检索结果-南通市图书馆

Friction and wear behaviors of biodegradable Mg-6Gd-0.5Zn-0.4Zr alloy under simulated body fluid condition

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2017年第4期5卷 448-453页

作者： Jianwei Dai Xiaobo Zhang Qiao Yin shengnan ni Zhixin Ba Zhangzhong Wang School of Materials Science and Engineering Nanjing Institute of TechnologyNanjingChina Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology NanjingChina

The friction and wear behaviors of biodegradable Mg-6Gd-0.5Zn-0.4Zr(wt%,GZ60K)alloy were evaluated under simulated body fluid(SBF)condition using ball-on-disk configuration and compared with those under dry sliding *** results show that under dry sliding and SBF conditions,the friction coefficient declines with increasing applied load and keeps stable with prolonging sliding *** friction coefficient of the alloy effectively decreases in SBF as compared to dry sliding due to lubrication caused by *** real wear rates under SBF condition are lower than those under dry sliding condition for each ***,the nominal wear rates are higher in SBF which are attributed to the more mass loss caused by corrosion but not *** the nominal wear rate in SBF and the dry sliding wear rate increase with increasing applied load,and they decline firstly and then keep stable with prolonging sliding *** is concluded that the wear of the alloy is restricted by the SBF,but the corrosion of the alloy is aggravated by the wear.

关键词： Biodegradable Mg alloy SBF Friction coefficient Wear behavior

Long-term and inter-annual mass changes of Patagonia Ice Field from GRACE

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2019年第2期10卷 100-109页

作者： Jin Li Jianli Chen shengnan ni Lu Tang Xiaogong Hu Shanghai Astronomical Observatory Chinese Academy of Sciences School of Astronomy and Space Science University of Chinese Academy of Sciences Center for Space Research University of Texas at Austin School of Communication and Information Engineering Shanghai University

Using more than 14 years of GRACE(Gravity Recovery and Climate Experiment) satellite gravimetry observations, we estimate the ice loss rate for the Patagonia Ice Field(PIF) of South America. After correcting the effects of glacier isostatic adjustment(GIA) and hydrological variations, the ice loss rate is -23.5 ± 8.1 Giga ton per year(Gt/yr) during the period April 2002 through December 2016, equivalent to an average ice thickness change of-1.3 m/yr if evenly distributed over PIF. The PIF ice mass change series also show obvious inter-annual variations during the entire period. For the time spans April 2002 to December 2007, January 2008 to December 2012 and January 2013 to December 2016, the ice loss rates are -26.4,-9.0 and -25.0 Gt/yr, respectively, indicating that the ice melting experienced significant slowing down and accelerating again in the past decade. Comparison with time series from temperature and precipitation data over PIF suggests that the inter-annual ice losses might not be directly correlated with the temperature changes and precipitation anomalies, and thus their interrelation is intricate. However, the dramatic ice loss acceleration in 2016(with more than 100 Gt within the first half of the year) appears closely related with the evident temperature increase and severe precipitation shortage over 2016, which are likely correlated with the strong E1 nino event around 2016. Moreover, we compare the GRACE spherical harmonic(SH) and mass concentration(Mascon) solutions in estimating the PIF ice loss rate, and find that the Mascon result has larger uncertainty in leakage error correction,while the SH solutions can better correct leakage errors based on a constrained forward modeling iterative method. Thus the GRACE SH solutions with constrained forward modeling recovery are recommended to evaluating the ice mass change of PIF or other glacier regions with relatively smaller spatial scales.

关键词： GRACE Spherical harmonic solution Mascon solution Patagonia Ice Field Inter-annual mass change

On-chip structure-switching aptamer-modified magnetic nanobeads for the continuous monitoring of interferon-gamma ex vivo

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2019年第1期5卷 281-291页

作者： Guozhen Liu Chaomin Cao shengnan ni Shilun Feng Hui Wei Graduate School of Biomedical Engineering ARC Centre of Excellence in Nanoscale Biophotonics(CNBP)Faculty of EngineeringThe University of New South WalesSydneyNSW 2052Australia Australian Centre for NanoMedicine UNSW SydneySydneyNSW 2052Australia International Joint Research Center for Intelligent Biosensor Technology and Health College of ChemistryCentral China Normal University430079 WuhanPR China School of Engineering Faculty of Science and EngineeringMacquarie UniversitySydneyNSW 2109Australia

