56 research outputs found
Synergistic Formation of Radicals by Irradiation with Both Vacuum Ultraviolet and Atomic Hydrogen: A Real-Time In Situ Electron Spin Resonance Study
We report on the surface modification of polytetrafluoroethylene (PTFE) as an
example of soft- and bio-materials that occur under plasma discharge by
kinetics analysis of radical formation using in situ real-time electron spin
resonance (ESR) measurements. During irradiation with hydrogen plasma,
simultaneous measurements of the gas-phase ESR signals of atomic hydrogen and
the carbon dangling bond (C-DB) on PTFE were performed. Dynamic changes of the
C-DB density were observed in real time, where the rate of density change was
accelerated during initial irradiation and then became constant over time. It
is noteworthy that C-DBs were formed synergistically by irradiation with both
vacuum ultraviolet (VUV) and atomic hydrogen. The in situ real-time ESR
technique is useful to elucidate synergistic roles during plasma surface
modification.Comment: 14 pages, 4 figure
Rhodium nanoparticles for ultraviolet plasmonics
The nonoxidizing catalytic noble metal rhodium is introduced for ultraviolet plasmonics. Planar tripods of 8 nm Rh nanoparticles, synthesized by a modified polyol reduction method, have a calculated local surface plasmon resonance near 330 nm. By attaching p-aminothiophenol, local field-enhanced Raman spectra and accelerated photodamage were observed under near-resonant ultraviolet illumination, while charge transfer simultaneously increased fluorescence for up to 13 min. The combined local field enhancement and charge transfer demonstrate essential steps toward plasmonically enhanced ultraviolet photocatalysis.This work has
been supported by NSF-ECCS-12-32239. This work was
partially supported by the Army’s In-house Laboratory
Innovative Research program. Financial support from USAITCA
(project no. W911NF-13-1-0245) and MICINN (Spanish
Ministry of Science and Innovation, project no. FIS2013-
45854-P) is also acknowledged
Novel Liquid Crystalline Organic−Inorganic Hybrid for Highly Sensitive Photoinscriptions
Formation of high electrical-resistivity thin surface layer on carbonyl-iron powder (CIP) and thermal stability of nanocrystalline structure and vortex magnetic structure of CIP
This study focuses on the carbonyl-iron powder (CIP) used in the metal composite bulk magnetic core for high-efficient/light-weight SiC/GaN power device MHz switching dc-dc converter, where the fine CIP with a mean diameter of 1.1 μm is used to suppress the MHz band eddy current inside the CIP body. When applying the CIP to composite core together with the resin matrix, high electrical resistivity layer must be formed on the CIP-surface in order to suppress the overlapped eddy current between adjacent CIPs. In this study, tens nm thick silica (SiO2) was successfully deposited on the CIP-surface by using hydrolysis of TEOS (Si(OC2H5)4). Also tens nm thick oxidized layer of the CIP-surface was successfully formed by using CIP annealing in dry air. The SiC/GaN power device can operate at ambient temperature over 200 degree-C, and the composite magnetic core is required to operate at such ambient temperature. The as-made CIP had small coercivity below 800 A/m (10 Oe) due to its nanocrystalline-structure and had a single vortex magnetic structure. From the experimental results, both nanocrystalline and single vortex magnetic structure were maintained after heat-exposure of 250 degree-C, and the powder coercivity after same heat-exposure was nearly same as that of the as-made CIP. Therefore, the CIP with thermally stable nanocrystalline-structure and vortex magnetic state was considered to be heat-resistant magnetic powder used in the iron-based composite core for SiC/GaN power electronics
Thin Layers of Low Molecular Azobenzene Materials with Effective Light-Induced Mass Transport
Formation of high electrical-resistivity thin surface layer on carbonyl-iron powder (CIP) and thermal stability of nanocrystalline structure and vortex magnetic structure of CIP
