scholarly journals Synthesis of Air-Stable Cu Nanoparticles Using Laser Reduction in Liquid

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 814
Author(s):  
Ashish Nag ◽  
Laysa Mariela Frias Batista ◽  
Katharine Moore Tibbetts
Keyword(s):  
Carbon Matrix ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Cu Nanoparticles ◽  
Ambient Conditions ◽  
Tem Analysis ◽  
Highly Active ◽  
Nitrophenol Reduction ◽  
The Stability ◽  
Laser Reduction

We report the synthesis of air-stable Cu nanoparticles (NPs) using the bottom-up laser reduction in liquid method. Precursor solutions of copper acetlyacetonate in a mixture of methanol and isopropyl alcohol were irradiated with femtosecond laser pulses to produce Cu NPs. The Cu NPs were left at ambient conditions and analyzed at different ages up to seven days. TEM analysis indicates a broad size distribution of spherical NPs surrounded by a carbon matrix, with the majority of the NPs less than 10 nm and small numbers of large particles up to ∼100 nm in diameter. XRD collected over seven days confirmed the presence of fcc-Cu NPs, with some amorphous Cu2O, indicating the stability of the zero-valent Cu phase. Raman, FTIR, and XPS data for oxygen and carbon regions put together indicated the presence of a graphite oxide-like carbon matrix with oxygen functional groups that developed within the first 24 h after synthesis. The Cu NPs were highly active towards the model catalytic reaction of para-nitrophenol reduction in the presence of NaBH4.

Laser Ion Kinetics: Dynamics of Intramolecular Reactions in Substituted Benzalacetones

2000 ◽  
Vol 6 (2) ◽  
pp. 143-152 ◽  
Author(s):  
R. Heinicke ◽  
C. Grun ◽  
J. Grotemeyer
Keyword(s):  
Femtosecond Laser ◽  
Mass Spectrometer ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Photon Absorption ◽  
Single Shot ◽  
Pump Probe ◽  
Intramolecular Reactions ◽  
The Stability ◽  
Fragmentation Processes

Measurements of a single shot femtosecond laser pump-probe technique on substituted benzalacetones are reported. The technique is based on counter propagating femtosecond laser pulses in a supersonic beam of low density of sample molecules and simultaneous probe detection by ion or fragment ion formation through a reflectron time-of-flight mass spectrometer. It will be shown that the range of the pump-probe delays covers the time span between 100 fs and 10 ps depending on the pulse width of the laser used and the stability of the voltages of the mass spectrometer. The application of this technique to medium-sized organic molecules reveals some insight into the electron transfer process during ionisation through a 1 + 1 multi-photon absorption procedure. Furthermore it is demonstrated that this technique is also applicable to the investigation of ultra-fast isomerisation and fragmentation processes.

scholarly journals 3-D aluminum nanostructure with microhole array synthesized by femtosecond laser radiation for enhanced light extinction

2021 ◽  
Author(s):  
Abdul Salam Mahmood ◽  
Krishnan Venkatakrishnan ◽  
Bo Tan
Keyword(s):  
Femtosecond Laser ◽  
Light Absorption ◽  
Target Surface ◽  
Laser Pulses ◽  
Pulse Frequency ◽  
Femtosecond Laser Pulses ◽  
Light Extinction ◽  
Ambient Conditions ◽  
Aluminum Target ◽  
Microhole Array

This article presents 3-D aluminum micro-nanostructures for enhanced light absorption. Periodic microhole arrays were created by firing a train of femtosecond laser pulses at megahertz pulse frequency onto the surface of an aluminum target at ambient conditions. The laser trains ablated the target surface and created microholes leading to the generation of deposited nanostructures inside and around the microholes. These micro-nanostructures showed enhanced light absorption, which is attributed to surface plasmonics induced by the generation of both nano- and microstructures. These micro-nanostructures may be promising for solar cell applications.

scholarly journals 3-D aluminum nanostructure with microhole array synthesized by femtosecond laser radiation for enhanced light extinction

2021 ◽  
Author(s):  
Abdul Salam Mahmood ◽  
Krishnan Venkatakrishnan ◽  
Bo Tan
Keyword(s):  
Femtosecond Laser ◽  
Light Absorption ◽  
Target Surface ◽  
Laser Pulses ◽  
Pulse Frequency ◽  
Femtosecond Laser Pulses ◽  
Light Extinction ◽  
Ambient Conditions ◽  
Aluminum Target ◽  
Microhole Array

