Fast Reaction Limits and Liesegang Bands

2006 ◽  
pp. 241-250 ◽  
Author(s):  
D. Hilhorst ◽  
R. van der Hout ◽  
M. Mimura ◽  
I. Ohnishi
Keyword(s):  
Fast Reaction ◽  
Liesegang Bands

Gravity Effect on the Formation of Periodic Precipitation Patterns

2000 ◽  
Vol 65 (9) ◽  
pp. 1438-1442 ◽  
Author(s):  
Vladislav Holba ◽  
Frederik Fusek
Keyword(s):  
Gravitational Field ◽  
Spatial Arrangement ◽  
Experimental Results ◽  
Single Sample ◽  
Gravity Effect ◽  
Periodic Precipitation ◽  
Precipitation Patterns ◽  
Liesegang Bands

The effect of gravity on the formation of Liesegang patterns of Ag2Cr2O7in gelatin and that of PbI2in agar was investigated. Spatial arrangement of Liesegang bands was measured in the parallel and antiparallel orientation to the gravitational field in a single sample with all other parameters kept fixed. The experimental results are discussed in terms of the prenucleation theory of periodic precipitation.

Phoretic self-propulsion of Janus disks in the fast-reaction limit

2020 ◽  
Vol 5 (11) ◽  
Author(s):  
Ehud Yariv ◽  
Darren Crowdy
Keyword(s):  
Fast Reaction ◽  
Fast Reaction Limit

scholarly journals Ultra-small Fe3O4 nanodots encapsulated in layered carbon nanosheets with fast kinetics for lithium/potassium-ion battery anodes

RSC Advances ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 1261-1270
Author(s):  
Qianqian Peng ◽  
Chuan Guo ◽  
Shuo Qi ◽  
Weiwei Sun ◽  
Li-Ping Lv ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Robust Stability ◽  
Potassium Ion ◽  
High Conductivity ◽  
Fast Reaction ◽  
Fast Kinetics ◽  
Carbon Nanosheets

Ultra-small Fe3O4 nanodots encapsulated in layered carbon nanosheet nanocomposites were synthesized, showing fast reaction kinetics, high conductivity, and robust stability.

scholarly journals Fast Reaction Limits via $$\Gamma $$-Convergence of the Flux Rate Functional

2021 ◽  
Author(s):  
Mark A. Peletier ◽  
D. R. Michiel Renger
Keyword(s):  
Evolution Equations ◽  
Detailed Balance ◽  
Approximate Solutions ◽  
Reaction Rates ◽  
Convergence Result ◽  
Rate Function ◽  
Jump Processes ◽  
Kolmogorov Equations ◽  
Markov Jump ◽  
Fast Reaction

AbstractWe study the convergence of a sequence of evolution equations for measures supported on the nodes of a graph. The evolution equations themselves can be interpreted as the forward Kolmogorov equations of Markov jump processes, or equivalently as the equations for the concentrations in a network of linear reactions. The jump rates or reaction rates are divided in two classes; ‘slow’ rates are constant, and ‘fast’ rates are scaled as $$1/\epsilon $$ 1 / ϵ , and we prove the convergence in the fast-reaction limit $$\epsilon \rightarrow 0$$ ϵ → 0 . We establish a $$\Gamma $$ Γ -convergence result for the rate functional in terms of both the concentration at each node and the flux over each edge (the level-2.5 rate function). The limiting system is again described by a functional, and characterises both fast and slow fluxes in the system. This method of proof has three advantages. First, no condition of detailed balance is required. Secondly, the formulation in terms of concentration and flux leads to a short and simple proof of the $$\Gamma $$ Γ -convergence; the price to pay is a more involved compactness proof. Finally, the method of proof deals with approximate solutions, for which the functional is not zero but small, without any changes.

scholarly journals Sonochemical and Sonoelectrochemical Production of Energy Materials

