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生活饮用水中丁基黄原酸测定方法的优化

江苏科技信息 2016年第27期33卷 38-40,43页

作者：罗劼朱源陈云武昌工学院食品工程学院湖北武汉430065 苏州华测检测技术有限公司江苏苏州215100 武汉工程大学湖北武汉430205

丁基黄原酸是饮用水的测定指标,通常采用铜试剂亚铜分光光度法测定,测定时灵敏度低、重现性差,是水质监测难点之一。文章对测定时影响较大的因素和未明确的技术点进行了优化,推荐调整盐酸羟胺投加量为2.00 g、振摇萃取时间5 min,确定DDT... 详细信息

丁基黄原酸是饮用水的测定指标,通常采用铜试剂亚铜分光光度法测定,测定时灵敏度低、重现性差,是水质监测难点之一。文章对测定时影响较大的因素和未明确的技术点进行了优化,推荐调整盐酸羟胺投加量为2.00 g、振摇萃取时间5 min,确定DDTC投加量0.1-0.2 g、显色反应时间10 min。优化后方法检出限0.50μg,低于国标方法的检出限1μg,方法灵敏度明显提升,解决了操作中的一些技术问题,以便更好地应用。

关键词：丁基黄原酸铜试剂亚铜分光光度法

The origin and evolution of Earth's nitrogen

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National Science Review 2024年第06期11卷 56-75页

作者： yuan Li State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of Sciences Bayerisches Geoinstitut Universit?t Bayreuth

Nitrogen is a vital element for life on Earth. Its cycling between the surface(atmosphere + crust) and the mantle has a profound influence on the atmosphere and climate. However, our understanding of the origin and evolution of Earth's nitrogen is still incomplete. This review presents an overview of the current understanding of Earth's nitrogen budget and the isotope composition of different reservoirs, laboratory constraints on deep nitrogen geochemistry, and our understanding of the origin of Earth's nitrogen and the deep nitrogen cycle through plate subduction and volcanism. The Earth may have acquired its nitrogen heterogeneously during the main accretion phase, initially from reduced, enstatite-chondrite-like impactors,and subsequently from increasingly oxidized impactors and minimal CI-chondrite-like materials. Like Earth's surface, the mantle and core are also significant nitrogen reservoirs. The nitrogen abundance and isotope composition of these three reservoirs may have been fundamentally established during the main accretion phase and have been insignificantly modified afterwards by the deep nitrogen cycle, although there is a net nitrogen ingassing into Earth's mantle in modern subduction zones. However, it is estimated that the early atmosphere of Earth may have contained ～1.4 times the present-day atmospheric nitrogen(PAN),with ～0.4 PAN being sequestered into the crust via biotic nitrogen fixation. In order to gain a better understanding of the origin and evolution of Earth's nitrogen, directions for future research are suggested.

关键词： nitrogen isotopes silicate Earth atmosphere magma ocean

Robustness of the octupole collectivity in 144Ba within the cranking covariant density functional theory in 3. lattice

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Nuclear Science and Techniques 2024年第8期35卷 124-131页

作者： Ze‑Kai Li yuan‑yuan Wang Mathematics and Physics Department North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and Energy Technology North China Electric Power UniversityBaoding 071000China

The octupole deformation and collectivity in octupole double-magic nucleus 144Ba are investigated using the Cranking covariant density functional theory in a three-dimensional lattice *** reduced B(E3.transition probability is implemented for the first time in semiclassical approximation based on the microscopically calculated electric octupole *** available data,including the I-ωrelation and electric transitional probabilities B(E2)and B(E3.are well ***,it is shown that the ground state of 144Ba exhibits axial octupole and quadrupole deformations that persist up to high spins(I≈24h).

关键词： Octupole collectivity Cranking covariant density functional theory Rotational spectrum Electric transitional probabilities

参附强心汤治疗射血分数保留慢性心衰的临床研究

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南京中医药大学学报 2017年第4期33卷 335-338页

作者：张苏洁方祝元张一炎陈晓栋谷明林南京中医药大学附属中西医结合医院江苏南京210028 南京中医药大学第一临床医学院江苏南京210023 南京中医药大学附属医院江苏南京210029

目的观察参附强心汤对射血分数保留的慢性心衰(阴阳两虚,水瘀内停证)患者超声心动图指标的影响及临床疗效情况,并初步探讨其作用机制。方法选取2014年8月-2015年8月来我院治疗并经检查确诊为射血分数保留的慢性心功能不全(阴阳两虚,水... 详细信息

