Design Optimization of Structural Acoustic Problems Using FEM-BEM

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76869/1/AIAA-2003-1630-545.pd

Ultraviolet photodepletion spectroscopy of dibenzo-18-crown-6-ether complexes with alkali metal cations

Ultraviolet photodepletion spectra of dibenzo-18-crown-6-ether complexes with alkali metal cations (M+-DB18C6, M = Cs, Rb, K, Na, and Li) were obtained in the gas phase using electrospray ionization quadrupole ion-trap reflectron time-of-flight mass spectrometry. The spectra exhibited a few distinct absorption bands in the wavenumber region of 35450−37800 cm^(−1). The lowest-energy band was tentatively assigned to be the origin of the S_0-S_1 transition, and the second band to a vibronic transition arising from the “benzene breathing” mode in conjunction with symmetric or asymmetric stretching vibration of the bonds between the metal cation and the oxygen atoms in DB18C6. The red shifts of the origin bands were observed in the spectra as the size of the metal cation in M^+-DB18C6 increased from Li^+ to Cs^+. We suggested that these red shifts arose mainly from the decrease in the binding energies of larger-sized metal cations to DB18C6 at the electronic ground state. These size effects of the metal cations on the geometric and electronic structures, and the binding properties of the complexes at the S_0 and S_1 states were further elucidated by theoretical calculations using density functional and time-dependent density functional theories

Network Analysis of TV-Viewing Patterns in Multi-Channel Circumstances

Translated from the article published in Korean Journal of Broadcasting vol. 24, no. 6, 2010, with permission from the Korean Association for Broadcasting and Telecommunication Studies.This study uses the network analysis method to overcome limitations of previous research that had inaccurately examined the phenomena of fragmentation and polarization in TV viewing behaviors. First of all, viewer ratings were analyzed, which consisted of 298 panels in 2004 and 2007. The benefit of this panel data was not only to secure the validity and credibility of the data, but also to figure out the change of viewing patterns. The result of network centralization and centrality analysis was that fragmentation became stronger as the number of channels increased. In other words, audiences dispersed to professional and specialized channels. However, they came together from terrestrial broadcastings to other channels again. The re-concentration phenomenon appeared apparently in drama channels that belonged to terrestrial (non-satellite or cable) broadcastings. In addition, sub-network analysis showed that small but loyal viewer groups kept on increasing. This result indicates the depth of polarization, which means audiences have a tendency to view common genre programs according to their preference

Production of Hydrogen and Carbon Black by Methane Decomposition Using DC-RF Hybrid Thermal Plasmas

A continuous production of carbon black and hydrogen has been investigated by thermal decomposition of methane using a prototype processing system of DC-RF hybrid thermal plasma, which has great advantage over other thermal sources like combustion or DC plasma torches in synthesizing new nanostructured materials by providing high-temperature environment and longer residence time for reactant gases due to its larger hot core region and lower flow velocity. Appropriate operation conditions and reactor geometries for the effective synthesis process are predicted first from the relevant theoretical bases, such as thermodynamic equilibrium calculations, two-dimensional thermal flow analysis, and chemical kinetic simulation. Based on these derived operation and design parameters, a reaction chamber and a DC-RF hybrid torch are fabricated for the processing system, which is followed by methane decomposition experiments with it. The methane injected into the processing system is converted mostly into hydrogen with a small volume fraction of acetylene, and fine carbon particles of 20-50 nm are identified from their TEM images. Material analyses of BET, DBP and XRD indicate that the synthesized carbon black has excellent properties such as large surface area, high electrical conductivity, and highly graphitized structures with good crystallization

Inhibition of RAGE signaling through the intracellular delivery of inhibitor peptides by PEI cationization

The receptor for advanced glycation end products (RAGE) is a multi-ligand cell surface receptor and a member of the immunoglobulin superfamily. RAGE is involved in a wide range of inflammatory, degenerative and hyper-proliferative disorders which span over different organs by engaging diverse ligands, including advanced glycation end products, S100 family proteins, high-mobility group protein B1 (HMGB1) and amyloid beta. We previously demonstrated that the cytoplasmic domain of RAGE is phosphorylated upon the binding of ligands, enabling the recruitment of two distinct pairs of adaptor proteins, Toll-interleukin 1 receptor domain-containing adaptor protein (TIRAP) and myeloid differentiation protein 88 (MyD88). This engagement allows the activation of downstream effector molecules, and thereby mediates a wide variety of cellular processes, such as inflammatory responses, apoptotic cell death, migration and cell growth. Therefore, inhibition of the binding of TIRAP to RAGE may abrogate intracellular signaling from ligand-activated RAGE. In the present study, we developed inhibitor peptides for RAGE signaling (RAGE-I) by mimicking the phosphorylatable cytosolic domain of RAGE. RAGE-I was efficiently delivered into the cells by polyethylenimine (PEI) cationization. We demonstrated that RAGE-I specifically bound to TIRAP and abrogated the activation of Cdc42 induced by ligand-activated RAGE. Furthermore, we were able to reduce neuronal cell death induced by an excess amount of S100B and to inhibit the migration and invasion of glioma cells in vitro. Our results indicate that RAGE-I provides a powerful tool for therapeutics to block RAGE-mediated multiple signaling

Continuous process of carbon nanotubes synthesis by decomposition of methane using an arc-jet plasma

Author's version; The Joint Meeting of 7th APCPST (Asia Pacific Conference on Plasma Science and Technology) and 17th SPSM (Symposium on Plasma Science for Materials) - 7th APCPST/17th SPSMWe present a method of producing carbon nanotubes by means of the thermal plasma decomposition of methane in an arc-jet plasma of high temperature (5000–20,000 K). Carbon nanotubes are produced under a floating condition by introducing methane and a mixture of Ni–Y powders into the arc-jet plasma flame generated by a non-transferred plasma torch. Material evaluations of the synthesized product by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) reveal that the growth rate of carbon nanotubes is very high, and that the multi-walled carbon nanotubes of high purity are mainly produced. Since this process is continuously operable and easily scalable, it is expected to be a promising technique for large-scale commercial production of carbon nanotubes.Korea Institute of Science and Technology Evaluation and Planning (KISTEP

A case study on swell correction of Chirp sub-bottom profiler (SBP) data using multi-beam echo sounder (MBES) data

High-resolution marine seismic data acquisition and subsequent analyses are highly influenced by sea conditions, directly affecting data quality and interpretation. Traditional swell effect correction methods are effective in improving reflector continuity; however, they are less useful for enhancing travel time consistency at intersection points of crossing lines. To develop a robust swell-removal technique for a set of crossing lines multi-beam echo sounder (MBES) data and Chirp sub-bottom profiler (SBP) data were acquired. After generation of a time structure map of the sea-bottom converted from the final processed multi-beam data, a moving average was used to improve the event continuity of the sea-bottom reflection of the Chirp SBP data. Using the position of the Chirp SBP data, the difference between the travel time of the sea-bottom from the smoothed map and the original travel time of the sea-bottom is calculated as a static correction. The static correction method based on the MBES data was compared and verified using three different cases: (i) simple 2D swell effect correction on a line-by-line basis, (ii) comparing the swell corrections at the crossing positions of 2D lines acquired from different dates, and (iii) comparison of ties of intersection points between 2D lines after new swell correction applied. Although a simple 2D swell correction showed great enhancement of reflector continuity, only the full static correction using the newly proposed method using MBES data produced completely corrected reflection events especially at the crossing points of 2D lines