Chemical synthesis and structural studies of thiol-capped gold nanoparticles

2009 ◽  
Vol 87 (1) ◽  
pp. 335-340 ◽  
Author(s):  
Peng Zhang ◽  
Andy Yuan-Chi Chu ◽  
Tsun-Kong Sham ◽  
Yun Yao ◽  
Shuit-Tong Lee
Keyword(s):  
Chemical Synthesis ◽  
Chain Length ◽  
Silicon Nanowires ◽  
Au Nanoparticles ◽  
Silicon Nanowire ◽  
Spherical Particles ◽  
Phase System ◽  
Structural Studies ◽  
Two Phase ◽  
Au Nps

We report the chemical synthesis and structural studies of thiol-capped Au nanoparticles (NPs) using extended X-ray absorption fine structures (EXAFS) and high-resolution transmission electron microscopy (HRTEM). Synthesis of Au NPs was conducted in one case in a toluene/water two-phase system using alkanethiols with varied hydrocarbon chain length (C6, C12, and C18), resulting in NPs of sizes ranging from 1.6 nm to 5.4 nm. Au L3-edge EXAFS reveals a systematical trend of the local structure of Au in the NPs when the Au/S ratio and chain-length of thiols are varied. In another synthesis, thiol-capped Au NPs were prepared on the surface of silicon nanowires, which act as both substrates and reducing agents. HRTEM reveals that not only spherical particles but also very small quasi-1D nanostructures of Au were formed. The formation and structure of these Au NPs was discussed in terms of ligand and template effect associated with the silicon nanowire substrates.Key words: thiol-capped Au nanoparticles, EXAFS, silicon nanowires, electroless deposition, quasi-1D Au nanostructures.

Aqueous Two-Phase System Formation Kinetics for Elastin-Like Polypeptides of Varying Chain Length

2006 ◽  
Vol 7 (7) ◽  
pp. 2192-2199 ◽  
Author(s):  
Yanjie Zhang ◽  
Kimberly Trabbic-Carlson ◽  
Fernando Albertorio ◽  
Ashutosh Chilkoti ◽  
Paul S. Cremer
Keyword(s):  
Chain Length ◽  
Phase System ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
System Formation ◽  
Formation Kinetics

scholarly journals Preparation and Characterization of Bio-Based PLA/PBAT and Cinnamon Essential Oil Polymer Fibers and Life-Cycle Assessment from Hydrolytic Degradation

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 38 ◽  
Author(s):  
Zormy Nacary Correa-Pacheco ◽  
Jaime Daniel Black-Solís ◽  
Pedro Ortega-Gudiño ◽  
Marcos Antonio Sabino-Gutiérrez ◽  
José Jesús Benítez-Jiménez ◽  
...  
Keyword(s):  
Essential Oil ◽  
Hydrolytic Degradation ◽  
Fiber Surface ◽  
Industrial Applications ◽  
Spherical Particles ◽  
Poly Lactic Acid ◽  
Phase System ◽  
Special Importance ◽  
Two Phase ◽  
Cinnamon Essential Oil

Nowadays, the need to reduce the dependence on fuel products and to achieve a sustainable development is of special importance due to environmental concerns. Therefore, new alternatives must be sought. In this work, extruded fibers from poly (lactic acid) (PLA) and poly (butylene adipate-co-terephthalate) (PBAT) added with cinnamon essential oil (CEO) were prepared and characterized, and the hydrolytic degradation was assessed. A two-phase system was observed with spherical particles of PBAT embedded in the PLA matrix. The thermal analysis showed partial miscibility between PLA and PBAT. Mechanically, Young’s modulus decreased and the elongation at break increased with the incorporation of PBAT and CEO into the blends. The variation in weight loss for the fibers was below 5% during the period of hydrolytic degradation studied with the most important changes at 37 °C and pH 8.50. From microscopy, the formation of cracks in the fiber surface was evidenced, especially for PLA fibers in alkaline medium at 37 °C. This study shows the importance of the variables that influence the performance of polyester-cinnamon essential oil-based fibers in agro-industrial applications for horticultural product preservation.

scholarly journals Fabrication of Needle-Like Silicon Nanowires by Using a Nanoparticles-Assisted Bosch Process for Both High Hydrophobicity and Anti-Reflection

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1009
Author(s):  
Zengxing Zhang ◽  
Guohua Liu ◽  
Kaiying Wang
Keyword(s):  
Silicon Nanowires ◽  
Silicon Nanowire ◽  
Nanowire Array ◽  
Film Deposition ◽  
Au Nps ◽  
Aspect Ratios ◽  
Hydrophobic Behavior ◽  
Hydrophobic Chemical ◽  
Wave Range ◽  
Reflection Characteristics

In this work, a modified Bosch etching process is developed to create silicon nanowires. Au nanoparticles (NPs) formed by magnetron sputtering film deposition and thermal annealing were employed as the hard mask to achieve controllable density and high aspect ratios. Such silicon nanowire exhibits the excellent anti-reflection ability of a reflectance value of below 2% within a broad light wave range between 220 and 1100 nm. In addition, Au NPs-induced surface plasmons significantly enhance the near-unity anti-reflection characteristics, achieving a reflectance below 3% within the wavelength range of 220 to 2600 nm. Furthermore, the nanowire array exhibits super-hydrophobic behavior with a contact angle over ~165.6° without enforcing any hydrophobic chemical treatment. Such behavior yields in water droplets bouncing off the surface many times. These properties render this silicon nanowire attractive for applications such as photothermal, photocatalysis, supercapacitor, and microfluidics.

