基礎講座 電気泳動(Electrophoresis)

The detection and measurement of gas concentrations using the characteristic optical absorption of the gas species is important for both understanding and monitoring a variety of phenomena from industrial processes to environmental change. This study reviews the field, covering several individual gas detection techniques including non-dispersive infrared, spectrophotometry, tunable diode laser spectroscopy and photoacoustic spectroscopy. We present the basis for each technique, recent developments in methods and performance limitations. The technology available to support this field, in terms of key components such as light sources and gas cells, has advanced rapidly in recent years and we discuss these new developments. Finally, we present a performance comparison of different techniques, taking data reported over the preceding decade, and draw conclusions from this benchmarking.

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Optical gas sensing: a review

Sequences of basis sets that systematically converge towards the complete basis set (CBS) limit have been developed for the first-row transition metal elements Sc–Zn. Two families of basis sets, nonrelativistic and Douglas-Kroll-Hess (-DK) relativistic, are presented that range in quality from triple-ζ to quintuple-ζ. Separate sets are developed for the description of valence (3d4s) electron correlation (cc-pVnZ and cc-pVnZ-DK; n=T,Q, 5) and valence plus outer-core (3s3p3d4s) correlation (cc-pwCVnZ and cc-pwCVnZ-DK; n=T,Q, 5), as well as these sets augmented by additional diffuse functions for the description of negative ions and weak interactions (aug-cc-pVnZ and aug-cc-pVnZ-DK). Extensive benchmark calculations at the coupled cluster level of theory are presented for atomic excitation energies, ionization potentials, and electron affinities, as well as molecular calculations on selected hydrides (TiH, MnH, CuH) and other diatomics (TiF, Cu2). In addition to observing systematic convergence towards the C...

http://tyr0.chem.wsu.edu/~kipeters/Pages/pdfs/JCP123.064107.2005.pdf

Systematically convergent basis sets for transition metals. I. All-electron correlation consistent basis sets for the 3d elements Sc–Zn

Sequences of basis sets that systematically converge towards the complete basis set (CBS) limit have been developed for the coinage metals (Cu, Ag, Au) and group 12 elements (Zn, Cd, Hg). These basis sets are based on recently published small-core relativistic pseudopotentials [Figgen D, Rauhut G, Dolg M, Stoll H (2005) Chem Phys 311:227] and range in size from double- through quintuple-ζ. Series of basis sets designed for valence-only and outer-core electron correlation are presented, as well as these sets augmented by additional diffuse functions for the accurate description of negative ions and weak interactions. Selected benchmark calculations at the coupled cluster level of theory are presented for both atomic and molecular properties. The latter include the calculation of both spectroscopic and thermochemical properties of the homonuclear dimers Cu2, Ag2, and Au2, as well as the van der Waals species Zn2, Cd2, and Hg2. The CBS limit results, including the effects of core-valence correlation and spin-orbit coupling, represent some of the most accurate carried out to date and result in new recommendations for the equilibrium bond lengths of the group 12 dimers. Comparisons are also made to a limited number of all-electron Douglas–Kroll–Hess (DKH) calculations (second and third order) carried out using new correlation consistent basis sets of triple-ζ quality.

http://tyr0.chem.wsu.edu/~kipeters/pages/pdfs/tca114.283.2005.pdf

Systematically convergent basis sets for transition metals. II. Pseudopotential-based correlation consistent basis sets for the group 11 (Cu, Ag, Au) and 12 (Zn, Cd, Hg) elements

Objectives. We analyzed differences in pediatric elevated blood lead level incidence before and after Flint, Michigan, introduced a more corrosive water source into an aging water system without adequate corrosion control. Methods. We reviewed blood lead levels for children younger than 5 years before (2013) and after (2015) water source change in Greater Flint, Michigan.We assessed the percentage of elevated blood lead levels in both time periods, and identified geographical locations through spatial analysis. Results. Incidence of elevated blood lead levels increased from 2.4% to 4.9% (P<.05) after water source change, and neighborhoods with the highest water lead levels experienced a 6.6% increase. No significant change was seen outside the city. Geospatial analysis identified disadvantaged neighborhoods as having the greatest elevated blood lead levelincreases andinformed response prioritization during the now-declared public health emergency. Conclusions. The percentage of children with elevated blood lead levels increased after water source change, particularly in socioeconomically disadvantaged neighborhoods. Water is a growing source of childhood lead exposure because of aging infrastructure. (Am J Public Health. 2016;106:283–290. doi:10.2105/AJPH.2015.303003)

https://ajph.aphapublications.org/doi/pdf/10.2105/AJPH.2015.303003

Elevated Blood Lead Levels in Children Associated With the Flint Drinking Water Crisis: A Spatial Analysis of Risk and Public Health Response

A novel refractive index (RI) sensor based on a fiber Mach-Zehnder interferometer was realized by concatenating two single-mode fiber tapers separated by a middle section. The proposed device had a minimum insertion loss of 3 dB and maximum interferometric extinction ratio over 20 dB. The resolution (0.171 nm) of the two-taper sensor to its surrounding RI change (0.01) was found to be comparable to that (0.252 nm) of similar structures made from an identical long-period gratings pair, and its ease of fabrication makes it a low-cost alternative to existing sensing applications.

