Gold Nanowire Scattering and Absorption Measurements

2011 ◽  
Vol 1347 ◽  
Author(s):  
Andrew J. Green ◽  
Michael T. Carlson ◽  
Aurangzeb Khan ◽  
Hugh H. Richardson
Keyword(s):  
Dark Field ◽  
Excitation Wavelength ◽  
Thermal Sensor ◽  
Heat Absorption ◽  
Wire Length ◽  
Gold Nanowire ◽  
Sensor Film ◽  
Scattering Measurements ◽  
Laser Flux ◽  
Absorption Measurements

ABSTRACTLithographically prepared gold nanodots and nanowires were placed onto a thermal sensor film to measure heat absorption. These identical wires are also subjected to dark field scattering measurements allowing for a comparison between absorption and scattering at the excitation wavelength. An increasing liner trend is found to exist between nanowires of increasing aspect ratio. The nanostructures also exhibit a decreasing temperature change with increasing wire length with a constant laser flux of 1.3 x 1010 W/m2.

Optical and Luminescence Properties of Dy3+ Doped in Soda Lime Borate Glasses

2016 ◽  
Vol 702 ◽  
pp. 51-56 ◽  
Author(s):  
Suwimon Ruengsri ◽  
Nattapon Srisittipokakun ◽  
Falak Zaman ◽  
Gul Rooh ◽  
Jakrapong Kaewkhao
Keyword(s):  
Photo Luminescence ◽  
Soda Lime ◽  
Luminescence Properties ◽  
Luminescence Spectra ◽  
Excitation Wavelength ◽  
White Led ◽  
Photoluminescence Spectra ◽  
Melt Quenching ◽  
Hypersensitive Transition ◽  
Absorption Measurements

The aim of this study is to develop soda lime borate (SLB) doped with Dy3+ glass and investigate their optical and luminescence properties, for different applications in photonics and optoelectronics. The glass were melt by conventional melt quenching technique. Optical properties have been determined by measuring their absorption spectra and luminescence properties were studied by photo luminescence spectra. From optical absorption measurements, there are ten peaks with transition 6H15/2 to 6F11/2 + 6H9/2 at 1262 nm has higher spectral intensity and is a hypersensitive transition. As a result of 350 nm excitation the photoluminescence spectra have four peaks. Higher luminescence intensity peak was observed for 0.5 mol% Dy3+ doped SLB glass at 4F9/2 to 6H13/2 (575 nm). Hence it is suggest from the chromaticity results that SLB glasses with different Dy2O3 concentration may be a promising glass for white LED under 350 nm excitation wavelength. Further investigation is under way for the optimization of different dopend concentration in the SLB glass.

scholarly journals Facilitating Hotspot Alignment in Tip-Enhanced Raman Spectroscopy via the Silver Photoluminescence of the Probe

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6687
Author(s):  
Yuan Fan ◽  
Dan Jin ◽  
Xiuju Wu ◽  
Hui Fang ◽  
Xiaocong Yuan
Keyword(s):  
Raman Spectroscopy ◽  
Plasmon Resonance ◽  
Near Field ◽  
Resonance Wavelength ◽  
Dark Field ◽  
Intensity Change ◽  
Localized Surface Plasmon ◽  
Excitation Wavelength ◽  
Alignment Procedure ◽  
Tip Enhanced Raman Spectroscopy

A tip-enhanced Raman spectroscopy (TERS) system based on an atomic force microscope (AFM) and radially polarized laser beam was developed. A TERS probe with plasmon resonance wavelength matching the excitation wavelength was prepared with the help of dark-field micrographs. The intrinsic photoluminescence (PL) from the silver (Ag)-coated TERS probe induced by localized surface plasmon resonance contains information about the near-field enhanced electromagnetic field intensity of the probe. Therefore, we used the intensity change of Ag PL to evaluate the stability of the Ag-coated probe during TERS experiments. Tracking the Ag PL of the TERS probe was helpful to detect probe damage and hotspot alignment. Our setup was successfully used for the TERS imaging of single-walled carbon nanotubes, which demonstrated that the Ag PL of the TERS probe is a good criterion to assist in the hotspot alignment procedure required for TERS experiments. This method lowers the risk of contamination and damage of the precious TERS probe, making it worthwhile for wide adoption in TERS experiments.