This article presents 3-D aluminum micro-nanostructures for enhanced light absorption. Periodic microhole arrays were created by firing a train of femtosecond laser pulses at megahertz pulse frequency onto the surface of an aluminum target at ambient conditions. The laser trains ablated the target surface and created microholes leading to the generation of deposited nanostructures inside and around the microholes. These micro-nanostructures showed enhanced light absorption, which is attributed to surface plasmonics induced by the generation of both nano- and microstructures. These micro-nanostructures may be promising for solar cell applications.

Structurally colored stainless steel processed by using femtosecond laser pulses

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040016
Author(s):  
Caizhen Yao ◽  
Yuan Li ◽  
Shizhen Xu ◽  
Xinxiang Miao ◽  
Yayun Ye ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Femtosecond Laser ◽  
Periodic Structures ◽  
Normal Incidence ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Control Surface ◽  
Laser Polarization ◽  
Ambient Conditions ◽  
In Situ Preparation

Structurally colored stainless steel (SS) surfaces were produced by using femtosecond laser at normal incidence at ambient conditions. The influence of laser polarization on the surface properties was investigated. The surface morphologies, roughness and color of the laser-treated surface were characterized by using environmental scanning electron microscope (ESEM), roughmeter and atomic force microscope (AFM). Results indicated that the circular polarization leads to more random structures than the horizontally linear polarization. Specimen with the highest surface roughness shows the brightest color. Different colors are cyclically exhibited by changing view angles due to different orders of diffraction. This investigation developed the technique of using femtosecond laser in situ preparation of periodic structures on 304 SS, and indicating that laser polarization is an important parameter to control surface structures to achieve different colors.

Therapeutic strategies to fight HIV-1 latency: progress and challenges

Biologia ◽  
2017 ◽  
Vol 72 (10) ◽  
Author(s):  
Sello Lebohang Manoto ◽  
Lebogang Thobakgale ◽  
Rudzani Malabi ◽  
Charles Maphanga ◽  
Saturnin Ombinda-Lemboumba ◽  
...  
Keyword(s):  
Immune System ◽  
Highly Active Antiretroviral Therapy ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Host Immune System ◽  
Highly Active ◽  
Immunodeficiency Virus ◽  
Latently Infected ◽  
Infected Cells ◽  
Hiv 1

AbstractThe life-long persistence of human immunodeficiency virus type-1 (HIV-1) in latent reservoirs is a major hurdle in the eradication of HIV-1, even though highly active antiretroviral therapy (HAART) can be effective in reducing the plasma HIV-1 RNA to less than 50 copies per mL, which is below the detection limit of most clinical assays. In the latent reservoirs the provirus is integrated in the host genome but does not actively replicate and thus is not inhibited by HAART or recognized by the host immune system. There has been increasing scientific interest and investment into research towards HIV cure due to the challenges and limitation of life long treatment. The various strategies that have been developed aim to activate gene expression in HIV latent cells which might lead to the elimination of the virus by HAART or the immune system. In this review we discuss latency and therapeutic approaches that are being evaluated to eradicate HIV latently infected cells to overcome the burden of life long HAART. In addition, we explore the possibility of delivering HAART in latently infected cells using femtosecond laser pulses, a topic closely studied in our research.

Confinement of Cu nanoparticles in the nanocages of large pore SBA-16 functionalized with carboxylic acid: enhanced activity and improved durability for 4-nitrophenol reduction

2019 ◽  
Vol 48 (23) ◽  
pp. 8227-8237 ◽  
Author(s):  
Juti Rani Deka ◽  
Mu-Hsin Lee ◽  
Diganta Saikia ◽  
Hsien-Ming Kao ◽  
Yung-Chin Yang
Keyword(s):  
Carboxylic Acid ◽  
Mesoporous Silica ◽  
Cu Nanoparticles ◽  
Highly Active ◽  
Large Pore ◽  
Enhanced Activity ◽  
Nitrophenol Reduction

Fabrication of a highly active mesoporous silica SBA-16 supported Cu nanocatalyst with superb durability for the reduction of 4-nitrophenol into 4-aminophenol.

