Magnetic matchstick micromotors with switchable motion modes

2021 ◽  
Author(s):  
Xiaoliang Zhang ◽  
Wenqing Xie ◽  
Huaguang Wang ◽  
Zexin Zhang
Keyword(s):  
Practical Applications ◽  
Motion Modes

The ability to in situ tune various motion modes of micromotors is challenging, yet critical for any practical applications of micromotors in complex microenvironments. Here, we designed and synthesized magnetic...

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

scholarly journals A Novel Cobalt Metallopolymer with Redox-Matched Conjugated Organic Backbone via Electropolymerization of a Readily Available N4 Cobalt Complex

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1667
Author(s):  
Mikhail Karushev
Keyword(s):  
Redox Reactions ◽  
Repeat Unit ◽  
Cobalt Complex ◽  
Radical Cations ◽  
Electrochemical Quartz Crystal Microbalance ◽  
Practical Applications ◽  
Sensing Applications ◽  
Novel Approach ◽  
Redox Switching

Fast and reversible cobalt-centered redox reactions in metallopolymers are the key to using these materials in energy storage, electrocatalytic, and sensing applications. Metal-centered electrochemical activity can be enhanced via redox matching of the conjugated organic backbone and cobalt centers. In this study, we present a novel approach to redox matching via modification of the cobalt coordination site: a conductive electrochemically active polymer was electro-synthesized from [Co(Amben)] complex (Amben = N,N′-bis(o-aminobenzylidene)ethylenediamine) for the first time. The poly-[Co(Amben)] films were investigated by cyclic voltammetry, electrochemical quartz crystal microbalance (EQCM), in situ UV‑vis-NIR spectroelectrochemistry, and in situ conductance measurements between −0.9 and 1.3 V vs. Ag/Ag+. The polymer displayed multistep redox processes involving reversible transfer of the total of 1.25 electrons per repeat unit. The findings indicate consecutive formation of three redox states during reversible electrochemical oxidation of the polymer film, which were identified as benzidine radical cations, Co(III) ions, and benzidine di-cations. The Co(II)/Co(III) redox switching is retained in the thick polymer films because it occurs at potentials of high polymer conductivity due to the optimum redox matching of the Co(II)/Co(III) redox pair with the organic conjugated backbone. It makes poly-[Co(Amben)] suitable for various practical applications based on cobalt-mediated redox reactions.

scholarly journals Synthesis and Characterization of Highly Efficient Oil-Water Separation, Recyclable, Magnetic Particles CoFe2O4/SDB

2021 ◽  
Author(s):  
Cailin Liu ◽  
Li Yu ◽  
Yue Fan ◽  
Chang Li ◽  
Xianyan Ren ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Magnetic Particles ◽  
In Situ Polymerization ◽  
Solid Phase ◽  
Sol Gel ◽  
Water Separation ◽  
Practical Applications ◽  
Oil Water Separation ◽  
Oil Water

Abstract In the oil-water separation, the difficulty to recover and low hydrophobicity are key limitation factors for practical applications. In this paper, we design Cobalt ferrite hybird Polystyrene divinylbenzene microspheres (CoFe2O4/SDB), which were conducted through in-situ suspension copolymerization. The CoFe2O4 is prepared by low heat solid phase sol-gel method. It had been found that the CoFe2O4/SDB have a spherical structure, good adsorption behavior, highly hydrophobicity and even superhydrophobicity. The adsorption capacity of CoFe2O4/SDB composites could absorb kerosene up to 6 times of its own weight. Interestingly, kerosene can be easily separated from the surface of CoFe2O4/SDB particles with ultrasonic operation. CoFe2O4/SDB particles can still maintain good hydrophobicity and adsorption capacity of kerosene after 11 cycles after drying. With in situ polymerization of St、DVB and CoFe2O4, CoFe2O4/SDB as a promising absorbent of kerosene which has great potential in application of oil-water separation.

scholarly journals Large Scale Operational Soil Moisture Mapping from Passive MW Radiometry: SMOS product evaluation in Europe & USA

