The nature of non-crystalline materials causes the local potential energy of a cluster of atoms or molecules to vary significantly in space. Different configurations of an ensemble of atoms in a metallic glass lead therefore to a distribution of elastic constants which also changes in space. This is totally different to their crystalline counterparts, where a long-range order exists in space and therefore a much more unified elastic modulus is expected. Using atomic force acoustic microscopy, we present data which show that the local so-called indentation modulus M indeed exhibits a wide distribution on a scale below 10 nm in amorphous PdCuSi, with ΔM/M≈30%. About 10(4) atoms are probed in an individual measurement. Crystallized PdCuSi shows a variation that is 10-30 times smaller and which is determined by the resolution of the microscope and by the polycrystalline structure of the material.

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The effect of different alkali metal ions (Li+, Na+, K+) incorporated into aluminas on the gate dielectric behavior of solution processed oxide field-effect transistors (FETs) was studied. High field-effect mobility (ca. 20 cm2·V–1·s–1), high saturation drain current (about 1 mA), and low subthreshold swing (ca. 200 mV/decade) were achieved in low-voltage (2 V), spin-coated zinc-tin-oxide (ZTO) FETs with potassium alumina (PA) and lithium alumina (LA) dielectrics, as we had previously demonstrated with sodium alumina (SA). To investigate the effect of alkali metal ion on the detailed alumina capacitance and AC conductivity response, the frequency, temperature, and thickness dependences of alumina capacitance were determined. Ion-incorporated alumina metal–insulator–metal (MIM) capacitors showed a possible electric double layer capacitor (EDLC) behavior, in contrast to what was observed for alumina itself. The frequency dependence of observed capacitance varied with the included ion. These dependences were consistent with expected ion–oxygen atom bonding and numbers of surrounding water molecules. Theoretical calculations gave a proposed structure for the amorphous phase of these aluminas, comprising dense ion-free alumina regions and more open, ion-intercalated channel regions, where ions appear to migrate to the double layer at low frequency and are polarized on short length scales at high frequency. The magnitudes of calculated ion migration activation energies indicate that the ions move through continuous pores or channels, rather than through domains of nonintercalated alumina, and that they migrate in hydrated forms.

Aims Methadone maintenance treatment has been made available in China in response to the rapid spread of HIV, but high rates of dropout and relapse are problematic. The aim of this study was to apply and test if a contingency management (or motivational incentives) intervention can improve treatment retention and reduce drug use. Design Random assignment to usual care with (n=160) or without (n=159) incentives during a 12-week trial. Incentives participants earned draws for a chance to win prizes on two separate tracks targeting opiate-negative urine sample or consecutive attendance; the number of draws increased with continuous abstinence or attendance. Setting Community-based methadone maintenance clinics in Shanghai and Kunming. Participants The sample was 23.8 % female, mean age was 38, mean years of drug use was 9.4, and 57.8 % had injected drugs in the past 30 days. Measurements Treatment retention and negative drug urine. Findings Relative to the treatment-as-usual (control) group, better retention was observed among the Incentives group in Kunming (44% vs. 75%), but no difference was found in Shanghai (90% vs. 86%). Submission of negative urine samples was more common among the Incentive group than the usual care (74% vs. 68% in Shanghai, 27% vs. 18% in Kunming), as was the longest duration of sustained abstinence (7.7 wks vs. 6.5 in Shanghai, 2.5 vs. 1.6 in Kunming). The average total prize amount was 371 Yuan (or $55) per participant (527 for Shanghai vs. 216 in Kunming). Conclusions Contingency management improves treatment retention and drug abstinence in methadone maintenance treatment clinics in China, although there can be considerable site differences in magnitude of effects.

Electrochemical reduction of aqueous CO2 into formate is subject to poor selectivity and low current density with conventional Sn-based catalysts owing to the inert nature of CO2 molecules and the low number of active sites.

Local structures play a crucial role in glass formation and properties. In addition to topological short-range order, the geometric property of site symmetry is another important but less known characteristic of local structures. It is shown that the observed sharp increase of glass forming ability of Ce70-xAl10Cu20Cox upon Co addition is correlated with a dramatic increase of Al site symmetry, as reflected by decreasing quadrupole frequency measured by 27Al NMR. The result is consistent with the structure model of Al-centered icosahedral clusters as the predominant structural building blocks.

The Ag/Al 2 O 3 catalyst possesses high activity for selective catalytic oxidation of ammonia (NH 3 −SCO), and its activity could be significantly improved by H 2 pretreatment. It is generally accepted that the enhancement of Ag/Al 2 O 3 activity after H 2 reduction is due to the promoted O 2 activation by metallic Ag species. Here, we show that the recovery of Brønsted acid sites via H 2 reduction is also an important factor.

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