This study focuses on the carbonyl-iron powder (CIP) used in the metal composite bulk magnetic core for high-efficient/light-weight SiC/GaN power device MHz switching dc-dc converter, where the fine CIP with a mean diameter of 1.1 μm is used to suppress the MHz band eddy current inside the CIP body. When applying the CIP to composite core together with the resin matrix, high electrical resistivity layer must be formed on the CIP-surface in order to suppress the overlapped eddy current between adjacent CIPs. In this study, tens nm thick silica (SiO2) was successfully deposited on the CIP-surface by using hydrolysis of TEOS (Si(OC2H5)4). Also tens nm thick oxidized layer of the CIP-surface was successfully formed by using CIP annealing in dry air. The SiC/GaN power device can operate at ambient temperature over 200 degree-C, and the composite magnetic core is required to operate at such ambient temperature. The as-made CIP had small coercivity below 800 A/m (10 Oe) due to its nanocrystalline-structure and had a single vortex magnetic structure. From the experimental results, both nanocrystalline and single vortex magnetic structure were maintained after heat-exposure of 250 degree-C, and the powder coercivity after same heat-exposure was nearly same as that of the as-made CIP. Therefore, the CIP with thermally stable nanocrystalline-structure and vortex magnetic state was considered to be heat-resistant magnetic powder used in the iron-based composite core for SiC/GaN power electronics
Highly Photosensitive Surface Relief Gratings Formation in a Liquid Crystalline Azobenzene Polymer: New Implications for the Migration Process
Sub-2 nm Thick Fluoroalkylsilane Self-Assembled Monolayer-Coated High Voltage Spinel Crystals as Promising Cathode Materials for Lithium Ion Batteries
AI-STRATA: A User-Centered Model for Content-Based Description and Retrieval of Audiovisual Sequences
Vertical profile of tropospheric ozone derived from synergetic retrieval using three different wavelength ranges, UV, IR, and microwave: sensitivity study for satellite observation
We performed a feasibility study of constraining the vertical
profile of the tropospheric ozone by using a synergetic retrieval
method on multiple spectra, i.e., ultraviolet (UV), thermal infrared
(TIR), and microwave (MW) ranges, measured from space. This work provides, for the first time,
a quantitative evaluation of the retrieval sensitivity of the
tropospheric ozone by adding the MW measurement to the UV and TIR
measurements. Two
observation points in East Asia (one in an urban area and one in an
ocean area) and two observation times (one during summer and one
during winter) were assumed. Geometry of line of sight was nadir
down-looking for the UV and TIR measurements, and limb sounding for
the MW measurement. The retrieval sensitivities of the ozone
profiles in the upper troposphere (UT), middle troposphere (MT), and
lowermost troposphere (LMT) were estimated using the degree of
freedom for signal (DFS), the pressure of maximum sensitivity,
reduction rate of error from the a priori error, and the averaging
kernel matrix, derived based on the optimal estimation method. The
measurement noise levels were assumed to be the same as those for
currently available instruments. The weighting functions for the
UV, TIR, and MW ranges were calculated using the SCIATRAN radiative
transfer model, the Line-By-Line Radiative Transfer Model (LBLRTM), and the
Advanced Model for Atmospheric Terahertz Radiation Analysis and
Simulation (AMATERASU), respectively. The DFS value was increased by
approximately 96, 23, and 30 % by adding the MW measurements to the
combination of UV and TIR measurements in the UT, MT, and LMT
regions, respectively. The MW measurement increased the DFS value
of the LMT ozone; nevertheless, the MW measurement alone has no
sensitivity to the LMT ozone. The pressure of maximum sensitivity
value for the LMT ozone was also increased by adding the MW
measurement. These findings indicate that better information on LMT
ozone can be obtained by adding constraints on the UT and MT ozone
from the MW measurement. The results of this study are applicable
to the upcoming air-quality monitoring missions, APOLLO, GMAP-Asia,
and uvSCOPE
- …