目的观察参附强心汤对射血分数保留的慢性心衰(阴阳两虚,水瘀内停证)患者超声心动图指标的影响及临床疗效情况,并初步探讨其作用机制。方法选取2014年8月-2015年8月来我院治疗并经检查确诊为射血分数保留的慢性心功能不全(阴阳两虚,水瘀内停证)的患者57例,随机分为对照组(28例)和观察组(29例)。对照组给予常规治疗,观察组在常规治疗基础上加用参附强心汤,2组均2周为1个疗程,1个疗程后进行疗效评估。观察2组治疗前后血浆脑钠肽(BNP)、6min步行距离(6MWT)、超声心动图等指标变化。结果 2组治疗后血浆BNP、6MWT均有改善(P0.05),二尖瓣环舒张早期最大血流速度(E峰)/二尖瓣环室间隔及左室侧壁组织舒张早期最大速度(Ea)比值、肺动脉收缩压(PSA)2组患者均有明显改善(P<0.05~0.01),与对照组相比,观察组变化幅度更为显著(P<0.05)。结论参附强心汤能有效改善射血分数保留的慢性心功能不全患者血浆BNP水平、6min步行距离、超声心动图等指标。

关键词：射血分数保留慢性心衰参附强心汤脑钠肽 6 min步行距离超声心动图

Collective Molecular Machines: Multidimensionality and Reconfigurability

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Nano-Micro Letters 2024年第8期16卷 309-340页

作者： Bin Wang yuan Lu Department of Chemical Engineering Tsinghua UniversityBeijing 100084People’s Republic of China Key Laboratory of Industrial Biocatalysis Ministry of EducationTsinghua UniversityBeijing 100084People’s Republic of China

Molecular machines are key to cellular activity where they are involved in converting chemical and light energy into efficient mechanical *** the last 60 years,designing molecular structures capable of generating unidirectional mechanical motion at the nanoscale has been the topic of intense *** progress has been made,attributed to advances in various fields such as supramolecular chemistry,biology and nanotechnology,and ***,individual molecular machines are only capable of producing nanometer work and generally have only a single *** order to address these problems,collective behaviors realized by integrating several or more of these individual mechanical units in space and time have become a new *** this review,we comprehensively discuss recent developments in the collective behaviors of molecular *** particular,collective behavior is divided into two *** is the appropriate integration of molecular machines to efficiently amplify molecular motions and deformations to construct novel functional *** other is the construction of swarming modes at the supramolecular level to perform nanoscale or microscale *** discuss design strategies for both modes and focus on the modulation of features and ***,in order to address existing challenges,the idea of transferring experience gained in the field of micro/nano robotics is presented,offering prospects for future developments in the collective behavior of molecular machines.

关键词： Molecular machines Collective control Collective behaviors DNA Biomolecular motors

Global adaptive output-feedback tracking with prescribed performance for uncertain nonlinear systems

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Science China(Information Sciences) 2024年第5期67卷 150-164页

作者： yuan WANG Yungang LIU School of Control Science and Engineering Shandong University

At present, one typical control strategy for guaranteeing transient and steady-state performance is funnel control and prescribed performance control. The strategy features completely discarding the system nonlinearities, even if they are completely known and available. Such an intrinsic feature requires the controller to produce a larger control effect to eliminate the negative impact caused by the high nonlinearities, leading to a conservative controller. In this paper, we fully take advantage of known information on nonlinearities in control design, instead of completely discarding it as done in funnel control. Particularly, we leverage adaptive techniques(i.e., high-gain dynamic compensation) to deal with unknown system nonlinearities. Meanwhile, we integrate the tools of output feedback, tracking control, and the performance *** such, an adaptive output-feedback scheme is developed for global tracking with spatiotemporal performance specifications: arbitrarily given tracking accuracy and accuracy-ensured time. A simulation example supports the developed approach.

关键词： uncertain nonlinear systems output feedback prescribed performance unknown control direction dynamic high gain global tracking

Theoretical study on the synergistic mechanism of Fe–Mn in sodium-ion batteries

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Particuology 2024年第10期93卷 284-290页

作者： Yang You Mingliang yuan School of Mineral Processing and Bioengineering Central South UniversityChangsha410083China