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 284
Author(s):  
Faranak Foroughi ◽  
Jacob J. Lamb ◽  
Odne S. Burheim ◽  
Bruno G. Pollet
Keyword(s):  
Reaction Rates ◽  
Surface Cleaning ◽  
Energy Materials ◽  
Fast Reaction ◽  
Ultrasound Frequency ◽  
Production Of Hydrogen ◽  
Scientists And Engineers ◽  
Electrocatalyst Materials ◽  
Made In ◽  
Semiconductor Photocatalyst

Sonoelectrochemistry is the combination of ultrasound and electrochemistry which provides many advantages in electrochemistry, such as fast reaction rates, surface cleaning and activation, and increased mass transport at an electrode. Due to the advantages, some efforts have been made in order to benefit sonoelectrochemistry in the field of energy and environmental engineering. This review paper highlights the developed progress of the application of sonoelectrochemistry in the production of hydrogen, electrocatalyst materials and electrodes for fuel cells and semiconductor photocatalyst materials. This review also provides the experimental methods that are utilized in several sonoelectrochemical techniques, such as different set-ups generally used for the synthesis of energy-related materials. Different key parameters in the operation of sonoelectrochemical synthesis including ultrasonication time, ultrasound frequency and operation current have been also discussed. There are not many research articles on the sonoelectrochemical production of materials for supercapacitors and water electrolyzers which play crucial roles in the renewable energy industry. Therefore, at the end of this review, some articles which have reported the use of ultrasound for the production of electrocatalysts for supercapacitors and electrolyzers have been reviewed. The current review might be helpful for scientists and engineers who are interested in and working on sonoelectrochemistry and electrocatalyst synthesis for energy storage and energy conversion.

Self-Powered Droplet Manipulation System for Microfluidics Based on Triboelectric Nanogenerator Harvesting Rotary Energy

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Junjie Yu ◽  
Xiaoxiang Wei ◽  
Yuanchao Guo ◽  
Ziwei Zhang ◽  
Pinshu Rui ◽  
...  
Keyword(s):  
Microfluidic System ◽  
Triboelectric Nanogenerator ◽  
Cross Contamination ◽  
Fast Reaction ◽  
Microfluidic Technology ◽  
Manipulation System ◽  
Droplet Manipulation ◽  
Self Powered

Microfluidic technology, as a method for manipulating tiny fluids, has the advantages of low sample consumption, fast reaction, and no cross-contamination. In the microfluidic system, accurate manipulation of droplets is...

scholarly journals Effects of Synthetic Procedures and Postsynthesis Incubation pH on Size, Shape, and Antibacterial Activity of Copper (I) Oxide Nanoparticles

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Vinh Tien Nguyen ◽  
Khanh Son Trinh
Keyword(s):  
Antibacterial Activity ◽  
High Surface ◽  
Size Variation ◽  
Reaction Rates ◽  
Bacterial Suspension ◽  
Oxide Nanoparticles ◽  
Surface Charges ◽  
Fast Reaction ◽  
Sem Images ◽  
Etching Effect

Copper (I) oxide nanoparticles (Cu2O NP) were synthesized by reducing CuSO4 with glucose in the presence of polyvinyl alcohol as a capping agent. We used three different synthetic procedures with a fast reaction (procedure 1p), a fast-then-slow reaction (procedure 2p), and a slow-then-fast reaction (procedure 3p). The reaction rates were controlled by changing the temperature and the speed of adding reagents. The synthesized Cu2O NP were subsequently incubated for 24 h in a pH 6 solution (Cu2O NP6) or a pH 8 solution (Cu2O NP8) at 5°C. XRD and SEM images analysis revealed that the 1p procedure produced smaller NP, while the 2p procedure produced larger but more uniform NP. The 3p procedure produced the largest NP with a higher size variation. The 24-hour acidic postsynthesis incubation resulted in an etching effect, which reduced the size and size variation of Cu2O NP6. To evaluate the antibacterial activity, E. coli suspensions were mixed with the obtained Cu2O NP (32, 96, or 160 ppm) for different time intervals (1 or 24 h) and then grown on Petri dishes at 37°C for 24 h. Higher doses, smaller sizes of Cu2O NP, and longer contact times with the bacterial suspension resulted in higher inactivation efficiencies. Cu2O NP6 showed higher antibacterial effects at low doses, possibly due to the etching effect and the positive surface charge. Increasing the Cu2O doses from 32 to 96 and 160 ppm noticeably increased the antibacterial effect of the Cu2O NP8, but not significantly for Cu2O NP6. We suggested that the Cu2O NP6 suffered from agglomeration at high doses due to their high surface activity and low surface charges.

