Laser deposition of polymer and biomaterial films.

A catalytic application of Cu2O and CuO films deposited over fiberglass

This paper presents extensive {bias determination} analyses of ozone observations from the Atmospheric Chemistry Experiment (ACE) satellite instruments: the ACE Fourier Transform Spectrometer (ACE-FTS) and the Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (ACE-MAESTRO) instrument. Here we compare the latest ozone data products from ACE-FTS and ACE-MAESTRO with coincident observations from nearly 20 satellite-borne, airborne, balloon-borne and ground-based instruments, by analysing volume mixing ratio profiles and partial column densities. The ACE-FTS version 2.2 Ozone Update product reports more ozone than most correlative measurements from the upper troposphere to the lower mesosphere. At altitude levels from 16 to 44 km, the average values of the mean relative differences are nearly all within +1 to +8%. At higher altitudes (45–60 km), the ACE-FTS ozone amounts are significantly larger than those of the comparison instruments, with mean relative differences of up to +40% (about +20% on average). For the ACE-MAESTRO version 1.2 ozone data product, mean relative differences are within ±10% (average values within ±6%) between 18 and 40 km for both the sunrise and sunset measurements. At higher altitudes (~35–55 km), systematic biases of opposite sign are found between the ACE-MAESTRO sunrise and sunset observations. While ozone amounts derived from the ACE-MAESTRO sunrise occultation data are often smaller than the coincident observations (with mean relative differences down to −10%), the sunset occultation profiles for ACE-MAESTRO show results that are qualitatively similar to ACE-FTS, indicating a large positive bias (mean relative differences within +10 to +30%) in the 45–55 km altitude range. In contrast, there is no significant systematic difference in bias found for the ACE-FTS sunrise and sunset measurements.

/pdf/validation-of-ozone-measurements-from-the-atmospheric-4dsmaphg5g.pdf

Validation of ozone measurements from the Atmospheric Chemistry Experiment (ACE)

To reveal the light-color modulation mechanism of firefly (beetle) bioluminescence, we investigated the spectroscopic properties of the phenolate anion 1-O(-) generated from 5,5-dimethyloxyluciferin (1-OH) using various base/solvent combinations. Phenolate anion 1-O(-) is a model compound for the keto form of wild-type oxyluciferin phenolate anion (OL(-)), which is postulated to be the emitter of the bioluminescence. The fluorescence maxima of 1-O(-) were found to depend on the base/solvent combination used, and they varied in the range 541-640 nm, which covers the almost whole range of the bioluminescence emission maximum. In a polar solvent, where (1)(1-O(-))* and the countercation (the conjugate acid of a base) make a solvent-separated ion pair or a free ion couple, the emission maxima of 1-O(-) were found to be modulated by the solvent polarity. In a less polar solvent, where (1)(1-O(-))* and the countercation are formed as a contact ion pair, the strength of the covalent character of the O8'...H bond between (1)(1-O(-))* and the countercation is operative. The effect of the base/solvent combination on the emission properties of (1)(1-O(-))* was also verified using fluorescence lifetime measurements and density functional theory calculations on 1-O(-) and its ion-pair models. On the basis of these results, we propose the following light-color modulation mechanism: (1) the light emitter is the excited singlet state of OL(-) [(1)(OL(-))*], and (2) light emission from (1)(OL(-))* is modulated by the polarity of the active-site environment of a luciferase and the degree of covalent character of the O8'...H bond between (1)(OL(-))* and a protonated basic moiety in the active site. Mechanisms for variation of the bioluminescence colors and their applications are discussed.

Spectroscopic studies of the light-color modulation mechanism of firefly (beetle) bioluminescence.

The Improved Limb Atmospheric Spectrometer (ILAS) on board the Advanced Earth Observing Satellite (ADEOS) obtained 8 months of data for trace gas species from November 1996 to June 1997 for studies of the stratospheric ozone layer over the high-latitude regions in both the Southern and Northern Hemispheres. The atmospheric parameters observed by ILAS were vertical profiles of ozone, nitric acid, nitrogen dioxide, nitrous oxide, methane, water vapor, aerosol extinction coefficient (at 780 nm), temperature, and pressure. Version 3.10 of the operational data processing algorithm was used to retrieve the corresponding geophysical profiles, which have been compared whenever possible with independent correlative measurements. Selected examples of ILAS products for ozone, nitric acid, and aerosol extinction coefficient (at 780 nm) are provided. The corresponding data is now publicly available for further analyses by the atmospheric community.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1998GL900276

Improved Limb Atmospheric Spectrometer (ILAS) for stratospheric ozone layer measurements by solar occultation technique

The time-resolved emission spectrum and its temperature dependence were observed with gaseous CS2 excited by an N2 laser. The spectrum was found to consist of three band systems, one of them being demonstrated to be emission from the 1A2 state. The collision-free lifetimes and the collisional quenching constants were determined for the three band systems. The emission from the 1A2 state was found to be quenched by a magnetic field because of the enhancement of an intramolecular energy-transfer process. This is the first observation of the magnetic quenching of emission from an excited singlet state.