This article conducts first-principles calculations to initially explore the construction of two configurations,NaFeO_(2)(NFO)and NaMnO_(2)(NMO),and studies the mixing enthalpies under different Fe–Mn *** results indicate that NaFe3.8Mn5/8O_(2)(NFMO)exhibits the most thermodynamically stable *** calculations on the mixing enthalpies and volume changes during the sodium extraction process for NFO,NMO,and NFMO configurations are presented,along with the partial density of states(PDOS)and Bader charges of transition metals(TM)and *** calculations reveal the synergistic mechanism of Fe and *** and Mn can engage in more complex electron exchanges during sodium extraction,optimizing the internal electron density distribution and overall charge balance,thereby stabilizing the crystal structure and reducing the migration of Fe^(3.)to the sodium layers during deep sodium *** interaction between Fe’s 3. electrons and Mn’s 3. electrons through the shared oxygen atoms’2p orbitals occurs in the Fe–Mn–O *** interaction can lead to a rebalancing of the electron density around Mn³⁺atoms,mitigating the asymmetric electron density distribution caused by the d4 configuration of the lone Mn³⁺and suppressing the Jahn-Teller effect of Mn^(3.).Moreover,the synergistic effects between Fe and Mn can provide a more balanced charge distribution,reducing extreme changes to the charge state of oxygen atoms and decreasing the irreversible oxygen release caused by anionic redox reactions during deep sodium extraction,thereby enhancing the material’s *** in-depth study of the interaction mechanism at the microscopic level when co-doping Fe and Mn offers valuable insights for the rational design and development of high-performance cathode materials.

关键词： First-principles calculations Sodium-ionbatteries Layered oxides NaFe_(3.8)Mn_(3.8)O_(2)

MAUN:Memory-Augmented Deep Unfolding Network for Hyperspectral Image Reconstruction

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1139-1150页

作者： Qian Hu Jiayi Ma yuan Gao Junjun Jiang Yixuan yuan Electronic Information School Wuhan UniversityWuhan 430072China School of Computer Science and Technology Harbin Institute of TechnologyHarbin 150001China Department of Electronic Engineering Chinese University of Hong KongHong Kong 999077China

Spectral compressive imaging has emerged as a powerful technique to collect the 3. spectral information as 2D *** algorithm for restoring the original 3. hyperspectral images(HSIs)from compressive measurements is pivotal in the imaging *** approaches painstakingly designed networks to directly map compressive measurements to HSIs,resulting in the lack of interpretability without exploiting the imaging *** some recent works have introduced the deep unfolding framework for explainable reconstruction,the performance of these methods is still limited by the weak information transmission between iterative *** this paper,we propose a Memory-Augmented deep Unfolding Network,termed MAUN,for explainable and accurate HSI ***,MAUN implements a novel CNN scheme to facilitate a better extrapolation step of the fast iterative shrinkage-thresholding algorithm,introducing an extra momentum incorporation step for each iteration to alleviate the information ***,to exploit the high correlation of intermediate images from neighboring iterations,we customize a cross-stage transformer(CSFormer)as the deep denoiser to simultaneously capture self-similarity from both in-stage and cross-stage features,which is the first attempt to model the long-distance dependencies between iteration *** experiments demonstrate that the proposed MAUN is superior to other state-of-the-art methods both visually and *** code is publicly available at https://***/HuQ1an/MAUN.

关键词： Deep folding iteration

Gradient microstructure and superior strength-ductility synergy of AZ61 magnesium alloy bars processed by radial forging with different deformation temperatures

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Journal of Materials Science & Technology 2024年第3期170卷 65-77页

作者： Jingfeng Zou Lifeng Ma Yanchun Zhu Ling Qin yuan yuan School of Mechanical Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China Heavy Machinery Engineering Research Center of the Ministry Education Taiyuan University of Science and TechnologyTaiyuan 030024China Department of Engineering University of HullCottingham RdHull HU67RXUK National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China

Gradient microstructure modification is a cost-efficient strategy for high strength without compromising ductility,which is urgently needed in the fundamental science of engineering *** this study,heterogeneous structures of AZ61 alloy bars with anisotropic gradients(with different grain size distributions from the surface to the center)were observed to exhibit strong strength-ductility synergies under different deformation tem *** results reveal that the grain refinement process under mediumlow temperature deformation conditions(≤3.0℃)consists of four transition stages along the radial direction,i.e.,twin activations and deformation band formations,dislocation cells and pile-ups,ultrafine sub-grains,and randomly orientated quasi-micron *** deformation temperatures have a great influence on twin activations and deformation band formations,and the high temperature can easily provoke the initiation of non-basal *** deformation bands were determined as a primary nucleation site due to their highly unstable dislocation hindrance *** in combination with the Radial forging(RF)deformation process,the differences of dynamic precipitates can be attributed to microstructural difference and solubility limit of Al at different tem *** summarizing the tensile test results,the sample forged at 3.0℃exhibited the best strength-ductility synergy,exhibiting the highest elongation(EL)of 23.2%with a 251 MPa yield strength(YS)and 3.4 MPa ultimate tensile strength(UTS)in center region,and combined with the highest strength value of 256 MPa YS and 420 MPa UTS in the center region,while the EL was slightly degraded to 19.8%.

关键词： Gradient microstructure Radial forging Strength-ductility synergy Magnesium alloy Strengthening mechanism