1 H and 19 F FFC-NMR of catalyst layer materials for polymer electrolyte membrane fuel cells

1H and 19F spin lattice relaxation rates of catalyst layer materials (CLM) of polymer electrolyte membrane fuel cells were measured by the fast field cycling (FFC) method. In contrast to ionomer membranes, 1H relaxation rates of adsorbed water in both platinum-Ketjen black (Pt-KB) catalyst powder and CLM were strongly dependent on Larmor frequency approximated by a power law due to the strong surface interaction of adsorbed water. The difference in the frequency dependence in the Pt-KB and the CLM was attributed to higher acidity of the CLM

Compressible bag model and the phase structure

The phase structure of hadrons and quark-gluon plasma is investigated by two types of equation of hadron state, namely ideal hadron gas model and the compressible bag model. It is pointed out that, while the ideal gas model produces unrealistic extra hadron phase, the compressible bag model gives an expected and reasonable phase diagram even if rich hadron spectrum is taken into account.Comment: 14 pages, 11 figures, LaTeX2

Surface Recombination Velocity and Bulk Carrier Lifetime Measurement of Silicon Crystals by Using Photoluminescence Time Decay

The time decay for photoluminescence (PL) emitted from silicon crystals has been used to obtain both bulk carrier lifetime (Tb) and surface recombination velocity (S). Experimental results were interpreted with the assumptions that the sample was under a low-excitation condition and that the ratio of radiative to non-radiative recombination rates was constant throughout the carrier decay process. Analysis was applied to several wafers covered with different kinds of silicon dioxide (SiO2). The results indicate that PL time decay measurement is effective to obtain the values of Tb and S

Reactivation of Alternate Bars to Increased Sediment Supply

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

PMMA-BN composites incorporated with Au nanoparticle fabricated by laser ablation

As a class of layered materials, two dimensional (2D) materials have attracted great attention all around the world due to their inherent use for next generation nano technology devices. We can see 2D materials including carbon in our daily life and at many places, for instance, graphite, diamond and so on. New study is also being conducted to produce new functional materials by combining 2D material and polymer. Hexagonal boron nitride (h-BN) which is one kind of 2D material is dispersed in Poly methyl methacrylate (PMMA) or poly styrene (PS). The composite material of h-BN coated with polymer shows an improvement in the properties such as the higher thermal conductivity and higher mechanical strength. In this study, the composite material of PMMA, h-BN and gold nanoparticles has been synthesized. Boron nitride nano-structures were prepared by nanosecond laser ablation in acetone and was carried out at room temperature with laser ablation time of 120 min. The PMMA films were made by PMMA granules dissolved in acetone solvent and then mix with h-BN and gold colloid solution. The prepared composite films were characterized by scanning electron microscopy (SEM), and UV-vis spectroscopy. Such type of unique 2D nano-composite materials make their mark for the future exploitation in electronics and nanocomposite-related applications

Self-Assembly of Lyotropic Chromonic Liquid Crystal Mixtures

Molecular self-assembly in the formation of lyotropic chromonic liquid crystals (LCLCs) offers potential for generating novel materials and biomedical applications, because of their similarity to DNA liquid crystals. In order to better understand the phase behavior of LCLCs, we investigated the mixture of two LCLCs (Sunset Yellow FCF (SSY) and disodium cromoglycate (DSCG)). Properties of interest include orientational and positional order as well as the potential dependence of LC phases on concentration and temperature. These mixtures exhibited nematic and columnar phases

Clinical Diversity in Biliary Pancreatitis — Classification of Two Types

One hundred and seven patients with biliary pancreatitis undergoing operation from 1976 to 1989 were reviewed. To clarify the reason for failure to respond to conventional supportive therapy, 73 patients (68%) who underwent emergency surgery were retrospectively divided into two groups according to the severity of the pancreatitis evaluated at laparotomy and compared. Sixty-two had minimal or mild pancreatitis (Group I), among whom 44 (71%) had life-threatening acute biliary tract disease. All underwent biliary surgery and 4 (6%) subsequently died, 2 due to acute obstructive suppurative cholangitis. Eleven had hemorrhagic necrotizing pancreatitis (Group II), among whom 7 had complications of acute pancreatitis such as pancreatic ascites or abscess. These underwent pancreatic and/or biliary surgery and 3 (27%) died of multi-organ failure

Etiology and Pathogenesis of Marked Elevation of Serum Transaminase in Patients With Acute Gallstone Disease

From 1980 through 1988, biliary surgery was performed in 197 patients with acute gallstone disease and concomitant elevation of serum glutamic oxalacetic transaminase (SGOT) or serum glutamic pyruvic transaminase (SGPT) of over 300 Karmen units. In 137 patients, anatomic inspection and liver biopsy were performed during the acute stage of the disease. Impacted and floating bile duct stones were found in 69 (50%) and in 43 (32%) of the 137 patients, respectively. The main liver histology was necrosis of liver cells. After surgery, high serum transaminase fell rapidly with immediate recovery in 99% of the patients. In the remaining 60 patients, their signs and symptoms settled soon after initial conservative treatment and surgery was performed after an average time of 21 days. At laparotomy, impacted bile duct stones were found in 2 (3%) and liver histology revealed regeneration of liver cells