing HA or THA have not been fully elucidated.AIM To examine what patient characteristics are associated with undergoing THA or HA.To determine if outcomes differ between the groups.METHODS We queried the Nationwide Inpatient Sample(NIS)for patients that underwent HA or THA for a femoral neck fracture between 2005 and 2014.The NIS comprises a large representative sample of inpatient hospitalizations in the United States.International Classifications of Disease,Ninth Edition(ICD-9)codes were used to identify patients in our sample.Demographic variables,hospital characteristics,payer status,medical comorbidities and mortality rates were compared between the two procedures.Multivariate logistic regression analysis was then performed to identify independent risk factors of treatment utilized.RESULTS Of the total 502060 patients who were treated for femoral neck fracture,51568(10.3%)underwent THA and the incidence of THA rose from 8.3%to 13.7%.Private insurance accounted for a higher percentage of THA than hemiarthroplasty.THA increased most in urban teaching hospitals relative to urban non-teaching hospitals.Mean length of stay(LOS)was longer for HA.The mean charges were less for HA,however charges decreased steadily for both groups.HA had a higher mortality rate,however,after adjusting for age and comorbidities HA was not an independent risk factor for mortality.Interestingly,private insurance was an independent predictor for treatment with THA.CONLUSION There has been an increase in the use of THA for the treatment of femoral neck fractures in the United States,most notably in urban hospitals.HA and THA are decreasing in total charges and LOS. 展开更多
关键词 Hip fracture Total hip arthroplasty HEMIARTHROPLASTY COST Length of stay National Inpatient Sample
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Localization and macroscopic instability in nanoporous metals
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作者 Zhangtao Sun Tianfu Guo +3 位作者 Khalil I.Elkhodary Hang Yang Nian Zhou Shan Tan 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2022年第12期15-32,共18页
Ductile fracture generally relates to microscopic voiding and to strain localization in metallic materials.When the void size is reduced to the nanoscale,size effects often lead to a different macroscopic plastic beha... Ductile fracture generally relates to microscopic voiding and to strain localization in metallic materials.When the void size is reduced to the nanoscale,size effects often lead to a different macroscopic plastic behavior from that established for the same material with larger voids.For example,irradiation of metallic materials can generate a large number of voids at the nanoscale,leading to complex deformation behaviors.The present work advances the understanding of strain localization in nanoporous metallic materials,connecting both the microscopic(nano-)and macroscopic scales.To explore the physical mechanisms at the nanoscale,molecular dynamics(MD)simulations were here carried out,capturing multiple nanovoids explicitly.Then,a homogenized continuum theory based in Gurson's constitutive framework is proposed,which enables us to explore how localized behavior at the macroscopic scale evolves.The homogenized model incorporates the surface tension associated with nanosized void.The importance of this surface tension is illustrated by several parametric studies on the conditions of localization,when a specimen is subjected to uniaxial tension.Our parametric studies show that for smaller nanovoid sizes,and for a hardening matrix material,shear localization onset is delayed.Our proposed homogenization model was then used to predict localization behavior captured by our MD simulation.The yield stress and the localization strain predicted by our continuum model are in general agreement with the trends obtained by MD simulation.Moreover,based on our present study,experimental results of shear failure strain vs.dose of irradiation for several metals could be qualitatively explained rather successfully.Our model can therefore help shed light on prolonging the operation limits and the lifetime of irradiated metallic materials under complex loading conditions. 展开更多
关键词 Nanovoids MD simulations LOCALIZATION Surface tension Shear band
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Location-Based Routing Algorithms for Wireless Sensor Network
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作者 Zheng Kai,Tong Libiao,Lu Wenjun(New star Research Institute of Applied Technologies,Hefei 230031,P.R.China) 《ZTE Communications》 2009年第1期40-44,共5页
Routing algorithms based on geographical location is an important research subject in the Wireless Sensor Network(WSN).They use location information to guide routing discovery and maintenance as well as packet forward... Routing algorithms based on geographical location is an important research subject in the Wireless Sensor Network(WSN).They use location information to guide routing discovery and maintenance as well as packet forwarding,thus enabling the best routing to be selected,reducing energy consumption and optimizing the whole network.Through three aspects involving the flooding restriction scheme,the virtual area partition scheme and the best routing choice scheme,the importance of location information is seen in the routing algorithm. 展开更多
关键词 NODE Location-Based Routing Algorithms for Wireless Sensor Network
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基于浸没光滑有限元法的双圆柱体运动问题研究 被引量:1
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作者 王双强 回达 +2 位作者 张桂勇 张智谦 宗智 《船舶力学》 EI CSCD 北大核心 2021年第2期146-155,共10页
本文采用浸没光滑有限元方法对二维流域内双圆柱体运动时的干扰问题进行研究。通过引入虚拟流体假设将流固耦合控制方程进行分解,采用新型光滑有限元方法离散固体运动方程,并用半隐式特征线分裂方法(CBS)求解不可压缩粘性流体N-S方程,... 本文采用浸没光滑有限元方法对二维流域内双圆柱体运动时的干扰问题进行研究。通过引入虚拟流体假设将流固耦合控制方程进行分解,采用新型光滑有限元方法离散固体运动方程,并用半隐式特征线分裂方法(CBS)求解不可压缩粘性流体N-S方程,流固相互作用力通过虚拟流体域进行计算。结果表明该方法能很好地模拟双体运动干扰作用及引起流场特性的变化。 展开更多
关键词 浸没光滑有限元 流固耦合 半隐式特征线分裂方法 干扰
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家蝇幼虫可作为可持续蛋鸡营养的来源 被引量:1
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作者 张相鑫(译) 潘雪男(校) +2 位作者 何闪(制表) Laura star Gert Hemke 《国外畜牧学(猪与禽)》 2021年第3期69-73,共5页
斯科特霍斯特饲料研究中心的大量研究证明,家蝇幼虫在可持续蛋鸡营养中是一种可行的蛋白质来源,可以完全替代大豆。如果可以扩大家蝇幼虫的生产规模,并将其用于蛋鸡场,那么家蝇幼虫在价格上与豆粕具有竞争性。目前,欧盟限制在家禽营养... 斯科特霍斯特饲料研究中心的大量研究证明,家蝇幼虫在可持续蛋鸡营养中是一种可行的蛋白质来源,可以完全替代大豆。如果可以扩大家蝇幼虫的生产规模,并将其用于蛋鸡场,那么家蝇幼虫在价格上与豆粕具有竞争性。目前,欧盟限制在家禽营养中使用家蝇幼虫,但在未来这种情况很可能会发生改变。 展开更多
关键词 家蝇幼虫 家禽 营养
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