Refractive Index Sensing With Mach–Zehnder Interferometer Based on Concatenating Two Single-Mode Fiber Tapers

A simple refractive index sensor based on a Michelson interferometer in a single-mode fiber is constructed and demonstrated. The sensor consists of a single symmetrically abrupt taper region in a short piece of single-mode fiber that is terminated by ~500 nm thick gold coating. The sensitivity of the new sensor is similar to that of a long-period-grating-type sensor, and its ease of fabrication offers a low-cost alternative to current sensing applications.

/pdf/refractive-index-sensor-based-on-an-abrupt-taper-michelson-4anbvgiyho.pdf

Refractive index sensor based on an abrupt taper Michelson interferometer in a single-mode fiber

The limit of detection (LOD) and the sensitivity of a chemical sensor are defined using IUPAC guidelines. The LOD from simulated and experimental data is calculated from a calibration curve using a simple statistical model that was implemented into a spreadsheet program. This definition of the LOD is compared with the commonly used definition of the LOD, which is based on the product of sensitivity and the theoretical instrument resolution.

/pdf/detection-limits-of-chemical-sensors-applications-and-34st5shigs.pdf

Detection Limits of Chemical Sensors: Applications and Misapplications

Mach-Zehnder and Michelson interferometers using core-offset attenuators were demonstrated. As the relative offset direction of the two attenuators in the Mach-Zehnder interferometer can significantly affect the extinction ratio of the interference pattern, single core-offset attenuator-based sensors appear more robust and repeatable. A novel fiber Michelson interferometer refractive index (RI) sensor was subsequently realized by a single core-offset attenuator and a layer of ~ 500-nm gold coating. The device had a minimum insertion loss of 0.01 dB and maximum extinction ratio over 9 dB. The sensitivity (0.333 nm) of the new sensor to its surrounding RI change (0.01) was found to be comparable to that (0.252 nm) of an identical long period gratings pair Mach-Zehnder interferometric sensor, and its ease of fabrication makes it a low-cost alternative to existing sensing applications.

/pdf/single-mode-fiber-refractive-index-sensor-based-on-core-v0szfh8sys.pdf

Single-Mode Fiber Refractive Index Sensor Based on Core-Offset Attenuators

From the Contents: Cavity-Enhanced Spectroscopy and Sensing.- Introduction to Cavity-Enhanced Absorption Spectroscopy.- Detection and Characterization of Reactive Chemical Intermediates Using Cavity Ringdown Spectroscopy.- Quantum Cascade Laser Based Chemical Sensing Using Optically Resonant Cavities.- Saturated-Absorption Cavity Ringdown (SCAR) for High-Sensitivity and High-Resolution Molecular Spectroscopy in the Mid-IR.- Cavity-Enhanced Absorption Spectroscopy with Optical Feedback.- NICE-OHMS - Frequency Modulation Cavity-Enhanced Spectroscopy - Principles and Performance.- Applications of NICE-OHMS to Molecular Spectroscopy.- Cavity-Enhanced Direct Frequency Comb Spectroscopy.- Whispering Gallery Mode Biomolecular Sensors.- Cavity-Enhanced Spectroscopy on Silica Microsphere Resonators.- Cavity-Ringdown Spectroscopy for the Analysis of Small Liquid Volumes.- Fiber Loop Ringdown Sensors and Sensing.- Fiber-Optic Resonators for Strain-Acoustic Sensing and Chemical Spectroscopy.- Broadband Cavity-Enhanced Absorption Spectroscopy with Incoherent Light.

/pdf/cavity-enhanced-spectroscopy-and-sensing-8014h7bocw.pdf

Hans-Peter Loock

Papers

Refractive Index Sensing With Mach–Zehnder Interferometer Based on Concatenating Two Single-Mode Fiber Tapers

Refractive index sensor based on an abrupt taper Michelson interferometer in a single-mode fiber

Detection Limits of Chemical Sensors: Applications and Misapplications

Single-Mode Fiber Refractive Index Sensor Based on Core-Offset Attenuators

Cavity-enhanced spectroscopy and sensing