Cytokines are cell signaling molecules that indicate the health status of the *** this study,we developed a microfluidic device integrated with structure-switching aptamers capable of continuously tracking the concentration of the cytokine interferon gamma(IFN-γ)in cell culture medium and blood ***,a ferrocene(Fc)-labeled structure-switching signaling aptamer with a hairpin structure targeting IFN-γwas immobilized on magnetic nanobeads by the strongest noncovalent interactions between streptavidin and *** aptamer-modified magnetic nanobeads were trapped on a customized microfluidic chip by a magnetic field to form the sensing *** binding of IFN-γcould trigger the hairpin structure of the aptamer to unfold,pushing Fc redox molecules away from the sensing interface and consequently switching off the electrochemical *** change in the redox current of Fc was quantitatively related to the concentration of IFN-γin a linear range of 10–500 pg mL^(−1)and with the lowest detection limit of 6 pgmL^(−1).This microfluidic device was specific to IFN-γin the presence of overabundant serum proteins and allowed the continuous monitoring of IFN-γwithout adding exogenous *** provided a universal point-of-care biosensing platform for the real-time detection of a spectrum of analytes.

关键词： beads structure magnetic

Recent progress in MnBi2nTe3n+1 intrinsic magnetic topological insulators: crystal growth, magnetism and chemical disorder

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2024年第2期11卷 65-80页

作者： Chaowei Hu Tiema Qian ni ni Department of Physics and Astronomy and California Nano Systems Institute University of California-Los Angeles

The search for magnetic topological materials has been at the forefront of condensed matter research for their potential to host exotic states such as axion insulators, magnetic Weyl semimetals, Chern insulators,etc. To date, the MnBi2nTe3n+1family is the only group of materials showcasing van der Waals-layered structures, intrinsic magnetism and non-trivial band topology without trivial bands at the Fermi level. The interplay between magnetism and band topology in this family has led to the proposal of various topological phenomena, including the quantum anomalous Hall effect, quantum spin Hall effect and quantum magnetoelectric effect. Among these, the quantum anomalous Hall effect has been experimentally observed at record-high temperatures, highlighting the unprecedented potential of this family of materials in fundamental science and technological innovation. In this paper, we provide a comprehensive review of the research progress in this intrinsic magnetic topological insulator family, with a focus on single-crystal growth, characterization of chemical disorder, manipulation of magnetism through chemical substitution and external pressure, and important questions that remain to be conclusively answered.

关键词： MnBi2Te4 magnetic topological insulator magnetism tuning antiferromagnetism ferromagnetism pressure chemical doping

Regional features of pollen R-values in China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第1期67卷 295-308页

作者： Jie XIA Jian ni College of Life Sciences Zhejiang Normal UniversityJinhua 321004China Jinhua Mountain Observation and Research Station for Subtropical Forest Ecosystems Jinhua 321004China

Establishing a quantitative relationship between modern pollen and vegetation remains a pivotal but intricate pursuit within the field of Quaternary *** R-value,a well-established and traditional metric characterized by its simplicity and direct applicability,serves to calibrate the nonlinear disparities between surface pollen and modern *** study entails the construction of a comprehensive pollen R-value dataset for China derived from R-values published between 1987 and *** dataset,compiled after rigorous screening,calibration,and standardization processes,encompasses 898 modern pollen sampling sites and 2115 pollen R-value data entries,encapsulating 152 pollen taxa spanning 65 families and 113 *** the extracted R-values yielded the following insights:(1)A macrospatial analysis validates previously established knowledge at a site-specific ***,pollen R-value variations across China are statistically *** two-thirds of pollen taxa exhibit underrepresentation(e.g.,Taxodiaceae,Corylus,nitraria,Tamarix,Cyperaceae,Poaceae,and Fabaceae),while the remaining one-third display overrepresentation(e.g.,Pinus,Picea,Betula,Ephedra,Chenopodiaceae,and Artemisia).The degree of underrepresentation surpasses that of overrepresentation,and the representation patterns of Castanea,Quercus,Polygonaceae,and Asteraceae are contingent upon vegetation types.(2)Pollen R-values follow distinct spatial distribution patterns within *** the woody vegetation region of eastern China,R-values progressively decline from north to south,correlating with rising temperatures and ***,in herbaceous vegetation regions of northern and western China,R-values decrease from east to west and from northeast to southwest,corresponding to increased ***,pollen R-values manifest variation contingent on pollen taxa,vegetation types,and climatic regions,even differing for the same taxa across varying

关键词： Pollen R-value Modern pollen-vegetation relationship Regional pattern Variability Paleovegetation reconstruction

Theoretical optimization of micropillar arrays for structurally stable bioinspired dry adhesives

在线全文

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2024年第2期14卷 124-129页

作者： Ke ni Zhengzhi Wang Department of Engineering Mechanics School of Civil EngineeringWuhan UniversityWuhan 430072China Wuhan University Shenzhen Research Institute Shenzhen 518108China

