A spectrophotometric study of Fe(II)-chloride complexes in aqueous solutions from 10 to 100°C

2001 ◽  
Vol 79 (2) ◽  
pp. 131-144 ◽  
Author(s):  
Renhai Zhao ◽  
Pujing Pan
Keyword(s):  
Stability Constants ◽  
Near Infrared ◽  
Chloride Concentration ◽  
Pitzer Model ◽  
Nonlinear Least Squares ◽  
Ionic Species ◽  
Spectrophotometric Study ◽  
Chloride Complexes ◽  
Near Ir ◽  
Coordination Change

The absorption spectra of Fe(II)-chloride solutions were measured in both the UV (ultraviolet) and near-IR (near infrared) regions at temperatures ranging from 10 to 100°C with chloride concentrations from 0.1 to 16 mol kg-1. The stability constants of all Fe(II)-chloride complexes were derived from the spectra using a non-negative nonlinear least-squares computer program (SQUAD). Earlier work on this system reported in the literature was rigorously reassessed. The activity coefficients of the ionic species were calculated using both the Pitzer model and the Helgeson model. The results obtained with UV and near-IR spectra and with different activity coefficient calculation models are in general agreement. Other useful thermodynamic data, including the Gibbs energies, enthalpies, and entropies for complex formation, were also obtained. It was found that the Fe(II)-chloride complexes gradually undergo a configuration transformation from octahedral to tetrahedral coordination as the temperature and (or) chloride concentration increases. This coordination change is of significant importance to the nuclear reactors, as the presence of the tetrahedral complex can increase the solubility of iron in steam generator crevices.Key words: Fe(II)-chloride complexes, stability constants, solution thermodynamics, spectrophotometry, reactor chemistry.

Plasmon-assisted interaction of Si with light, for cancer hyperthermia and electromagnetic energy harvest

2020 ◽  
Vol 92 (2) ◽  
pp. 20101
Author(s):  
Behnam Kheyraddini Mousavi ◽  
Morteza Rezaei Talarposhti ◽  
Farshid Karbassian ◽  
Arash Kheyraddini Mousavi
Keyword(s):  
Silicon Nanowires ◽  
Metallic Nanoparticles ◽  
Near Infrared ◽  
Optical Transition ◽  
Electromagnetic Energy ◽  
Energy Harvest ◽  
Absorption Enhancement ◽  
Ir Absorption ◽  
Absorption Mechanism ◽  
Near Ir

Metal-assisted chemical etching (MACE) is applied for fabrication of silicon nanowires (SiNWs). We have shown the effect of amorphous sheath of SiNWs by treating the nanowires with SF6 and the resulting reduction of absorption bandwidth, i.e. making SiNWs semi-transparent in near-infrared (IR). For the first time, by treating the fabricated SiNWs with copper containing HF∕H2O2∕H2O solution, we have generated crystalline nanowires with broader light absorption spectrum, up to λ = 1 μm. Both the absorption and photo-luminescence (PL) of the SiNWs are observed from visible to IR wavelengths. It is found that the SiNWs have PL at visible and near Infrared wavelengths, which may infer presence of mechanisms such as forbidden gap transitions other can involvement of plasmonic resonances. Non-radiative recombination of excitons is one of the reasons behind absorption of SiNWs. Also, on the dielectric metal interface, the absorption mechanism can be due to plasmonic dissipation or plasmon-assisted generation of excitons in the indirect band-gap material. Comparison between nanowires with and without metallic nanoparticles has revealed the effect of nanoparticles on absorption enhancement. The broader near IR absorption, paves the way for applications like hyperthermia of cancer while the optical transition in near IR also facilitates harvesting electromagnetic energy at a broad spectrum from visible to IR.

scholarly journals Anisotropies of the infrared background and primordial galaxies

2006 ◽  
Vol 2 (14) ◽  
pp. 266-266
Author(s):  
Asantha R. Cooray
Keyword(s):  
Galaxy Formation ◽  
Near Infrared ◽  
Imaging Data ◽  
Near Ir ◽  
Infrared Background ◽  
Cosmic Infrared Background ◽  
Galactic Background

AbstractWe discuss anisotropies in the near-IR background between 1 to a few microns. This background is expected to contain a signature of primordial galaxies. We have measured fluctuations of resolved galaxies with Spitzer imaging data and we are developing a rocket-borne instrument (the Cosmic Infrared Background ExpeRiment, or CIBER) to search for signatures of primordial galaxy formation in the cosmic near-infrared extra-galactic background.

