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31.
Regtmeier J Eichhorn R Duong TT Reimann P Anselmetti D Ros A 《The European physical journal. E, Soft matter》2007,22(4):335-340
We demonstrate the proof-of-principle of a new separation concept for micrometer-sized particles in a structured microfluidic
device. Under the action of externally applied, periodic
voltage-pulses two different species of like-charged polystyrene beads are observed to simultaneously migrate into opposite
directions. Based on a theoretical model of the particle motion in the microdevice that shows good agreement with the experimental
measurements, the underlying separation mechanism is identified and explained. Potential biophysical applications, such as
cell sorting, are briefly addressed. 相似文献
32.
N. M. Berezina Vu Thi Thao D. R. Karimov R. S. Kumeev A. V. Kustov M. I. Bazanov D. B. Berezin 《Russian Journal of General Chemistry》2014,84(4):737-744
Spectral properties and chemical stability of Mn(III), Mn(IV), Fe(III), Fe(IV), and Cu(III) complexes of β-octabromotriphenylcorrole [(β-Br)8(ms-Ph)3Cor], synthesized from β-unsubstituted compounds by their reaction with molecular bromine, were studied. Cyclic voltammetry, electron microscopy, and X-ray spectral microanalysis were used to obtain electrochemical characteristics of metal corroles M(β-Br)8(ms-Ph)3Cor and gain insight into the surface texture of active catalysts on the basis of metal corroles. The electron-acceptor β-bromine substitution in the MCor macrocycle shifts the equilibrium in electron-donor solvents to lower oxidation states of the metals and also stabilizes manganese and destabilizes copper complexes in the protondonor medium HOAc-H2SO4. The electrocatalytic activity of the complexes in the reduction of molecular oxygen depends on the nature of the ligand and increases in the order Mn ≤ Cu ? Fe in the case of β-octabrominated macrocycles. The character of distribution of active centers on the surface of the catalysts was established for the first time. 相似文献
33.
Avik Khan Khanh Dang Vu Gregory Chauve Jean Bouchard Bernard Riedl Monique Lacroix 《Cellulose (London, England)》2014,21(5):3457-3468
Microfluidization, which is a high-pressure homogenization technique, was used to develop highly dispersed cellulose nanocrystal (CNC) reinforced chitosan based nanocomposite films. A three factor central composite design with five levels was designed to systematically optimize the microfluidization process. The three factors were the CNC content, the microfluidization pressure and the number of microfluidization cycles. Response surface methodology was used to obtain relationship between the mechanical properties of the nanocomposite films and the factors. Polynomial equations were generated based on the regression analysis of the factors and the predicted properties of the nanocomposite films were in good agreement with the experimental results. Microfluidization effectively reduced the CNC–chitosan aggregates and improved the mechanical properties of the nanocomposite films. Microscopic analysis of the microfluidized nanocomposite films revealed a 10–15 times reduction in the size of the aggregates compared to the non-microfluidized CNC/chitosan films and an increase in the root mean square surface roughness (Rq). 相似文献
34.
Son Tung Ngo Trung Hai Nguyen Nguyen Thanh Tung Pham Cam Nam Khanh B. Vu Van V. Vu 《Journal of computational chemistry》2020,41(7):611-618
Determination of the ligand-binding affinity is an extremely interesting problem. Normally, the free energy perturbation (FEP) method provides an appropriate result. However, it is of great interest to improve the accuracy and precision of this method. In this context, temperature replica exchange molecular dynamics implementation of the FEP computational approach, which we call replica exchange free energy perturbation (REP) was proposed. In particular, during REP simulations, the system can easily escape from being trapped in local minima by exchanging configurations with high temperatures, resulting in significant improvement in the accuracy and precision of protein–ligand binding affinity calculations. The distribution of the decoupling free energy was enlarged, and its mean values were decreased. This results in changes in the magnitude of the calculated binding free energies as well as in alteration in the binding mechanism. Moreover, the REP correlation coefficient with respect to experiment ( RREP = 0.85 ± 0.15 ) is significantly boosted in comparison with the FEP one ( RFEP = 0.64 ± 0.30 ). Furthermore, the root-mean-square error (RMSE) of REP is also smaller than FEP, RMSEREP = 4.28 ± 0.69 versus RMSEFEP = 5.80 ± 1.11 kcal/mol, respectively. © 2019 Wiley Periodicals, Inc. 相似文献
35.
