Impedance-type measurements using XPS

Cataloged from PDF version of article.An impedance type of measurement using X-ray photoelectron spectroscopy is applied for probing charging/discharging dynamics of a sample containing Rb deposited on a SiO(2)/Si substrate containing an octadecyltrichlorosilane (OTS) bilayer coating. The OTS bilayer coatings have possible use as anti-relaxation wall coatings for alkali atom vapor cells in miniaturized instruments such as chip-scale atomic clocks, and/or magnetometers. The measurement consists of the application of bipolar square wave pulses of +/- 10.0 V amplitude to the sample with varying frequencies in the range of 10(-2) to 10(2) Hz while recording X-ray photoemission data. For a conducting sample this type of measurement twins all the photoemission peaks at -10.0 and +10.0 eV positions at all frequencies with exactly 20.0 eV difference between them. However, for samples amenable to charging, the difference between the twinned peaks is less than 20.0 eV, and gradually decreases at correspondingly lower frequencies. For the sample under consideration here at 0.01 Hz, the twinned O1s and Si2p peaks, representing the SiO(2) substrate, are separated by 18.2 eV, displaying a 1.8 eV charging shift. These positions differ from those of the C1s (18.0 eV) representing the OTS bilayer and the Rb3d peaks (18.1 eV). These results reveal that the Rb is electrically (perhaps also chemically) isolated from the OTS bilayer, which may be correlated with the improved performance of the OTS bilayers as anti-relaxation coatings in these alkali atom magnetometer cells. (C) 2009 Elsevier B. V. All rights reserved

The impact of shared financial decision making on overconfidence for married adults

Previous research has shown that overconfidence is associated with a decrease in the quality of decision making and, therefore, decision outcomes. However, less is known about the conditions or circumstances that reduce financial overconfidence. Using data from two national studies, this study was designed to provide insights into the dynamics of intrahousehold financial decision making by examining the role of shared decision making in reducing overconfidence bias. Findings suggest that a psychological sense of shared ownership of money is associated with lower levels of overconfidence. With regard to financial planning practice, these results suggest that married individuals who believe in shared ownership of household money tend to have lower levels of overconfidence

Does Gender Affect Investors' Appetite for Risk? Evidence from Peer-to-Peer Lending

This study investigates the role of gender in financial risk-taking. Specifically, I ask whether female investors tend to fund less risky investment projects than males. To answer this question, I use real-life investment data collected at the largest German market for peer-to-peer lending. Investors' utility is assumed to be a function of the projects expected return and its standard deviation, whereas standard deviation serves as a measure of risk. Gender differences regarding the responses to projects' risk are tested by estimating a random parameter regression model that allows for variation of risk preferences across investors. Estimation results provide no evidence of gender differences in investors' risk propensity: On average, male and female investors respond similarly to the changes in the standard deviation of expected return. Moreover, no differences between male and female investors are found with respect to other characteristics of projects that may serve as a proxy for projects' risk. Significant gender differences in investors' tastes are found only with respect to preferred investment duration, purpose of investment project and borrowers' age

Impedance-type measurements using XPS

An impedance type of measurement using X-ray photoelectron spectroscopy is applied for probing charging/discharging dynamics of a sample containing Rb deposited on a SiO2/Si substrate containing an octadecyltrichlorosilane (OTS) bilayer coating. The OTS bilayer coatings have possible use as anti-relaxation wall coatings for alkali atom vapor cells in miniaturized instruments such as chip-scale atomic clocks, and/or magnetometers. The measurement consists of the application of bipolar square wave pulses of ±10.0 V amplitude to the sample with varying frequencies in the range of 10-2 to 102 Hz while recording X-ray photoemission data. For a conducting sample this type of measurement twins all the photoemission peaks at -10.0 and +10.0 eV positions at all frequencies with exactly 20.0 eV difference between them. However, for samples amenable to charging, the difference between the twinned peaks is less than 20.0 eV, and gradually decreases at correspondingly lower frequencies. For the sample under consideration here at 0.01 Hz, the twinned O1s and Si2p peaks, representing the SiO2 substrate, are separated by 18.2 eV, displaying a 1.8 eV charging shift. These positions differ from those of the C1s (18.0 eV) representing the OTS bilayer and the Rb3d peaks (18.1 eV). These results reveal that the Rb is electrically (perhaps also chemically) isolated from the OTS bilayer, which may be correlated with the improved performance of the OTS bilayers as anti-relaxation coatings in these alkali atom magnetometer cells. © 2009 Elsevier B.V. All rights reserved

Lipase activity enhancement by SC-CO2 treatment

The activity of lipases from porcine pancreas, Candida antartica recombinant from Aspergillus oryzae, Candida cylindracea (immobilized), Penicilium roqueforti, Aspergillus niger, Rhizopus arrhizus, Mucor miehei (two types of immobilization), and Pseudomonas cepacia (two types of immobilization) was studied after using them as biocatalysts of blackcurrant oil hydrolysis under SC-CO2 conditions. The reaction was performed at 40°C and 15 MPa in a continuous-flow reactor. Increased relative activity of all used lipases after the hydrolytic reaction was observed. The most remarkable increase in the activity was noted for the lipase from Rhizopus arrhizus which was increased by more than 50 times. The highest activity was shown by Lipozyme®, lipase from Mucor miehei, immobilized on macroporous resin. Both treated and untreated Lipozyme® were used as biocatalysts in hydrolytic resolution of the racemic cis- or frani-isomers of 2-(4-methoxybenzyl) cyclIohexyl acetates. Satisfactory reaction yields (40 %) and excellent enantiomeric purity of the products (E = 472) were obtained when hydrolysis of the frans-isomer of 2-(4-methoxybenzyl)cyclohexyl acetate was catalyzed by Lipozyme® treated with SC-CO2. © 2008 Verlag der Zeitschrift für Naturforschung, Tübingen