Luminescent properties of Pr doped ZrSiO4 phosphors

Mixtures of ZrO₂, SiO₂, Pr₂O₃, and H₃BO₃ were fired at the temperature of 1150–1350 °C under H₂ atmosphere. A single phase ZrSiO₄:Pr phosphors could be achieved at the firing temperature above 1150 °C. Crystallinity and PL properties strongly depended on the flux amounts, firing temperature, and dopant concentrations. ZrSiO₄:Pr phosphors showed a strong red emission at 615 nm and a weak red emission at 622 nm with an excitation wavelength of 295 and 450 nm, respectively. Two sets of the emission bands and excitation spectra originated from Pr³⁺ ions at Zr and Si sites, respectively.     

Cure‐on‐demand wood adhesive based on the frontal polymerization of acrylates

We demonstrated for the first time a cure‐on‐demand wood adhesive using thermal frontal polymerization with Southern Pine wood. Monomer structure, initiator loading, and filler loading all had an impact on the strength of the adhesive and the cure‐on‐demand ability. More flexible, ethoxylated monomers produced stronger adhesives; though, the ethoxylate groups reduce the ability of the system to be polymerized frontally. Addition of a highly reactive comonomer (acrylic acid) to increase molecular weight between crosslinks along with the ethoxylated triacrylate increased the propensity for frontal polymerization and made a tougher polymer. Increasing initiator loading could help ensure front propagation, but a maximum initiator loading was reached where the gaseous byproducts of the peroxide initiator made the network highly porous and thus lacking strength. Fillers such as kaolin and sawdust helped overcome decreases in strength at high initiator loadings. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44064.     

Fabrication of flexible carbon dioxide gas sensor with conductive polymer/reduced graphene oxide hybrids: Effects of substrate type and mass ratio

Flexible gas sensors made of polyaniline (PANI)-reduced graphene oxide (rGO) nanocomposite were prepared using three different substrates, namely filter paper, cotton fabric, and weighing paper, through in-situ reduction of GO and in-situ polymerization of aniline. Preliminary analysis showed that the PANI/rGO coated on filter paper possesses a superior electrical conductance than PANI/rGO coated on cotton fabric and weighing paper. Such observation was attributed to the good attachment of the PANI/rGO nanocomposites onto the high-density mesh-like structure of the filter paper with rough surfaces. In contrast, PANI/rGO coated onto weighing paper and cotton fabric of different surface structures presented lower-to-almost negligible conductance. Accordingly, PANI/rGO filter paper was selected for the subsequent evaluation of gas sensing properties. The gas-sensing performances of the PANI/rGO filter paper sensors indicated that the 5 wt% PANI/rGO (i.e., 5 wt% rGO) sample exhibited the best response of 306% for 500 ppm carbon dioxide (CO₂) gas at room temperature with a recovery rate of 41.5%. On the other hand, the optimum recovery rate of 59.5% was identified at 0.5 wt% PANI/rGO sample which exhibited a response of 155%. Owing to the synergy effect, the PANI/rGO sensor outperformed the sensor made of pure PANI or pure rGO.     

Immediate post-reminder injection of gamma-amino butyric acid (GABA) agonist midazolam attenuates reactivation of forgotten fear in the infant rat.

J. H. Kim, G. McNally, and R. Richardson (2006) reported that pretest injection of FG7142, a GABA inverse agonist, alleviated infantile amnesia in rats. From this, it was concluded that GABAergic neurotransmission is involved in the forgetting seen in the developing rat. The present study extends that finding by examining the role of GABA in the reactivation of a forgotten memory in the infant rat. Sixteen-day-old rats were conditioned to fear a white noise. When tested 3 days later, rats that had not received a reminder treatment exhibited substantial forgetting. Reactivation of memory (as assessed by high levels of freezing) was observed in rats that were given a reminder shock and injected with saline the day before test. However, rats given a reminder shock and injected with midazolam immediately afterward failed to exhibit the reactivation effect. A subsequent experiment replicated this finding and further showed that midazolam did not reduce the memory reactivation effect when injected 2 hr after the reminder episode. From this, it appears that alterations in GABAergic neurotransmission may be an underlying process mediating memory reactivation in the infant rat. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A developmental dissociation of context and GABA effects on extinguished fear in rats.

Although extinction has attracted considerable attention in recent years, there has been very little empirical work on extinction during development. Using Pavlovian fear conditioning, the authors provide evidence for developmental differences in extinction. Specifically, Postnatal Day (PND) 23 rats exhibited recovery of an extinguished freezing response to an auditory conditioned stimulus when tested in a context different from that in which extinction occurred (i.e., renewal) or when injected with the gamma-amino butyric acid (GABA) inverse agonist FG7142 prior to test. In contrast, PND 16 rats failed to exhibit either of these effects, although a subsequent experiment demonstrated that FG7142 alleviated spontaneous forgetting in PND 16 rats. Taken together, it appears that there are fundamental differences in the processes involved in extinction across development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

MM-Wave Band Transversal Filter with Improved Spurious Characteristics

A spurious-suppressed transversal filter using the multiple-coupled line is proposed. The frequency characteristics of the multiple-coupled line are analyzed in detail. In order to compare the performances, the novel spurious-suppressed transversal filter using triple-coupled half-wavelength directional couplers is designed at 30 GHz. The spurious-suppression characteristics of the proposed transversal filter are verified by the full wave analysis and the measurement. The spurious response of the fabricated filter is effectively suppressed and the large attenuation is obtained in the stopband.     

Systematic evaluation of fault trees using real-time model checker UPPAAL

Fault tree analysis, the most widely used safety analysis technique in industry, is often applied manually. Although techniques such as cutset analysis or probabilistic analysis can be applied on the fault tree to derive further insights, they are inadequate in locating flaws when failure modes in fault tree nodes are incorrectly identified or when causal relationships among failure modes are inaccurately specified. In this paper, we demonstrate that model checking technique is a powerful tool that can formally validate the accuracy of fault trees. We used a real-time model checker UPPAAL because the system we used as the case study, nuclear power emergency shutdown software named Wolsong SDS2, has real-time requirements. By translating functional requirements written in SCR-style tabular notation into timed automata, two types of properties were verified: (1) if failure mode described in a fault tree node is consistent with the system's behavioral model; and (2) whether or not a fault tree node has been accurately decomposed. A group of domain engineers with detailed technical knowledge of Wolsong SDS2 and safety analysis techniques developed fault tree used in the case study. However, model checking technique detected subtle ambiguities present in the fault tree.     

An evaluation of integration procedures for improving the precision of a.c. polarography

Two integration procedures for improving the precision of a.c. polarography have been studied. Both methods are single electrode techniques and involve integration of the rectified a.c. current over the complete peak or at the peak potential respectively. The time integration procedure was found to be seriously influenced by small variations in the reference electrode potential and applied voltage, resulting in poor reproducibility between different samples. In the area integration procedure, however, where the accurate control of potential is less critical, the standard deviation between replicate samples was found to be within the statistically expected limits and this method was therefore preferred. Standard deviations were measured for a range of inorganic and organic species and typical values of ±0.25% at the optimum concentration level (4.10^–4M) were obtained.