Nhat Anh Thi Thieu Minh Canh Vu Dae Hoon Kim Won Kook Choi Sung‐Ryong Kim 《先进技术聚合物》2020,31(10):2351-2359
The composites comprising vertically aligned network of copper nanowires (CuNWs) in the presence of cellulose nanofibers were fabricated by using the freeze‐templating method and the effect of aspect ratio (A/R) of CuNWs on the thermal conductivity of epoxy composites was investigated. The thermal conductivity of epoxy composites increased to 0.79 W m?1 K?1 at 1.12 vol% of high A/R CuNWs loading, corresponding to the thermal conductivity enhancement of 365% as compared to the pure epoxy. The thermal conductivity of vertically aligned higher A/R CuNWs/epoxy, which is 38.5% and 51.9% higher than those of the lower A/R CuNWs and the randomly aligned CuNWs, respectively. The application of the epoxy composites in heat dissipation was demonstrated by the temperature changes of composites on a hot plate with the increase of heating time. These results indicate that the thermally conductive composites in this study could be applied for thermal dissipating materials in electronic devices. 相似文献
36.
Van H. Vu 《Journal of Graph Theory》1996,22(2):137-149
A graph is called of type k if it is connected, regular, and has k distinct eigenvalues. For example graphs of type 2 are the complete graphs, while those of type 3 are the strongly regular graphs. We prove that for any positive integer n, every graph can be embedded in n cospectral, non-isomorphic graphs of type k for every k ≥ 3. Furthermore, in the case k ≥ 5 such a family of extensions can be found at every sufficiently large order. Some bounds for the extension will also be given. © 1996 John Wiley & Sons, Inc. 相似文献
37.
The gauge symmetry group of any slave boson representation allows to gauge away the phase of bosonic fields. One benefit of this radial field formulation is the elimination of spurious Bose condensations when saddle-point approximation is performed. Within the Kotliar–Ruckenstein representation, three of the four bosonic fields can be radial while the last one has to remain complex. In this work, the procedure to carry out the functional integration involving constrained fermionic fields, complex bosonic fields, and radial bosonic fields is presented. The correctness of the representation is verified by exactly evaluating the partition function and the Green's function of the Hubbard model in the atomic limit. 相似文献
38.
We present the first realisation of ferromagnetic Fe nanotips. Studies of the field emitted beams of electrons and metallic ions above and under the Curie temperature Tc were made. We have observed a reversible splitting of the electron beams when the temperature crossed through Tc and multiple spot patterns for the emitted metallic ion beams. These phenomena were not observed with Fe microtips or non-magnetic nanotips and thus were correlated to a strong magnetic interaction at the atomic scale apex of the nanotips. The Fe nanotips constitute an atomic scale beam-splitter. 相似文献
39.
David M. Whalley Hung A. Duong Prof. Michael F. Greaney 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(8):1927-1930
A light-mediated Truce–Smiles arylative rearrangement is described that proceeds in the absence of any photocatalyst. The protocol creates two C−C bonds from simple starting materials, with the installation of an aryl ring and a difluoroacetate moiety across unactivated alkenes. The reaction proceeds via a radical mechanism, utilizing a light-mediated reduction of ethyl bromodifluoroacetate by N,N,N′,N′-tetramethylethylenediamine (TMEDA) to set up intermolecular addition to an unactivated alkene, followed by Truce–Smiles rearrangement. 相似文献
40.
A dynamic mathematical model is developed for production of Cerenol polyether from 1,3‐propanediol in a batch reactor system. The model accounts for polycondensation reactions and side reactions in the liquid phase and for mass transfer of volatile species to the vapor. Parameters are estimated using measured liquid‐phase concentrations of monomer, oligomers, water, and end groups as well as the mass and composition of condensate collected from the overhead condenser system. The proposed model uses novel probability factors to keep the model equations relatively simple while accounting for the complex influence of superacid catalyst on reaction rates. The model is a significant advance over previous Cerenol models because it better accounts for mass‐transfer rates and for the dynamic behavior of the condenser. In addition, the proposed model accounts for the inhibitory influence of water on polycondensation kinetics due to hydration of hydroxyl ends. The model equations and parameter estimates provide a substantial improvement in fit to the data, especially for long reaction times and high catalyst levels, resulting in a 97% reduction in the value of the weighted least squared objective function compared to equations and parameters from a previous model. 相似文献