排序方式: 共有24条查询结果,搜索用时 15 毫秒
1.
Takeshita N Paradis LA Oner D McCarthy TJ Chen W 《Langmuir : the ACS journal of surfaces and colloids》2004,20(19):8131-8136
Wettability was controlled in a rational manner by individually and simultaneously manipulating surface topography and surface chemical structure. The first stage of this research involved the adsorption of charged submicrometer polystyrene latex particles to oppositely charged poly(ethylene terephthalate) (PET) film samples to form surfaces with different topographies/roughness; adsorption time, solution pH, solution ionic strength, latex particle size, and substrate charge density are external variables that were controlled. The introduction of discrete functional groups to smooth and rough surfaces through organic transformations was carried out in the second stage. Amine groups (-NH(2)) and alcohol groups (-OH) were introduced onto smooth PET surfaces by amidation with poly(allylamine) and adsorption with poly(vinyl alcohol) (PVOH), respectively. On latex particle adsorbed surfaces, a thin layer of gold was evaporated first to prevent particle redistribution before chemical transformation. Reactions with functionalized thiols and adsorption with PVOH on patterned gold surfaces successfully enhanced surface hydrophobicity and hydrophilicity. Particle size and biomodal particle size distribution affect both hydrophobicity and hydrophilicity. A very hydrophobic surface exhibiting water contact angles of 150 degrees /126 degrees (theta(A)/theta(R)) prepared by adsorption of 1-octadecanethiol and a hydrophilic surface with water contact angles of 18 degrees /8 degrees (theta(A)/theta(R)) prepared by adsorption of PVOH were prepared on gold-coated surfaces containing both 0.35 and 0.1 microm latex particles. The combination of surface topography and surface-chemical functionality permits wettability control over a wide range. 相似文献
2.
Description of the response of a fiber optic velocity sensor applied to capillary gas chromatography
This paper explores the response of a novel fiber optics sensor allowing real-time determination of the migration rate of vapor zones in capillary gas chromatography. The sensitivity is related to the gradient of the vapor zone distribution in the capillary and it is highest when vapor zones show steep variations in concentration. The expected linearity between the height of the velocity peaks and the response of a thermal conductivity detector is demonstrated experimentally. The sensor can be used to infer an approximate value of the analyte diffusion coefficient from the time response. Finally, the time evolution of the envelope of the optical signal is explained with experimental evidences. 相似文献
3.
Emmanuel Paradis 《Journal of computational and graphical statistics》2013,22(4):935-939
Multidimensional scaling has a wide range of applications when observations are not continuous but it is possible to define a distance (or dissimilarity) among them. However, standard implementations are limited when analyzing very large datasets because they rely on eigendecomposition of the full distance matrix and require very long computing times and large quantities of memory. Here, a new approach is developed based on projection of the observations in a space defined by a subset of the full dataset. The method is easily implemented. A simulation study showed that its performance are satisfactory in different situations and can be run in a short time when the standard method takes a very long time or cannot be run because of memory requirements. 相似文献
4.
Pierre-Alexandre Paquet-Côté Kellie L. Tuck Jean-Philippe Paradis Bim Graham Normand Voyer 《Tetrahedron letters》2017,58(50):4672-4676
Seeking to increase the selectivity of antimicrobial peptides for prokaryotic cells, we incorporated a bis-dipicolyl amine (bis-DPA) ligand at the N-terminus of de novo designed model peptides. The Zn2·bisDPA complex increases the interaction of peptides with anionic model membranes, while decreasing interactions with zwitterionic model membranes. Further, it improves the peptides’ antimicrobial activity and decreases their hemolytic activity without substantial changes to their secondary structure. Therefore, incorporating a Zn2·bisDPA complex is a useful strategy to enhance the selectivity of antimicrobial peptides. 相似文献
5.
6.
Aashka Y. Patel Keertana S. Jonnalagadda Nicholas Paradis Timothy D. Vaden Chun Wu Gregory A. Caputo 《Molecules (Basel, Switzerland)》2021,26(2)
In the past decade, innovative protein therapies and bio-similar industries have grown rapidly. Additionally, ionic liquids (ILs) have been an area of great interest and rapid development in industrial processes over a similar timeline. Therefore, there is a pressing need to understand the structure and function of proteins in novel environments with ILs. Understanding the short-term and long-term stability of protein molecules in IL formulations will be key to using ILs for protein technologies. Similarly, ILs have been investigated as part of therapeutic delivery systems and implicated in numerous studies in which ILs impact the activity and/or stability of protein molecules. Notably, many of the proteins used in industrial applications are involved in redox chemistry, and thus often contain metal ions or metal-associated cofactors. In this review article, we focus on the current understanding of protein structure-function relationship in the presence of ILs, specifically focusing on the effect of ILs on metal containing proteins. 相似文献
7.
8.
Serge Caron Claude ParéPatrick Paradis Huimin ZhengAntoine Proulx André Fougères 《Journal of chromatography. A》2010,1217(20):3435-3440
A fiber optic sensor has been used for real-time measurement of the migration rates of all the compounds in a mixture separated by gas chromatography. The sensor makes use of a coated capillary optical fiber as the column. This new type of waveguide consists in a polarization-maintaining optical core positioned close to the capillary edge along the entire fiber length. The optical detection is performed through the coupling of the two polarization modes of the waveguide and this coupling is detected by a polarimetric interferometry technique. Through some signal processing, the resulting interferogram provides the migration rates of the various compounds of a gas mixture flowing in the capillary. One of the major benefits of this optical migration rate sensing is that the detection of each velocity peak appears as soon as the analyte enters the capillary fiber and the peaks are constantly measured during the whole separation process. Carrier gas acceleration occurring in the column is plainly demonstrated. This paper presents a proof-of-concept on a qualitative basis. The experiments were done at 29 °C because the current opto-fluidic set-up cannot withstand a higher temperature. 相似文献
9.
Junpei T. Okada Takehiko Ishikawa Yuki Watanabe Paul-François Paradis 《The Journal of chemical thermodynamics》2010,42(7):856-859
Surface tension and viscosity of molten vanadium were measured over a wide temperature range by the oscillating drop method in an electrostatic levitation furnace. Over the (2023 to 2517) K temperature range, the surface tension can be expressed as γ(T)/(10?3 N/m) = 1935 ? 0.27 {(T ? Tm)/K} with Tm = 2183 K. Over the same temperature span, the viscosity can be expressed as η(T)/(10?3 Pa · s) = 1.23exp[2.27 · 104/(RTK?1)], where R is the gas constant. 相似文献
10.
An image-processing method is proposed to obtain the distribution of the removal efficiency of particles on a plate by an
air jet. This method can be used to measure particle removal from a flat surface by processing the image of the reflected
light from the surface. Factors affecting the particle removal efficiency such as air pressure, distance between the nozzle
and the impinging surface and the impinging angle are discussed. Optimal conditions are determined to obtain the most effective
particle removal by the air jet.
Received: 10 April 2001 / Accepted: 2 August 2001 相似文献