Insight into the chemical reaction of CH2OH with NO: Formation of N-hydroxy formamide as an isocyanic acid precursor

This study has explored the potential energy surface on the chemical reaction of CH₂OH with NO by using ab initio calculation. We have found the new reaction pathway producing N-hydroxy formamide, which can further decompose to generate isocyanic acid as a reducing agent of hydrocarbons selective catalytic reduction.     

Effective dielectric constant of a medium with spherical inclusions

The Maxwell-Garnett theory is frequently used to predict the effective, or the average, dielectric constant of a mixture composed of spherical inclusions embedded in a host medium. This effective medium theory assumes that the volume fraction occupied by the spherical inclusions is small and that the size of the inclusions is small compared to the wavelength. Experiments using controlled samples have shown that the Maxwell-Garnett theory is applicable up to an inclusion volume fracton of 0.2. At higher volume fractions, the effective dielectric constant appears to be dependent on the inclusion sizes     

The effect of dopamine and PGI2 on indomethacin and alcohol-induced gastric lesions in rats of various ages in relation to gastric vascular permeability and HCl secretion

Gastric lesions induced by indomethacin (20 mg.kg-1 i.p.) and ethanol (1 ml 95% intragastrically) were studied in rats after a 24 hour fast. The size of gastric lesions was correlated with gastric HCl secretion and with gastric vascular permeability (determined from the Evan's blue concentration in the gastric tissue after its i.v. administration). These parameters were also studied in rats pretreated with either PGI2 (5 micrograms.kg-1) or dopamine (0.5 mg.kg-1). It was found that in 12-months old rats the gastric lesions were significantly higher compared with the 3-month old group. PGI2 and dopamine significantly decreased gastric lesions in the 3-month rats but not in 12-month old rats. Both indomethacin and ethanol increased gastric vascular permeability in both age groups. It was observed that the decrease of gastric lesions after pretreatment with PGI2 and dopamine in the 3-month old rats was followed with decreased gastric vascular permeability and HCl secretion. On the other hand the increased susceptibility of the gastric mucosa due to indomethacin in the 12-month old rats was followed by a decrease of HCl secretion. PGI2 or dopamine had any effect on the 12-month old rats. These results show that susceptibility of gastric mucosa to PGI2 and dopamine is dependent on age. (Fig. 3, Ref. 31.)     

Design and analysis of quasi-integrated horn antennas formillimeter and submillimeter-wave applications

The authors present a systematic process for the design of multimode quasi-integrated horn antennas, and provide a full range of practical antenna designs for millimeter- and submillimeter-wave applications. The design methodology is based on the Gaussian beam approach and the structures are optimized for achieving maximum fundamental Gaussian coupling efficiency. For this purpose, a hybrid technique is used in which the integrated part of the antennas is treated using full-wave analysis, whereas the machined part is treated using an approximate model. This results in a simple and efficient design process. The design procedure has been applied to the design of 20-, 23-, and 25-dB quasi-integrated horn antennas, all with a Gaussian coupling efficiency exceeding 97%. The designed antennas have been tested and characterized using both full-wave analysis and 91/370-GHz measurements. The quasi-integrated horn antennas are also examined as feed elements for Cassegrain antenna systems and are proved to be comparable to the traditional machined corrugated horn feeds     

Pore‐free mold‐pattern‐transfer method for barrier ribs of HD PDPs

Abstract— Among various barrier‐rib manufacturing processes, the mold‐pattern‐transfer method has potential to reduce processing cost as well as the manufacture of high‐resolution pixels. In this study, the effects of major processing variables of the mold‐pattern‐transfer process on the formation of air‐trapped pores within barrier ribs were examined. The results indicated that with an optimum combination of the processing variables, barrier ribs without trapped defects can be produced, demonstrating the possibility of reducing the number of processing steps and costs of barrier ribs.     