Solute Effects on Interfacial Thermal Conductance

2013 ◽  
Vol 1543 ◽  
pp. 151-157
Author(s):  
Andrew J. Green ◽  
Hugh H. Richardson
Keyword(s):  
Laser Intensity ◽  
Pure Water ◽  
Thermal Conductance ◽  
Adhesion Energy ◽  
Thermal Sensor ◽  
Water Interface ◽  
Incident Laser ◽  
Gold Nanowire ◽  
Interfacial Thermal Conductance ◽  
Incident Laser Intensity

ABSTRACTThe thermal conductance of a gold/water interface has been found to change as a function of the surrounding’s adhesion energy. We measure the thermal conductance of a lithographically prepared gold nanowire with a thin film nanoscale thermal sensor composed of AlGaN:Er3+. The temperature of the nanowire is measured as a function of incident laser intensity. The slope of this plot is inversely proportional to the thermal conductance of the nanoparticle/surrounding’s interface. We show that the conductance of the nanoparticle/water interface increases with the molality of the solution. This was tested with multiple solutes including NaCl, and D-Glucose. The interfacial conductance of pure water is reported to be 44 MW/m2K and the conductance saturates to 100 MW/m2K at a molality of 0.21 m.

scholarly journals Analysis of Dynamic and Thermodynamic Adsorption of Nanoparticles on Solid Surfaces by Dark-Field Light Scattering Measurements

2007 ◽  
Vol 54 (4) ◽  
pp. 869-878
Author(s):  
Cho-Chun Hu ◽  
Jia-Ching Lin ◽  
Wei-Lung Tseng ◽  
Ming-Feng Huang ◽  
Tai-Chia Chiu ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dark Field ◽  
Solid Surfaces ◽  
Scattering Measurements

scholarly journals A Sensor Array Realized by a Single Flexible TiO2/POMs Film to Contactless Detection of Triacetone Triperoxide

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 915 ◽  
Author(s):  
Xiaorong Lü ◽  
Puqi Hao ◽  
Guanshun Xie ◽  
Junyuan Duan ◽  
Bingxin Liu
Keyword(s):  
Sensor Array ◽  
Sensor Arrays ◽  
Ambient Air ◽  
Detection Sensitivity ◽  
Excitation Wavelength ◽  
Triacetone Triperoxide ◽  
Sensor Film ◽  
Vapor Sensor ◽  
The Stability

The homemade explosive, triacetone triperoxide (TATP), is easy to synthesize, sensitive to detonation but hard to detect directly. Vapor sensor arrays composed of a few sensor materials have the potential to discriminate TATP, but the stability of the sensor array is always a tricky problem since each sensor may encounter a device fault. Thus, a sensor array based on a single optoelectronic TiO2/PW11 sensor was first constructed by regulating the excitation wavelength to discriminate TATP from other explosives. By in situ doping of Na3PW12O40, a Keggin structure of PW11 formed on the TiO2 to promote the photoinduced electron-hole separation, thus obviously improving the detection sensitivity of the sensor film and shortening the response time. The response of the TiO2/PW11 sensor film to TATP under 365, 450 and 550 nm illumination is 81%, 42%, and 37%, respectively. The TiO2/PW11 sensor features selectivity to TATP and is able to detect less than 50 ppb. The flexibility and stability of the flexible sensor film is also demonstrated with the extent of bending. Furthermore, the sensing response cannot be affected by ambient air below 60% relative humidity.

Utilizing Dark Field Electron Microscopy to Produce Lantern Slides

1974 ◽  
Vol 32 ◽  
pp. 116-117
Author(s):  
J. N. Meador ◽  
C. N. Sun ◽  
H. J. White
Keyword(s):  
Electron Microscope ◽  
Electron Micrographs ◽  
Dark Field ◽  
Limiting Factor ◽  
Clinical Laboratories ◽  
Field Electron ◽  
Time Element ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Dark Field Micrographs

The electron microscope is being utilized more and more in clinical laboratories for pathologic diagnosis. One of the major problems in the utilization of the electron microscope for diagnostic purposes is the time element involved. Recent experimentation with rapid embedding has shown that this long phase of the process can be greatly shortened. In rush cases the making of projection slides can be eliminated by taking dark field electron micrographs which show up as a positive ready for use. The major limiting factor for use of dark field micrographs is resolution. However, for conference purposes electron micrographs are usually taken at 2.500X to 8.000X. At these low magnifications the resolution obtained is quite acceptable.