scholarly journals A Versatile Method for Preparing Polysaccharide Conjugates via Thiol-Michael Addition

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1905
Author(s):  
Junyi Chen ◽  
Xutao Ma ◽  
Kevin J. Edgar
Keyword(s):  
Michael Addition ◽  
Quaternary Ammonium ◽  
Synthetic Approach ◽  
Renewable Materials ◽  
Fast Reaction ◽  
Michael Additions ◽  
Antimicrobial Performance ◽  
A Charge ◽  
Post Modification ◽  
Fast Reaction Rate

Polysaccharide conjugates are important renewable materials. If properly designed, they may for example be able to carry drugs, be proactive (e.g., with amino acid substituents) and can carry a charge. These aspects can be particularly useful for biomedical applications. Herein, we report a simple approach to preparing polysaccharide conjugates. Thiol-Michael additions can be mild, modular, and efficient, making them useful tools for post-modification and the tailoring of polysaccharide architecture. In this study, hydroxypropyl cellulose (HPC) and dextran (Dex) were modified by methacrylation. The resulting polysaccharide, bearing α,β-unsaturated esters with tunable DS (methacrylate), was reacted with various thiols, including 2-thioethylamine, cysteine, and thiol functional quaternary ammonium salt through thiol-Michael addition, affording functionalized conjugates. This click-like synthetic approach provided several advantages including a fast reaction rate, high conversion, and the use of water as a solvent. Among these polysaccharide conjugates, the ones bearing quaternary ammonium salts exhibited competitive antimicrobial performance, as supported by a minimum inhibitory concentration (MIC) study and tracked by SEM characterization. Overall, this methodology provides a versatile route to polysaccharide conjugates with diverse functionalities, enabling applications such as antimicrobial activity, gene or drug delivery, and biomimicry.

The Pose of Data Model and Research Based on Analysis of Intelligent Test Paper

2013 ◽  
Vol 303-306 ◽  
pp. 2203-2206
Author(s):  
Cai Li Fang ◽  
Lin Wu
Keyword(s):  
Data Model ◽  
Paper Analysis ◽  
Calculation Model ◽  
Test Paper ◽  
Fast Reaction ◽  
Analysis Algorithm ◽  
The Future ◽  
Education Measurement ◽  
Calculation Models

As a important part of teaching, Traditional paper analysis algorithm is complicated and not comprehensive enough. This paper according to the indicators of education measurement and improves the traditional calculation models, the system assesses the perfect calculation model, The teacher also can get the true and fast reaction to students' knowledge and the quality of the paper. This method thereby provides a convincing basis for the improvement on the future teaching and increase the effectiveness in teaching

PET-RAFT single unit monomer insertion of β-methylstyrene derivatives: RAFT degradation and reaction selectivity

2021 ◽  
Author(s):  
Lei Zhang ◽  
Ruizhe Liu ◽  
Shiyang Lin ◽  
Jiangtao Xu
Keyword(s):  
Reaction Kinetics ◽  
Single Unit ◽  
Chain Transfer ◽  
Fast Reaction ◽  
Reaction Selectivity ◽  
Reversible Addition

Reversible addition-fragmentation chain transfer (RAFT) single unit monomer insertion (SUMI) of β-Methylstyrene derivatives into diverse RAFT agents presented fast reaction kinetics, but a significant degradation of the SUMI products occurred...

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