Further increase in energy density of lithium batteries is needed for zero emission vehicles. However, energy density is restricted by unavoidable theoretical limits for positive electrodes used in commercial applications. One possibility towards energy densities exceeding these limits is to utilize anion (oxide ion) redox, instead of classical transition metal redox. Nevertheless, origin of activation of the oxide ion and its stabilization mechanism are not fully understood. Here we demonstrate that the suppression of formation of superoxide-like species on lithium extraction results in reversible redox for oxide ions, which is stabilized by the presence of relatively less covalent character of Mn4+ with oxide ions without the sacrifice of electronic conductivity. On the basis of these findings, we report an electrode material, whose metallic constituents consist only of 3d transition metal elements. The material delivers a reversible capacity of 300 mAh g−1 based on solid-state redox reaction of oxide ions.

Low electrical efficiency for the lithium-oxygen (Li-O2) electrochemical reaction is one of the most significant challenges in current nonaqueous Li-O2 batteries. Here we present ruthenium oxide nanoparticles (RuO2 NPs) dispersed on multiwalled carbon nanotubes (CNTs) as a cathode, which dramatically increase the electrical efficiency up to 73%. We demonstrate that the RuO2 NPs contribute to the formation of poorly crystalline lithium peroxide (Li2O2) that is coated over the CNT with large contact area during oxygen reduction reaction (ORR). This unique Li2O2 structure can be smoothly decomposed at low potential upon oxygen evolution reaction (OER) by avoiding the energy loss associated with the decomposition of the more typical Li2O2 structure with a large size, small CNT contact area, and insulating crystals.

N-Arachidonoylethanolamine (anandamide) is cannabimimetic, and N-palmitoylethanolamine is anti-inflammatory and immunosuppressive. We found an amidase that is more active with the latter than the former in contrast to the previously known anandamide amidohydrolase for which N-palmitoylethanolamine is a poor substrate. Proteins solubilized by freezing and thawing from the 12,000 ؋ g pellet of various rat organs hydrolyzed [ 14 C]N-palmitoylethanolamine to palmitic acid and ethanolamine. The specific enzyme activity was higher in the order of lung > spleen > small intestine > thymus > cecum, and high activity was found in peritoneal and alveolar macrophages. The enzyme with a molecular mass of 31 kDa was purified from rat lung to a specific activity of 1.8 mol/min/mg protein. Relative reactivities of the enzyme with various N-acylethanolamines (100 M) were as follows: N-palmitoylethanolamine, 100%; N-myristoylethanolamine, 48%; N-stearoylethanolamine, 21%; N-oleoylethanolamine, 20%; N-linoleoylethanolamine, 13%; anandamide, 8%. The enzyme was the most active at pH 5 and was activated 7-fold by Triton X-100. The enzyme was almost insensitive to methyl arachidonyl fluorophosphonate, which inhibited anandamide amidohydrolase potently. Thus, the new enzyme referred to as N-palmitoylethanolamine hydrolase was clearly distinguishable from anandamide amidohydrolase.

We present a novel method for nanometer resolution subsurface imaging. When a sample of atomic force microscope (AFM) is vertically vibrated at ultrasonic frequencies much higher than the cantilever resonance, the tip cannot vibrate but it is cyclically indented into the sample. By modulating the amplitude of ultrasonic vibration, subsurface features are imaged from the cantilever deflection vibration at the modulation frequency. By adding low-frequency lateral vibration to the ultrasonic vibration, subsurface features with different shear rigidity are imaged from the torsional vibration of cantilever. Thus controlling the direction of vibration forces, we can discriminate subsurface features of different elastic properties.For the development of nanometer scale electronic and mechanical devices, there is an increasing need for nanometer resolution imaging method of subsurface features (groups of ions, clusters, lattice defects, crystal grains, etc.). Some relating methods have been proposed in scanning force microscopy (SFM) where the tipl'2 or the sample3,a is vibrated to modulate the force. The response to the force modulation is measured to image ion implanted layers,l embedded wires,2 carbon fiber and epoxy composites,3 and Langmuir-Blodgett films.a These methods are characterized, by a tip mounting spring with a spring constant comparable to that of the sample. It is sometimes different from the usual AFM requirement for the spring constant to be as small as possible.s In this letter we propose an alternative imaging method, ultrasonic force microscopy (UFM) that employs a tip mounting cantilever much softer than the tip-sample contact rigidity. We vibrate the sample at frequencies much higher than the resonant frequency of the cantilever6 and measure the deflection and/or torsional vibration of the cantilever. It gives nanometer resolution elastic or subsurface images, and moreoveq discriminates features of different elastic properties, by controlling the direction of vibration forces. We present a general imaging scheme extending our preliminary work,7 and an analysis to compare the elastic contrast of the force modulation mode3'a and the UFM. Then, it is verified by imaging two different subsurface features in a highly oriented pyrolytic graphite (HOPG) sample.We model the AFM with springs and the mass of tip cantilever rn as illustrated in Fig. 1. First, the cantilever is displaced by z" from its free position due to a static repulsive force. When the sample is vibrated at a frequency F lower than the cantilever resonant frequency Fs, the cantilgver is also vibrated following the sample vibration. The tip-sample contact rigidity is expressed as a spring constant s, as a slope u)Also at of the force-displacement relation.5 If s is approximated by a linear spring, the peak{o-peak cantilever vibration amplitude is given by a/zV :2211fu, where a is the sample vibration amplitude and /r is the cantilever spring constant. The amplitude V does not significantly depend upon the spring constant ratio K:t/s repre...

A new method is proposed to detect ultrasonic vibration of the samples in the Atomic Force Microscope (AFM) using nonlinearity in the tip-sample interaction force curve F(z). Small amplitude ultrasonic vibration less than 0.2 nm is detected as an average displacement of a cantilever. This Ultrasonic Force Mode (UFM) of operation is advantageous in detecting ultrasonic vibration with frequencies up to the GHz range, using an AFM cantilever with a resonant frequency below 100 kHz. It was found that a strong repulsive force is acting after an ultrasonic amplitude threshold of the is crossed, with the amplitude of this threshold depending upon the average force applied to the tip.