Protamine-DNA interaction

1978 ◽  
Vol 36 (2) ◽  
pp. 200-201
Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer
Keyword(s):  
Small Volume ◽  
Double Helix ◽  
Dna Interaction ◽  
Dark Field ◽  
Sperm Head ◽  
Nuclear Proteins ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Dna Double Helix ◽  
Positively Charged

Dark field electron microscopy has been used for the study of the structure of individual macromolecules with a resolution to at least the 5Å level. The use of this technique has been extended to the investigation of structure of interacting molecules, particularly the interaction between DNA and fish protamine, a class of basic nuclear proteins of molecular weight 4,000 daltons.Protamine, which is synthesized during spermatogenesis, binds to chromatin, displaces the somatic histones and wraps up the DNA to fit into the small volume of the sperm head. It has been proposed that protamine, existing as an extended polypeptide, winds around the minor groove of the DNA double helix, with protamine's positively-charged arginines lining up with the negatively-charged phosphates of DNA. However, viewing protamine as an extended protein is inconsistent with the results obtained in our laboratory.

Evaluation of the dark field method for large association of spread DNA

1978 ◽  
Vol 36 (2) ◽  
pp. 190-191
Author(s):  
Douglas C. Barker
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Mitochondrial Dna ◽  
Extraction Method ◽  
Field Method ◽  
Dark Field ◽  
Kinetoplast Dna ◽  
Field Electron ◽  
Field Electron Microscopy ◽  
Dark Field Electron

A number of satisfactory methods are available for the electron microscopy of nicleic acids. These methods concentrated on fragments of nuclear, viral and mitochondrial DNA less than 50 megadaltons, on denaturation and heteroduplex mapping (Davies et al 1971) or on the interaction between proteins and DNA (Brack and Delain 1975). Less attention has been paid to the experimental criteria necessary for spreading and visualisation by dark field electron microscopy of large intact issociations of DNA. This communication will report on those criteria in relation to the ultrastructure of the (approx. 1 x 10-14g) DNA component of the kinetoplast from Trypanosomes. An extraction method has been developed to eliminate native endonucleases and nuclear contamination and to isolate the kinetoplast DNA (KDNA) as a compact network of high molecular weight. In collaboration with Dr. Ch. Brack (Basel [nstitute of Immunology), we studied the conditions necessary to prepare this KDNA Tor dark field electron microscopy using the microdrop spreading technique.

Thin Pyrolytic Graphite Films for Electron Microscope Substrates

1971 ◽  
Vol 29 ◽  
pp. 226-227 ◽  
Author(s):  
George H. N. Riddle ◽  
Benjamin M. Siegel
Keyword(s):  
Vacuum Chamber ◽  
Pyrolytic Graphite ◽  
High Vacuum ◽  
Dark Field ◽  
Ultra High Vacuum ◽  
Graphite Substrate ◽  
Nickel Substrate ◽  
Routine Procedure ◽  
Field Electron Microscopy ◽  
Dark Field Electron

A routine procedure for growing very thin graphite substrate films has been developed. The films are grown pyrolytically in an ultra-high vacuum chamber by exposing (111) epitaxial nickel films to carbon monoxide gas. The nickel serves as a catalyst for the disproportionation of CO through the reaction 2C0 → C + CO2. The nickel catalyst is prepared by evaporation onto artificial mica at 400°C and annealing for 1/2 hour at 600°C in vacuum. Exposure of the annealed nickel to 1 torr CO for 3 hours at 500°C results in the growth of very thin continuous graphite films. The graphite is stripped from its nickel substrate in acid and mounted on holey formvar support films for use as specimen substrates.The graphite films, self-supporting over formvar holes up to five microns in diameter, have been studied by bright and dark field electron microscopy, by electron diffraction, and have been shadowed to reveal their topography and thickness. The films consist of individual crystallites typically a micron across with their basal planes parallel to the surface but oriented in different, apparently random directions about the normal to the basal plane.

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