One-step formation of a hybrid material of graphene and porous Ni with highly active Ni(OH)2 used for glucose detection.

A hybrid material of graphene and porous Ni with highly active Ni(OH)2 was formed through a one-step electrochemical exfoliation assisted method. The porous Ni with a pore size of 2-10 micrometers obtained by a hydrogen bubble template method was used as the cathode while the graphite foil was used as the anode with only (NH4)2SO4 as the electrolyte. Both the high surface areas of porous Ni and the oxygen radicals in graphene favored the formation of the Ni(OH)2. It is confirmed by energy dispersion spectrum, transmission electron microscope, Raman spectroscopy, x-ray diffraction and x-ray photoelectron spectroscopy analysis. Both the active area and the glucose sensing property of the as-prepared hybrid material were estimated by electrochemical methods of cyclic voltammetry with current-voltage (C-V) curve, chronoamperometry with current-time (I-t) curve and electrochemical impedance spectroscopy analysis, respectively. It shows an extraordinary active area as well as a low charge transfer resistance and absorption resistance. As a result, a high sensitivity of 6504 µA/mM-1 cm-2 within a linear range of 4 µM-1.0 mM was obtained for glucose detection.

An event-semantic account of spatial modification in the acquisition of Mandarin.

This study investigates Mandarin-speaking children's knowledge of event semantics in interpreting spatial modifiers with zai 'at' after a posture verb or before a placement verb. The event-semantic principles investigated include subevent modification (Parsons, 1990) and aspect shift (Fong, 1997). We conducted an experimental study using modified forced choice, video choice, and elicited production techniques with five groups of children (two- to six-year-olds) and an adult control group. Three-year-olds were sensitive to the ambiguity of zai-PPs with placement verbs and posture verbs, suggesting guidance from principles of aspect shift and subevent modification. On the other hand, distributional properties of the input play a role in acquiring the interpretation and word order of zai: e.g., four-year-olds significantly differed from adults in accepting non-target V-zai sentences, as some verb classes can take postverbal prepositional phrases with zai while others cannot in adult usage.

(S)-6-{[(S)-2,2-Dimethyl-1,3-dioxolan-4-yl]meth-yl}-5,5-difluoro-5,6-dihydro-2H-pyran-2-one.

The title compound, C(11)H(14)F(2)O(4), is a γ,γ-gem-difluorinated α,ß-unsaturated δ-lactone. The dioxolane five-membered ring and the lactone ring adopt half-chair conformations. There are two inter-molecular C-H⋯O inter-actions involving the carbonyl group as an acceptor which stabilize the crystal structure.