Inspired by the excellent adhesion performances of setae structure from organisms,micro/nano-pillar array has become one of the paradigms for adhesive *** micropillar arrays are composed of the resin pillars for adhesion and the substrate with different elastic modulus for *** stress singularity at the bi-material corner between the pillars and the substrate can induce the failure of the micropillar-substrate corner and further hinder the fabrication and application of micropillar arrays,yet the design for the stability of the micropillar array lacks systematical and quantitative *** this work,we develop a semi-analytical method to provide the full expressions for the stress distribution within the bi-material corner combining analytical derivations and numerical *** predictions for the stress within the singularity field can be obtained based on the full expressions of the *** good agreement between the predictions and the FEM results demonstrates the high reliability of our *** adopting the strain energy density factor approach,the stability of the pillar-substrate corner is assessed by predicting the failure at the *** the elastic mismatch between the pillar and substrate given in this paper,the stability can be improved by increasing the ratio of the shear modulus of the substrate to that of the *** study provides accurate predictions for the stress distribution at the bi-material corner and can guide the optimization of material combinations of the pillars and the substrate for more stable bioinspired dry adhesives.

关键词： Micropillar array Stability Bi-material corner Dry adhesive

Oligomerization of drug transporters:Forms,functions,and mechanisms

在线全文

学校读者我要写书评

暂无评论

Acta Pharmaceutica Sinica B 2024年第5期14卷 1924-1938页

作者： Chunxu ni Mei Hong College of Life Sciences South China Agricultural UniversityGuangzhou 510642China Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms South China Agricultural UniversityGuangzhou 510642China

Drug transporters are essential players in the transmembrane transport of a wide variety of clinical *** broad substrate spectra and versatile distribution pattern of these membrane proteins infer their pharmacological and clinical *** our accumulating knowledge on the three-dimensional structure of drug transporters,their oligomerization status has become a topic of intense study due to the possible functional roles carried out by such kind of post-translational modification(PTM).In-depth studies of oligomeric complexes formed among drug transporters as well as their interactions with other regulatory proteins can help us better understand the regulatory mechanisms of these membrane proteins,provide clues for the development of novel drugs,and improve the therapeutic *** this review,we describe different oligomerization forms as well as their structural basis of major drug transporters in the ATP-binding cassette and solute carrier superfamilies,summarize our current knowledge on the influence of oligomerization for protein expression level and transport function of these membrane proteins,and discuss the regulatory mechanisms of ***,we highlight the challenges associated with the current oligomerization studies and propose some thoughts on the pharmaceutical application of this important drug transporter PTM.

关键词： Drug development Drug transporters Oligomerization Protein expression Protein–protein interaction Regulatory mechanism Structural basis Transport function

Aubry-Mather theory for contact Hamiltonian systems Ⅲ

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2024年第11期67卷 2541-2570页

作者： Panrui ni Lin Wang Shanghai Center for Mathematical Sciences Fudan University School of Mathematics and Statistics Beijing Institute of Technology

By exploiting the contact Hamiltonian dynamics（T*M × R,Φ_t） around the Aubry set of contact Hamiltonian systems,we provide a relation among the Mather set,the Φ_t-recurrent set,the strongly static set,the Aubry set,the Ma?é set,and the Φ_t-non-wandering ***,we consider the strongly static set,as a new flow-invariant set between the Mather set and the Aubry set in the strictly increasing *** show that this set plays an essential role in the representation of certain minimal forward weak Kolmogorov-Arnold-Moser（KAM） solutions and the existence of transitive orbits around the Aubry set.

关键词： Aubry-Mather theory weak KAM theory contact Hamiltonian systems Hamilton-Jacobi equations

Modern phenomics to empower holistic crop science, agronomy, and breeding research

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Genetics and Genomics 2024年第8期51卷 790-800页

作者： ni Jiang Xin-Guang Zhu Institute of Genetics and Developmental Biology Chinese Academy of SciencesBeijing 100101China Center of Excellence for Molecular Plant Sciences Chinese Academy of SciencesShanghai 200032China

Crop phenomics enables the collection of diverse plant traits for a large number of samples along different time scales,representing a greater data collection throughput compared with traditional *** modern crop phenomics use different sensors to collect reflective,emitted,and fluorescence signals,etc.,from plant organs at different spatial and temporal *** multi-modal,high-dimensional data not only accelerates basic research on crop physiology,genetics,and whole plant systems modeling,but also supports the optimization of field agronomic practices,internal environments of plant factories,and ultimately crop *** challenges and opportunities facing the current crop phenomics research community include developing community consensus or standards for data collection,management,sharing,and processing,developing capabilities to measure physiological parameters,and enabling farmers and breeders to effectively use phenomics in the field to directly support agricultural production.

关键词： Crop phenomics High-throughput phenotyping Traits Crop designer breeding Agronomy