Piezoelectric Multilayer Ceramic/Polymer Composite Transducer with 2–2 Connectivity

A multilayer piezoelectric ceramic/polymer composite with 2–2 connectivity was fabricated by thermoplastic green machining after co-extrusion. The multilayer ceramic body was composed of piezoelectrically active lead zirconate titanate (PZN)–lead zinc niobate (PZN)-lead zirconate titanate (PZT) layers and electrically conducting PZN–PZT/Ag layers. After co-extruding the thermoplastic body, which consisted of five piezoelectric layers interspersed with four conducting layers, it was computer numeric-controlled machined to create periodic channels within it. Following binder burnout and sintering, an 18 vol% array of 190 μm thin PZT slabs with a channel size of 880 μm was fabricated. The channels were filled with epoxy in order to fabricate a PZN–PZT/epoxy composite with 2–2 connectivity. The piezoelectric coefficient (effective d ₃₃) and hydrostatic figure of merit ( d _h× g _h) of the PZN–PZT/epoxy composite were 1200 pC/N and 20 130 × 10⁻¹⁵ m²/N, respectively. These excellent piezoelectric characteristics as well as the relatively simple fabrication procedure will contribute in widening the application range of the piezoelectric transducers.     

Multiple cerebellar infarction due to vertebral artery obstruction and bulbar symptoms associated with vertical subluxation and atlanto-occipital subluxation in ankylosing spondylitis

Ankylosing spondylitis (AS) results in disease-specific inflammation at the site of ligamentous insertion into the bone. Atlantoaxial joint subluxation and vertical subluxation of the axis may occur as a consequence of instability resulting from the inflammatory process. Spontaneous anterior atlantoaxial subluxation is a well recognized complication in about 2% of patients with AS, and presents with or without signs of spinal cord compression. Vertical subluxation may follow anterior or posterior subluxation. It was noted in 3-8% of patients with rheumatoid arthritis, but is an exceedingly rare complication of AS. Moreover, it has never been reported that multiple cerebellar infarction and bulbar symptoms developed spontaneously due to atlanto-occipital subluxation and vertical subluxation in a patient with a long [corrected] history of AS. We describe a man with AS who developed multiple cerebellar infarction due to vertebral artery obstruction and bulbar symptoms associated with atlanto-occipital subluxation and vertical subluxation.     

Characterisation and catalytic properties of MCM-41 and Pd/MCM-41 materials

Pure silica MCM-41 mesoporous molecular sieve material was synthesised and characterised by in situ synchrotron XRD, TEM, TGA/DTA and DRIFTS techniques. In situ energy dispersive XRD (EDXRD) confirmed the exact nature of the pore diameter of MCM-41 and the change in crystal structure on calcination. The IR band at 1057 cm^-1 of as-synthesised MCM-41 was shifted by 14 cm^-1 on heating to 673 K due to increased condensation of silanol groups to form Si-O-Si bridges. Calcined MCM-41 materials were used to support Pd, and the catalytic activities for 1-hexene and benzene selective hydrogenation were investigated. The Pd/MCM-41 catalyst showed high activity in hydrogenation of 1-hexene at an inlet reaction temperature of 298 K, but did not show any activity in hydrogenation for benzene. TEM results for the reduced Pd/MCM-41 catalysts revealed that the average Pd particle size was around 2-2.5 nm and these particles were located in the pores of MCM-41 and showed good distribution. TPR measurements showed that about 70% of palladium oxide (PdO) loading in the calcined catalysts was reduced at sub-ambient temperature. This revised version was published online in July 2006 with corrections to the Cover Date.     

Physical characteristics of sweet potato pulp/polycaprolactone blends

Sweet potato pulp (SSP) obtained as a by‐product from starch extraction was blended with polycaprolactone (PCL) to prepare a biodegradable plastic material. In the blends, PCL was used as a reinforcing agent. The SPP/PCL blends were prepared by compression‐molding under high temperature and pressure, at different SPP/PCL ratios, and the mechanical properties of the molded specimens were tested. Matrix structure and thermal properties were measured by using a Fourier transform infrared (FTIR) spectrophotometer, scanning electron microscope (SEM), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA). Mechanical properties (tensile and flexural properties) were also measured to find the most suitable ratio in a SSP/PCL blend. During compression molding of the SPP/PCL blends under high pressure and temperature, chemical reaction occurred between SPP and PCL, and thus, thermal stability and mechanical strength of the blends increased and water uptake decreased. Also, by increasing the PCL content in the blend, the matrix in the blend became more homogeneous, and consequently, mechanical strength of the molded specimen increased. At 7/3 or 6/4 weight ratio of SSP/PCL, water uptake of the molded specimen became substantially less than that at 8/2. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 861–866, 2004