scholarly journals Quantifying lower tropospheric methane concentrations using GOSAT near-IR and TES thermal IR measurements

2015 ◽  
Vol 8 (8) ◽  
pp. 3433-3445 ◽  
Author(s):  
J. R. Worden ◽  
A. J. Turner ◽  
A. Bloom ◽  
S. S. Kulawik ◽  
J. Liu ◽  
...  
Keyword(s):  
Near Infrared ◽  
Surface Fluxes ◽  
Vertical Profiles ◽  
Monthly Average ◽  
Near Ir ◽  
Surface Measurements ◽  
Increased Sensitivity ◽  
The Impact ◽  
Total Column ◽  
Methane Concentrations

Abstract. Evaluating surface fluxes of CH4 using total column data requires models to accurately account for the transport and chemistry of methane in the free troposphere and stratosphere, thus reducing sensitivity to the underlying fluxes. Vertical profiles of methane have increased sensitivity to surface fluxes because lower tropospheric methane is more sensitive to surface fluxes than a total column, and quantifying free-tropospheric CH4 concentrations helps to evaluate the impact of transport and chemistry uncertainties on estimated surface fluxes. Here we demonstrate the potential for estimating lower tropospheric CH4 concentrations through the combination of free-tropospheric methane measurements from the Aura Tropospheric Emission Spectrometer (TES) and XCH4 (dry-mole air fraction of methane) from the Greenhouse gases Observing SATellite – Thermal And Near-infrared for carbon Observation (GOSAT TANSO, herein GOSAT for brevity). The calculated precision of these estimates ranges from 10 to 30 ppb for a monthly average on a 4° × 5° latitude/longitude grid making these data suitable for evaluating lower-tropospheric methane concentrations. Smoothing error is approximately 10 ppb or less. Comparisons between these data and the GEOS-Chem model demonstrate that these lower-tropospheric CH4 estimates can resolve enhanced concentrations over flux regions that are challenging to resolve with total column measurements. We also use the GEOS-Chem model and surface measurements in background regions across a range of latitudes to determine that these lower-tropospheric estimates are biased low by approximately 65 ppb, with an accuracy of approximately 6 ppb (after removal of the bias) and an actual precision of approximately 30 ppb. This 6 ppb accuracy is consistent with the accuracy of TES and GOSAT methane retrievals.

scholarly journals Characterization of conichalcite by SEM, FTIR, Raman and electronic reflectance spectroscopy

2005 ◽  
Vol 69 (2) ◽  
pp. 155-167 ◽  
Author(s):  
B. J. Reddy ◽  
R. L. Frost ◽  
W. N. Martens
Keyword(s):  
Near Infrared ◽  
Adsorbed Water ◽  
Reflectance Spectroscopy ◽  
Sem Images ◽  
X Ray ◽  
Near Ir ◽  
Ir Reflectance ◽  
Yavapai County ◽  
Ir Bands

AbstractThe mineral conichalcite from the western part of Bagdad mine, Bagdad, Eureka District, Yavapai County, Arizona, USA has been characterized by electronic, near-infrared (NIR), Raman and infrared (IR) spectroscopy. Scanning electron microscopy (SEM) images show that the mineral consists of bundles of fibres. Calculations based on the results of the energy dispersive X-ray analyses on a stoichiometric basis show the substitution of arsenate by 12 wt.% of phosphate in the mineral. Raman and IR bands are assigned in terms of the fundamental modes of AsO43− and PO43− molecules and are related to the mineral structure. Near-IR reflectance spectroscopy shows the presence of adsorbed water and hydroxyl units in the mineral. The Cu(II) coordination polyhedron in conichalcite can have at best pseudo-tetragonal geometry. The crystal field and tetragonal field parameters of the Cu(II) complex were calculated and found to agree well with the values reported for known tetragonal distortion octahedral complexes.

scholarly journals Near–Infrared Imaging of Proto-Planetary Nebulae

1993 ◽  
Vol 155 ◽  
pp. 340-340 ◽  
Author(s):  
R.E.S. Clegg ◽  
N. A. Walton ◽  
M.J. Barlow
Keyword(s):  
Molecular Hydrogen ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Planetary Nebulae ◽  
Agb Stars ◽  
Intermediate Mass ◽  
Preliminary Results ◽  
Near Ir ◽  
Intermediate Mass Stars ◽  
Hydrogen Lines