The gas-phase emission spectrum of carbon disulfide excited by an N2 laser - magnetic quenching effect.

Extensive control of structures of deposited polymer films has been realized when the films have been prepared on a quartz or KBr substrate by laser ablation of polyacrylonitrile (PAN) with 308 (XeCl), 248 (KrF), and 193 nm (ArF) excimer laser beams, as revealed by scanning electron microscopy, infrared spectroscopy, x‐ray photoelectron spectroscopy, electron spin resonance, and x‐ray diffraction measurements. The original structure of PAN is essentially retained for the films deposited by ablation at 308 nm. Deformation and elimination of nitrile groups occur for the films prepared by ablation at 248 and 193 nm, respectively. Furthermore, a remarkable power‐dependent structural change has been observed at 248 nm; an increase in the laser power has led to ring closure of nitrile groups, resulting in the development of π‐conjugated systems. In addition, a rather high electric conductivity on the order of 10−2S cm−1 has been given to the films deposited by ablation at 248 and 193 nm on reirradiation with lo...

Control of structures of deposited polymer films by ablation laser wavelength: Polyacrylonitrile at 308, 248, and 193 nm

[1] The Improved Limb Atmospheric Spectrometer (ILAS) was a satellite-based solar occultation sensor that was developed by the Environment Agency of Japan (EA) to monitor and study the stratospheric ozone layer. This paper describes the characteristics of the ILAS instrument and its performance in orbit. ILAS measured the vertical distribution of ozone, nitric acid, nitrogen dioxide, nitrous oxide, methane, water vapor, temperature, pressure, and aerosol extinction coefficients at 1.6-km vertical resolution. ILAS was equipped with two spectrometers: an infrared (IR) spectrometer with an uncooled pyroelectric linear array detector to sense between 6.21 and 11.76 μm and a visible spectrometer to monitor 753–784 nm. In addition, a Sun-edge sensor (SES) assigned the tangent height of the instantaneous field-of-view (IFOV). A two-axis gimbals control system on ILAS used two Sun position sensors to track the center of brightness of the Sun during occultation measurements. Before launch onboard the Advanced Earth Observing Satellite (ADEOS), the performance of ILAS was checked on the ground using several methods, including gas-cell measurements, time response measurements, Sun-tracking tests, and hollow-cathode lamp measurements. After the launch of ADEOS on 17 August 1996, ILAS functioned successfully for 8 months of routine operation, from 30 October 1996 to 30 June 1997, collecting more than 6700 solar occultation measurements, after which time the satellite failed due to a failure in a solar paddle. The time delay response of the IR channel was characterized using stepwise IR input. Instrument functions of the ILAS IR and visible spectrometers were determined by combining theoretical optical calculations, experimental measurements using a gas-cell before launch, and in-orbit data. The signal-to-noise ratio (SNR) of each element in the IR channel was estimated to be 400–1200. In the visible channel, it was 1600–1800 for a 100% direct Sun signal. At sunset occultation, ILAS was able to track the Sun below a tangent height of 10 km in some cases. The method of determining the solar edges from the SES data worked correctly, giving adequate tangent height information for observations. Output signal levels of the SES, visible channel, and IR channel showed slight degradation during the period that ILAS was operational, which is attributed to space-borne contaminants. However, changes in absolute signal levels do not affect data retrieval, because the solar occultation technique was self-calibrating. Overall, ILAS worked as designed during its operation in orbit and gathered valuable data for ozone layer studies.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2001JD001439

Characteristics and performance of the Improved Limb Atmospheric Spectrometer (ILAS) in orbit

ILAS, the Improved Limb Atmospheric Spectrometer, on the Advanced Earth Observing Satellite

Proton donor-acceptor interactions in excited states were studied by measuring mainly time-resolved fluorescence spectra for β-naphthol–TEA in toluene and in acetonitrile, and for β-naphthylamine–TEA in nonpolar mixed solvents. The Stern-Volmer relation was found to be satisfied for β-naphthol–TEA in toluene. The rate constant and activation energy of hydrogen bond formation in the excited state of this system were obtained to be 2.2×109 M−1 s−1 at 30 °C and 1.6 kcal/mol, respectively, indicating that the process is diffusion-controlled. The time dependences of the intensities of the fluorescence bands due to the free and complexed β-naphthol were measured with the solutions containing various concentrations of triethylamine in acetonitrile. From the analysis of the result, it is shown that this system is led to the ion-pair formation via the hydrogen-bonded species in the excited state. For β-naphthylamine–TEA in nonpolar mixed solvents, the bands due to hydrogen-bonded species in the ground and excited ...

Akiyoshi Matsuzaki

Papers

The gas-phase emission spectrum of carbon disulfide excited by an N2 laser - magnetic quenching effect.

Control of structures of deposited polymer films by ablation laser wavelength: Polyacrylonitrile at 308, 248, and 193 nm

Characteristics and performance of the Improved Limb Atmospheric Spectrometer (ILAS) in orbit

ILAS, the Improved Limb Atmospheric Spectrometer, on the Advanced Earth Observing Satellite

Interactions of β-Naphthol and β-NaphthyIamine in Their Excited Singlet States with Triethylamine