7,667 research outputs found
Investigation of electrochemistry of high energy compounds in organic electrolytes Third progress report, Nov. 1, 1965 - Apr. 30, 1966
Electrochemical properties, and chemical reactions between cyclic esters and certain metal
Investigation of electrochemistry of high energy compounds in organic electrolytes, May 1 - October 31, 1965
High energy compounds in organic electrolytes - electrochemical and chemical properties of cyclic esters, gamma butyrolactone, gamma valerolactone, and propylene carbonat
Dipolar and scalar He and Xe frequency shifts in mm-sized cells
We describe a He-Xe comagnetometer operating in stemless
anodically bonded cells with a 6 mm volume and a Xe spin coherence
time of 300 sec. We use a Rb pulse-train magnetometer with co-linear
pump and probe beams to study the nuclear spin frequency shifts caused by spin
polarization of He. By systematically varying the cell geometry in a
batch cell fabrication process we can separately measure the cell shape
dependent and independent frequency shifts. We find that a certain aspect ratio
of the cylindrical cell can cancel the effects of He magnetization that
limit the stability of vapor-cell comagnetometers. Using this control we also
observe for the first time a scalar He-Xe collisional frequency
shift characterized by an enhancement factor .Comment: 4 pages, 4 figure
Recommended from our members
Dust devils on Mars: Effects of surface roughness on particle threshold
Abstract not available
Quantifying Soil Chemical Properties Using Near Infrared Reflectance Spectroscopy
Methodologies for determining soil chemical properties have evolved dramatically during the past century. Early geochemical analyses were conducted exclusively through the use of wet chemistry techniques that were relatively reliable but painstaking and subject to errors at various stages of analysis. Near infrared reflectance spectroscopy (NIRS) has emerged as a new approach for rapidly analyzing a variety of materials including soils. In this study soil samples were taken from eight study areas across the Ozark Highlands of Arkansas, and NIRS calibration models were developed to determine the accuracy of using NIRS to analyze soils compared with standard soil chemical analysis protocols. Multivariate regression models were highly effective for analyzing several important elements. C and N models explained 92% and 88% of their variation, respectively, and Ca, Mg, P, and Mn models explained 72-88% of the variability in these elements. Models for C:N and pH explained 82% and 86% of their variability, respectively. Models for micronutrients Cu and Zn did not fit as well with 22% and 40% of their variability explained, respectively. Our findings suggest that additional NIRS calibration and modeling is promising for rapidly analyzing the chemical composition of soils, and it is desirable to develop model libraries that are calibrated for the soils of a given region
Children's suggestibility in relation to their understanding about sources of knowledge
In the experiments reported here, children chose either to maintain their initial belief about an object's identity or to accept the experimenter's contradicting suggestion. Both 3– to 4–year–olds and 4– to 5–year–olds were good at accepting the suggestion only when the experimenter was better informed than they were (implicit source monitoring). They were less accurate at recalling both their own and the experimenter's information access (explicit recall of experience), though they performed well above chance. Children were least accurate at reporting whether their final belief was based on what they were told or on what they experienced directly (explicit source monitoring). Contrasting results emerged when children decided between contradictory suggestions from two differentially informed adults: Three– to 4–year–olds were more accurate at reporting the knowledge source of the adult they believed than at deciding which suggestion was reliable. Decision making in this observation task may require reflective understanding akin to that required for explicit source judgments when the child participates in the task
- …