Cross-Sectional TEM Analysis of Structural Change in 4H-SiC Single Crystal Irradiated by Femtosecond Laser Pulses

2008 ◽  
Vol 600-603 ◽  
pp. 883-886
Author(s):  
Hiroyuki Kawahara ◽  
Tatsuya Okada ◽  
Ryota Kumai ◽  
Takuro Tomita ◽  
Shigeki Matsuo ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Single Crystal ◽  
Surface Deformation ◽  
Crystal Surface ◽  
Three Dimensional ◽  
Laser Pulses ◽  
Amorphous Layer ◽  
Femtosecond Laser Pulses ◽  
Tem Analysis ◽  
Cross Sectional

We carried out cross-sectional transmission electron microscopy (TEM) investigation of femtosecond laser-induced ripples formed on 4H-SiC single crystal surface. Here, we paid attention to the crystal structures underlying the coarse and fine ripples and the three-dimensional distribution of amorphous phase. Conventional and high-resolution TEM analyses made clear that a continuous amorphous layer approximately of 50 nm thick exist at the topmost region of both coarse and fine ripples. The result strongly suggests that the fundamental surface deformation process is common for coarse and fine ripples, even though the factors which determine their periods are different.

TEM Analysis of Long-Period Polytypes in SiC—S

1976 ◽  
Vol 34 ◽  
pp. 630-631
Author(s):  
S. Shinozaki ◽  
J. W. Sprys
Keyword(s):  
Electron Diffraction ◽  
Isothermal Annealing ◽  
Tem Analysis ◽  
Long Period ◽  
Transmission Electron ◽  
Average Grain Size ◽  
High Resolution Tem ◽  
Structural Lattice ◽  
The Stability ◽  
Continuous Curves

In reaction sintered SiC (∽ 5um average grain size), about 15% of the grains were found to have long-period structures, which were identifiable by transmission electron microscopy (TEM). In order to investigate the stability of the long-period polytypes at high temperature, crystal structures as well as microstructural changes in the long-period polytypes were analyzed as a function of time in isothermal annealing.Each polytype was analyzed by two methods: (1) Electron diffraction, and (2) Electron micrograph analysis. Fig. 1 shows microdensitometer traces of ED patterns (continuous curves) and calculated intensities (vertical lines) along 10.l row for 6H and 84R (Ramsdell notation). Intensity distributions were calculated based on the Zhdanov notation of (33) for 6H and [ (33)3 (32)2 ]3 for 84R. Because of the dynamical effect in electron diffraction, the observed intensities do not exactly coincide with those intensities obtained by structure factor calculations. Fig. 2 shows the high resolution TEM micrographs, where the striped patterns correspond to direct resolution of the structural lattice periodicities of 6H and 84R structures and the spacings shown in the figures are as expected for those structures.

Inorganic-organic Hybrid Materials for Real 3-D Sub-νm Lithography

2003 ◽  
Vol 780 ◽  
Author(s):  
R. Houbertz ◽  
J. Schulz ◽  
L. Fröhlich ◽  
G. Domann ◽  
M. Popall ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Sol Gel ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Hybrid Polymer ◽  
Organic Hybrid ◽  
Two Photon ◽  
Applied Technology ◽  
Scale Structures ◽  
Sol Gel Synthesis

AbstractReal 3-D sub-νm lithography was performed with two-photon polymerization (2PP) using inorganic-organic hybrid polymer (ORMOCER®) resins. The hybrid polymers were synthesized by hydrolysis/polycondensation reactions (modified sol-gel synthesis) which allows one to tailor their material properties towards the respective applications, i.e., dielectrics, optics or passivation. Due to their photosensitive organic functionalities, ORMOCER®s can be patterned by conventional photo-lithography as well as by femtosecond laser pulses at 780 nm. This results in polymerized (solid) structures where the non-polymerized parts can be removed by conventional developers.ORMOCER® structures as small as 200 nm or even below were generated by 2PP of the resins using femtosecond laser pulses. It is demonstrated that ORMOCER®s have the potential to be used in components or devices built up by nm-scale structures such as, e.g., photonic crystals. Aspects of the materials in conjunction to the applied technology are discussed.

Sign in / Sign up

Export Citation Format

Share Document