2019 ◽  
Author(s):  
Khidir Abdalla Kwal Deng ◽  
Salim Lamine ◽  
Andrew Pavlides ◽  
Yansong Bao ◽  
George Petropoulos ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Large Scale ◽  
Water Security ◽  
Product Evaluation ◽  
Practical Applications ◽  
Study Results ◽  
Different Seasons ◽  
Lower Correlation ◽  
Land Types

Earth Observation (EO) allows deriving from a range of sensors, often globally, operational estimates of surface soil moisture (SSM) at range of spatiotemporal resolutions. Yet, an evaluation of the accuracy of those products in a variety of environmental conditions has been often limited. In this study the accuracy of the SMOS SSM global operational product across 2 continents (USA, and Europe) is investigated. SMOS predictions were compared against near concurrent in-situ SSM measurements from the FLUXNET observational network. In total, 7 experimental sites were used to assess the accuracy of SMOS derived soil moisture for 2 complete years of observations (2010 to 2011). The accuracy of the SMOS SSM product is investigated in different seasons for the seasonal cycle as well as different continents and land types. Results showed a generally reasonable agreement between the SMOS product and the in-situ soil moisture measurements in the 0-5 cm soil moisture layer. Root Mean Square Error (RMSE) in most cases was close to 0.1 m3 m-3 (minimum 0.067 m3 m-3). With a few exceptions, Pearson’s correlation coefficient was found up to approx. 55%. Grassland, shrublands and woody savanna land cover types attained a satisfactory agreement between satellite derived and in-situ measurements but needleleaf forests had lower correlation. Better agreement was found for the grassland sites in both continents. Seasonally, summer and autumn underperformed spring and winter. Our study results provide supportive evidence of the potential value of this operational product for meso-scale studies in a range of practical applications, helping to address key challenges present nowadays linked to food and water security.

scholarly journals Observation Strategies Based on Singular Value Decomposition for Ocean Analysis and Forecast

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3445
Author(s):  
Maria Fattorini ◽  
Carlo Brandini
Keyword(s):  
Singular Value Decomposition ◽  
Maximum Error ◽  
Ocean Model ◽  
Singular Value ◽  
Practical Applications ◽  
Positioning Strategy ◽  
Value Decomposition ◽  
Observation Strategies

In this article, we discuss possible observing strategies for a simplified ocean model (Double Gyre (DG)), used as a preliminary tool to understand the observation needs for real analysis and forecasting systems. Observations are indeed fundamental to improve the quality of forecasts when data assimilation techniques are employed to obtain reliable analysis results. In addition, observation networks, particularly in situ observations, are expensive and require careful positioning of instruments. A possible strategy to locate observations is based on Singular Value Decomposition (SVD). SVD has many advantages when a variational assimilation method such as the 4D-Var is available, with its computation being dependent on the tangent linear and adjoint models. SVD is adopted as a method to identify areas where maximum error growth occurs and assimilating observations can give particular advantages. However, an SVD-based observation positioning strategy may not be optimal; thus, we introduce other criteria based on the correlation between points, as the information observed on neighboring locations can be redundant. These criteria are easily replicable in practical applications, as they require rather standard studies to obtain prior information.

Sodium Selenosulfate from Sodium Sulfite and Selenium Powder: An Odorless Selenylating Reagent for Alkyl Halides to Produce Dialkyl Diselenide Catalysts

Synlett ◽  
2019 ◽  
Vol 30 (14) ◽  
pp. 1698-1702
Author(s):  
Yonghong Liu ◽  
Hai Ling ◽  
Chao Chen ◽  
Qing Xu ◽  
Lei Yu ◽  
...  
Keyword(s):  
Selective Oxidation ◽  
Carbonyl Compounds ◽  
Sodium Sulfite ◽  
Alkyl Halides ◽  
Production Costs ◽  
Synthetic Method ◽  
Practical Applications ◽  
Sodium Selenosulfate ◽  
Villiger Oxidation

Na2SeSO3, which can be generated in situ by the reaction of Na2SO3 with Se power, was found to be an odorless reagent for the selenenylation of alkyl halides to produce dialkyl diselenides. These products have been recently shown to be good catalysts for the Baeyer–Villiger oxidation of carbonyl compounds, for the selective oxidation of alkenes, or for the oxidative deoximation of oximes. By using aqueous EtOH as the solvent and avoiding the generation of a malodourous selenol intermediate, the selenylation reaction with Na2SeSO3 is much more environmentally friendly than conventional methods. Owing to the cheap and abundant starting materials and selenium reagents, our novel synthetic method reduces the production costs of dialkyl diselenides as organoselenium catalysts, thereby advancing practical applications of organoselenium-catalysis technologies.