It is not really known how low and intermediate mass stars eject mass to form PNs. We present preliminary results from a programme of near–IR imaging, in which we study a sequence of objects, from extreme AGB stars through proto–planetaries to young, compact PNs. We aim to study the sequence of morphologies, to see where the onset of bipolar shaping occurs, and to use the IR molecular hydrogen lines to map neutral regions around ionized nebulae.

scholarly journals Satellite data interpretation of causes and controls on groundwater-seawater flow directions, Merseyside, UK: implications for assessing saline intrusions

2005 ◽  
Vol 2 (3) ◽  
pp. 887-916 ◽  
Author(s):  
S. Mukherjee ◽  
E. A. Mohammad ◽  
R. H. Worden
Keyword(s):  
Satellite Data ◽  
Intertidal Zone ◽  
Near Infrared ◽  
Water Movement ◽  
Coastal Region ◽  
Chloride Concentration ◽  
Fault Zones ◽  
Fault Rocks ◽  
Grain Crushing ◽  
Clay Deposits

Abstract. Groundwater in the Triassic Sherwood Sandstone aquifer, Liverpool, UK, has locally elevated chloride concentrations (~4000 mg/l) in parts of the coastal region although there is freshwater right up to the coast line in other areas. The aquifer is cut my numerous faults with vertical displacements of as much 300 m. SPOT satellite data have been used for the Merseyside area of Liverpool. The satellite data revealed and confirmed the location of some of the main faults since the fault zones of the aquifer have low permeability (due to grain crushing, cataclasis, and clay smearing). Where fault zones outcrop at the surface, below the well-developed regolith, there is locally elevated soil water and thus anomalous vegetation patterns in comparison to unfaulted and highly porous aquifer. The ability to identify fault zones by this satellite-based method strongly suggests that they are at least partially sealing, sub-vertical features in the aquifer. Digitally enhanced and processed satellite data were used to define the relative proportions of sand and clay in the near-coastal (inter-tidal) part of the Mersey estuary. Sand-dominated sediment has higher pixel values in comparison with clay deposits in the near infrared spectral region (NIR). Where open and weathered fault rocks crop out at the surface near the intertidal zone, water movement in these potential surface water conduits is limited where the intertidal zone is clay-dominated since clay will plug the conduit. Where these weathered and open fault-rocks crop out against sand-dominated parts of the coastline, fresh water outflux into the seawater has been imaged using the satellite data. Furthermore, the high and low chloride concentration parts of the aquifer are separated by major, sub-vertical fault zones and have allowed a very steep water table gradient to remain in the aquifer.

scholarly journals In Vitro Photothermal Destruction of Cancer Cells Using Gold Nanorods and Pulsed-Train Near-Infrared Laser

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Jui-Teng Lin ◽  
Yueh-Sheng Chiang ◽  
Guang-Hong Lin ◽  
Hsinyu Lee ◽  
Hsia-Wei Liu
Keyword(s):  
Cancer Cells ◽  
Diode Laser ◽  
Near Infrared ◽  
Irradiation Time ◽  
Laser System ◽  
Gold Nanorod ◽  
Near Ir ◽  
Laser Heated ◽  
Train System

We present a novel pulsed-train near-IR diode laser system with real-time temperature monitoring of the laser-heated cancer cell mixed in gold nanorod solution. Near-IR diode laser at 808 nm matching the gold nanorod absorption peak (with an aspect ratio about 4.0) was used in this study. Both surface and volume temperatures were measured and kept above 43°C, the temperature for cancer cells destruction. The irradiation time needed in our pulsed-train system with higher laser fluence for killing the cancel cells is about 1–3 minutes, much shorter than conventional methods (5–10 minutes). Cell viabilities in gold nanorod mixed and controlled solutions are studied by green fluorescence.

scholarly journals Near-IR-induced dissociation of thermally-sensitive star polymers

2017 ◽  
Vol 8 (3) ◽  
pp. 1815-1821 ◽  
Author(s):  
Yuqiong Dai ◽  
Hao Sun ◽  
Sunirmal Pal ◽  
Yunlu Zhang ◽  
Sangwoo Park ◽  
...  
Keyword(s):  
Near Infrared ◽  
Star Polymers ◽  
Tissue Penetration ◽  
Triggered Release ◽  
Deep Tissue ◽  
Responsive Systems ◽  
Nir Light ◽  
Near Ir ◽  
Triggering Events ◽  
Spatiotemporal Control

Responsive systems sensitive to near-infrared (NIR) light are promising for triggered release due to efficient deep tissue penetration of NIR irradiation relative to higher energy sources (e.g., UV), allowing for spatiotemporal control over triggering events with minimal potential for tissue damage.

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