Intersect distributions of a `dead leaves' model with spherical primary grains

2005 ◽  
Vol 38 (3) ◽  
pp. 520-527 ◽  
Author(s):  
Wilfried Gille
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Length Distribution ◽  
Hard Core ◽  
Spherical Particles ◽  
Characteristic Functions ◽  
Phase System ◽  
Two Phase ◽  
Linear Integration ◽  
Dead Leaves Model

This article analyses a tightly packed random two-phase system possessing spherical particles having the volume fraction of 1/8. For a three-dimensional hard-core `dead leaves' model of spheres of constant diameter, the chord length distribution density of typical chords m i of the connected phase (outside the hard particles) is investigated. The calculation starts from the second derivative of the small-angle scattering correlation function of the model and applies characteristic functions. The result fulfills Rosiwal's linear integration principle.

scholarly journals Hydrodynamic characteristics of a two-phase gas-liquid flow upward through a fixed bed of spherical particles

2001 ◽  
Vol 66 (1) ◽  
pp. 53-64 ◽  
Author(s):  
Snezana Serbula ◽  
Velizar Stankovic
Keyword(s):  
Pressure Drop ◽  
Liquid Velocity ◽  
Fixed Bed ◽  
Particle Diameter ◽  
Packed Bed ◽  
Spherical Particles ◽  
Hydrodynamic Characteristics ◽  
Phase System ◽  
Relative Pressure ◽  
Two Phase

The influence of an electrochemically generated gas phase on the hydrodynamic characteristics of a three-phase system has been examined. The two-phase fluid, (gas-liquid), in which the liquid phase is the continuous one, flows through a packed bed with glass spheres. The influence of the liquid velocity was examined, as well as the gas velocity and particle diameter on the pressure drop through the fixed bed. It was found that with increasing liquid velocity (wl = 0.0162-0.03 m/s), the relative pressure drop decreases through the fixed bed. With increasing current density, the pressure drop increases, since greater gas quantities stay behind in the fixed bed. Besides, it was found that with decreasing diameter of the glass particles, the relative pressure drop also decreases. The relationship betweeen the experimentally obtained friction factor and the Reynolds number was established.

On the Problem of “Two-Phase” Activated Sludge

1991 ◽  
Vol 24 (7) ◽  
pp. 59-64 ◽  
Author(s):  
R. W. Szetela
Keyword(s):  
Activated Sludge ◽  
Single Phase ◽  
Phase System ◽  
Two Phase ◽  
Wastewater Treatment Process ◽  
Sludge Stabilization ◽  
Technological Advantage ◽  
In Series ◽  
State Models ◽  
Activated Sludge Systems

Steady-state models are presented to describe the wastewater treatment process in two activated sludge systems. One of these makes use of a single complete-mix reactor; the other one involves two complete-mix reactors arranged in series. The in-series system is equivalent to what is known as the “two-phase” activated sludge, a concept which is now being launched throughout Poland in conjunction with the PROMLECZ technology under implementation. Analysis of the mathematical models has revealed the following: (1) treatment efficiency, excess sludge production, energy consumption, and the degree of sludge stabilization are identical in the two systems; (2) there exists a technological equivalence of “two-phase” sludge with “single-phase” sludge; (3) the “two-phase” system has no technological advantage over the “single-phase” system.

Interphase distribution of 2-furylethylenes

1985 ◽  
Vol 50 (8) ◽  
pp. 1642-1647 ◽  
Author(s):  
Štefan Baláž ◽  
Anton Kuchár ◽  
Ernest Šturdík ◽  
Michal Rosenberg ◽  
Ladislav Štibrányi ◽  
...  
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Transport Rate ◽  
Phase System ◽  
Two Phase ◽  
Interphase Distribution ◽  
Distribution Kinetics ◽  
System 1 ◽  
Kinetics Of

The distribution kinetics of 35 2-furylethylene derivatives in two-phase system 1-octanol-water was investigated. The transport rate parameters in direction water-1-octanol (l1) and backwards (l2) are partition coefficient P = l1/l2 dependent according to equations l1 = logP - log(βP + 1) + const., l2 = -log(βP + 1) + const., const. = -5.600, β = 0.261. Importance of this finding for assesment of distribution of compounds under investigation in biosystems and also the suitability of the presented method for determination of partition coefficients are discussed.

Enhancing the Sensitivity of DNA and Aptamer Probes in the Dextran/PEG Aqueous Two-Phase System

2021 ◽  
Author(s):  
Qiaoshu Chen ◽  
Yanwen Zhang ◽  
Hui Chen ◽  
Jianbo Liu ◽  
Juewen Liu
Keyword(s):  
Phase System ◽  
Two Phase ◽  
Aqueous Two Phase System
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