Expediting polysulfide catalytic conversion for lithium–sulfur batteries via in situ implanted ultrafine Fe3O4 nanocrystals in carbon nanospheres

2020 ◽  
Vol 8 (45) ◽  
pp. 24117-24127
Author(s):  
Zhe Su ◽  
Mingqi Chen ◽  
Yankai Pan ◽  
Yajing Liu ◽  
Hai Xu ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Catalytic Conversion ◽  
Carbon Nanospheres ◽  
Practical Applications ◽  
Lithium Sulfur Batteries ◽  
Solid Liquid ◽  
Lithium Sulfur

The sluggish reaction kinetics and notorious polysulfide shuttling arising from the multistep solid/liquid conversion are the significant obstacles to practical applications of lithium–sulfur (Li–S) batteries.

scholarly journals Scaling, rotation, and channeling behavior of helical and skyrmion spin textures in thin films of Te-doped Cu2OSeO3

2020 ◽  
Vol 6 (13) ◽  
pp. eaax2138 ◽  
Author(s):  
M.-G. Han ◽  
J. A. Garlow ◽  
Y. Kharkov ◽  
L. Camacho ◽  
R. Rov ◽  
...  
Keyword(s):  
Thin Films ◽  
Precise Measurement ◽  
Information Science ◽  
Practical Applications ◽  
Phase Microscopy ◽  
Emergent Phenomena ◽  
Hall Effects ◽  
Anisotropic Scaling ◽  
Important Challenge

Topologically nontrivial spin textures such as vortices, skyrmions, and monopoles are promising candidates as information carriers for future quantum information science. Their controlled manipulation including creation and annihilation remains an important challenge toward practical applications and further exploration of their emergent phenomena. Here, we report controlled evolution of the helical and skyrmion phases in thin films of multiferroic Te-doped Cu2OSeO3 as a function of material thickness, dopant, temperature, and magnetic field using in situ Lorentz phase microscopy. We report two previously unknown phenomena in chiral spin textures in multiferroic Cu2OSeO3: anisotropic scaling and channeling with a fixed-Q state. The skyrmion channeling effectively suppresses the recently reported second skyrmion phase formation at low temperature. Our study provides a viable way toward controlled manipulation of skyrmion lattices, envisaging chirality-controlled skyrmion flow circuits and enabling precise measurement of emergent electromagnetic induction and topological Hall effects in skyrmion lattices.

scholarly journals Disclosing violence in calls for help

2021 ◽  
Author(s):  
Emma Tennent ◽  
Ann Weatherall
Keyword(s):  
New Zealand ◽  
Conversation Analysis ◽  
Violence Against Women ◽  
Direct Reference ◽  
Shared Knowledge ◽  
Practical Applications ◽  
The World ◽  
Victim Support ◽  
Effects Of Violence

© 2019, equinox publishing. Violence against women is a pervasive problem, both in New Zealand society and around the world. Yet assessing the scale and effects of violence is difficult, as many women face barriers to disclosure. This paper examines women's disclosures of violence in calls for help to a victim support agency. We use conversation analysis and focus on membership categorisation to describe the different ways disclosures are built and understood in situ. It was only in a minority of cases (around 20%), that callers made direct reference to violence, or categorised themselves explicitly as victims, albeit with indications of problems in speaking. However, for the majority, women did not mention the words 'victim' or 'violence' at all. Instead, culturally shared knowledge associated with categories of people (e.g. ex-partners) and places (e.g. home and jail) were used to build and interpret a description as a disclosure of violence. Our work contributes to an understanding of women's disclosures of violence by examining them directly in the setting where they occur. We discuss some of the insights gained from examining interactions in situ, and the practical applications of our work for improving services for women who have experienced violence.

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